Search Results (1,709)

Objectives: To evaluate the in vitro antimicrobial activity of TiAB, a compound based on silver-bound titanium dioxide, against clinical isolates from dermatological infections. Methods: We tested 155 strains clinically isolated from ulcers and skin infections, including MRSA, ESBL-producing Enterobacterales, and P. aeruginosa. MIC and MBC values were determined using broth microdilution according to CLSI guidelines. Time-kill assays were performed at 0.5×, 1×, and 2× MIC. Median values were used to describe susceptibility profiles. Results: TiAB exhibited strong bactericidal activity against Gram-negative bacteria, including ESBL-positive E. coli and K. pneumoniae, with complete killing at 2× MIC (4–8%) within 4–8 h. Gram-positive pathogens exhibited higher MICs (≥8%) and limited response within 24 h; however, extending exposure to 48 h resulted in enhanced activity. Conclusions: TiAB exhibited in vitro bactericidal activity with median MIC values ranging from 1% to 2% (w/v) against Gram-negative clinical isolates such as E. coli and P. aeruginosa, and 2% to 4% against Gram-positive strains including MRSA. Time-kill assays confirmed ≥3 log₁₀ CFU/mL reductions for Gram-negative bacteria at 2× MIC within 24 h. These results suggest TiAB’s potential as a topical antimicrobial agent, though further in vivo studies are needed to validate its safety and efficacy. Full article

Background: Cellulosimicrobium, formerly known as the Oerskovia genus, is a Gram-positive organism known for its characteristic bright yellow colonies. While abundant in nature, it is very rarely linked to pathogenesis in humans. While there is no classical presentation for Cellulosimicrobium-associated infections, cases tend to be foreign body-related or involve immunocompromised patients. Rates of Cellulosimicrobium-associated infections have been hypothesised to rise in the future, due to rising numbers of immunocompromised patients in the community and increasing usage of foreign bodies such as prostheses and long-term catheters. Existing technical difficulties regarding misidentifying cultures as other species (often other coryneforms) may also play a significant role in the low number of documented cases, and this may change in the near future with diagnostic advancements such as whole genomic sequencing. Case Presentation: A 57-year-old immunocompetent Irish male presented with concomitant neck and lung masses. Notably, this was found to be directly following a recent dental procedure. During extensive investigations, Cellulosimicrobium was isolated from biopsied lung tissue using 16S ribosomal ribonucleic acid gene-sequencing analysis. The patient was treated with long-term oral amoxicillin and safely discharged, with both masses showing measurable reductions in size on subsequent imaging. Conclusions: Should Cellulosimicrobium represent the causative pathological organism in this case, then we believe this to represent a potential novel documented presentation of the organism’s pathogenesis in humans. We provide detailed discussion surrounding the successful management of this patient and the evaluation of the evolving differential diagnosis throughout this case. Full article

Background/Objectives: Children and adolescents with haematologic malignancies or other causes of immunosuppression are at high risk of severe infections. Determining the probability of Gram-negative bacilli bloodstream infections (GNB-BSI) within 24 h of blood culture (BC) incubation could support early antibiotic de-escalation, compared to the current guidelines recommending de-escalation after 48–72 h. Methods: Retrospective, observational single-centre study describing BC time-to-positivity (TTP) in GNB-BSI in a paediatric cohort of immunocompromised children. Results: In 128 episodes (100 patients), TTP was less than 24 h in >95% cases. TTP did not differ based on sex, underlying disease, degree of neutropenia, or PICU admission. Antibiotic initiation prior to BC collection and microbiological aetiology (microbiological aetiology different from Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, or Enterobacter cloacae) were the only identified risk factors associated with BC growth beyond 24 h. No patients with late BC growth died or required PICU admission. Conclusions: If BC remains negative after 24 h of incubation, GNB-BSI is unlikely in immunocompromised children and adolescents with fever. These results support early de-escalation strategies, shortening unnecessary exposure to broader-spectrum antibiotics, and potentially decreasing adverse events and costs. Full article

