Chlorhexidine, cetrimide, chloroxylenol, and povidone iodine, in various combinations and concentrations are widely used antiseptics in clinical settings for skin antisepsis and hand hygiene in India. Evidences suggest that exposure of bacterial pathogens to antiseptics over a period of time can result in adaptation of bacteria resulting in tolerance and cross-resistance towards antiseptics and antibiotics. Given the crucial role that antiseptics play in reducing infection and preventing the spread of AMR, understanding the adaptation to antiseptics becomes a critical element in using them effectively. This study is aimed at determining the behavior of two clinically relevant species Escherichia coli and Acinetobacter baumannii adapted to chlorhexidine (CHG), cetrimide, chloroxylenol (PCMX), and povidone iodine (PVP-I). In particular, we have evaluated changes in minimum inhibitory concentration (MIC), cross-tolerance/resistance to both antibiotics and antiseptics and biofilm formation capability post the evolution study towards respective biocides. Both the studied bacterial species adapted to concentrations of antiseptics higher than their initial MICs. Among the adapted strains, E. coli cetrimide showed tolerance to cetrimide with a 16-fold increase in MIC. Similarly, a 4-fold increase in MIC against PVP-I was observed in A. baumannii PVP-I strain, indicating tolerance to PVP-I. Cross-adaptation studies indicated cross-tolerance of E. coli CHG and E. coli cetrimide to cetrimide and CHG, respectively. Among seven antibiotics tested, A. baumannii PCMX showed antibiotic resistance towards tetracycline and imipenem. A concomitant change in biofilm formation, indicated by an increased specific biofilm formation value was also observed. Moreover, CHG, cetrimide and PVP-I adapted A. baumannii strains showed sensitivity towards antibiotics, gentamicin, piperacillin, and tetracycline, a functional trade-off for survival at high antiseptic concentrations. Collectively, these in vitro findings suggest that the decision to use appropriate antiseptics should be based not solely on antiseptic and antibiotic susceptibility data, but also on pathogens to be neutralized, and specific phenotypic factors like bacterial fitness and biofilm-formation capabilities. Thus, frequent clinical microbiological monitoring with respect to antiseptic usage is crucial in controlling infection and spread of AMR.

Caseous lymphadenitis (CLA), caused by Corynebacterium pseudotuberculosis, is endemic in Korean native goats, but relationships among antimicrobial resistance (AMR), spatial distribution, and population structure remain unclear. We profiled AMR and multidrug resistance (MDR) in 286 pld-positive isolates from CLA lesions of 1177 goats in the Jeolla provinces, South Korea, integrating spatial analysis with five-locus multilocus sequence typing (MLST) and phylogenetics. Susceptibility to 12 antimicrobials was determined by disk diffusion, and MDR was defined as resistance to ≥ 3 antimicrobial classes. Farm-level spatial analyses included 54 farms with valid MDR estimates. Resistance was dominated by aminoglycosides, with streptomycin and gentamicin resistance of 99.7% and 88.1%, respectively. MDR occurred in 96 of 286 isolates (33.6%) and comprised 35 resistance-class patterns; the eight most frequent accounted for 61.5% of MDR isolates. Local indicators of spatial association (LISA) identified three significant farm-level patterns: one high-low outlier, one low-high outlier, and one low-low cluster, whereas no significant local patterns were detected at the gun/si level. Global Moran's I was non-significant at both scales. The CLA-MDR association was non-significant at the farm level but positive at the gun/si level by Pearson correlation. Neither AMR-profile dissimilarity nor differences in MDR prevalence showed significant isolation by distance using Haversine or road-network distances. MLST of 49 representative isolates indicated a cohesive, locally diversified lineage, with MDR distributed across related isolates rather than confined to a dominant typed lineage. These findings support herd-level antimicrobial stewardship and integrated phenotypic, spatial, and molecular surveillance for CLA control.

