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Med. Sci. Forum, 2022, ECA 2022

The 2nd International Electronic Conference on Antibiotics—Drugs for Superbugs: Antibiotic Discovery, Modes of Action and Mechanisms of Resistance

Online | 15–30 June 2022

Volume Editors:
Manuel Simões, University of Porto, Portugal
Marc Maresca, Aix-Marseille University, France

Number of Papers: 44
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Cover Story (view full-size image): This volume presents a collection of contributions that were made to the virtual event, “The 2nd International Electronic Conference on Antibiotics—Drugs for Superbugs: Antibiotic [...] Read more.
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Editorial

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1 pages, 198 KiB  
Editorial
Statement of Peer Review
by Manuel Simões and Marc Maresca
Med. Sci. Forum 2022, 12(1), 44; https://doi.org/10.3390/msf2022012044 - 25 Nov 2022
Viewed by 543
Abstract
In submitting conference proceedings to Medical Sciences Forum, the volume editors of the proceedings certify to the publisher that all papers published in this volume have been subjected to peer review administered by the volume editors [...] Full article

Research

Jump to: Editorial, Other

2 pages, 216 KiB  
Abstract
Antimicrobial Activity of a Bacterial Nanocellulose Film Functionalized with Nisin Z for Prospective Burn Wounds Treatment
by Liliana Melro, Tânia D. Tavares, Jorge Padrão, Fernando Dourado, Miguel Gama, Carla Silva, Joana C. Antunes, Helena P. Felgueiras and Andrea Zille
Med. Sci. Forum 2022, 12(1), 1; https://doi.org/10.3390/eca2022-12708 - 15 Jun 2022
Viewed by 668
Abstract
Burn wounds can lead to numerous severe complications including bacterial infections causing patient morbidity and mortality, mostly in low- and middle-income countries. The considerable increase in microbial resistance against traditional antibiotics is leading towards alternative strategies to treat bacterial infections. Nisin Z is [...] Read more.
Burn wounds can lead to numerous severe complications including bacterial infections causing patient morbidity and mortality, mostly in low- and middle-income countries. The considerable increase in microbial resistance against traditional antibiotics is leading towards alternative strategies to treat bacterial infections. Nisin Z is an antimicrobial peptide which exhibits a significant antibacterial activity against Gram-positive bacteria. Its efficacy against Gram-negative bacteria is limited, nonetheless it can be improved with the addition of surfactants, such as ethylenediaminetetraacetic acid (EDTA). The incorporation of peptide and other biomolecules within a biopolymer matrix provides protection maintaining their antimicrobial potential. Bacterial nanocellulose (BNC) has been widely used as wound dressings. Its impressive water retention capacity (>99%) and porosity are beneficial to manage wounds due to its potential to absorb exudates, providing a breathable and humid environment. In this work, the functionalization of BNC with Nisin Z (BNC-NZ) via vacuum filtration is reported. The entrapment of the peptide inside the BNC films was confirmed through morphological characterization using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometry. Typical absorbance peaks of Nisin Z are easily identifiable at 1647 cm−1 (amide group) and 1520 cm−1 (bending of primary amines). Thermal gravimetric analysis (TGA) suggested that Nisin Z did not interfere with the BNC matrix. The antimicrobial activity of Nisin Z against five of the most common bacteria found in burn wounds was verified by minimum bactericidal concentration (MBC) ranging 8.0–256.0 µg/mL. Agar diffusion and shake flask methods revealed the potential of BNC-NZ for prospective applications in burn wound dressings. Full article
2 pages, 200 KiB  
Abstract
The Antibiofilm Potential of Vapor Fractions of Selected Essential Oils against Pseudomonas aeruginosa 
by Malwina Brożyna, Justyna Paleczny and Adam Junka
Med. Sci. Forum 2022, 12(1), 3; https://doi.org/10.3390/eca2022-12702 - 15 Jun 2022
Viewed by 854
Abstract
Biofilm is a major causative factor of persistent, hard-to-heal infections. Due to the biofilm’s persistence, even high-dose, systemic antibiotic therapy displays low antimicrobial efficacy. Therefore, there is an urgent need to search for novel bactericidal agents. Essential oils [EOs] are of great interest [...] Read more.
Biofilm is a major causative factor of persistent, hard-to-heal infections. Due to the biofilm’s persistence, even high-dose, systemic antibiotic therapy displays low antimicrobial efficacy. Therefore, there is an urgent need to search for novel bactericidal agents. Essential oils [EOs] are of great interest in this matter because of their broad spectrum of antimicrobial activity and non-specific mechanism of action. This study aimed to evaluate the antimicrobial activity of vapor fractions of three commercially available essential oils: menthol mint (Mentha arvensis, L.), lavender (Lavandula angustifolia, Mill.), and eucalyptus (Eucalyptus globulus, Labill.) against Pseudomonas aeruginosa biofilm. For the research purposes, fourteen clinical multidrug-resistant strains and one reference bacterial strain from American Type Culture Collection (ATCC 15441) were used. The self-developed evaluation method was applied, based on the optimized resazurin staining protocol, to determine the biofilm survival after the exposure to volatile agents. The results indicated that the EOs’ antibiofilm activity depends on the pseudomonal strains’ intraspecies variability. The lavender oil was active against five clinical strains, with the reduction rate ranging from 33% to 44%. The highest reduction level obtained for eucalyptus oil was 20%. The results for menthol mint oil were differentiated among the tested strains and ranged from 5% to 53%. The obtained outcomes indicate that the tested volatile fractions of EOs possess the potential to be applied in the treatment of infections caused by Pseudomonas aeruginosa biofilm. Further research is required to determine if they can be used in monotherapy or as adjuvants of other antimicrobial agents. Full article
2 pages, 232 KiB  
Abstract
Evaluation of Antifungal Activities of Actinobacterial Extracts Isolated from Deep-Sea Laminaria ochroleuca against Pathogenic Fungi
by Rita Maioto, Inês Ribeiro, Mariana Girão, Maria F. Carvalho and Ana Sampaio
Med. Sci. Forum 2022, 12(1), 10; https://doi.org/10.3390/eca2022-12716 - 15 Jun 2022
Viewed by 653
Abstract
Marine actinobacteria produce secondary metabolites with many biological activities of interest, including antifungals [...] Full article
1 pages, 195 KiB  
Abstract
Resveratrol, A Novel Inhibitor of the NorA Efflux Pump and Resistance Modulator in Staphylococcus aureus
by Madalena Santos, Raquel Santos and Susana Ferreira
Med. Sci. Forum 2022, 12(1), 16; https://doi.org/10.3390/eca2022-12718 - 15 Jun 2022
Cited by 1 | Viewed by 929
Abstract
Among the bacterial resistance mechanisms, active efflux pumps play a role in the extrusion of different molecules, and, thus, contribute to antimicrobial resistance. Staphylococcus aureus is a Gram-positive bacterium that can present resistance to various antibiotics, for which NorA, a predominant efflux pump [...] Read more.
Among the bacterial resistance mechanisms, active efflux pumps play a role in the extrusion of different molecules, and, thus, contribute to antimicrobial resistance. Staphylococcus aureus is a Gram-positive bacterium that can present resistance to various antibiotics, for which NorA, a predominant efflux pump of these strains, is known to promote resistant to fluoroquinolones. Thus, the inhibition of this efflux pump may modulate resistance in S. aureus, namely, to fluoroquinolones. Therefore, this study aimed to investigate the ability of a natural compound, resveratrol, to modulate fluoroquinolone resistance in S. aureus. The antimicrobial activity of resveratrol, ethidium bromide (EtBr) and norfloxacin was determined through the minimum inhibitory concentration (MIC). Then, the modulatory effect of resveratrol was evaluated by the determination of the MIC of the antibiotic or EtBr in the presence and absence of resveratrol at a sub-MIC level. The results showed that the MIC of norfloxacin against a wildtype S. aureus strain decreased by 2-fold, and for a NorA-overexpressing (norA++) strain decreased by 16-fold when in the presence of resveratrol. A similar behavior was observed for EtBr. Furthermore, an EtBr accumulation assay was also performed, showing that, in the presence of resveratrol, the norA++ strain had an augmented fluorescence as a consequence of the accumulation of EtBr. Altogether, the results suggested that resveratrol may act by inhibiting NorA. The postantibiotic effect (PAE) of norfloxacin alone and in combination with resveratrol was also determined, showing that the most extended PAE was observed with norfloxacin at 32 mg/L when tested in combination with resveratrol. Furthermore, there was a decrease in the mutation prevention concentration of norfloxacin when combined with resveratrol. Our findings demonstrated that resveratrol could modulate norfloxacin resistance by the inhibition of NorA, increasing the effectiveness of this antibiotic against S. aureus. Full article
2 pages, 200 KiB  
Abstract
New Fluoroquinolone–Phenothiazine Hybrids and Their Antimicrobial Activity
by Marina Cassago Posso, João Lourenço Serrano, Paulo Almeida, Fernanda Domingues, Samuel Silvestre and Susana Ferreira
Med. Sci. Forum 2022, 12(1), 18; https://doi.org/10.3390/eca2022-12722 - 15 Jun 2022
Viewed by 507
Abstract
Antimicrobial resistance is a worldwide health problem, and with this awareness, some fluoroquinolones are classified by WHO AWaRe as “Watch”, a group with higher resistance potential [...] Full article
2 pages, 212 KiB  
Abstract
Putative Role of the YbhFSR Efflux Pump in Resistance of Aliarcobacter butzleri to Several Antimicrobials
by Inês Martins, Cristiana Mateus, Fernanda Domingues, Mónica Oleastro and Susana Ferreira
Med. Sci. Forum 2022, 12(1), 20; https://doi.org/10.3390/eca2022-12717 - 15 Jun 2022
Viewed by 759
Abstract
The genus Aliarcobacter belongs to the Arcobacteraceae family, which has nine validly published species. Among them, the species Aliarcobacter butzleri is considered the fourth most frequently found Campylobacter-like microorganism in human diarrheal stool samples and has also been included in the list of [...] Read more.