If untreated, skin wounds can lead to severe complications. Depending on the type of injury, long-term antibiotic administration is often required, and this decreases patient compliance. This limitation could be addressed by applying dressings capable of preventing infections by controlling drug release to the wound site. In this research, biodegradable wound dressings were investigated, based on natural polymers chitosan and alginate and incorporating the broad-spectrum gentamicin as antibiotic. Specifically, gentamicin was loaded into alginate nanoparticles, which were then loaded into chitosan-based films. This approach aimed at obtaining a system capable of modulating antibiotic release. The obtained nanoparticles had an average diameter of 86 nm and polydispersity index of 0.15. Antibiotic loading was around 600 µg/mg, with loading efficiency close to 100%. Films incorporating nanoparticles were compared to control films, which contained only gentamicin. Results showed that nanoparticles incorporation decreased film’s swelling in phosphate buffer saline, thus leading to a decrease in burst release while cytocompatibility for human dermal fibroblasts was maintained. Antibacterial activity was confirmed against both gram-positive and gram-negative bacteria. Moreover, the antibiotic was released as a function of pH, with distinct behavior at pHs ranging from 7.4 to 5.5. This indicates that alginate nanoparticles dispersed in chitosan films effectively release gentamicin on demand. Full article

Propolis, also known as bee glue, is a natural resinous mixture produced by Western honeybees and has long been recognized for its potential therapeutic properties. Recent research has focused on its diverse bioactivities, particularly its antimicrobial effects against a broad spectrum of microorganisms, including human but also animal pathogens. However, further investigation is required to fully elucidate the pharmacological properties and potential toxicity of propolis to support its broader application. This study investigated the antimicrobial efficacy and safety of an ethanol extract of Portuguese propolis collected from the Gerês region (G23.EE). The antimicrobial activity was assessed in vitro against both Gram-positive and Gram-negative bacteria associated with infections in companion animals, using the agar dilution method. To evaluate potential toxicity, the extract was administered via injection and topical application in an in vivo Galleria mellonella larval model, with health parameters monitored over a 96 hours period. The in vitro results showed that G23.EE was more effective against Gram-positive bacteria, including Staphylococcus spp. (e.g., S. felis, S. hominis, S. simulans, and S. pseudintermedius; MIC = 0.5 mg/mL) and Enterococcus faecium (MIC = 1.5 mg/mL), than against Gram-negative bacteria, such as Escherichia coli and Klebsiella oxytoca (MIC > 8.0 mg/mL). No significant adverse effects were observed in G. mellonella larvae following injection or brushing with propolis extract concentrations up to 8.0 mg/mL. Overall, these findings suggest that Portuguese propolis from Gêres is a promising, safe, and effective natural antimicrobial agent for targeting Gram-positive bacterial infections in companion animals. Full article

Background: Severe sepsis and septic shock remain major contributors to ICU mortality. Polymyxin B hemoperfusion (PMX-HP) has been widely adopted as adjunctive therapy in Asian ICUs for endotoxemia, but its real-world effectiveness and prognostic factors remain uncertain, especially in high Gram-negative settings. Methods: This retrospective cohort study included 64 adult patients with severe sepsis or septic shock who received at least one session of PMX-HP in a 25-bed tertiary medical ICU in Taiwan between July 2013 and December 2019. Demographic, clinical, microbiological, and treatment data were extracted. The primary outcome was 28-day mortality. Prognostic factors were analyzed using logistic regression. Results: The mean age was 66.1 ± 12.3 years; 67.2% were male. Pneumonia (29.7%) and intra-abdominal infection (18.8%) were the most common sources of sepsis, with E. coli and K. pneumoniae as leading pathogens. Median APACHE II score at ICU admission was 26 (IQR 21–32), and 79.7% received two PMX-HP sessions. The 28-day mortality rate was 46.9%, with ICU and hospital mortality both 53.1%. Non-survivors were older, had higher APACHE II scores, and more frequent use of continuous renal replacement therapy (CRRT). Positive changes in vasoactive-inotropic score (VIS) after PMX-HP were also more common among non-survivors. Multivariate analysis identified advanced age, higher APACHE II score, and CRRT requirement as independent predictors of mortality. Conclusions: In this real-world Asian ICU cohort, PMX-HP was used mainly for severe cases with a high disease burden and Gram-negative predominance. Despite its frequent use, overall mortality remained high. Prognosis was primarily determined by underlying disease severity, organ dysfunction (especially renal failure), and persistent hemodynamic instability. In this high-severity cohort, mortality appeared to be primarily driven by baseline organ dysfunction and persistent hemodynamic instability; PMX-HP session number or sequencing showed no association with survival. Given the absence of a contemporaneous non-PMX-HP control group, mortality observations in this cohort cannot be causally attributed to PMX-HP and should be interpreted with caution as hypothesis-generating rather than definitive evidence of efficacy. Further multicenter studies are needed to clarify the optimal role of PMX-HP in modern sepsis management. Full article