Background Uropathogenic Escherichia coli (UPEC) is responsible for 50-90% of all urinary tract infections (UTIs) worldwide, with increasing antimicrobial resistance posing a significant public health threat. This study aimed to characterise UPEC isolates from a tertiary care hospital in Bihar by detecting virulence factors and determining their antibiogram. Methods A total of 246 UPEC isolates were collected from outpatient department (OPD) and inpatient department (IPD) patients at IGIMS, Patna, over 12 months. Identification was confirmed by Matrix-Assisted Laser Desorption/Ionisation Time-of-Flight Mass Spectrometry (MALDI-TOF MS) (Bruker Daltonics, Bremen, Germany). Virulence factors, including haemolysin, haemagglutination, and cell surface hydrophobicity, were assessed. Extended-spectrum beta-lactamase (ESBL) production was confirmed by a phenotypic combination of disk diffusion test. Results Of 246 isolates, females predominated (52.0%). Haemolysin was detected in 44 (17.9%) isolates, haemagglutination in 30 (12.2%), cell surface hydrophobicity in 13 (5.3%), and ESBL production in 15 (6.1%). Most isolates showed lactose fermenting (LF) colonies on CLED (80.1%). High resistance rates to ampicillin and co-trimoxazole were noted. Nitrofurantoin and gentamicin retained better activity. Conclusion UPEC isolates from IGIMS, Patna, showed considerable virulence factor prevalence and antimicrobial resistance. Nitrofurantoin and aminoglycosides remain useful therapeutic options. Routine characterisation of UPEC is essential for effective UTI management in this region.

Mobile phones are used by most of the global population, particularly by college and university students and healthcare professionals. Despite their benefits, potential health risks associated with mobile-phone contamination may be overlooked. Therefore, this study aimed to determine bacterial contamination, associated factors, and antimicrobial susceptibility patterns of bacterial isolates from mobile phones among students and employees of Haramaya University College of Health and Medical Sciences, Harar, Eastern Ethiopia. An institution-based cross-sectional study was conducted among 238 students and employees from July 1 to August 30, 2022. Participants were selected using stratified sampling techniques. A structured questionnaire was used to collect the data. A swab sample was collected from each participant's mobile phone using a sterilized cotton swab and transported to the laboratory within 2 hours for microbiological investigation. Bacterial isolates were identified using colony morphology, gram staining, and biochemical tests. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Bivariable and multivariable logistic regression analyses were used to identify factors associated with bacterial contamination. Bacterial contamination was detected on 89.5% (95% confidence interval [CI]: 87-92) of sampled mobile phones. A total of 235 bacterial isolates were recovered, of which Staphylococcus epidermidis was the predominant isolate (70.6%), followed by Staphylococcus saprophyticus (14.9%) and Staphylococcus aureus (6.4%). Among the bacterial isolates tested for antimicrobial susceptibility, susceptibility was highest to gentamicin and chloramphenicol (94.0% each), followed by clindamycin (83.4%). Resistance was highest to ampicillin (98.7%), kanamycin (88.2%), cefotaxime (71.5%), cefoxitin (54.9%), and ciprofloxacin (52.8%). Overall, 181 (77.02%) isolates were multidrug-resistant, and 25 (10.64%) were extensively drug-resistant. Male sex (adjusted odds ratio [AOR]: 3.92, 95% CI: 1.364-11.282), lack of regular mobile-phone cleaning (AOR: 7.25, 95% CI: 2.161-24.336), and lack of awareness about mobile-phone bacterial contamination (AOR: 4.25, 95% CI: 1.293-13.970) were independently associated with bacterial contamination. This study demonstrated a high level of bacterial contamination of mobile phones among students and employees. S epidermidis was the predominant bacterial isolate. High levels of antimicrobial resistance were observed, particularly to ampicillin, kanamycin, and cefotaxime. The findings support the need to promote regular mobile-phone cleaning and improve awareness of mobile-phone hygiene.

Background: Canine otitis externa caused by Pseudomonas aeruginosa is frequently chronic and treatment refractory, yet integrated historical phenotype-genotype data remain limited. We characterized an archival Hungarian collection obtained in 2010 and 2017. Methods: Broth microdilution minimum inhibitory concentrations (MICs) were determined for 67 isolates against 13 antimicrobial agents and chlorhexidine, and 59 isolates had matched long-read whole-genome assemblies. Resistance-associated determinants were identified using the Comprehensive Antibiotic Resistance Database, and their predicted proximity to mobile genetic elements and plasmid-like contigs was evaluated. Results: Current canine Clinical and Laboratory Standards Institute breakpoints classified 59/67 isolates (88.1%) as enrofloxacin resistant and 43/67 (64.2%) as marbofloxacin resistant. European Committee on Antimicrobial Susceptibility Testing epidemiological cut-off values identified non-wild-type subsets for ciprofloxacin (7/67), tobramycin (4/67), imipenem (1/67), and piperacillin-tazobactam (51/67), whereas all isolates remained within the available wild-type distributions for ceftazidime, gentamicin, and amikacin. No continuous MIC distribution changed significantly between sampling years after false-discovery-rate correction, although categorical marbofloxacin resistance decreased from 87.5% in 2010 to 42.9% in 2017. Resistance-gene screening identified 64 unique determinants, including near-universal efflux-system components, PDC and OXA-50-like β-lactamases, APH(3')-IIb, arnA, and basS. The fluoroquinolone-associated determinant crpP occurred in 37/59 genomes and was located on plasmid-predicted contigs in six isolates. No determinant-MIC association remained significant after correction for multiple testing. Conclusions: The discordance between conserved resistance-gene repertoires and heterogeneous MICs demonstrates that sequence-based detection alone is insufficient for therapeutic inference. Integrated phenotypic and genomic surveillance is therefore required to support evidence-based antimicrobial stewardship in canine pseudomonal otitis.

