Search Results (2,008)

Background/Objectives: Pseudomonas aeruginosa is an opportunistic pathogen frequently implicated in healthcare-associated infections, particularly ventilator-associated pneumonia and other device-related infections. The global emergence of carbapenem-resistant P. aeruginosa (CRPA) represents a major clinical challenge due to its limited therapeutic options and high mortality rates. Methods: Relevant clinical data were obtained from medical records. Isolates were identified via 16S PCR, and antimicrobial susceptibility testing was performed using the Vitek2 Compact system following CLSI guidelines. Carbapenemase genes (blaGES, blaKPC, blaIMP, blaNDM, blaVIM) were detected via PCR. Clonal relationships were determined via RAPD-PCR, and some sequence types were assigned according to the global P. aeruginosa MLST database. Results: In this study, 40 non-duplicate CRPA isolates were collected from 35 patients in a tertiary-care hospital in Mexico. Most isolates originated from adult patients, predominantly from tracheal aspirates (32.5%) and urine cultures (25.0%). Mechanical ventilation was the most common invasive device associated with infection, and the overall mortality rate reached 14.3%. Antimicrobial susceptibility testing showed that 95% of isolates exhibited a multidrug-resistant phenotype, with high resistance rates to ciprofloxacin (70.0%) and β-lactams. Carbapenemase genes were detected in 55% of isolates, mainly bla_IMP, bla_GES, and bla_VIM, either alone or in combination. Notably, this is the first report of ST309 (bla_IMP), ST411 (bla_GES + bla_IMP), and ST167 (bla_GES + bla_VIM) carrying carbapenemase genes in Mexico. Conclusions: These findings highlight the persistence and genetic diversity of CRPA circulating in hospital settings and emphasize the urgent need for strengthened genomic surveillance and infection control programs to prevent the spread of these high-risk multidrug-resistant clones. Full article

Background: Pseudomonas aeruginosa is one of the leading agents causing healthcare-associated infections (HAIs) due to its intrinsic resistance, its capacity to acquire resistance mechanisms, and its persistence in hospital environments. In Mexico, it ranks among the most frequently reported pathogens in national surveillance systems. The aim of this study was to characterize antimicrobial resistance profiles and the genetic determinants associated with MDR/XDR phenotypes in P. aeruginosa strains from HAIs at Hospital Juárez de México (HJM). Methods: Sixty-three strains from patients with HAIs were analyzed. Identification was confirmed by 16S rRNA gene sequencing. Antimicrobial susceptibility testing followed CLSI guidelines. MDR/XDR phenotypes were classified according to the Latin American consensus for categorizing MDR, XDR, and PDR pathogens. Screening for resistance mechanisms was carried out by PCR for the main β-lactamases circulating at HJM. Finally, mutations in the oprD gene were detected in imipenem-resistant isolates through amino acid sequence alignment. Results: Resistant phenotypes allowed the identification of MDR and XDR profiles. Only the metallo-β-lactamase bla_VIM was detected. Analysis of oprD porin sequences revealed recurrent mutations (S103T, T115K, L170F, G186P, and T189V) associated with imipenem resistance. Conclusions: In P. aeruginosa, the presence of bla_VIM and structural alterations in OprD confirms the multifactorial nature of carbapenem resistance. These findings underscore the need to strengthen microbiological surveillance programs and antimicrobial stewardship strategies to mitigate the impact and spread of MDR/XDR isolates. Full article

Bacterial infections remain a major challenge to human health, especially in wound healing, where they can cause prolonged inflammation, delayed recovery, and severe complications. Current research is increasingly focused on developing innovative antimicrobial materials capable of overcoming the limitations of conventional antibiotics, whose effectiveness has declined due to the rise in bacterial resistance. Among the various alternatives, silver nanoparticles have gained particular attention for their broad-spectrum antibacterial properties and have already been successfully applied in the functionalization of commercial wound dressings. The aim of this study was to optimize the functionalization of commercial cotton gauzes based on in situ UV-assisted reduction of silver nanoparticles, reducing methanol usage and identifying the minimal silver nitrate precursor concentration to achieve antimicrobial efficacy while maintaining biocompatibility. Different precursor concentrations were then evaluated through cytocompatibility assays (MTT, Live/Dead, and scratch tests on fibroblasts) and antimicrobial analyses against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus (including an antibiotic-resistant strain), and Candida albicans. The results demonstrated that a 0.5% w/w silver nitrate concentration provided strong antimicrobial and antibiofilm activity without compromising textile properties or cytocompatibility. Furthermore, this optimized process reduced material waste, highlighting its potential for scalable production of antimicrobial wound dressings. Full article

