Search Results (650)

Background: Colistin- and carbapenem-resistant Acinetobacter baumannii (CRAB) represent a critical threat in intensive care unit (ICU) settings. This study aimed to provide a comprehensive molecular epidemiological characterization of extensively drug-resistant (XDR) A. baumannii clinical isolates from a tertiary-care hospital in Kırşehir, Central Anatolia, a region previously absent from the national surveillance literature. Methods: A total of 43 non-duplicate XDR A. baumannii isolates recovered from ICU patients between November 2021 and December 2023 were included. Antimicrobial susceptibility testing was performed by automated systems and broth microdilution for colistin. Resistance genes, including OXA-type carbapenemases, extended-spectrum β-lactamases (ESBLs), metallo-β-lactamases, plasmid-mediated colistin resistance (mcr-1 to mcr-5), plasmid-mediated quinolone resistance genes (qnr, qepA, oqxAB, aac(6′)-Ib-cr), and class 1 and 2 integrons, were screened by PCR. Integron gene cassettes were characterized by sequencing. Clonal relatedness was assessed by pulsed-field gel electrophoresis (PFGE) using ApaI digestion. Results: All 43 isolates exhibited the XDR phenotype with universal resistance to carbapenems, colistin, fluoroquinolones, aminoglycosides (except amikacin), piperacillin, cephalosporins, and tobramycin. Amikacin susceptibility was retained in 58.1% of isolates. blaOXA-51 was detected in all isolates (100%), and blaOXA-23 was the predominant acquired carbapenemase (90.7%). Notably, blaOXA-48, a carbapenemase typically associated with Enterobacteriaceae, was identified in 3 isolates (7.0%), each belonging to a distinct pulsotype. No blaOXA-24/40, blaOXA-58, or class B metallo-β-lactamase genes were detected. ESBL genes were found in a subset of isolates, with blaCTX-M group 1 being the most prevalent (20.9%). The aac(6′)-Ib-cr gene was detected in 81.4% of isolates, and oqxA/oqxB in 60.5% and 39.5%, respectively. No mcr or classical qnr genes were identified. Class 1 and 2 integrons were detected in 4.7% and 7.0% of isolates, respectively, carrying dfrA12-DUF1010-aadA2 (class 1) and dfrA1-sat-1 (class 2) gene cassettes. PFGE identified 12 pulsotypes among the typeable isolates; PT4 (n = 20, 47.6%) and PT11 (n = 8, 19.0%) were the dominant clonal clusters, together accounting for 65.1% of typeable isolates. Conclusions: This study presents one of the first comprehensive molecular epidemiological analyses of XDR A. baumannii from Central Anatolia. The dominance of OXA-23-carrying clonal lineages, the detection of blaOXA-48 in A. baumannii distributed across three distinct pulsotypes, the high prevalence of aac(6′)-Ib-cr, and the concurrent distribution of resistance determinants across genetically diverse clonal backgrounds indicate that both clonal expansion and possible horizontal gene transfer contribute to resistance dissemination in this setting. These findings underscore the need for systematic molecular surveillance and reinforced infection control strategies in ICU settings, at both the regional and national levels. Full article

Background/Objectives: Probiotic feed additives are increasingly used in livestock production as antimicrobial-sparing tools, yet viable microbial products should not introduce clinically relevant antimicrobial resistance genes (ARGs) into the intestinal resistome. This study evaluated farm-animal probiotic products using an integrated phenotypic, metagenomic and mobilome-aware safety framework. Methods: Seven commercially available products intended for poultry, pigs, cattle or horses were assessed using product metadata, culture-based recovery, broth microdilution minimum inhibitory concentration (MIC) profiling and Illumina short-read sequencing as a screening-level resistome approach. Reads were quality controlled, assembled, screened using the Comprehensive Antibiotic Research Database (CARD)/Resistance Gene Identifier (RGI) workflow and interrogated for plasmid-, phage- and insertion sequence/mobile genetic element-associated genomic context. Results: MIC profiles were generated for viable bacterial isolates representing Enterococcus faecium, Pediococcus acidilactici, Pediococcus pentosaceus and Bacillus subtilis. One labelled Lactobacillus plantarum component was not recovered as viable culture, and one labelled P. acidilactici component was recorded as P. pentosaceus. Sequencing-based resistome screening identified 30 antimicrobial resistance (AMR)-associated CARD antibiotic-resistant organism (ARO) hits belonging to 13 determinants across six ARG-positive coded products, while one coded product had no retained CARD/RGI hit. Profiles were dominated by recurrent Enterococcus-associated background determinants, including aac(6′)-Ii, msrC and eatAv. Plasmid prediction was positive for five hits, whereas no iMGE- or phage-associated ARG context was detected. No vanA/vanB, mcr, optrA, poxtA, cfr, extended-spectrum β-lactamase (ESBL) or carbapenemase gene was detected. Conclusions: The investigated products did not show evidence of high-priority mobile ARG carriage. Nevertheless, AMR-associated determinants and occasional predicted mobile contexts support routine integrated MIC-sequencing-based resistome–mobilome assessment of veterinary probiotic products. Because short-read assemblies do not fully resolve plasmid architecture or transferability, mobile-context predictions should be considered screening-level indicators requiring confirmatory long-read or functional testing for higher-priority findings. Full article