Background: Periprosthetic joint infections (PJIs) remain among the most challenging complications in orthopedic surgery, often requiring prolonged antibiotic therapy and complex surgical interventions. Oritavancin, a long-acting semisynthetic lipoglycopeptide approved for acute bacterial skin and skin structure infections, has emerged as a potential off-label agent in PJI treatment due to its favorable pharmacokinetic properties, potent Gram-positive coverage, and documented antibiofilm activity. Objectives: This comprehensive review aims to assess the current clinical and preclinical data regarding the potential use of oritavancin in the management of PJIs. Methods: A comprehensive literature search was conducted in three major databases. Results: Six studies were included. In vitro data demonstrated strong activity of oritavancin against methicillin-resistant Staphylococcus aureus and S. epidermidis biofilms, particularly in synergy with rifampin. Clinical reports described successful outcomes in both acute and chronic PJI cases, including those with limited surgical options. Weekly or monthly dosing regimens were well-tolerated and effective in suppressive and curative contexts. Adverse events were infrequent but included infusion-related reactions. Conclusions: Oritavancin represents a promising adjunct or alternative to conventional antimicrobial regimens in PJIs, particularly for outpatient management or in patients with multidrug-resistant Gram-positive infections. Further prospective studies are needed to define its role, optimal dosing, and long-term efficacy in this complex clinical setting. Full article

Toxic shock syndrome (TSS) is a serious, often fatal disease, rarely occurring in dogs via infection with Staphylococcus and Streptococcus. The development of TSS is mainly dependent on the presence of bacterial toxins recognized to be potent superantigens causing the release of massive amounts of host inflammatory cytokines, notably TNF-α, progressing to high fever, hypotension, haemoconcentration, thrombosis and neutrophil and endothelial activation with multiple organ failure. Rarely, TSS is associated with erythematous and exfoliative dermatitis progressing to ulceration with extremely extensive dermo-epidermal detachment, which is often very painful. Like in humans, very little is known about the transmission and prevention of this condition. In our paper, a case of TSS-like caused by a mixed bacterial infection with Staphylococcus aureus, Streptococcus halichoeri and Dermatophilus spp. has been described in an 11 year-old, cross-breed male dog, most probably following injury due to biting and fighting. Lesions consisted of severe and diffuse ulceration on the dorsum, and bacterial culture/cytology led to the isolation and identification of Gram-positive staphylococci and streptococci associated with an intense neutrophil reaction. Dermatophilus spp. was presumed morphologically based on cytological preps, not by culture or molecular analysis. PCR demonstrated the presence of the nuc thermonucleaze gene (for S. aureus confirmation) together with the genes encoding enterotoxin H (seh), protein A (spa), toxic shock syndrome toxin TSST-1 (tst) and methicillin resistance (mecC); the exfoliative toxins (eta, etb) were detected. Clinical signs, cytology, bacterial culture and the response to systemic antibiotic therapy were compatible with a TSS-like diagnosis. The patient has completely recovered after 1 year of treatment. Full article