Urinary tract infections (UTIs) and urolithiasis exhibit a complex bidirectional relationship in which microbial colonization and urinary obstruction may mutually reinforce each other. This retrospective observational study evaluated clinical and microbiological factors associated with UTI in patients with urolithiasis using a large institutional dataset. A total of 23,241 urine cultures obtained from 12,708 unique patients were analyzed, comparing individuals with and without urolithiasis. In stone-forming patients, demographic variables, urine pH, hydronephrosis, ureteral double J stent presence and indwelling duration, urinary anomalies, and stone characteristics were assessed. Logistic regression identified independent associations, and ROC analysis defined optimal risk thresholds. UTI were more frequent in the stone group (34.5%) compared with non-stone forming patients (28.9%, p < 0.001). Escherichia coli was the most common uropathogen overall, whereas Klebsiella pneumoniae, Enterococcus faecalis, and Pseudomonas aeruginosa were significantly enriched in patients with stones. Elevated urine pH (OR: 6.37; CI: 2.67–15.19; p = 0.001) and hydronephrosis (OR: 9.14; CI: 3.74–22.35; p = 0.001) were independently associated with UTI. A stent dwell time above 29.5 days was associated with infection with 85% sensitivity and 54% specificity (AUC: 0.70; CI: 0.68–0.73), and urine pH 6.2 or higher was associated with infection with 86% sensitivity and 67% specificity (AUC: 0.77; CI: 0.75–0.80). These findings underscore that urine alkalinity, obstruction, and prolonged stenting are key factors associated with infection risk, supporting the need for careful stent management and timely microbiological evaluation in patients with urolithiasis. Full article

Antimicrobial resistance in urinary tract infections (UTIs) poses a critical public health challenge, yet comparative data between outpatient and inpatient settings remain limited, particularly in Latin America. This study characterized the epidemiology, microbiology, and resistance patterns of UTIs in northwestern Mexico. A retrospective analysis of 1041 patients with UTI (May–November 2024) was conducted. Microorganism identification and antimicrobial susceptibility were determined using the MicroScan WalkAway system in accordance with CLSI guidelines. Results: Outpatients accounted for 80.5% of cases and inpatients for 19.4%, with a 3.1% mortality rate. Escherichia coli predominated (62.9%), with a significant association with outpatients (p = 0.02), whereas Enterobacter cloacae, Acinetobacter spp., Candida tropicalis, and C. albicans were associated with inpatients (p < 0.05). Pediatric patients exhibited distinctive microbiological profiles: Pseudomonas aeruginosa (9.7% vs. 2.1%, p = 0.032), Enterococcus faecalis (33.3% vs. 16.2%, p = 0.001), and Staphylococcus epidermidis (26.6% vs. 6.5%, p = 0.027) were significantly more prevalent than in adults. Multidrug resistance (MDR) was detected in 27.1% of isolates, and extensive drug resistance (XDR) in 3.2%. XDR was associated with Gram-positive bacteria (12.2% vs. 1.4%, p < 0.001). Carbapenem-resistant Enterobacteriaceae (CRE) were identified in 0.9% (7/772) of cases, with 42.9% occurring in outpatients. Hospitalization (OR: 2.01; 95% CI: 1.43–2.83), surgical services (OR: 1.41; 95% CI: 1.02–1.97), and recent surgery (OR: 2.37; 95% CI: 1.04–5.39) were independent predictors of MDR/XDR infections. Conclusions: These findings demonstrate the emergence of CRE within the community and distinctive pediatric resistance patterns, underscoring the need for tailored antimicrobial stewardship strategies in this region. Full article