Background/Objectives: Escherichia coli is the predominant pathogen in community-onset urinary tract infections (UTIs) requiring hospitalization. This study characterized antimicrobial resistance profiles, biofilm formation, extended-spectrum β-lactamase (ESBL) gene distribution, and phylogenetic background of E. coli isolates from hospitalized UTI patients in Western Mexico. Methods: Seventy isolates (September 2023–September 2024) underwent susceptibility testing (CLSI M100, 35th edition), multiplex PCR for blaTEM, blaCTX-M, and blaSHV genes, crystal violet biofilm quantification, and Clermont quadruplex PCR phylotyping. Associations were evaluated by Fisher’s exact test with Benjamini–Hochberg FDR (BH-FDR) correction. Results: ESBL phenotype and MDR were detected in 57.1% and 58.6% of isolates. After BH-FDR correction, ESBL production was significantly associated with amikacin (OR = 5.55; 95% CI: 1.80–18.74; q = 0.002) and TMP-SMX non-susceptibility (OR = 3.00; 95% CI: 1.02–9.23; q = 0.036); ciprofloxacin non-susceptibility was linked to MDR status (OR = 7.21; 95% CI: 1.28–75.66; q = 0.017) but not ESBL phenotype. Biofilm was detected in 77.1% of isolates. blaTEM predominated among ESBL producers (85.0%). Phylogroup B2 (51.4%) was inversely associated with recurrent UTI on both univariate (OR = 0.17; 95% CI: 0.03–0.73; p = 0.008) and adjusted analysis (adjusted OR = 0.19; 95% CI: 0.05–0.81; p = 0.025). Phylogroup C (22.9%) exhibited the highest MDR prevalence (81.3%) and the highest biofilm formation rate among phylogroups (87.5%). Conclusions: The high prevalence of ESBL-producing and MDR E. coli, combined with an unexpected predominance of blaTEM, reveals a distinctive local resistance landscape diverging from regional trends. The inverse association of phylogroup B2 with recurrence and TMP-SMX resistance reinforces the clinical value of phylogenetic surveillance in guiding UTI management strategies. Full article

Klebsiella pneumoniae is an opportunistic pathogen associated with both community-acquired and nosocomial infections. Multidrug-resistant (MDR) strains are increasingly implicated in urinary tract infections (UTIs), traveller’s diarrhoea, bacteraemia, and sepsis. β-lactam antibiotics are commonly used for treatment; however, antimicrobial resistance has emerged largely due to the production of extended-spectrum β-lactamases (ESBLs), which confer resistance mainly to penicillins, oxyimino-cephalosporins, and monobactams, while cephamycins and carbapenems usually remain stable to ESBL-mediated hydrolysis and compromise therapeutic efficacy. ESBL-producing strains represent a major cause of severe Gram-negative infections. This study aimed to determine the prevalence of ESBL-producing K. pneumoniae among UTI patients in Jordanian hospitals (Al Mafraq, Ma’an, and Islamic Hospitals), evaluate their antimicrobial susceptibility patterns, and detect antimicrobial resistance genes at the molecular level. A total of 450 urine isolates of K. pneumoniae were collected from UTI patients between November 2023 and May 2024. Isolates were identified in hospital laboratories using standard microbiological methods. Antimicrobial susceptibility testing was performed, and molecular characterisation of ESBL-associated genes was conducted using polymerase chain reaction (PCR). Out of 450 K. pneumoniae isolates collected from UTI patients across three Jordanian regions, 72 (16%) were confirmed as ESBL producers. Among the 72 ESBL-positive K. pneumoniae isolates, 34 (47.2%) were recovered from the Central region, 20 (27.8%) from the North, and 18 (25.0%) from the South. Molecular analysis revealed that 41.7% of ESBL-producing isolates carried the blaCTX-M gene, while 33.3% harboured the blaOXA gene. All ESBL-producing isolates demonstrated antimicrobial resistance to third-generation cephalosporins. A significantly higher proportion of ESBL-producing isolates was identified in female patients (84.7%) compared with males (15.3%). A significant association was observed between blaOXA gene distribution and geographic region (p = 0.016), whereas blaCTX-M gene distribution showed no significant regional association. ESBL-producing K. pneumoniae accounted for a substantial proportion of UTI isolates in Jordan, with blaCTX-M identified as the predominant resistance gene. The higher burden observed in the Central region and among female patients highlights notable distribution patterns in this cohort. These findings emphasise the necessity for sustained molecular surveillance and strengthened antimicrobial stewardship strategies to limit the dissemination of ESBL-producing strains in Jordanian healthcare settings. Full article