Bartonella spp. is a Gram-negative bacterium transmitted by arthropod vectors, implicated in a range of zoonotic infections affecting both humans and animals. Among zoonotic species, B. henselae is primarily associated with domestic cats and B. vinsonii with dogs. In Italy, Bartonella infections have been reported in both southern and northern regions. This study investigates the presence of Bartonella spp. in fleas and ticks collected from companion animals in Piedmont region, northwestern Italy. A total of 176 flea and 85 tick specimens were obtained from 92 animals (dogs and cats) between May 2018 and February 2020. Arthropods were morphologically identified using identification keys, and screened for Bartonella DNA by PCR targeting the 16s rRNA gene. Positive samples were further analyzed by amplifying the rpoB gene. Selected 16s-positive and all rpoB-positive samples were sequenced and subjected to phylogenetic analysis. Fleas were mostly identified as Ctenocephalides felis, recovered from 44 cats and 12 dogs; a single C. canis specimen was found in one cat. Ticks were Ixodes ricinus (from 14 cats and 10 dogs), Rhipicephalus sanguineus s.l. (3 cats, 7 dogs), and Dermacentor marginatus (one dog). Bartonella prevalence was 38.4%, with 34.2% positivity in fleas and 45.6% in ticks. All sequences corresponded to B. henselae. These findings confirm the active circulation of B. henselae in ectoparasites of pets and raise questions about the potential role of ticks in its transmission. Full article

Background/Objectives: Infections after stroke are a serious medical problem and have a significant impact on the outcome of stroke, but data regarding the Asian population are limited. This study aims to determine the bacterial and fungal profile of pathogenic organisms of infections after acute ischemic stroke (AIS). Methods: This is a retrospective study using the medical records of patients at least 18 years old who were hospitalized with AIS in a tertiary stroke hospital from 1 January 2018 to 31 December 2022. Demographic, patient-related, and other examination data were extracted from hospital medical records. Infections after AIS were defined as any infection that developed during the acute phase of ischemic stroke and was confirmed by microbiologic culture as the gold standard. Factors associated with infection were analyzed using multiple logistic regression. Results: Among 599 AIS patients with infection who underwent microbiologic culture, the prevalence of infection with an isolated pathogen was 21.4%, and most organisms were from sputum. Positive microbiologic culture revealed that bacteria such as K. pneumoniae, E. coli, A. baumannii, and S. aureus were the most common causes of infection, while fungi were rare. During the COVID-19 period, bacteria developed resistance to antimicrobials, including β-lactamase antibiotics for Gram-negative bacteria and methicillin for Gram-positive bacteria. Care in the intensive ward, including the stroke unit, reduced the risk of a positive microbiological culture in the COVID-19 and non-COVID-19 period. Urinary catheters promoted infections in the non-COVID-19 period, whereas steroids, total parenteral nutrition, and tracheostomy were negatively associated with infections after AIS in the COVID-19 period. Conclusions: The prevalence and factors associated with infection after stroke changed during the COVID-19 period. The risk of infection after stroke requires preventive measures such as early dysphagia screening. Full article