Background/Objectives: The development of multifunctional biomaterials for bone regeneration remains a key challenge in additive manufacturing. Although polylactic acid (PLA) is widely used in fused deposition modeling (FDM), its limited bioactivity and lack of intrinsic antibacterial functionality restrict its application in implantable constructs. This study aimed to develop a PLA-based composite filament combining ion-mediated bioactive potential and local antibacterial functionality using a Quality by Design (QbD) approach. Methods: PLA-based composite filaments incorporating a mollusk shell-derived biogenic calcium-containing filler (20 wt.%) and gentamicin (5 wt.%) were fabricated by solvent-free melt extrusion. A QbD framework was applied to define the Quality Target Product Profile (QTPP), identify critical quality attributes (CQAs), and assess critical material attributes (CMAs) and critical process parameters (CPPs). The material was characterized by SEM-EDS combined with ImageJ-based quantitative image analysis, TGA/DSC, mechanical testing, ICP-AES analysis of aqueous extracts, agar diffusion antibacterial assays, FDM printability assessment, and in vivo biocompatibility testing in a rat subcutaneous implantation model. Results: The developed PLA-Gen-MS material was obtained as a continuous filament with a diameter of 1.75 ± 0.05 mm and was successfully used for FDM printing of model scaffold structures. SEM-EDS confirmed matrix continuity and distribution of the calcium-containing mineral phase. ICP-AES revealed a calcium-dominant multicomponent ion release profile, with Ca as the predominant element and measurable levels of Sr, Mg, P, Mn, and Fe. TGA/DSC confirmed thermal compatibility of the components under melt-processing conditions. PLA-Gen-MS demonstrated antibacterial activity against all tested strains, with inhibition zones of approximately 20-21 mm. In vivo, the material showed a favorable preliminary tissue response compared with TiLOOP[®], including faster reduction of inflammatory infiltration and absence of foreign body giant cells by day 14. Conclusions: The QbD-guided strategy enabled the development of a multifunctional PLA-based filament integrating melt processability, structural integrity, ion-mediated bioactive potential, antibacterial functionality, printability, and favorable preliminary biocompatibility. PLA-Gen-MS can be considered a promising platform for further development of personalized bioactive and antibacterial scaffold constructs for bone regeneration.