Extended-spectrum β-lactamase (ESBL)-producing bacteria are a growing public health concern within the One Health framework. This study aimed to characterize ESBL-producing Enterobacterales in industrial and artisanal organic fertilizers marketed in southwestern Colombia. Five commercial fertilizer brands were analyzed using a selective culture on ceftriaxone supplemented media (4 µg/mL), antimicrobial susceptibility testing by broth microdilution to determine minimum inhibitory concentrations (MICs), phenotypic synergy testing for ESBL confirmation, and polymerase chain reaction (PCR) to detect bla_TEM, bla_SHV, and bla_CTX-M genes. Overall, 18.6% of the samples showed growth of ceftriaxone-resistant Enterobacterales, predominantly Escherichia coli and Klebsiella pneumoniae. ESBL producers accounted for 84% of the isolates, all of which carried at least one bla gene, predominantly bla_CTX-M. Statistically significant differences in bacterial growth frequency were observed among fertilizer types, with higher positivity rates observed in manure-based artisanal formulations (p < 0.05). Whole-genome sequencing of selected isolates identified Klebsiella pneumoniae ST37 and Escherichia coli ST224, both harboring bla_CTX-M-55 and additional resistance and virulence determinants. These findings demonstrate that organic fertilizers, particularly manure-derived products, may act as reservoirs and potential dissemination routes for clinically relevant antimicrobial-resistant bacteria. This is the first study in Colombia documenting the presence of ESBL-producing bacteria in organic fertilizers. These results underscore the need to incorporate surveillance of these products into national policies under a One Health perspective. Full article

During the COVID-19 pandemic carbapenem-resistant Acinetobacter baumannii (CRAB) was found to be the major pathogen associated with ventilator-associated pneumonia in mechanically ventilated patients. This prompted us to analyze the post-pandemic mechanisms of carbapenem resistance, antibiotic resistance trends, and molecular epidemiology of CRAB in Croatia. In total, 94 CRAB isolates from two hospital centers, including outpatient settings, were investigated. Antimicrobial susceptibility testing was performed by broth microdilution. PCR was used to detect genes encoding carbapenemases of group A, B and D and extended-spectrum β-lactamases (ESBL). Randomly selected isolates were subjected to whole resistome analysis by Inter-array CarbaResist Kit and whole-genome sequencing (WGS). Phylogenetic tree and sequence types (STs) were retrieved from WGS. Plasmid incompatibility groups were determined by PCR-based replicon typing (PBRT). All isolates were extensively drug resistant (XDR), showing resistance to ceftazidime, cefepime, piperacillin–tazobactam, imipenem, meropenem, gentamicin, amikacin and ciprofloxacin, and 13% (n = 12) were also resistant to colistin. The Hodge and CIM test exhibited poor sensitivity with only 32 and 30% of isolates being identified as carbapenemase producers, respectively. PCR identified bla_OXA-23 as the dominant carbapenemase gene in both hospitals, found in 71% of the isolates (67/94). In an outpatient setting, bla_OXA-24/40 was dominant. bla_OXA-23 and bla_OXA-72 were the only allelic variants. The Inter-array CarbaResist Kit and whole-genome sequencing (WGS) identified a variety of aminoglycoside (armA, ant(3″)-IIa, aph(3″)-Ib, aph(6)-Id) and sulphonamide resistance (sul1 and sul2) genes. The representative bla_OXA-23-positive isolates belonged to ST2, while bla_OXA-72-positive isolates were allocated to ST492. These data show that there are different populations of XDR A. baumannii between hospital and outpatients. Full article