Jacquemontia pentantha (Jacq.) G. Don. (Convolvulaceae): This is a plant with rich ethnobotanical uses, but its essential oil (EO) composition and overall biological properties remain largely uninvestigated. In this research, the J. pentantha EO (JPEO) is characterized in a thorough manner, with an evaluation of its in vitro antioxidant, antimicrobial, and cytotoxic properties, aiming to provide scientific support for ethnobotanical uses, as well as the definition of new potentialities. The EOs were isolated from the aerial part of the plant via hydrodistillation, and a qualitative analysis of the components was carried out via GC–MS. The biological properties were investigated by means of standard in vitro assays: namely, DPPH and ABTS for the measurement of antioxidant activity, the disk diffusion technique, and the microbroth dilution assay for the evaluation of antimicrobial activity against six bacterial species, as well as for the assessment of the activity against five species of Candida fungi, whereas the cytotoxic activity against MCF-7 and HepG2 cells was assessed using the MTT assay. Preliminary characterization of the EOs via GC/MS revealed a particular “chemical profile” with a high concentration of himachalene-type sesquiterpenes, namely, β-himachalene (6.47%) and (+)-α-himachalene (6.46%), together with phenolic monoterpenoids. The EOs showed significant antioxidant activity (IC₅₀ = 172.41 and 378.94 µg/mL, respectively), high phenolic content (97.34 mg GAE/g), and significant antibacterial activity (MIC = 4.68 µg/mL), especially against Pseudomonas aeruginosa, as well as against Candida albicans (MFC = 3.90 µg/mL), together with dose-dependent cytotoxic effects on the two cell lines, with IC₅₀ = 161.62 and 151.87 µg/mL, respectively. This research indicates that the EO of this plant is a potential source of a certain “chemical profile” with noteworthy antibacterial and cytotoxic properties, thus providing scientific support for its ethnobotanical use and highlighting its particular potential for developing pharmaceutical agents against infections and cancer. Full article

Microbial biosurfactants (mBSs) are bioactive molecules with diverse applications, notably as antimicrobial agents against antibiotic-resistant pathogens. Produced by bacteria and yeasts, mBSs are classified as glycolipids, lipopeptides, polymeric, and particulate types. The global rise in multidrug-resistant organisms, such as Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, Pseudomonas aeruginosa, and Acinetobacter baumannii, underscores the urgent need for new antimicrobial strategies. mBSs disrupt microbial growth by interacting with the lipid components of pathogens, offering promising alternatives to conventional antibiotics. This review highlights the sources, chemical structures, and properties of mBSs, their antimicrobial activities, synergistic effects with antibiotics, and structure–activity relationships. Special emphasis is placed on surfactant modification, where targeted changes—such as valine substitution in surfactin—significantly lower critical micelle concentrations (CMC) and enhance antimicrobial potency. Such rational engineering demonstrates how biosurfactants can be tailored for improved biomedical performance while minimizing cytotoxicity. In parallel, artificial intelligence (AI) algorithms, including artificial neural networks and genetic algorithms, optimize yields, predict substrate suitability from agricultural residues, and guide microbial strain engineering. AI models can predict interfacial behavior and synchronize fermentation with purification. Advancing the understanding of mBS interactions with microbial membranes, combined with modification strategies and AI-guided optimization, is essential for developing targeted therapies against resistant infections. Future research should integrate these approaches to engineer novel derivatives, reduce costs, and validate clinical potential through comprehensive in vivo studies. Full article