Background: Invasive filamentous fungal infections carry substantial mortality among immunocompromised hosts, and diagnostic delay associated with morphology-based mould identification is a recognised contributor to poor outcomes. The Mycelium Transfer (MyT) method, implemented on the Bruker MALDI Biotyper[®] platform, allows direct mass spectrometric profiling of leading-edge mycelium sampled from routine solid agar without solvent extraction. We conducted a single-centre analytical validation of an optimised, triplicate-spot MyT workflow as a standalone identification platform at a Canadian tertiary care academic centre. Methods: Fifty-six archived, pre-characterised clinical isolates spanning five fungal categories-Aspergillus species (n = 21), other hyaline non-Aspergillus moulds (n = 14), Mucorales (n = 8), dermatophytes (n = 8), and dematiaceous fungi (n = 5). These isolates were selected to represent our local isolate population and tested by MyT on a Bruker Microflex LT/SH system, with acquisition and scoring performed prospectively by technologists blinded to the archived reference identification. Spectra were interrogated against the MBT Myco 4.1 Filamentous Fungi Library. Each isolate was spotted in triplicate; a final identification required ≥2/3 concordant spots at a score ≥ 1.8, consistent with CLSI M58 guidance. A parallel formic acid-ethanol extraction was performed for a subset of 11 isolates as an exploratory, within-study comparator. Primary culture media were Brain Heart Infusion (BHI) agar and Sabouraud Dextrose Agar with chloramphenicol and gentamicin (SAB-CG). Agreement was assessed against CLSI M52 criteria, with an a priori target of ≥90% overall concordance. Results: Applying the triplicate-spot consensus rule at the ≥1.8 threshold, species- or complex-level identification was achieved for 43/56 isolates (76.8%; 95% CI 64.2-85.9%), and overall acceptable identification (species/complex plus acceptable genus-level calls) for 50/56 isolates (89.3%; 95% CI 78.5-95.0%). No misidentifications were observed. Aspergillus spp. and dermatophytes each achieved 100% overall identification; performance was lowest for dematiaceous fungi (2/5, 40.0%). In a post hoc analysis restricted to the categories in which discordant single-spot results occurred (other hyaline non-Aspergillus moulds and Mucorales, combined n = 22), triplicate consensus corrected three isolates in which a single high-scoring spot would have produced a false identification, and enabled identification of four further isolates that a single spot would have missed, corresponding to an estimated single-spot equivalent identification rate of 12/22 (54.5%) versus 19/22 (86.4%) with triplicate consensus, which is an approximately 32 percentage point absolute difference restricted to this 22-isolate subgroup and not an effect demonstrated across the complete 56-isolate panel. Growth sufficient for MyT sampling at 72 h was numerically higher on BHI agar than SAB-CG for hyaline moulds at 72 h (88.6% vs. 77.1%), although this difference was not statistically significant (McNemar's test, p = 0.29). In a smaller exploratory subset of 11 isolates tested in parallel by both methods, MyT showed similar performance to formic acid-ethanol extraction (equivalent or higher scores in 8/11 isolates tested in parallel); this was not a formally powered non-inferiority comparison. Conclusions: A triplicate-spot MyT workflow at a ≥1.8 score threshold achieved 89.3% overall concordance, with reference identification and zero misidentifications across a 56-isolate panel, approaching the CLSI M52 ≥ 90% benchmark overall and meeting it for Aspergillus species and dermatophytes specifically. To our knowledge, this is among the first Canadian evaluations of the MyT method for routine clinical mould identification. Dematiaceous fungi and several individual species within other categories remained underpowered and of limited performance, reflecting both small subgroup sizes and known gaps in current spectral library coverage. These findings support MyT as a practical frontline identification method for Aspergillus, Mucorales, and dermatophytes within existing laboratory infrastructure, with chemical extraction or molecular methods retained as adjuncts for isolates that do not achieve threshold identification; broader implementation and clinical outcome benefits remain to be evaluated prospectively.

Microbacterium species, a genus of aerobic Gram-positive coryneform rods, are rare causes of human infection with only a few sporadic cases reported worldwide. MALDI-TOF MS, 16S rRNA gene sequencing, and even whole-genome sequencing are used to identify the species in a clinical laboratory setting. The study reports a case of Microbacterium paraoxydans bloodstream infection and reviews the literature, including eight additional reported cases of M. paraoxydans infection. We summarize the characteristics of each case, highlight the identification methods, and identify recurrent characteristics for M. paraoxydans infection. A 65-year-old man presented with stable condition of esophageal cancer and long-term prednisolone therapy for psoriasis. A central venous catheter (CVC) was placed for years for treatment of esophageal cancer. The patient presented with fever and chills, and Microbacterium paraoxydans was identified by MALDI-TOF MS from blood culture samples via chemo port. After the chemo port was removed, vancomycin followed by levofloxacin was administered for the entire 14-day treatment course according to susceptibility tests. This study highlights that a long-term central venous catheter and immunocompromised status were common characteristics among the reported cases of Microbacterium spp. infection. The susceptibility of Microbacterium spp. is not fully characterized and varies across reports; gentamicin and trimethoprim/sulfamethoxazole appeared more consistently active, whereas susceptibility to vancomycin was variable. We report this case to highlight the increasing number of infections caused by Microbacterium spp. in the current era and to provide information on the treatment of M. paraoxydans.

Antimicrobial resistance (AMR) is one of the main public health problems that also affects environmental ecosystems. Sinkholes are understudied groundwater ecosystems that may act as reservoirs and dissemination routes for AMR. This study evaluated the composition, distribution, and antimicrobial resistance profiles of culturable ampicillin-resistant Gram-negative bacteria recovered from sinkholes of the Yucatán Peninsula, Mexico. Water samples were collected from 27 sinkholes during dry and rainy seasons. The isolates were identified by MALDI-TOF MS and evaluated by broth microdilution. Representative E. coli isolates were analyzed by whole-genome sequencing. A total of 193 ampicillin-resistant Gram-negative isolates were recovered. The most frequently recovered genera were Enterobacter, Klebsiella, and Escherichia, which were detected across all hydrogeological zones. Resistance to cefotaxime, levofloxacin, gentamicin, and tetracycline was detected among several bacterial genera. Opportunistic bacterial species associated with healthcare-associated infections, including K. pneumoniae, A. baumannii, and P. aeruginosa, were also identified. Genomic analysis of 19 E. coli isolates revealed resistance determinants associated with multiple antimicrobial classes and a diverse population structure dominated by phylogroup B1. These findings show that the Ring of Cenotes aquifer harbors diverse populations of culturable ampicillin-resistant Gram-negative bacteria and emphasize the importance of groundwater ecosystems as environmental reservoirs of AMR.