Introduction: Staphylococcus aureus is a high-priority foodborne pathogen contributing to several food poisoning outbreaks. Methicillin- and vancomycin-resistant S. aureus (MRSA and VRSA), pose significant public health concerns due to their potential for serious illness, antibiotic resistance, and transmission within both healthcare and community settings. These bacteria can cause numerous infections, ranging from skin and soft tissue infections to life-threatening conditions like bloodstream infections, pneumonia, and endocarditis. Although several publications are concerned with Staphylococcus aureus contamination in ready-to-eat (RTE) food products, little published data is available about its prevalence in pizza, which is widely distributed and consumed worldwide. Methods: The current study is intended to determine the prevalence, virulence genes, and antimicrobial resistance profiles of S. aureus in three hundred ready-to-eat pizza samples (100 each of meat, chicken, and canned tuna pizzas) collected from different restaurants in Mansoura City, Egypt. The typical colonies on Baird–Parker selective agar supplemented with egg yolk tellurite emulsion were counted and further confirmed based on Gram staining, coagulase testing, catalase testing, carbohydrate fermentation, and thermostable nuclease production. The genomic DNA of the confirmed coagulase-positive isolates was prepared and subjected to PCR analyses for detecting the nuc gene, mecA (methicillin resistance gene), and vancomycin resistance gene (vanA), as well as six selected S. aureus virulence genes: sea, seb, sec, sed, hla, and tsst. The antimicrobial resistance profile of the S. aureus isolates was determined against 16 antimicrobial agents belonging to six classes using the agar disc diffusion method according to the Clinical and Laboratory Standards Institute guidelines (CLSI), except for oxacillin and vancomycin, which were assessed using the MIC test. Results: The results revealed that 56% (56/100), 56% (56/100), and 40% (40/100) of chicken, meat, and canned tuna pizzas were positive for S. aureus, with an overall prevalence of 50.7% (152/300). All 560 isolates (100%) were verified as S. aureus based on molecular confirmation of the nuc gene. Interestingly, 48.6% (272/560) and 8.6% (48/560) of the isolates tested were identified as methicillin- and vancomycin-resistant S. aureus (MRSA and VRSA) through detection of mecA and vanA genes, respectively. Among the S. aureus isolates tested, the hla gene was detected in 87.1% (488/560), while the enterotoxin genes sea, seb, sec, and sed were identified in 50% (280/560), 78.6% (440/560), 9.8% (55/560), and 24.5% (137/560) of isolates, respectively. All recovered isolates (n = 560) were classified as multidrug-resistant and were resistant to penicillin, oxacillin, and ampicillin. Moreover, 77% (431/560), 24% (134/560), 8% (45/560), and 8.6% (48/560) of isolates were resistant to cefotaxime, ciprofloxacin, azithromycin, and vancomycin, respectively. Conclusions: The current study emphasizes that ready-to-eat pizza is highly contaminated with multidrug-resistant S. aureus, highlighting the urgent need for rationalizing antibiotic use in both veterinary and human medicine to prevent the transmission of resistant bacteria through the food chain. Additionally, strict adherence to good hygienic practices throughout all stages of the food chain is essential to minimize overall contamination and enhance food safety. Full article

Chronic wounds pose a great challenge due to their slow healing and susceptibility to infections, hence the need for innovative alternatives to conventional antibiotics, as increasing bacterial resistance limits the efficacy of current treatments. This paper addresses the development of novel electrospun membranes based on polyvinyl alcohol (PVA) and sodium alginate, incorporating therapeutic ZnO and bioglass (54SiO₂:40CaO:6P₂O₅) nanoparticles. While nanocomposites presented smaller fiber diameters than pure polymers, ternary nanocomposites displayed higher values, e.g., in porous areas, values were in the ca. 80–240 nm range and 0.06–0.60 μm², respectively. The Young’s modulus of the PVA/SA membrane, initially 15.9 ± 2.0 MPa, decreased by 65% with 10 wt.% ZnO NPs, whereas 10 wt.% BG NPs increased it by 100%. The membranes demonstrated efficacy against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) isolated from a human wound secretion, as well as two ATCC strains: Staphylococcus aureus and Staphylococcus epidermidis. A cell viability assay conducted with HaCaT cells demonstrated nearly complete survival following 72 h of membrane exposure. Their combined Gram-positive antibacterial activity and cytocompatibility support their potential application as biofunctional dressings for the management of chronic and hospital-acquired topical infections, while also contributing to the global effort to combat antibiotic resistance. Full article

Background/Objectives: Hemodialysis catheter-related bloodstream infection (HD-CRBSIs) is a main cause of morbidity in hemodialysis. New preventive strategies have emerged, such as using lock solutions with antiseptic or antibiotic capacity. In this study, the antimicrobial effect was analyzed in vitro and with a catheter model of lock solutions of gentamicin (LSG), gentamicin/heparin (LSG/H), and gentamicin/citrate (LSG/C) in clinical and ATCC strains of Pseudomonas aeruginosa and Staphylococcus aureus. Methods: The formation, minimum inhibitory concentration, and minimum inhibitory concentration of the biofilm and minimum biofilm eradication concentration of the lock solutions were determined. Additionally, colony-forming unit assays were performed to evaluate the antimicrobial efficacy of the lock solutions in a hemodialysis catheter inoculation model. Results: The minimum inhibitory concentration (MIC) of planktonic cells of both P. aeruginosa and S. aureus for LSG/H and LSG/C was 4 µg/mL. In the minimum biofilm inhibitory concentration (MBIC) tests, the LSG/H was less effective than LSG/C, requiring higher concentrations for inhibition, contrary to the minimum biofilm eradication concentration (MBEC), where LSG/H was more effective. All lock solutions eradicated P. aeruginosa biofilms in the HD catheter model under standard conditions. Nevertheless, under modified conditions, the lock solutions were not as effective versus ATCC and clinical strains of S. aureus. Conclusions: Our analysis shows that the lock solutions studied managed to eradicate intraluminal mature P. aeruginosa in non-tunneled HD catheters under standard conditions. Biofilm inhibition and eradication were observed at low gentamicin concentrations, which could optimize the gentamicin concentration in lock solutions used in HD catheters. Full article