The genus Aliarcobacter belongs to the Arcobacteraceae family, which has nine validly published species. Among them, the species Aliarcobacter butzleri is considered the fourth most frequently found Campylobacter-like microorganism in human diarrheal stool samples and has also been included in the list of microorganisms considered a serious risk to human health by the International Commission on Microbiological Specifications for Food. Increasing rates of multidrug resistance to different antimicrobials have been described in A. butzleri isolates, with efflux pumps being one of the described resistance mechanisms. Efflux pumps of the ATP-binding cassette (ABC) family are known to export a wide variety of substances and are ubiquitous in almost all organisms. Several genes coding for efflux pumps of this family are described in the A. butzleri genome. Despite the resistance associated with this species being widely described, research on the mechanisms involved in this process is scarce. Therefore, the objective of this work was to evaluate the role of an ABC family efflux pump system in the resistance of A. butzleri. To this end, a mutant was constructed via deletion of the ybhF gene from the ybhFSR operon, a transporter with relevance in the extrusion of antibiotics and metals in other bacterial species. After ensuring that the mutation did not modify bacterial growth, the resistance profile of the native and mutant strains to different antimicrobial agents was evaluated. This analysis included metals, disinfectants, antibiotics, germicides, and an efflux pump substrate. The evaluation was based on the determination of the minimum inhibitory concentration of the antimicrobials using the agar dilution method. The results show differences in the susceptibility of the mutant strain to some of the compounds tested, namely heavy metals and antibiotics, compared to the native strain. It can therefore be assumed that the YbhFSR efflux pump contributes to resistance in A. butzleri. Full article
2 pages, 189 KiB  
Abstract
Structure–Activity Relationship for Natural Tetracenomycin X Congeners
by Vera A. Alferova, Tinashe P. Maviza, Mikhail V. Biryukov, Yuliya V. Zakalyukina, Dmitrii A. Lukianov, Dmitry A. Skvortsov, Lilia A. Vasilyeva, Vadim N. Tashlitsky, Vladimir I. Polshakov, Petr V. Sergiev, Ilya A. Osterman and Vladimir A. Korshun
Med. Sci. Forum 2022, 12(1), 21; https://doi.org/10.3390/eca2022-12695 - 15 Jun 2022
Viewed by 753
Abstract
The aromatic polyketide tetracenomycin X (TcmX) was recently found to be a potent inhibitor of protein synthesis; its binding site is located in a unique locus within the tunnel of the large ribosomal subunit. The distinct mode of action makes this relatively narrow [...] Read more.
The aromatic polyketide tetracenomycin X (TcmX) was recently found to be a potent inhibitor of protein synthesis; its binding site is located in a unique locus within the tunnel of the large ribosomal subunit. The distinct mode of action makes this relatively narrow class of aromatic polyketides promising for drug development in the quest to prevent the spread of drug-resistant pathogens. We isolated two novel tetracenomycin congeners: 6-hydroxytetracenomycin X (6-OH-TcmX) and O4-Me-Tcm C (TcmX isomer). Spectral properties of the compounds were studied. 6-OH-TcmX exhibited lower antimicrobial and cytotoxic activity, whereas the TcmX isomer was found to be completely inactive. Interestingly, the in vitro protein synthesis inhibition ability of TcmX and 6-OH-TcmX were found to be comparable, suggesting a significant influence of 6-hydroxylation on the tetracenomycin X cell penetration ability. The complete absence of both antimicrobial activity and the in vitro protein synthesis inhibition ability of the TcmX isomer corroborates the crucial role of the 4-OH group in ribosome binding. Full article
2 pages, 189 KiB  
Abstract
Study of the Biodiversity and Antibiotic Activity of Microorganisms Isolated from the Nasal Mucosa of the Mangalica Pig
by Anna A. Baranova, Vera A. Alferova, Yuliya V. Zakalyukina and Vladimir A. Korshun
Med. Sci. Forum 2022, 12(1), 23; https://doi.org/10.3390/eca2022-12698 - 15 Jun 2022
Viewed by 659
Abstract
Mammals ubiquitously interact with environmental and symbiotic microbes, and the effects of these interactions on animal physiology are currently the subject of intense interest. Symbionts of mammals are interesting from the point of view of their adaptation to their environment, including the emergence [...] Read more.
Mammals ubiquitously interact with environmental and symbiotic microbes, and the effects of these interactions on animal physiology are currently the subject of intense interest. Symbionts of mammals are interesting from the point of view of their adaptation to their environment, including the emergence of defense mechanisms against competitors, antibiotic activity, the absence of a cytotoxic effect on host cells, competition for mucosal attachment sites and food sources. Microflora and mucous membranes closely interact, exerting a mutual influence on the health of a mammal. In this study, samples of the nasal mucosa of Mangalica pigs (a Hungarian breed of domestic pig) were studied. The samples were taken in January 2022 from the noses of one-year-old domestic pigs that had not been seriously ill or treated with antibiotics. Cultures of microorganisms were isolated on SMS agar (0.125 g/L of casein digest, 0.1 g/L of potato starch, 1 g/L of casamino acids, 15 g/L of bacto agar («HiMedia Laboratories Pvt. Ltd. Mumbai, India»)) and Mueller–Hinton agar («HiMedia Laboratories Pvt. Ltd. Mumbai, India»). The biodiversity of microorganisms and their antibiotic and antagonistic activity were studied. The resistance of the obtained cultures to the main human antibiotics was also tested. Antimicrobial activity of the isolated strains against a number of microorganisms was evaluated. The following test strains were used: a fungus (Aspergillus niger INA 00760), a yeast (Candida albicans CBS 8836), Gram-positive bacteria (Bacillus subtilis ATCC 6633, Staphylococcus aureus 29213, Staphylococcus aureus ATCC 25293, Staphylococcus aureus ATCC 43300 (MRSA), Staphylococcus epidermidis ATCC 14990, Enterococcus faecalis ATCC 29212) and Gram-negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853). As a result, the strain SM-11 with pronounced antimicrobial properties was selected for further investigation. The active strain was found to produce bright green fluorescent pigment. Full article
2 pages, 190 KiB  
Abstract
Etiological Spectrum and Antimicrobial Resistance of Most Frequently Isolated Pathogens, Associated with Urinary Tract Infections in Ambulatory Patients
by Viktoriya Snegarova, Neli Ermenlieva, Denis Nyazi, Marina Miroshnikova, Stoyan Stoyanov and Temenuga Stoeva
Med. Sci. Forum 2022, 12(1), 25; https://doi.org/10.3390/eca2022-12703 - 15 Jun 2022
Viewed by 745
Abstract
Introduction: Urinary tract infections (UTIs) are one of the most common infections both in the community and in the hospital setting. Aim: The aim of this study is to investigate the etiological spectrum and antimicrobial resistance of the most frequently isolated pathogens associated [...] Read more.
Introduction: Urinary tract infections (UTIs) are one of the most common infections both in the community and in the hospital setting. Aim: The aim of this study is to investigate the etiological spectrum and antimicrobial resistance of the most frequently isolated pathogens associated with UTIs in ambulatory patients in Varna city, Bulgaria during a seven-month period (October 2020–April 2021). Materials and methods: A total of 1600 urine samples, collected from patients with suspected UTIs were tested. Screening for bacterial growth was performed using an HB&L Uroquattro instrument (ALIFAX, Italy). Species identification and antimicrobial susceptibility testing were performed using a VITEK 2 Compact System (bioMerieux) and the Kirby–Bauer disk diffusion method. Results: A total of 127 urine samples (7.9%) were positive for bacterial growth using the HB&L. From these samples, 127 bacterial pathogens were isolated: Gram negative bacteria were found in 62.2% (n = 79) and Gram positive bacteria were found in 37.8% (n = 48). E. coli was the predominant species associated with UTIs in the group of patients studied (77%, n = 61). The Gram-positive bacteria accounted for 37.8% (n = 48), with E. faecalis being the leading pathogen in this group (87.5%, n = 42). Staphylococcus saprophyticus and Streptococcus agalactiae were diagnosed in 8% (n = 4) and 4% (n = 2), respectively. The resistance rates in the group of Gram-negative isolates (n = 79) in decreasing order were as follows: ampicillin, 64.5% > trimethoprim/sulfamethoxazole, 35.4% > ciprofloxacin, 29.1% > amoxicillin-clavulanic acid, 27.8% > cefuroxime, levofloxacin, 21.5% > fosfomycin, 12.6% > ceftriaxone, 13.9% > ceftazidime, 10.1% > gentamicin, nitrofurantoin, 6.3% > nitroxoline, 5%. The resistance rates among the isolates of E. faecalis (n = 42) were as follows: ciprofloxacin, 28.6% > gentamicin, 23.8% > levofloxacin, 19% > nitrofurantoin, 4.7% > amoxicillin, 2.4%. A low rate of third-generation cephalosporin resistance (ceftazidime, cefotaxime and ceftriaxone) was detected among the representative of order Enterobacterales in this study. The rates of ESBL-producing isolates, confirmed by the phenotypic DDST, were as follows: 5% in E. coli (n = 4), and 2.5% in K. pneumoniae (n = 2) and Enterobacter cloacae (n = 2). No resistance to meropenem, amikacin, vancomycin and teicoplanin was found in the collection of isolates studied (n = 127). Conclusion: The etiological spectrum of UTIs in ambulatory patients was dominated by E. coli, followed by E. faecalis. In the group of Gram-negative uropathogens, high resistance rates to ampicillin, trimethoprim/sulfamethoxazole and quinolones were detected. Third-generation cephalosporins, fosfomycin, nitrofurantoin and nitroxoline retained very good activity. Among the Enterococcus faecalis isolates, the second most commonly isolated bacterial species, decreased activity of the quinolones was found too, but the aminopenicillins and nitrofurantoin remained highly active. Full article
2 pages, 178 KiB  
Abstract
Experience with HB&L Uroquattro Instrument for Rapid Diagnosis of Urinary Tract Infections in Ambulatory Patients
by Viktoriya Snegarova, Neli Ermenlieva, Marina Miroshnikova, Stoyan Stoyanov and Temenuga Stoeva
Med. Sci. Forum 2022, 12(1), 26; https://doi.org/10.3390/eca2022-12704 - 15 Jun 2022
Viewed by 873
Abstract
Urinary tract infections (UTIs) are one of the most common community and hospital-acquired infections. Rapid diagnosis and adequate etiological therapy are factors with direct impacts on the morbidity and mortality associated with these infections. The aim of this study was to evaluate the [...] Read more.