Background: This study evaluated the ecotoxicity of five synergistic antimicrobial combinations of terpineol-antibiotic (SACTA), developed to reduce antibiotic (ABX) doses while maintaining antimicrobial efficacy. The ABXs tested were gentamicin (GTM), chloramphenicol (CHL), tetracycline (TC), and florfenicol (FF). Methods: Median effective concentrations (EC50) were determined using Aliivibrio fischeri and Daphnia magna. In addition, the effects of SACTAs on the metabolic profile of an indigenous riverine microbial community were assessed using Biolog EcoPlates™. Results:α-Terpineol (TER) alone showed EC50 values of 21.49 and 17.64 µg/mL for D. magna and A. fischeri, respectively. The toxicity of SACTAs varied depending on the antimicrobial combination, exhibiting synergistic, additive, or antagonistic effects. Among the tested combinations, TER-CHL was the most toxic with EC50 values of 7.84 µg/mL for D. magna and 12.75 µg/mL for A. fischeri. In contrast, TER-FF and TER-GTM, with lower TER proportions, were the least toxic, with EC50 values exceeding 30 µg/mL for D. magna and 60 µg/mL for A. fischeri. Although SACTAs generally showed higher toxicity than ABXs tested individually, their EC50 values remained below the minimum inhibitory concentrations (MICs) determined in single-species antimicrobial assays. In contrast, riverine microbial communities displayed greater resilience, with only additive or antagonistic effects observed. Among the tested combinations, TER-FF produced the strongest effects on the microbial community, reducing metabolic fitness and decreasing the utilization of carbohydrates and polymers. Importantly, all SACTAs exhibited toxicity values equal to or lower than those of ABXs tested alone at their respective MICs, based on changes in community growth and metabolic profiles. Conclusions: Overall, these findings suggest that SACTAs may represent a promising strategy for reducing ABX use while minimizing additional ecotoxicological risks to freshwater ecosystems.

Background: Community-acquired intra-abdominal infections (CA-IAIs) exhibit significant clinical heterogeneity. However, most studies focusing on CA-IAIs do not stratify comparisons by infection site. Methods: This post hoc analysis of the prospective multicenter PERICOM cohort (13 French university hospitals, April 2018 to February 2019) included adult patients with CA-IAIs requiring surgical management. We compared clinical characteristics, microbiology, and outcomes between appendicular and non-appendicular sites. Secondary analyses assessed the impact of Enterococcus spp., Pseudomonas aeruginosa, or fungal documentation, and the theoretical coverage of empirical antibiotic regimens. Results: Of the 205 patients, 86 (42%) had appendicular and 119 (58%) had non-appendicular CA-IAIs. Appendicular CA-IAIs involved younger patients with fewer comorbidities and were followed by fewer major postoperative complications (Clavien-Dindo score ≥ 3: 10% versus 43%, p < 0.001) and no deaths (0% versus 12%, p < 0.001). Among 118 culture-positive patients, appendicular CA-IAIs showed higher rates of non-fermenting Gram-negative bacilli (25% versus 10%, p = 0.046) and anaerobes (53% versus 28%, p = 0.008) and were more often polymicrobial (76% versus 55%, p = 0.020). Conversely, Staphylococcus spp. (0% versus 9%, p = 0.036) and fungal co-infection (0% versus 12%, p = 0.010) were confined to non-appendicular CA-IAIs. Furthermore, Enterococcus spp. documentation (24/118, 20%) identified patients with greater admission severity and higher 28-day mortality (33% versus 2%, p < 0.001). Amoxicillin-clavulanic acid plus gentamicin covered the isolates of 92% of patients versus 61% for third-generation cephalosporin plus metronidazole (p < 0.001), a difference identical in both appendicular and non-appendicular sites. Conclusions: Appendicular and non-appendicular CA-IAIs appear to be distinct entities, supporting stratified management. Future guidelines should consider site-specific strategies, therapeutic individualization, and the integration of CA-IAI ecology.