Pseudomonas aeruginosa is a resilient Gram-negative pathogen frequently implicated in healthcare associated infections, particularly among immunocompromised individuals and those with chronic conditions such as cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), or cancer. It is well known for its high resistance to antibiotic treatment. This review briefly mentions P. aeruginosa’s resistance mechanisms, biofilm formation, and virulence factors, while primarily focusing on treatment challenges and recent advancements in therapeutic strategies aimed at overcoming resistance. Covered are novel non-antibiotic interventions such as quorum sensing inhibitors, quorum quenching agents, iron chelators, lectin and efflux pump inhibitors, as well as antimicrobial peptides and nanoparticles. Traditional medicine, phytochemicals, and probiotics are also evaluated. Additionally, this review explores the development of a viable vaccine, bacteriophage therapy, lactoferrin-hypothiocyanite combination, and topical use of electrochemical scaffolds. This review emphasizes the need for extensive safety studies and in vivo validation of these emerging non-antibiotic therapeutic strategies to determine their efficacy, pharmacological behavior, and clinical feasibility before they can be translated into practice. Many of these emerging treatments could play a vital role in future combination therapies by enhancing the efficacy of existing antibiotics and countering resistance and virulence mechanisms. Advancing these approaches from laboratory to clinical application remains a major challenge, making the development of approved therapies or vaccines a critical scientific and public health priority. Full article

Introduction: Temporary non-tunneled catheters are necessary in patients with chronic kidney disease requiring acute hemodialysis care, and complications associated with these catheters, such as infection and thrombosis, represent the most important sources of morbidity. There are no studies available that suggest the optimum duration of their use before catheter exchange or removal. This study aimed to explore the duration of temporary catheter insertion before the occurrence of catheter-related infection and mechanical complications in hemodialysis patients. Methods: Systematic searches were conducted according to the PRISMA 2020 guidelines on four databases up to 1 May 2025 (PROSPERO: CRD420251069657). The study outcome was the occurrence time to catheter-related infection and mechanical complications (thrombosis, obstruction, and kinking, causing dysfunction, failure, or insufficient blood flow) in days, pooled using a single-arm meta-analysis. Mean and 95% confidence interval (CI) were used as the summary statistics. Results: Nine studies involving 1448 participants undergoing hemodialysis using temporary catheters were included. Incidence of infection ranged from 0.7 to 13.58 per 1000 catheter-days. The most common bacterium identified was Staphylococcus aureus and Pseudomonas aeruginosa. The pooled mean time to catheter-related infection from 298 catheters was 15.98 days (95% CI 10.47–21.50; I² = 97.73%). We also found that the pooled mean time to mechanical complications from 507 catheters was 6.69 days (95% CI 2.49–10.90; I² = 98.03%). Conclusion: Among patients who developed complications, the mean time from temporary catheter insertion was approximately two weeks to the occurrence of catheter-related infection and one week to mechanical complications. Our finding was consistent with the recommendation of the KDOQI guideline, which suggests limiting catheter duration to typically less than two weeks. Full article

Multidrug resistance (MDR) in Gram-negative bacteria is a global issue and needs to be addressed urgently. MDR can emerge through genetic mutations and horizontal gene transfer and deteriorate under antibiotic selective pressure. The emergence of resistance to last-resort antibiotics, which are used to treat MDR bacteria, is of particular concern. Colistin has been recognized as a last-line antibiotic for the treatment of MDR Gram-negative bacterial infections caused by Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Recently, the increasing reports of colistin resistance pose a significant threat to public health, caused by both acquired and intrinsic mechanisms. The review aimed to elucidate the trends in colistin resistance, the use of colistin in human and veterinary medicine, underlying resistance mechanisms and transmission pathways, and potential mitigation of this emerging threat through novel intervention strategies. Colistin resistance is mediated by plasmid-encoded phosphoethanolamine transferases (mcr-1 to mcr-10) and chromosomal lipid A remodeling pathways. In Escherichia coli, resistance involves mcr-1–10, acrB efflux mutations, pmrA/pmrB, arnBCADTEF, and mgrB inactivation. Klebsiella pneumoniae exhibits mcr-1, mcr-8, mcr-9, mgrB disruption and phoP/phoQ–pmrAB activation. Acinetobacter baumannii harbors mcr-1–4, while Salmonella enterica and Enterobacter spp. carry mcr variants with arnBCADTEF induction. Therapeutic options include adjunct strategies such as antimicrobial peptides, nanomaterials, therapeutic adjuvants, CRISPR-Cas9-based gene editing, probiotics, vaccines, and immune modulators to restore susceptibility. This review identified that specific and wide actions are required to handle the growing colistin resistance, including genomic surveillance, tracing novel resistance mechanisms, and the application of alternative management strategies. The One Health approach is considered a key strategy to address this growing issue. Full article