Background/Objective: Staphylococcus aureus (S. aureus) is a clinically significant pathogenic bacterium. Daptomycin (DAP) is a cyclic lipopeptide antibiotic used to treat infections caused by multidrug-resistant Gram-positive bacteria, including S. aureus. However, DAP currently faces clinical limitations due to its short half-life, toxic side effects, and increasingly severe drug resistance issues. This study aimed to develop a biomimetic nano-drug delivery system to enhance targeting ability, prolong blood circulation, and mitigate resistance of DAP. Methods: DAP-loaded chitosan nanocomposite particles (DAP-CS) were prepared by electrostatic self-assembly. Macrophage membrane vesicles (MM) were prepared by fusion of M1-type macrophage membranes with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). A biomimetic nano-drug delivery system (DAP-CS@MM) was constructed by the coextrusion process of DAP-CS and MM. Key physicochemical parameters, including particle diameter, zeta potential, encapsulation efficiency, and membrane protein retention, were systematically characterized. In vitro immune escape studies and in vivo zebrafish infection models were employed to assess the ability of immune escape and antibacterial performance, respectively. Results: The particle size of DAP-CS@MM was 110.9 ± 13.72 nm, with zeta potential +11.90 ± 1.90 mV, and encapsulation efficiency 70.43 ± 1.29%. DAP-CS@MM retained macrophage membrane proteins, including functional TLR2 receptors. In vitro immune escape assays, DAP-CS@MM demonstrated significantly enhanced immune escape compared with DAP-CS (p < 0.05). In the zebrafish infection model, DAP-CS@MM showed superior antibacterial efficacy over both DAP and DAP-CS (p < 0.05). Conclusions: The DAP-CS@MM biomimetic nano-drug delivery system exhibits excellent immune evasion and antibacterial performance, offering a novel strategy to overcome the clinical limitations of DAP. Full article

Foodborne illness caused by bacterial pathogens is a global health concern and results in millions of infections annually. Therefore, food products typically undergo several processing stages, including sanitation steps, before being distributed in an attempt to remove pathogens. However, many sanitation methods have compounding effects on the color, texture, flavor, and nutritional quality of the product or do not effectively reduce the pathogens that food can be exposed to. Some bacterial pathogens particularly possess traits and tactics that make them even more difficult to mitigate such as biofilm formation. Non-thermal plasma sanitation techniques, including plasma-treated water (PTW), have proven to be promising methods that significantly reduce pathogenic bacteria that food is exposed to. Published work reveals that PTW can effectively mitigate both gram-positive and gram-negative bacterial biofilms. This study presents a novel analysis of the differences in antimicrobial effects of PTW treatment between biofilm-forming gram-positive bacteria, commonly associated with foodborne illness, that are sporulating (Bacillus cereus) and non-sporulating (Listeria monocytogenes). After treatment with PTW, the results suggest the following hypotheses: (1) that the non-sporulating species experiences less membrane damage but a greater reduction in metabolic activity, leading to a possible viable but non-culturable (VBNC) state, and (2) that the sporulating species undergoes spore formation, which may subsequently convert into vegetative cells over time. PTW treatment on gram-positive bacterial biofilms that persist in food processing environments proves to be effective in reducing the proliferating abilities of the bacteria. However, the variance in PTW’s effects on metabolic activity and cell vitality between sporulating and non-sporulating species suggest that other survival tactics might be induced. This analysis further informs the application of PTW in food processing as an effective sanitation method. Full article