Urinary tract infections (UTIs) are one of the most common community and hospital-acquired infections. Rapid diagnosis and adequate etiological therapy are factors with direct impacts on the morbidity and mortality associated with these infections. The aim of this study was to evaluate the HB&L Uroquattro instrument (ALIFAX, Italy) and the Residual Antimicrobial Activity test (RAA) for the rapid and correct diagnosis of UTIs in ambulatory patients in Varna city, Bulgaria during a seven-month period (October 2020–April 2021). Materials and methods: A total of 1620 urine samples, collected prospectively from 842 ambulatory patients with symptoms of UTIs, were studied. All patients reported information about recent antimicrobial treatment. All samples were screened for bacterial growth using a 4-h protocol and were tested for RAA by HB&L Uroquattro. Simultaneously, the samples were inoculated on blood agar, CLED, CPS, and McConkey agar plates. Results: A total of 343 urine samples (21.2%) were positive for bacterial growth by the rapid screening method. The standard cultural method was positive in 22% (n = 352). RAA was detected in 5.6% (n = 91). A total of 113 patients (13.4%) gave information for therapy with antimicrobial agents or substances with potential antimicrobial activity. Among the samples that demonstrated positive RAA, 69.2% (n = 63) were positive for bacterial growth and 30.7% (n = 28) were negative. Conclusion: A very good correlation between the results from the automated HB&L Uroquattro instrument and those from the traditional cultural method was found. The RAA positive results were detected in patients, receiving antimicrobial treatment. The RAA test result is of great value for the correct interpretation of the culture test and to help to avoid the reporting of false negative results. Full article
2 pages, 188 KiB  
Abstract
In Vitro Activity of Ceftazidime-Avibactam against Gram—Negative Bacteria Recovered from Blood and Fecal Samples of Patients after Hematopoietic Stem-Cell Transplantation
by Denis Niyazi, Ilina Micheva, Dobromira Savova and Temenuga Stoeva
Med. Sci. Forum 2022, 12(1), 27; https://doi.org/10.3390/eca2022-12691 - 15 Jun 2022
Cited by 1 | Viewed by 615
Abstract
Patients receiving hematopoietic stem-cell transplantation (HSCT) are prone to develop invasive infections due to disease and transplantation-related immunosuppression [...] Full article
2 pages, 231 KiB  
Abstract
Is There a Relationship between Biofilm Forming-Capacity and Antibiotic Resistance in Staphylococcus spp.? In Vitro Results
by Matthew Gavino Donadu, Marco Ferrari, Vittorio Mazzarello, Stefania Zanetti, Ivan Kushkevych, Simon K.-M. R. Rittmann, Anette Stájer, Boglárka Ónodi, Zoltán Baráth, Edit Urbán and Márió Gajdács
Med. Sci. Forum 2022, 12(1), 29; https://doi.org/10.3390/eca2022-12734 - 15 Jun 2022
Viewed by 800
Abstract
Staphylococcus species are considered important members of the normal skin microbiota, in addition to being common pathogens in human and animal infections. In addition to S. aureus, other members of the genus are now widely-recognized as pathogens, especially in immunocompromised individuals. One [...] Read more.
Staphylococcus species are considered important members of the normal skin microbiota, in addition to being common pathogens in human and animal infections. In addition to S. aureus, other members of the genus are now widely-recognized as pathogens, especially in immunocompromised individuals. One of the most important virulence factors of staphylococci is the formation of biofilm (slime), which enhances their survival on inanimate surfaces, in addition to providing protection against immune cells and antibiotics in vivo. There has been considerable interest in the study of the relationship between biofilm formation and the antibiotic resistant phenotype, however, the results in the available literature are inconsistent. Thus, this study aims to investigate the correlation between biofilm formation and antibiotic resistance in Staphylococcus spp. isolates using phenotypic methods. One hundred and eighty (n = 180) isolates were included in the study, with S. epidermidis (40.0%) and S. lugdunensis (10.0%) being the most numerous. Biofilm-forming capacity was assessed by means of the crystal violet microtiter-plate-based (CV-MTP) method. Methicillin-resistance (MR) was identified in 47.2% (n = 85) of isolates. Among the commonly-used antimicrobials, resistance was highest for clindamycin (51.1%), erythromycin (48.9%) and trimethoprim-sulfamethoxazole (51.1%). Based on the CV-MTP method, n = 13 (7.2%), n = 13 (7.2%), n = 42 (23.3%) and n = 113 (62.3%) staphylococcal isolates were non-biofilm-producing, weak, moderate and strong biofilm producers, respectively. No significant differences in biofilm-formation were shown to be observed on the basis of MR (susceptible (S): 0.881 ± 0.309 vs. resistant (R): 0.890 ± 0.347; p = 0.133) and according to the resistance, to most other antibiotics. Rifampin-resistant isolates were more potent biofilm-producers than their susceptible counterparts (S: 0.802 ± 0.296 vs. R: 1.194 ± 0.221; p = 0.024). The association of the antibiotic-resistant phenotype and biofilm-formation is still inconclusive, due to the heterogeneity of the results in presently available studies; however, the understanding of these mechanisms in Staphylococcus spp. is crucial to appropriately address the therapy and eradication of these pathogens. Full article
1 pages, 196 KiB  
Abstract
Solid-Phase Microextraction as an Antibiotic Resistance Detector in Staphylococcus aureus Strains
by Justyna Paleczny, Malwina Brożyna, Marzenna Bartoszewicz and Adam Feliks Junka
Med. Sci. Forum 2022, 12(1), 30; https://doi.org/10.3390/eca2022-12697 - 15 Jun 2022
Viewed by 687
Abstract
Bloodstream infections, which result from introducing contaminated implants or prostheses to a patient’s body, are commonly caused by Staphylococcus aureus strains. The occurrence of staphylococcal-related bloodstream infection correlates with an elevated risk of sepsis, which poses a threat to a patient’s health [...] Read more.
Bloodstream infections, which result from introducing contaminated implants or prostheses to a patient’s body, are commonly caused by Staphylococcus aureus strains. The occurrence of staphylococcal-related bloodstream infection correlates with an elevated risk of sepsis, which poses a threat to a patient’s health and life. The microbiological diagnostic procedure of bloodstream infection takes between 3 and 7 days, during which the patient receives broad-spectrum antibiotics that contribute to drug resistance. The application of the Solid-Phase Microextraction method (SPME) in sepsis diagnosis may reduce diagnostic time by up to 2 h. Therefore, the aim of this study was to investigate the suitability of the Solid-Phase Microextraction method in the differentiation of methicillin-susceptible Staphylococcus aureus (MSSA) from methicillin-resistant (MRSA) strains based on the volatile compounds secreted by these bacteria. For this purpose, five MSSA and five MRSA strains were tested. Volatile compounds were isolated using a headspace-SPME modification and distributed and analyzed by employing combined gas chromatography with mass spectrometry. Comparing the profiles of the secreted volatile metabolites, we found significant differences between the compositions of MRSA and MSSA metabolomes. The results may serve as a proof of concept for further research aiming to create a new analytical method. Shortening the time of diagnosis of sepsis to 2 h will significantly reduce patients’ risk of death. Full article
2 pages, 187 KiB  
Abstract
Resistance Rates to Third-Generation Cephalosporins and Carbapenems in Serratia marcescens Isolates Obtained from Various Clinical Samples from Two Bulgarian Hospitals
by Stephanie Radeva, Milena Bojkova, Denis Niyazi, Dobromira Savova and Temenuga Stoeva
Med. Sci. Forum 2022, 12(1), 32; https://doi.org/10.3390/eca2022-12693 - 15 Jun 2022
Viewed by 626
Abstract
Serratia marcescens is a bacterial species associated with different types of infections, including hospital-acquired infections [...] Full article
2 pages, 217 KiB  
Abstract
Ionic and Aerogel Levothyroxine Formulations with Improved Bioavailability Properties
by António Barreira, Ana B. Paninho, Luís C. Branco and Márcia G. Ventura
Med. Sci. Forum 2022, 12(1), 34; https://doi.org/10.3390/eca2022-12737 - 15 Jun 2022
Viewed by 567
Abstract
Thyroid diseases affect a considerable portion of the population, with hypothyroidism being one of the most commonly reported thyroid diseases [...] Full article
2 pages, 218 KiB  
Abstract
In Vitro Activity of Cefiderocol and Comparators against Multi-Drug Resistant Acinetobacter baumannii Isolates
by Areti Tychala, Efthymia Protonotariou, Paraskevi Mantzana, Georgios Meletis, Ioanna Gkeka and Lemonia Skoura
Med. Sci. Forum 2022, 12(1), 35; https://doi.org/10.3390/eca2022-12741 - 15 Jun 2022
Viewed by 500
Abstract
Acinetobacter baumannii is an aerobic Gram-negative bacterium which causes facultative hospital infections and, in settings such as Greece, exhibits high resistance rates against most antimicrobial agents [...] Full article
3 pages, 195 KiB  
Abstract
Using Antibiotics Scaffolds Will Warrant Novel Radiotracers for Effective Positron Emission Tomography Imaging of Infections: Triumph or Pitfall?
by Arno Christiaan Gouws, Hendrik Gerhardus Kruger, Mike Machaba Sathekge, Jan Rijn Zeevaart, Thavendran Govender, Tricia Naicker and Thomas Ebenhan
Med. Sci. Forum 2022, 12(1), 36; https://doi.org/10.3390/eca2022-12748 - 15 Jun 2022
Viewed by 689
Abstract
The excellent features of non-invasive molecular imaging, its progressive technology (real-time, whole-body imaging and quantification), and global impact by a growing infrastructure for positron emission tomography (PET) scanners are encouraging prospects to investigate new concepts which could transform clinical care of complex infectious [...] Read more.