Acinetobacter baumannii has been characterized by CDC, WHO and most National Healthcare Systems worldwide as a critical nosocomial pathogen, and classified as an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) pathogen. Mortality of invasive infections due to A. baumannii exceeds 40%. To highlight its impact on public health, ECDC has organized a special project on national lab co-ordination to accurately detect and report carbapenem-resistant strains, to identify epidemiological factors for infection (or colonization) with carbapenem-resistant A. baumanii at clonal and sub-genomic level. This review aims to describe the history, epidemiology, and evolution of resistance of A. baumannii, and stress the caveats associated with the management of systemic infections. Available active antimicrobials and drugs in the pipeline are listed, and available clinical evidence on their pharmacokinetics and efficacy in various types of infections are described. Clinician’s choice of treatment (drug, and monotherapy vs. combination treatment) depends on the patients’ profile, site of infection and antimicrobial resistance profile. Emphasis is laid on specific patient subpopulations, whose management is discussed. Full article

The growing global threat of antimicrobial resistance (AMR), particularly in cutaneous wound infections, represents a significant clinical and economic challenge. Biofilm formation by multidrug-resistant pathogens, such as Acinetobacter baumannii, often complicates healing and leads to therapeutic failure. Antimicrobial peptides (AMPs) are a promising alternative to conventional antibiotics due to their potent membrane-disrupting mechanism of action and lower propensity to induce resistance. Background/Objectives: This study aimed to evaluate the antibacterial, antibiofilm, and in vivo efficacy of four snake venom-derived cathelicidin-like peptides—Btn (15-34) and BotrAMP14 from Bothrops atrox, and Ctn (15-34) and CrotAMP14 from Crotalus durissus—against multidrug-resistant A. baumannii, Escherichia coli, and Pseudomonas aeruginosa clinical isolates from skin infections, with emphasis on A. baumannii, a WHO priority pathogen. Methods: Minimal Inhibitory Concentration (MIC), Minimal Bactericidal Concentration (MBC), and Minimal Biofilm Inhibitory Concentration (MBIC) were determined against A. baumannii, Escherichia coli, and Pseudomonas aeruginosa. Time-kill kinetics, hemolytic activity, and cytotoxicity assays were performed. A murine skin wound infection model was established to evaluate in vivo antibacterial efficacy and safety. Results: MIC/MBC values ranged from 0.78 to 25 µM against planktonic cells. In comparison, MBIC ranged from 1.56 to 12.5 µM against biofilms. BotrAMP14 eradicated A. baumannii within 4 min, while CrotAMP14 achieved bactericidal action in 20 min at 1.56 µM. Both peptides exhibited no hemolytic activity up to 128 µM and low cytotoxicity (IC₅₀ > 128 µM). In vivo, BotrAMP14 and CrotAMP14 demonstrated significant antibacterial activity at 24 h and 48 h post-infection, respectively, surpassing that of meropenem. Conclusions: These findings suggest that BotrAMP14 and CrotAMP14 are promising topical antimicrobial agents for managing multidrug-resistant skin infections and may help address the urgent need for alternative therapies against antibiotic-resistant pathogens. Full article