Carbapenemase-producing Enterobacterales (CPE) is a global threat. IMP-6, a prevalent carbapenemase in western Japan, is mostly disseminated via CTX-M-2 extended-spectrum β-lactamase (ESBL) co-producing Enterobacterales. However, the existence and characteristics of Enterobacterales harboring bla_IMP-6 without bla_CTX-M-2 remain unclear. We analyzed the phenotypic and genetic characteristics of clinical bla_IMP-6-harboring Enterobacterales isolates, focusing on those lacking bla_CTX-M-2. Overall, 220 bla_IMP-6-harboring isolates collected from 76 Japanese hospitals between 2014 and 2021 were characterized by antimicrobial susceptibility, presence of CTX-M-type ESBLs, plasmid incompatibility, plasmid transfer experiments, and genome sequencing and analysis. Among these, 203 co-harbored bla_CTX-M-2 group, with 90% of them demonstrating high conjugation frequency and broad-spectrum resistance to β-lactams. Of the remaining 17 isolates, nine lacked bla_CTX-M, while eight co-harbored bla_CTX-M-1 group (n = 2) or bla_CTX-M-9 group (n = 6). Eleven isolates carried nontransferable plasmids with genetic structures distinct from those of bla_IMP-6 and bla_CTX-M-2 co-encoding plasmids, including eight non-incompatibility N plasmids. Fifteen isolates carried only bla_IMP-6-encoding plasmids; two carried plasmids with bla_IMP-6 and bla_CTX-M (bla_CTX-M-27 or bla_CTX-M-65). This novel study revealed that bla_IMP-6 can exist without bla_CTX-M-2 on diverse, often nontransferable plasmids, suggesting distinct, lower dissemination pathways compared to those of epidemic bla_CTX-M-2 co-carrying plasmids and highlighting previously overlooked plasmids that necessitate close monitoring. Full article

The escalating crisis of antimicrobial resistance claims nearly 5 million lives annually. Resistant infections now account for 4.95 million deaths worldwide and economic losses projected to reach $300 billion by 2030. Despite this urgent threat, traditional antibiotic discovery has declined precipitously. New chemical entity approvals have fallen by over 50%, while existing therapeutics are rapidly rendered obsolete by sophisticated bacterial resistance mechanisms including extended-spectrum β-lactamases, carbapenemases, and multidrug efflux pumps. Bio-based products have historically provided humanity’s most transformative antibiotics, yet conventional discovery pipelines face insurmountable bottlenecks. A total of 99.9% of environmental microbes remain unculturable. Biosynthetic gene clusters are predominantly silent under laboratory conditions, and dereplication efforts achieve only 2 to 5% annotation rates. This review presents a comprehensive examination of how artificial intelligence (AI) is revolutionizing bio-based product-based antibacterial discovery. We analyze AI-driven genome mining tools that have identified over 170,000 biosynthetic gene clusters across bacterial genomes, deep learning architectures achieving 88.5% bioactivity prediction accuracy, and generative models delivering experimental hit rates exceeding 50%—representing 50- to 90-fold improvements over traditional screening. Through validated case studies spanning in silico prediction to in vivo efficacy, we demonstrate that AI integration is not merely accelerating discovery but fundamentally transforming our capacity to access nature’s previously inaccessible chemical diversity in the fight against antimicrobial resistance. Full article