The excellent features of non-invasive molecular imaging, its progressive technology (real-time, whole-body imaging and quantification), and global impact by a growing infrastructure for positron emission tomography (PET) scanners are encouraging prospects to investigate new concepts which could transform clinical care of complex infectious diseases [...] Full article
2 pages, 211 KiB  
Abstract
Determination of the Pattern of Resistance to Antibiotics among Strains of Staphylococcus aureus Isolated from the Nose or Pharynx
by Samuel González-García, Aida Hamdan-Partida, Anaid Bustos-Hamdan and Jaime Bustos-Martínez
Med. Sci. Forum 2022, 12(1), 38; https://doi.org/10.3390/eca2022-12720 - 15 Jun 2022
Viewed by 504
Abstract
The pathophysiology of Staphylococcus aureus in nasal carriers has been extensively studied, however, it must be admitted that the clinical relevance of S [...] Full article
2 pages, 220 KiB  
Abstract
Variability in Antibiotic Resistance of Persistent and Intermittent Staphylococcus aureus Strains
by Samuel González-García, Aida Hamdan-Partida, Julia Pérez Ramos and Jaime Bustos-Martínez
Med. Sci. Forum 2022, 12(1), 39; https://doi.org/10.3390/eca2022-12719 - 16 Jun 2022
Viewed by 540
Abstract
Introduction: Approximately 30% of the population is colonized with Staphylococcus aureus on the skin, mucous membranes, and in the anterior part of the nose [...] Full article
3 pages, 338 KiB  
Abstract
AlkylGuanidino Ureas, from a Serendipitous Discovery to a Rational Design: Innovative Membrane-Active Antibacterial Agents
by Ilaria D’Agostino, Jean-Denis Docquier and Maurizio Botta
Med. Sci. Forum 2022, 12(1), 40; https://doi.org/10.3390/eca2022-12756 - 23 Jun 2022
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Abstract
The relentless and global rise of bacterial resistance is undoubtedly one of the most worrisome Public Health issues [...] Full article
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7 pages, 265 KiB  
Proceeding Paper
Antibiotic Use, Incidence and Risk Factors for Orthopedic Surgical Site Infections in a Teaching Hospital in Madhya Pradesh, India
by Kristina Skender, Anna Machowska, Vivek Singh, Varun Goel, Yogyata Marothi, Cecilia Stålsby Lundborg and Megha Sharma
Med. Sci. Forum 2022, 12(1), 2; https://doi.org/10.3390/eca2022-12706 - 15 Jun 2022
Viewed by 949
Abstract
Orthopedic surgeries contribute to overall surgical site infection (SSI) events worldwide. In India, SSI rates vary considerably depending on geographical location (1.6–38%); however, there is a lack of a national SSI surveillance system.. This study aims to identify the SSI incidence, risk factors, [...] Read more.
Orthopedic surgeries contribute to overall surgical site infection (SSI) events worldwide. In India, SSI rates vary considerably depending on geographical location (1.6–38%); however, there is a lack of a national SSI surveillance system.. This study aims to identify the SSI incidence, risk factors, antibiotic prescription and susceptibility patterns among operated orthopedic patients in a teaching hospital in India. Data for 1205 patients were collected from 2013 to 2016. SSIs were identified based on the Centre for Disease Control and Prevention’s guidelines. The American Society for Anesthesiologists classification system was used to predict patients’ operative risk. Univariable and multivariable backward stepwise logistic regressions were performed to identify risk factors for SSIs. Overall, 7.6% patients developed SSIs over three years. Out of 68 samples sent for culture and susceptibility testing, 22% were culture positive. The most common SSI-causing microorganism was Staphylococcus aureus (7%), whose strains were resistant to penicillin (100%), erythromycin (80%), cotrimoxazole (80%), amikacin (60%) and cefoxitin (60%). Amikacin was the most prescribed antibiotic (36%). Male sex (OR 2.64; 95%CI 1.32–5.30), previous hospitalization (OR 2.15; 95%CI 1.25–3.69), prescription of antibiotics during hospitalization before perioperative antibiotic prophylaxis (OR 4.19; 95%CI 2.51–7.00) and postoperative length of stay >15 days (OR 3.30; 95%CI 1.83–5.95) were identified as significant risk factors for orthopedic SSIs. Additionally, a preoperative shower significantly increased the risk of SSIs (OR 4.73; 95% CI 2.72–8.22), which is unconfirmed in the literature so far. Full article
4 pages, 222 KiB  
Proceeding Paper
Experience of Real-Life Use of Dalbavancin as an Off-Label Treatment of Complicated Infectious Diseases in a Tertiary Care Hospital Experience
by Raquel Gracia, Mercedes Arenere, Beatriz Bonaga, Maria Angeles Allende, Alberto Jose Frutos, Transito Salvador, Raquel Fresquet, Oihana Pascual and Jose Manuel Vinuesa
Med. Sci. Forum 2022, 12(1), 4; https://doi.org/10.3390/eca2022-12736 - 15 Jun 2022
Cited by 1 | Viewed by 687
Abstract
Dalbavancin is a lipoglycopeptide indicated for the treatment of acute bacterial skin and skin structure infections. The aim of this study is to describe the cases in which dalbavancin has been used as an off-label treatment for infections by Gram-positive microorganisms. Methods: we [...] Read more.
Dalbavancin is a lipoglycopeptide indicated for the treatment of acute bacterial skin and skin structure infections. The aim of this study is to describe the cases in which dalbavancin has been used as an off-label treatment for infections by Gram-positive microorganisms. Methods: we carried out a case report series study of all patients treated with dalbavancin as an off-label treatment from January 2017 to March 2022. Results: Dalbavancin was administered to seventeen patients. The most frequent diagnosis was osteoarticular infection in 52.94% of patients. The principal isolated microorganism was Staphylococcus epidermidis (47.00%). The posology of dalbavancin was highly variable and the median number of days of treatment was 14 (1–56). At 3 months of treatment, only two patients died for other reasons and no patient experienced reinfection. Conclusion: dalbavancin is an antibiotic with a novel dosage in infectious diseases by Gram-positive microorganisms that has proven to be highly effective, since there have been no manifested symptoms of reinfection in patients. Full article
5 pages, 698 KiB  
Proceeding Paper
A Systematic In Silico Investigation of Phytochemicals from Artocarpus Species against Plasmodium falciparum Inhibitors
by Surabhi Chaurasia and Anima Pandey
Med. Sci. Forum 2022, 12(1), 5; https://doi.org/10.3390/eca2022-12712 - 15 Jun 2022
Cited by 2 | Viewed by 819
Abstract
Artemisinin-resistant plasmodium strains are becoming increasingly common in malaria patients, posing a serious threat to successful malaria management. Brosimone, a significant polyphenolic ingredient of Artocarpus lakoocha, has previously been shown to have antimalarial activity in vitro. However, research into the precise mechanism [...] Read more.
Artemisinin-resistant plasmodium strains are becoming increasingly common in malaria patients, posing a serious threat to successful malaria management. Brosimone, a significant polyphenolic ingredient of Artocarpus lakoocha, has previously been shown to have antimalarial activity in vitro. However, research into the precise mechanism of interactions is still in progress. The present study explored molecular modeling research in order to elucidate the likely mechanism of its anti-malarial effect in terms of Falcipain-2 (FP-2) inhibition. Brosimone shows a maximum binding affinity (docking score: −8.1 Kcal/mol) against FP-2 from Plasmodium falciparum, according to our molecular docking analysis of 50 lakoocha bioactive chemicals. For numerous Artocarpus lakoocha polyphenols (ALP), we used in-silico pharmacokinetics and toxicities, leading to critical insights into the mechanism of action of brosimone and other ALPs as potential therapeutic agents (2GHU) against malaria. Full article
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6 pages, 1464 KiB  
Proceeding Paper
A Systematic Implementation of Machine Learning Algorithms for Multifaceted Antimicrobial Screening of Lead Compounds
by Justin Shen and Davesh Valagolam
Med. Sci. Forum 2022, 12(1), 6; https://doi.org/10.3390/eca2022-12751 - 16 Jun 2022
Viewed by 837
Abstract
This study employed machine learning algorithms to identify lead compounds that inhibit the antibiotic targets DNA gyrase and Dihydrofolate reductase in Escherichia coli, and identified new, multifaceted antimicrobial compounds. This study used three separate datasets: (1) 326 Escherichia coli DNA gyrase inhibitors [...] Read more.