Background: Non-absorbable polyvinyl alcohol sponges (Merocel) are widely used in otolaryngology for nasal and ear packing but are prone to bacterial colonization and biofilm formation, which may increase infection risk and drive frequent use of systemic antibiotics. Sustained-release drug delivery systems enable prolonged local antiseptic activity at the site of packing while minimizing systemic exposure. Methods: We developed a sustained-release varnish containing chlorhexidine (SRV-CHX) and coated sterile Merocel sponges. Antibacterial, in vitro, activity against Staphylococcus aureus and Pseudomonas aeruginosa was evaluated using kinetic diffusion assays on agar, optical density (OD₆₀₀) measurements of planktonic cultures, drop plate, ATP-based viability assays, biofilm analysis by MTT metabolic assay, crystal violet bio-mass staining, high-resolution scanning electron microscopy (HR-SEM), and spinning disk confocal microscopy. Results: SRV-CHX-coated sponges produced sustained zones of inhibition on agar plates for up to 37 days against S. aureus and 39 days against P. aeruginosa, far exceeding the usual 3–5 days of clinical sponge use. Planktonic growth was significantly reduced compared with SRV-placebo, and a bactericidal effect persisted for up to 16 days for S. aureus and 5 days for P. aeruginosa before becoming predominantly bacteriostatic. Biofilm formation was markedly inhibited, with suppression of metabolic activity and biomass for at least 33 days for S. aureus and up to 16 days for P. aeruginosa. HR-SEM and confocal imaging confirmed sparse, discontinuous biofilms and predominance of non-viable bacteria on SRV-CHX-coated sponges compared with dense, viable biofilms on the placebo controls. Conclusions: Coating Merocel sponges with SRV-CHX provides prolonged antibacterial and anti-biofilm activity against clinically relevant pathogens. This strategy may reduce dependence on systemic antibiotics and improve infection control in nasal and ear packing applications in otolaryngology. Full article

Emerging antimicrobial resistance (AMR) in companion animals represents a global health concern as they serve as potential reservoirs for multidrug-resistant (MDR) bacteria, which can be transmitted to humans. Herein, we provide comprehensive surveillance data on resistance patterns in veterinary hospital settings, focusing on urinary tract infection. A total of 23 bacterial strains were isolated from urine specimens of hospitalized companion animals suspected of urinary tract infections (UTIs) between 2022 and 2024. 16S rRNA sequencing analysis revealed that Escherichia coli (47.8%), Klebsiella pneumoniae (21.7%), and Pseudomonas aeruginosa (8.7%) were predominant uropathogens. Minimum inhibitory concentration and minimum bactericidal concentration tests were employed to analyze AMR patterns across different classes of antibiotics. Moreover, antimicrobial susceptibility test exhibited 73.91% MDR according to the standard definition given by the Clinical and Laboratory Standards Institute (CLSI) M100 guidelines. Most Gram-negative bacteria have been shown to be resistant to beta-lactam antibiotics, especially carbapenems. Notably, an E. coli strain was confirmed to possess the bla_NDM-1 gene encoding the carbapenemase New Delhi metallo-β-lactamase. These findings support the implementation of targeted infection control measures and evidence-based treatment protocols to preserve antimicrobial efficacy in companion animal medicine to minimize potential public health risks through the One Health approach. Full article

Background/Objectives: Phages show efficacy against multidrug-resistant Pseudomonas aeruginosa, but limited host ranges require combining them in cocktails. In this work, we characterized 25 P. aeruginosa phages, developed therapeutic cocktails active against diverse clinical isolates, and tested phage efficacy in a mouse incisional wound model. Methods/Results: These phages represent seven genera, and genomic and phenotypic analyses indicate that 24/25 are lytic and suitable for phage therapy. Phage host ranges on a diversity panel of 156 P. aeruginosa strains that included 106 sequence types varied from 8% to 54%, and together the 24 lytic phages were active against 133 strains (85%). All of the phages reduced bacterial counts in biofilms. A cocktail of five lytic phages, WRAIR_PAM1, covered 56% of the strain panel, protected 100% of mice from lethal systemic infection (vs. 20% survival in the saline-treated group), and accelerated healing of infected wounds. An improved five-phage cocktail, WRAIR_PAM2, was formulated by a rational design approach (using phages with broader host ranges, more complementing activity, relatively low resistance background, and compatibility in mixes). Conclusions: WRAIR_PAM2 covered 76% of highly diverse clinical isolates and demonstrated significant efficacy against topical and systemic P. aeruginosa infection, indicating that it is a promising therapeutic candidate. Full article