Antimicrobial resistance (AMR) in Escherichia coli (E. coli) from food-producing animals constitutes a substantial public health concern. This study characterized antimicrobial resistance profiles, phylogenetic diversity, virulence-gene distribution, and plasmid-borne extended-spectrum β-lactamase (ESBL) determinants of E. coli isolates recovered from water buffaloes with subclinical mastitis. Among the 54 ESBL-producing E. coli isolates, all were resistant to ampicillin and cefotaxime. High resistance rates were also observed for cephalothin (75.9%), trimethoprim–sulfamethoxazole (74.0%), ceftiofur (70.4%), florfenicol (68.5%), and cefazolin (63.0%). Lower resistance was recorded for colistin sulfate (40.7%), enrofloxacin (33.3%), and gentamicin (25.9%). Phylogenetic analysis of ESBL producers identified phylogroup B1 (42.6%) as predominant, followed by groups A (29.6%) and D (25.9%). Multilocus sequence typing (MLST) revealed that ST50 (20.4%) was the most common sequence type, and serogroup O150 was dominant (70.4%). Virulence genes, such as iss (81.5%), astA (59.3%), and espP (38.9%), were frequently detected among ESBL isolates. ESBL genes were predominantly bla_CTX-M-1 (27.8%) in all isolates, while the narrow-spectrum β-lactamase genes bla_TEM-1 (55.6%) and bla_OXA-10 (14.8%) were also commonly co-detected. Bioinformatic analysis predicted that all ESBL genes were associated with plasmid-derived contigs, with the predicted plasmid size ranging from approximately 32 to 187 kb and belonging to IncFIB, IncFIA, IncI1, IncFIA + I1, and IncFII replicon types. Conjugation frequencies ranged from 4.8 × 10⁻⁷ to 4.1 × 10⁻², and plasmids were predicted to carry additional resistance genes mediating resistance to chloramphenicol (floR), sulfonamides (sul1, sul3), tetracyclines (tet(A) and tet(B)), and trimethoprim (dfrA1, dfrA12). The co-carriage of ESBL genes with additional antimicrobial resistance and virulence determinants suggests the potential role of water buffaloes as reservoirs of clinically relevant resistance traits that may disseminate through horizontal gene transfer. Full article

Background/Objectives: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a major nosocomial pathogen. Although newer agents have reduced colistin use in high-income countries, this polymyxin remains important in many low- and middle-income settings. Colistin resistance in K. pneumoniae is most commonly associated with chromosomal alterations affecting the MgrB–PhoPQ pathway, or with plasmid-mediated mcr genes. This study aimed to investigate chromosomally mediated colistin resistance in CRKP clinical isolates from a Tunisian tertiary hospital. Methods: Between 2010 and 2015, 317 non-duplicate CRKP isolates were collected at Charles Nicolle Hospital, Tunis. Colistin MICs were determined by broth microdilution. Phenotypic tests and PCR characterized carbapenemases, extended-spectrum β-lactamases, AmpC, plasmid-mediated quinolone resistance, mcr and virulence genes. Porins (OmpK35/OmpK36) and the mgrB, phoP and phoQ loci were analyzed by SDS-PAGE and sequencing. Clonal relatedness was assessed by ERIC-PCR and multilocus sequence typing. We additionally compared colistin-resistant isolates with a panel of colistin-susceptible CRKP controls and assessed phenotypic stability after serial passages without colistin. Results: Five isolates (1.6%) were colistin-resistant. All were multidrug-resistant, produced OXA-48, and two also carried NDM-1. The isolates belonged to five distinct sequence types, including high-risk clones (ST11, ST101, ST147). No mcr genes were detected. Four isolates carried disruptive mutations in mgrB, and the remaining strain harbored inactivating mutations in both phoP and phoQ with an intact mgrB. Truncating alterations in PhoP/PhoQ and frequent loss or truncation of OmpK35/OmpK36 were observed. No mgrB/phoP/phoQ alterations were detected among colistin-susceptible controls, and colistin MICs remained stable after 7 days of drug-free passaging. Conclusions: In Tunisian CRKP, colistin resistance was associated with chromosomal alterations, predominantly involving disruption of the MgrB–PhoPQ pathway, in the absence of mcr genes. These mechanisms in both high-risk and emerging sequence types underscore the adaptability of CRKP and the need for surveillance where colistin remains an important therapeutic option. Full article