This study employed machine learning algorithms to identify lead compounds that inhibit the antibiotic targets DNA gyrase and Dihydrofolate reductase in Escherichia coli, and identified new, multifaceted antimicrobial compounds. This study used three separate datasets: (1) 326 Escherichia coli DNA gyrase inhibitors and 132 non-inhibitors, (2) 346 Escherichia coli Dihydrofolate reductase inhibitors and 176 non-inhibitors, and (3) 18387 non-specific drug-like chemicals. All datasets were then processed using ECFP-4 fingerprints and split into train, test, and validation datasets according to a 70–15–15 train-test-validation split. We explored the potential of six different classification algorithms, all optimized with Bayesian optimization. Our results indicate that the Gradient Boosting Classifier (GBC) performed the best at identifying a compound’s efficacy towards DNA gyrase with an accuracy, precision, recall, F1-score, and AUC of 0.91, 0.92, 0.86, 0.88, and 0.933, respectively. The Random Forest Classifier (RFC) performed optimally for identifying a compound’s effectiveness towards Dihydrofolate reductase with an accuracy, precision, recall, F1-score, and AUC of 0.86, 0.83, 0.85, 0.84, and 0.944, respectively. As a result, the GBC and RFC were used to search for compounds that inhibited both DNA gyrase and Dihydrofolate reductase. Out of 18387 compounds, we identified five novel compounds that have a predicted probability greater than 95% to inhibit both DNA gyrase and Dihydrofolate reductase, suggesting a high antimicrobial potential. The models evaluated in this study, particularly the GBC and RFC models, hold tremendous promise in computationally screening large libraries of compounds for antimicrobial potential. Full article
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6 pages, 1426 KiB  
Proceeding Paper
Antimicrobial Activities of Compounds Produced by Newly Isolated Streptomyces Strains from Mountain Caves
by Weronika Jaroszewicz, Patrycja Bielańska, Daria Lubomska, Katarzyna Kosznik-Kwaśnicka, Piotr Golec, Łukasz Grabowski, Ewa Wieczerzak, Weronika Dróżdż, Lidia Gaffke, Karolina Pierzynowska, Zuzanna Cyske, Alicja Węgrzyn and Grzegorz Węgrzyn
Med. Sci. Forum 2022, 12(1), 7; https://doi.org/10.3390/eca2022-12749 - 16 Jun 2022
Viewed by 1040
Abstract
The “antibiotic crisis”, defined as the appearance of microbial strains resistant to most, if not all, already known antibiotics, indicates that searching for previously unknown antimicrobial agents is crucial for further development of novel drugs that can be used to combat infections caused [...] Read more.
The “antibiotic crisis”, defined as the appearance of microbial strains resistant to most, if not all, already known antibiotics, indicates that searching for previously unknown antimicrobial agents is crucial for further development of novel drugs that can be used to combat infections caused by bacteria and fungi. Bacteria living in untypical and extreme habitats appear to be a potentially reached source of such compounds. We recently reported an isolation of newly identified strains of Actinobacteria from the Szczelina Chochołowska cave (Tatra Mountains, Poland). Some of them produced molecules revealing antibacterial, antifungal and anticancer properties. Here, we describe further characterization of the selected strains. Their microbiological properties, ability to form biofilms and antimicrobial activities against various strains of bacteria and fungi are reported. The selected strains of newly isolated Actinobacteria belonging to the genus Streptomyces appear a promising source of previously unknown antimicrobial agents. Full article
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5 pages, 245 KiB  
Proceeding Paper
In Vitro Antifungal Activity of Boesenbergia rotundo Linn. and Syzygium aromaticum L. Merr. and Perry Extracts against Aspergillus flavus
by Pataraporn Uaraksakul and Pragatsawat Chanprapai
Med. Sci. Forum 2022, 12(1), 8; https://doi.org/10.3390/eca2022-12687 - 14 Jun 2022
Cited by 1 | Viewed by 989
Abstract
Aspergillus flavus is a common human pathogen that releases mycotoxin into the host and is frequently treated with synthetic fungicides, but these fungicides have serious human health consequences. Natural products derived from higher plant species have long been investigated as a potential means [...] Read more.
Aspergillus flavus is a common human pathogen that releases mycotoxin into the host and is frequently treated with synthetic fungicides, but these fungicides have serious human health consequences. Natural products derived from higher plant species have long been investigated as a potential means of controlling pathogenic microorganisms. The indigenous vegetables Boesenbergia rotunda and Syzygium aromaticum are widely distributed in the tropical area. These plants have also been reported in traditional uses for their antimicrobial activity. The purpose of the study was to explore the antifungal susceptibility of dichloromethane and ethanol extracts of B. rotunda rhizomes and S. aromaticum flower buds by Soxhlet’s apparatus against A. flavus using the poison food technique. The effective extract was also subjected to preliminary phytochemical screening tests. The experiment used a completely randomized design with triplications. B. rotunda ethanol extract demonstrated significantly higher potential antifungal activity. The values of minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of B. rotunda ethanol extract were 6.25 and 50 mg/mL, respectively, when tested using the macro-dilution method. According to phytochemical tests, the ethanol extract also contained alkaloids, flavonoids, cardiac glycosides, and saponins. The study suggests that a basic guideline for using this as an effective antifungal compound should be separated from the B. rotunda ethanol extract in the future for topical anti-pathogenic fungus. Full article
8 pages, 2554 KiB  
Proceeding Paper
Photodynamic Inactivation of Phage Phi6 as SARS-CoV-2 Model in Wastewater Disinfection: Effectivity and Safety
by Maria Bartolomeu, Cátia Vieira, Marta Gomes, Ana T. P. C. Gomes, Maria Amparo F. Faustino, Maria Graça P. M. S. Neves and Adelaide Almeida
Med. Sci. Forum 2022, 12(1), 9; https://doi.org/10.3390/eca2022-12707 - 15 Jun 2022
Viewed by 767
Abstract
The past 2 years have been marked by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. This virus is found in the intestinal tract and reaches the wastewater system, and, consequently, the natural receiving water bodies, and inappropriate or/and inefficient WW treatment [...] Read more.
The past 2 years have been marked by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. This virus is found in the intestinal tract and reaches the wastewater system, and, consequently, the natural receiving water bodies, and inappropriate or/and inefficient WW treatment is a means of contamination. In the present work, we used a SARS-CoV-2 model—the phage Phi6—to evaluate its survival under different environmental conditions (pH, temperature, salinity, solar, and UV-B irradiation). Then, we tested the efficiency of photodynamic inactivation (PDI) as a WW disinfection alternative method, and, additionally, the impact on the cultivable native marine microorganisms of the PDI-treated WW was evaluated. Full article
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5 pages, 255 KiB  
Proceeding Paper
Potential Antibacterial Action of α-Pinene
by Mirla Fontes de Araújo Borges, Roosveni de Sousa Lacerda, Jásny Pintor de Assis Correia, Thamara Rodrigues de Melo and Sávio Benvindo Ferreira
Med. Sci. Forum 2022, 12(1), 11; https://doi.org/10.3390/eca2022-12709 - 15 Jun 2022
Cited by 7 | Viewed by 1498
Abstract
The indiscriminate use of antibiotics generates several problems for human health, the main one being bacterial resistance. The abuse of antibiotics is responsible for reducing the effectiveness of medicines, making it difficult to treat diseases and representing a major obstacle for researchers and [...] Read more.
The indiscriminate use of antibiotics generates several problems for human health, the main one being bacterial resistance. The abuse of antibiotics is responsible for reducing the effectiveness of medicines, making it difficult to treat diseases and representing a major obstacle for researchers and health professionals. Natural alternatives have been widely studied, such as essential oils and their phyto-constituents, in order to verify their antibacterial action. This research aimed to identify the antibacterial activity of α-pinene. This is a descriptive study, using a qualitative approach, with methodological experience based on an integrative review. The bibliographic survey was carried out in the LILACS and MEDLINE, though the Virtual Health Library, PubMed and Web of Science databases, using the following search strategies: Anti-bacterial agents AND α-pinene for the PubMed and VHL databases, and (Antibacterial agents AND pinene) and (Antimicrobial AND α-pinene) on the Web of Science. After reading the articles in full, 10 works were selected. α-pinene was relatable, including its positive mix and its association with antimicrobials. The article points out that α-pinene has wide potential in antimicrobial therapy in order to inhibit the growth of bacteria as an isolated result or as a synergist of antibiotics. However, they are bactericidal and bacteriostatic when against bacterial strains. Therefore, it is concluded that it is relevant to develop scientific research to analyze the effectiveness of this compound to the most diverse microorganisms that affect human health. Full article
5 pages, 1060 KiB  
Proceeding Paper
Plant-Based Nanoantibiotics: An Effective Strategy to Overcoming Antibiotic Resistance
by Sepidar Seyyedi Mansour, Maria Carpena, Javier Echave, Franklin Chamorro, Antia G. Pereira, Marta Barral-Martinez, Anton Soria-Lopez, Lucia Cassani, Aurora Silva, Jianbo Xiao, Jesus Simal-Gandara and Miguel A. Prieto
Med. Sci. Forum 2022, 12(1), 12; https://doi.org/10.3390/eca2022-12727 - 15 Jun 2022
Viewed by 975
Abstract
Commonly used antibiotics use multiple administrations for providing a continuous bactericidal effect but can increase systemic toxicity, as well as lead to bacterial drug resistance. The use of plant-based antibacterial compounds in combination with conventional antibiotics to treat drug-resistant infections could be an [...] Read more.
Commonly used antibiotics use multiple administrations for providing a continuous bactericidal effect but can increase systemic toxicity, as well as lead to bacterial drug resistance. The use of plant-based antibacterial compounds in combination with conventional antibiotics to treat drug-resistant infections could be an alternative to overcoming the problem of bacterial resistance. The combination of antibiotics with plant-based antibacterial compounds has shown synergistic advantages due to the inhibition of drug efflux and the presence of alternative mechanisms of action. Moreover, the nanoencapsulation of antibiotics is another effective technique to overcome antibiotic resistance. Nano-encapsulated antimicrobials have a better performance in comparison with traditional antibiotics due to their small size which leads to better interaction with bacterial cells. The different nanocarriers are effective in efficiently administering antibiotics by improving pharmacokinetics and accumulation while reducing the adverse effects. Additionally, the surface engineering of nanocarriers provides benefits such as targeting and modulating various resistance mechanisms. Furthermore, most nanocarriers are suitable platforms for co-loading of plant-based antibacterial compounds and traditional antibiotics to provide synergistic effects. This study outlines recent attempts to combat infectious diseases, with a focus on the use of plant-based nanoantibiotics as novel tools to address today’s issues in infectious disease treatment. Full article
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7 pages, 1496 KiB  
Proceeding Paper
Photoinactivation of Bacterial and Fungal Planktonic/Biofilm Forms Using the Combination of a Porphyrinic Formulation with Potassium Iodide
by Cátia Vieira, Maria Bartolomeu, Adriele R. Santos, Mariana Q. Mesquita, Ana T. P. C. Gomes, Maria Graça P. M. S. Neves, Maria Amparo F. Faustino and Adelaide Almeida
Med. Sci. Forum 2022, 12(1), 13; https://doi.org/10.3390/eca2022-12711 - 15 Jun 2022
Viewed by 740
Abstract
Antimicrobial photodynamic therapy (aPDT) is a promising approach against multidrug-resistant microorganisms. In this work, we accessed the photodynamic efficiency of an affordable formulation composed of five cationic porphyrins (FORM) and its combined effect with potassium iodide (KI) on a large spectrum of microorganisms. [...] Read more.
Antimicrobial photodynamic therapy (aPDT) is a promising approach against multidrug-resistant microorganisms. In this work, we accessed the photodynamic efficiency of an affordable formulation composed of five cationic porphyrins (FORM) and its combined effect with potassium iodide (KI) on a large spectrum of microorganisms. For this purpose, the aPDT assays were conducted with FORM alone and FORM + KI on planktonic and biofilm forms of Gram(+) (Staphylococcus aureus) and Gram(−) (Escherichia coli) bacteria and of the yeast Candida albicans. The results obtained indicate that FORM, at low concentrations (0.5–5.0 μM), had an efficient photodynamic action on the planktonic forms of E. coli, S. aureus, and C. albicans. Moreover, the combination of FORM with KI improved the photodynamic action of this PS, promoting microbial inactivation with lower PS concentrations and treatment time. The combination of FORM + KI was also extremely efficient in the destruction of bacterial and fungal biofilms. This outstanding effect may be due to the action of longer-lived iodine reactive species produced by the reaction of KI with the ROS generated by FORM during the aPDT treatment. Full article
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3 pages, 252 KiB  
Proceeding Paper
Actinomycetes of the Genus Streptomyces from the Silty Mud of Tambukan Lake Are Producers of Antibiotic Compounds
by Olga N. Sineva, Olga P. Bychkova and Vera S. Sadykova
Med. Sci. Forum 2022, 12(1), 14; https://doi.org/10.3390/eca2022-12752 - 16 Jun 2022
Viewed by 711
Abstract
Actinomycetes of the genus Streptomyces are members of the phylum Actinomycetota, Gram-positive, filamentous, spore-forming bacteria. Members of the genus Streptomyces are known as producers many different bioactive natural products, such as antibiotics, antifungal, antitumor agents. Despite the large number of already known antibiotics, [...] Read more.
Actinomycetes of the genus Streptomyces are members of the phylum Actinomycetota, Gram-positive, filamentous, spore-forming bacteria. Members of the genus Streptomyces are known as producers many different bioactive natural products, such as antibiotics, antifungal, antitumor agents. Despite the large number of already known antibiotics, the actinomycetes of the genus Streptomyces still occupy an important position due to the rich variety of unique secondary metabolites and are excellent candidates for the search for new antibiotics and antifungal agents for medical purposes. Most species of the genus Streptomyces have been isolated from soils. Currently, the attention of researchers is directed to the study of actinomycetes complexes not only in soils, but also in reservoirs, plants, invertebrates. Tambukan is a lake (43°57′37″ N, 43°9′40″ E) with bitter-salt water on Northern Caucasus. The bottom of the lake consists of a thick layer of silty mud containing sulfates and chlorides of sodium and magnesium, with a mineralization of 55–60 g/L. The medicinal water and mud of Tambukan Lake is in pelotherapy offered by health resorts and have been used by famous individuals. Thus, the actinomycetes isolated from the silty mud of Tambukan Lake are of interest not only potential producers of new antibiotics, but also as inhabitants of extreme conditions. The goal of this study was to isolate actinomycetes from the silty mud of Tambukan Lake and to study their antimicrobial and antifungal activity. In the study ten cultures were isolated from the silty mud. The strains were classified as belonging to the Streptomyces genus using morphological, physiological, biochemical and molecular 16S rRNA methods. The isolated cultures showed antibiotic activity against the following pathogens: Micrococcus luteus ATCC 9341, Staphylococcus aureus INA 00985, Bacillus subtilis ATCC 6633, Staphylococcus aureus INA 00761 (MRSA—Methicillin-Resistant Staphylococcus aureus), Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Saccharomyces cerevisiae ИНА 01042, Aspergillus niger ATCC 16404, Fusarium solani ВКПМ F-890, Candida albicans ATCC 14053, Fusarium oxysporum ВКПМ F-148. Streptomyces fulvissimus 5T2, Streptomyces globisporus 20T2, Streptomyces intermedius 23T2 demonstrated strong antimicrobial activities against fungi. These strains can be considered as potential producers of new antifungal agents. Full article
5 pages, 246 KiB  
Proceeding Paper
Antimicrobial Activity Screening of Camellia japonica Flowers (var. Conde de la Torre)
by Antia G. Pereira, Aurora Silva, Marta Barral-Martinez, Javier Echave, Franklin Chamorro, Sepidar Seyyedi Mansour, Lucia Cassani, Paz Otero, Jianbo Xiao, Fatima Barroso, Jesus Simal-Gandara and Miguel A. Prieto
Med. Sci. Forum 2022, 12(1), 15; https://doi.org/10.3390/eca2022-12725 - 15 Jun 2022
Viewed by 963
Abstract
The increased resistance of pathogenic microorganisms to a wide range of antibiotics has driven recent research efforts towards exploring and developing effective preservatives with better potential and new strategies to prevent this multi-resistance. Many of these studies have been on natural matrices such [...] Read more.
The increased resistance of pathogenic microorganisms to a wide range of antibiotics has driven recent research efforts towards exploring and developing effective preservatives with better potential and new strategies to prevent this multi-resistance. Many of these studies have been on natural matrices such as plants. This is in line with consumer demand for more organic and natural products. A possible alternative could be using bioactive compounds from Camellia japonica flowers as bio-preservatives since they have been traditionally used in cosmetic products due to their biological properties. Among the bioactive molecules of camellias, it is worth highlighting phenolic compounds, anthocyanins, polysaccharides, polyphenols, polyunsaturated fatty acids, and pigments. However, to incorporate these bioactive molecules into products with antimicrobial purposes, it is necessary to conduct an extraction and purification of the target compounds. Thus, in this study, the antimicrobial activity of one variety of C. japonica flowers (var. Conde de la Torre), obtained by an easy and profitable extraction technique such as maceration, was analyzed. Results from this work showed that the variety under study has a significant antimicrobial activity in terms of inhibition zones against Staphylococcus epidermidis (14.02 mm), Staphylococcus aureus (10.84 mm), Pseudomonas aeruginosa (10.36 mm), Salmonella enteritidis (7.98 mm), and Bacillus cereus (5.05 mm). However, the var. Conde de la Torre of C. japonica did not show significant activity against Escherichia coli. In conclusion, Conde de la Torre can be used as a potential antimicrobial agent. However, more studies that determinate the compounds responsible for these bioactivities are needed. Full article
5 pages, 803 KiB  
Proceeding Paper
Evaluation of the Antimicrobial Potential of Extracts from Plants of the Family Asteraceae
by Marta Barral-Martinez, Lucia Cassani, Maria Carpena, Antia G. Pereira, Paula Garcia-Oliveira, Franklin Chamorro, Sepidar Seyyedi Mansour, Aurora Silva, Fatima Barroso, Hui Cao, Miguel A. Prieto and Jesus Simal-Gandara
Med. Sci. Forum 2022, 12(1), 17; https://doi.org/10.3390/eca2022-12726 - 15 Jun 2022
Viewed by 964
Abstract
Today, medicinal plants have multiple different uses since they can play an important role in the design of modern medicines and new healthy foods. Although their level of consumption is not high, these plants are attributed pharmacological properties with beneficial properties, such as [...] Read more.
Today, medicinal plants have multiple different uses since they can play an important role in the design of modern medicines and new healthy foods. Although their level of consumption is not high, these plants are attributed pharmacological properties with beneficial properties, such as antioxidant, anti-inflammatory, or antimicrobial, among others. This study aimed to evaluate extracts derived from Chamaemelum nobile and Arnica montana, two plants from the Asteraceae family that could be of interest for the industry, in terms of their antimicrobial capacity. After a previous bibliographic study, heat-assisted extraction (HAE) was selected and used to obtain extracts rich in bioactive compounds. Then, the antimicrobial activity was determined using three Gram-negative species, Pseudomonas aeruginosa (ATCC 10145), Escherichia coli (NCTC 9001), and Salmonella enteritidis (ATCC 13676), and two Gram-positive species, Bacillus cereus (ATCC 25923) and Staphylococcus aureus (ATCC 25923). The results obtained showed that A. montana showed a moderate antimicrobial activity with inhibition zones ranging from 6.82 to 8.36 mm while the C. nobile showed inhibition zones of 7.55 and 7.91 mm against S. enteritidis and P. aeruginosa, respectively. None of the plants showed activity against S. aureus. These results provide scientific evidence for the use of medicinal plant extracts for the development of new products with antimicrobial properties. Full article
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6 pages, 432 KiB  
Proceeding Paper
Antimicrobial Activity of Crude Extracts from Ascophyllum nodosum Obtained by Microwave-Assisted Extraction
by Aurora Silva, Lucia Cassani, Catarina Lourenço-Lopes, Stephanie L. Morais, Hui Cao, Paula Garcia-Oliveira, Pascual Garcia-Perez, Maria Carpena, Valentina Domingues, Maria Fátima Barroso, Jesús Simal-Gandara and Miguel Angel Prieto
Med. Sci. Forum 2022, 12(1), 19; https://doi.org/10.3390/eca2022-12724 - 15 Jun 2022
Cited by 1 | Viewed by 1480
Abstract
Ascophyllum nodosum (Linnaeus) Le Jolis is a brown alga from the Fucaceae family and a unique species from the Ascophyllum genus. This brown alga is an edible macroalga from the North Atlantic Ocean, commonly found on the European north-western coast. High-value bioactive molecules [...] Read more.
Ascophyllum nodosum (Linnaeus) Le Jolis is a brown alga from the Fucaceae family and a unique species from the Ascophyllum genus. This brown alga is an edible macroalga from the North Atlantic Ocean, commonly found on the European north-western coast. High-value bioactive molecules such as pigments, polyphenols, and phlorotannin were found in the macroalgae composition, which makes this alga particularly interesting for exploring potential biological activities. Among sustainable extraction technologies, microwave-assisted extraction (MAE) has many advantages such as a short extraction time and fewer solvent requirements. On the other hand, ethanol and water are eco-friendly solvents that have already been proven to be effective for obtaining bioactive compounds with antimicrobial capacity. Therefore, in this work, analytical conditions of MAE: t = 5 min; pressure = 10.5 bar; ethanol concentration (37%) as solvent were applied to obtain a polyphenol-rich extract from A. nodosum. The antimicrobial effect of the resulting extract against five food-borne microorganisms (Bacillus cereus, Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa, Staphylococcus aureus), and the opportunistic bacteria Staphylococcus epidermidis was assessed. The antimicrobial activity was performed through the Kirby–Bauer disk diffusion susceptibility test protocol and the microdilution method. The analytical results indicated that the A. nodosum extract was effective against all tested bacteria except for Escherichia coli. The highest antimicrobial activity was found against Staphylococcus aureus, presenting inhibitory capacity with a concentration of 400 µg/mL and an inhibition halo of 11.79 ± 1.92 mm. Full article
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6 pages, 278 KiB  
Proceeding Paper
Anti-Bacterial Perspective of Non-Antibiotic Drugs
by Hélida Maravilha Dantas e Sousa Almeida, Lara Bianca Soares Brandão, Thamara Rodrigues de Melo and Sávio Benvindo Ferreira
Med. Sci. Forum 2022, 12(1), 22; https://doi.org/10.3390/eca2022-12701 - 15 Jun 2022
Cited by 1 | Viewed by 876
Abstract
The scope of this paper is to provide a state of the art in pharmacological repositioning, envisioning the antibacterial activity of non-antibiotic drugs. The method of the narrative literature review was adopted. The investigation took place during the months of January and February [...] Read more.
The scope of this paper is to provide a state of the art in pharmacological repositioning, envisioning the antibacterial activity of non-antibiotic drugs. The method of the narrative literature review was adopted. The investigation took place during the months of January and February 2022 in electronic databases such as Medline, PubMed, VHL, and MDPI. Studies in Portuguese, English, and Spanish were included. The results reveal that several classes of drugs have antibiotic activity both in vitro and in vivo, such as the antihypertensive drug amlodipine, psychomodulators such as fluoxetine and thioridazine, and anti-inflammatory drugs such as ibuprofen. However, not everyone has an elucidated hypothesis of the reason for such an effect. Some of the mechanisms pointed out by the consulted authors were damage to the cell wall, modification of the permeability of porin proteins, and the inhibition of sliding hairpins that act with DNA polymerase. A synergistic effect was also identified. In conclusion, the antibacterial potential of pharmacological redirection is promising, with emphasis on anti-inflammatory, psychotropic, and cardiovascular intervention drugs. There is a need to deepen investigations on the mechanisms of action of the compounds already investigated, suggesting that the research of phases II and III be developed, as well as investigations of other pharmacological classes little explored. Full article
4 pages, 431 KiB  
Proceeding Paper
Methicillin-Resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) in Skin Infections from Company Animals in Portugal (2013–2021)
by Andreia Garcês, Augusto Silva, Ricardo Lopes, Filipe Sampaio, Daniela Duque and Paula Brilhante-Simões
Med. Sci. Forum 2022, 12(1), 24; https://doi.org/10.3390/eca2022-12689 - 15 Jun 2022
Cited by 3 | Viewed by 860
Abstract
This study aimed to investigate methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) in pyodermas admitted to the INNO Veterinary Laboratory (Braga, Portugal) in the period 2013–2021. From a total of 730 samples that tested positive for bacterial growth, 101 (13.8%) were [...] Read more.
This study aimed to investigate methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) in pyodermas admitted to the INNO Veterinary Laboratory (Braga, Portugal) in the period 2013–2021. From a total of 730 samples that tested positive for bacterial growth, 101 (13.8%) were S. pseudointermedius and 27 (3.7%) were S. aureus. The isolate tested for oxacillin n = 6 was MRSP, and for n = 4, it was MRSA. The presence of MRSA or MRSP in small animals indicates that they are part of the animal–human–environment transmission ‘triangle’, which should lead us to think of this issue as a public health problem. Full article
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7 pages, 2058 KiB  
Proceeding Paper
Combinations and Risks of Drug Interactions in Patients Admitted to a University Hospital in a Northeastern Brazilian State
by Sara Maria Gomes Bié, Felipe Lemos Esteves do Amaral, Rafael Rodrigues Leite, Sandriny Maria de Almeida Oliveira, Maria Fernanda Bandeira da Silva, Natália Bitu Pinto and Sávio Benvindo Ferreira
Med. Sci. Forum 2022, 12(1), 28; https://doi.org/10.3390/eca2022-12750 - 16 Jun 2022
Viewed by 817
Abstract
A drug is defined as a substance capable of influencing biological functions through chemical reactions, either by agonism or antagonism, to achieve the desired therapeutic effect. During this process, several pharmacokinetic and pharmacodynamic events occur, which can be potential sites for drug interactions [...] Read more.
A drug is defined as a substance capable of influencing biological functions through chemical reactions, either by agonism or antagonism, to achieve the desired therapeutic effect. During this process, several pharmacokinetic and pharmacodynamic events occur, which can be potential sites for drug interactions to occur. For patients undergoing hospital treatment, drugs of different classes are usually prescribed, and it is necessary to understand the risk of interactions between these drugs and their possible change in therapeutic efficacy or safety. Therefore, the study sought to identify the main classes of drugs, and their combinations, used in the treatment of pneumonia in pediatric patients at a teaching hospital in Brazil. This is a cross-sectional, retrospective and descriptive study, from September 2017 to December 2020, based on data obtained from medical records provided by the Júlio Bandeira University Hospital. Regarding the most used antibiotics in the analyzed period, we reported the following drugs: ampicillin (61.76%) and azithromycin (23.53%) in 2017; ampicillin (41.04%) and ceftriaxone (23.51%) in 2018; ampicillin (45.70%) and ceftriaxone (25.50%) in 2019; ceftriaxone (39.20%) and azithromycin (31.49%) in 2020. The main combinations identified in the study were as follows: dipyrone and fenoterol (60.70%), dipyrone and hydrocortisone (47.92%), dipyrone and ondansetron (34.66%) and dipyrone, hydrocortisone and fenoterol (37.38%). It is important to highlight that 58 different drugs were found in the prescriptions of this period, alerting us to the possibility of drug interactions of various types. In view of this, it is possible to highlight the combination of azithromycin and ondansetron as a potentially moderate risk of drug interaction, since both increase the QT interval, (The measurement from the beginning of the QRS complex to the end of the T wave), requiring patient monitoring by means of ECG (electrocardiogram). Therefore, an in-depth analysis of these data may be useful to prepare technical material and assist in therapeutic decision-making, improving the quality of prescriptions and the patient’s clinical response, adopt even more effective conducts and as close to what is expected from the pharmacological characteristics of drugs. Full article
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7 pages, 1598 KiB  
Proceeding Paper
Antibiotic Prescriptions in Pediatric Patients Hospitalized with Pneumonia at a University Hospital
by Rafael Rodrigues Leite, Felipe Lemos Esteves do Amaral, Sara Maria Gomes Bié, Maria Fernanda Bandeira da Silva, Sandriny Maria de Almeida Oliveira, José Dilbery Oliveira da Silva and Sávio Benvindo Ferreira
Med. Sci. Forum 2022, 12(1), 31; https://doi.org/10.3390/eca2022-12690 - 15 Jun 2022
Viewed by 839
Abstract
Community-acquired pneumonia (CAP) is the leading cause of hospitalization in the Brazilian Unified Health System, with a mortality rate of 18% in children under 5 years of age. Therefore, there is a need for an effective treatment, including antibiotic therapy, based on the [...] Read more.
Community-acquired pneumonia (CAP) is the leading cause of hospitalization in the Brazilian Unified Health System, with a mortality rate of 18% in children under 5 years of age. Therefore, there is a need for an effective treatment, including antibiotic therapy, based on the main causative agents of the infection. However, there is a risk of the development of bacterial resistance, making it necessary to monitor this use in order to reduce the speed of emergence of multidrug-resistant strains. Thus, this study aims to verify the profile of antibiotic use in children and adolescents treated at a Brazilian university hospital. The research consists of a cross-sectional retrospective and descriptive study based on data obtained from medical records provided by the institution, after approval by the ethics committee, and organized in Excel spreadsheets, covering the period from September 2017 to December 2020. It was observed that the profile of this group of patients consisted of: a female prevalence in 2017 and 2020 (59% and 57% respectively); while in the years 2018 and 2019, males were higher, 52% and 59%. Regarding age, the age group from 3 months to 4 years was predominant (59.64%). Regarding the use of antibiotics by age group, the following data were found: up to 3 months, the most used were ampicillin (44%) and azithromycin (24.25%); from 4 months to 4 years, ampicillin (32.9%), ceftriaxone (31.7%) and azithromycin (25.9%); and over 5 years, ceftriaxone (33.8%), ampicillin (29.95%) and azithromycin (22.22%). Thus, when comparing the profile found with that recommended by the protocol adopted by the hospital, we can conclude, with the data analyzed, that there is negligence in the prescription of antimicrobials in the treatment of pediatric CAP, which may corroborate the growth of bacterial resistance, longer hospital stays and, as a result, greater expenditure on care and a reduced favorable clinical outcome. Full article
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8 pages, 986 KiB  
Proceeding Paper
In Silico Analysis and PCR Characterization of non-Tn4401 Transposable Elements in Pseudomonas aeruginosa
by Julián Ruiz-Castellanos, Ricaurte Alejandro Márquez-Ortiz, Deisy Abril, Daniela Forero Hurtado, Ginna Tíjaro, Zayda Corredor-Rozo, Javier Escobar-Pérez and Natasha Vanegas
Med. Sci. Forum 2022, 12(1), 33; https://doi.org/10.3390/eca2022-12738 - 15 Jun 2022
Viewed by 1185
Abstract
The multi-resistance presented by P. aeruginosa has greatly increased due to the presence of genes for carbapenemases such as blaKPC. The dissemination of this gene has been associated with the Tn4401, the main mobile genetic element that carries bla [...] Read more.
The multi-resistance presented by P. aeruginosa has greatly increased due to the presence of genes for carbapenemases such as blaKPC. The dissemination of this gene has been associated with the Tn4401, the main mobile genetic element that carries blaKPC in its structure. However, some non-Tn4401 elements (NTEKPC) associated with blaKPC have been found in different bacteria. Here, we characterized in silico and in vitro blaKPC-associated elements in P. aeruginosa. To identify these elements, a search algorithm was performed using NCBI databases; sequences were filtered and pair-aligned to describe the blaKPC genetic environment. Additionally, a PCR-based strategy was designed to target Tn4401 variants and NTEKPC groups and assessed in 61 Colombian clinical isolates. Using an in silico approach, 51 blaKPC-positive entries longer than 3kb (in the blaKPC upstream region) were found; from these, 72.7% carried an NTEKPC. On the PCR assay, Tn4401 was the most frequent element among the P. aeruginosa in Colombia. However, NTEKPC-IIf was presented on 29.5% of the isolates, in different genetic lineages and at least in four hospitals. These results show high NTEKPC prevalence in P. aeruginosa. Full article
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2 pages, 215 KiB  
Proceeding Paper
In vitro Synergistic Activity of Colistin-Based Antimicrobial Combinations against Extensively Drug-Resistant (XDR) Acinetobacter baumannii from a Tertiary Hospital in Greece
by Paraskevi Mantzana, Efthymia Protonotariou, Angeliki Kassomenaki, Maria Arhonti, Georgios Meletis, Olga Vasilaki, Georgia Kagkalou and Lemonia Skoura
Med. Sci. Forum 2022, 12(1), 37; https://doi.org/10.3390/eca2022-12735 - 15 Jun 2022
Viewed by 661
Abstract
Over the past years, Acinetobacter baumannii has emerged as a serious nosocomial pathogen especially due to its extensively resistant antimicrobial profile [...] Full article
6 pages, 398 KiB  
Proceeding Paper
The Utilization of Antibiotic, Incidence and Risk Aspects for Surgical Site Infections Amongst Surgical Patients
by Devendra Kumar Mishra, Shilpi Mishra, Archita Tiwari, Vishwanath Dubey, Sandeep Yadav and Savita Upadhyay
Med. Sci. Forum 2022, 12(1), 41; https://doi.org/10.3390/eca2022-12731 - 15 Jun 2022
Viewed by 612
Abstract
Surgical site infections (SSI) are one of the main healthcare-related infections in developing nations. Regardless of upgrades in surgical strategy and the utilization of best disease avoidance techniques, SSI stayed the significant reason for medical clinic obtained infections. Subsequently, the target of this [...] Read more.
Surgical site infections (SSI) are one of the main healthcare-related infections in developing nations. Regardless of upgrades in surgical strategy and the utilization of best disease avoidance techniques, SSI stayed the significant reason for medical clinic obtained infections. Subsequently, the target of this paper was to describe risk factors for SSI and the utilization of antibiotics to decrease the risk involved for the SSI. SSI is a possibly morbid and expensive complications of medical procedures. In this way, an underlying pursuit recognized various titles distributed in 2012–2022. Extracted data, including design of study and procedure, revealed combined occurrence and time taken as post-surgery until the beginning of SSI, and probabilities proportions and associated inconstancy for all variables considered in univariate and additionally multivariable investigations. In a wide survey of available works, risk factors for SSI were portrayed as depicting decreased wellness, patient fragility, medical procedure length, and intricacy. The occurrence of SSI was high in the review set. There were critical quantities of contributing variables to the event of surgical site infections. Recognition of risk factors habitually connected with SSI considers the identification of such patients with the best requirement for ideal protective actions to be recognized and pre-treatment before medical procedure. Full article
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6 pages, 1530 KiB  
Proceeding Paper
Off-Target Activity of Spiramycin Disarms Pseudomonas aeruginosa by Inhibition of Biofilm Formation, Pigment Production and Phenotypic Differentiation
by Matteo Calcagnile and Pietro Alifano
Med. Sci. Forum 2022, 12(1), 42; https://doi.org/10.3390/eca2022-12723 - 15 Jun 2022
Viewed by 688
Abstract
Spiramycin is a 16-membered macrolide used in human medicine as an antibacterial and antiparasitic agent. Spiramycin is effective against bacterial pathogens including Gram-positive and Gram-negative bacteria. In contrast, Pseudomonas aeruginosa is intrinsically resistant to macrolides including azithromycin and spiramycin. Despite the results of [...] Read more.
Spiramycin is a 16-membered macrolide used in human medicine as an antibacterial and antiparasitic agent. Spiramycin is effective against bacterial pathogens including Gram-positive and Gram-negative bacteria. In contrast, Pseudomonas aeruginosa is intrinsically resistant to macrolides including azithromycin and spiramycin. Despite the results of in vitro susceptibility tests, interest in macrolides in the treatment of some pseudomonal infections arose from both clinical and preclinical studies. For this reason, macrolides have drawn attention as adjunct therapy against chronic and/or biofilm-mediated P. aeruginosa infections. While most of the studies on the antivirulence activity of macrolides focus on erythromycin and its derivative azithromycin, there is no information on spiramycin. We used in vitro methods to test the ability of spiramycin to inhibit certain phenotypic features or traits associated with virulence in P. aeruginosa. Moreover, we tested spiramycin using Galleria mellonella as an in vivo model. Full article
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6 pages, 502 KiB  
Proceeding Paper
Evidence and Perspectives on the Use of Phlorotannins as Novel Antibiotics and Therapeutic Natural Molecules
by Javier Echave, Catarina Lourenço-Lopes, Lucia Cassani, Maria Fraga-Corral, Pascual Garcia-Perez, Paz Otero, Anxo Carreira-Casais, Rosa Perez-Gregorio, Sergio Baamonde, Fermín Fernández Saa, Jesus Simal-Gandara and Miguel A. Prieto
Med. Sci. Forum 2022, 12(1), 43; https://doi.org/10.3390/eca2022-12728 - 15 Jun 2022
Cited by 1 | Viewed by 890
Abstract
Multiple drug-resistant bacterial strains are showing new different mechanisms to overcome the antimicrobial action, which reduces the efficacy of conventional antibiotics. Therefore, drug discovery research has focused on developing fast, effective, and safe alternatives to prevent this multi-resistance. Phlorotannins are a diverse class [...] Read more.
Multiple drug-resistant bacterial strains are showing new different mechanisms to overcome the antimicrobial action, which reduces the efficacy of conventional antibiotics. Therefore, drug discovery research has focused on developing fast, effective, and safe alternatives to prevent this multi-resistance. Phlorotannins are a diverse class of polyphenols, secondary metabolites described in brown algae, that are mainly constituted of polymers of phloroglucinol and, depending on their linkage and structure, can be classified mainly as fucols, fucophlorethols, eckols, and phloroethols. These polyphenols have been described in both macro- and microalgae, suggesting that they can be recovered from a great variety of sources. Phlorotannins have been extensively described to possess several biological properties, foremost as antioxidant and antimicrobial compounds. Several in vitro reports have described that phlorotannins showed growth inhibition and bactericidal effects against Gram+ (e.g., Bacillus cereus, Streptococcus epidermidis, Staphylococcus aureus) and Gram− bacteria (e.g., Salmonella sp., Campylobacter jejuni, Pseudomonas aeruginosa), also including antibiotic-resistant strains such as MRSA. Although the mechanisms of action of this group of compounds has not been fully elucidated, tannins could interact with membrane proteins and key metabolic enzymes, impeding bacterial growth and resulting in membrane lysis. Moreover, different phlorotannins were able to inhibit bacterial biofilm formation, production of quorum-sensing molecules, and also viral replication (e.g., influenza). Few in vivo studies support their effectiveness as antibiotics, whereas clinical trials studying other properties consistently report high bioavailability and null toxicity of phlorotannins. Considering current evidence, phlorotannins could be considered as interesting candidates for antibiotic therapy clinical trials. The diversity of these natural compounds provides a promising gateway for researchers and the pharmaceutical industry to develop novel nontoxic, cost-effective, and highly efficient antibacterial formulations with a broad scope of applications. Full article
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