Patients undergoing cervical conization for cervical intraepithelial neoplasia grade II (CIN II) may develop postoperative bloodstream infections (BSIs), and multidrug-resistant (MDR) Escherichia coli isolates with distinct resistance profiles can complicate antimicrobial management. In this case-based study, two E. coli strains, HBFY-1 and HBFY-2, were recovered from blood cultures obtained from a 38-year-old CIN II patient with postoperative fever. The isolates were characterized by antimicrobial susceptibility testing, whole-genome sequencing, conjugation assays, and comparative genomics against publicly available genomes matched by sequence type and serotype. Fever occurred on postoperative day 2. HBFY-1 was fluoroquinolone-resistant; belonged to ST744/O101:H9; carried the extended-spectrum β-lactamase (ESBL) gene bla_CTX-M-27; was phenotypically confirmed as an ESBL producer; and grouped within a multi-source near-neighbor clade consistent with a conserved fluoroquinolone-associated resistance backbone in ST744/O101:H9. HBFY-2 was carbapenem-resistant; belonged to ST48/O113:H32; carried bla_NDM-5 on an IncY-associated plasmid bin; was phenotypically confirmed as a metallo-carbapenemase producer; and did not harbor any ESBL gene. Within the matched ST48/O113:H32 dataset, bla_NDM-5 was detected only in HBFY-2, which clustered within an Asia-enriched lineage, including China-derived human and swine genomes. The bla_CTX-M-27-associated and bla_NDM-5-associated elements were transferred to E. coli C600 at frequencies of 5.3 × 10⁻² and 4.6 × 10⁻⁶, respectively, and transfer of the bla_NDM-5-associated element imposed no detectable growth penalty under the tested conditions. As this study is based on a single clinical case, the findings should be interpreted cautiously, yet they still highlight the potential value of integrating susceptibility testing with rapid genomic characterization for identifying mobilizable carbapenem-resistance platforms. Full article

Hospital wastewater represents a critical hotspot for the dissemination of antibiotic resistance genes (ARGs), serving both as an environmental reservoir and a transmission pathway for multidrug-resistant bacteria into receiving ecosystems. The intense antibiotic selective pressure within healthcare facilities promotes the emergence, persistence and amplification of resistant strains, posing substantial risks to public health and environmental integrity. This study aimed to characterize Escherichia coli (E. coli) isolates recovered from hospital wastewater effluents in multiple cities across Gabon, with emphasis on bacterial loads, antimicrobial resistance patterns and associated genetic determinants. Wastewater samples were aseptically collected from sewer outlets of eleven healthcare facilities distributed across five provinces over a 12-week period, structured into two six-week sampling campaigns to capture temporal variability. A total of 158 bacterial isolates were obtained, among which 49 were confirmed as E. coli. Mean concentrations of presumptive E. coli ranged from 7.1 × 10³ to 1.49 × 10⁹ CFU/mL, indicating substantial microbial contamination of hospital effluents. Antimicrobial susceptibility testing using the Kirby–Bauer disk diffusion method against 19 antibiotics revealed that all isolates exhibited multidrug-resistant phenotypes. Resistance rates were particularly high to β-lactams and third-generation cephalosporins, reaching 90–100% in most facilities, reflecting strong selective pressure and widespread circulation of resistance mechanisms in urban aquatic environments. In contrast, carbapenems and amikacin remained comparatively effective, with resistance levels below 40%, suggesting partial preservation of last-resort therapeutic options. The values of the Multiple Antibiotic Resistance Index (MARI) ranged from 0.21 to 0.84, indicating selection pressure on different classes of antibiotics. Phylogenetic analysis showed a predominance of phylogroup A, traditionally considered commensal but increasingly associated with the spread of resistance. Groups B2, D/E and F proved to be the most resistant. These groups showed marked resistance to first-line antibiotics. The blaCTX-M-1 was the most prevalent resistance determinant (66.6%), occurring twice as frequently as blaSHV (33.3%), a finding that confirms the significant circulation of extended-spectrum β-lactamase-producing E. coli. Overall, these findings highlight hospital wastewater as a major reservoir and dissemination source of multidrug-resistant E. coli, underscoring the urgent need for improved wastewater treatment, strengthened antimicrobial stewardship and integrated One Health-based surveillance strategies. Full article

Shiga toxin-producing Escherichia coli (STEC) has emerged globally as a critical enteric foodborne zoonotic pathogen with significant public health implications. This study aimed to isolate and characterize STEC strains from Rattus spp. and layer chickens, specifically evaluating their antimicrobial resistance (AMR) profiles and the prevalence of extended-spectrum β-lactamase (ESBL)-producing isolates. A total of 274 fecal samples were collected from Rattus spp. (n = 154) and layer chickens (n = 120). Isolates were characterized using standard microbiological techniques, PCR amplification of specific genes (including uidA and stx), and antimicrobial susceptibility testing via the disk diffusion method. Results: Of the 248 presumptive E. coli isolates, 237 (95.5%) were confirmed via uidA gene amplification. Fifty-eight isolates were confirmed as STEC, including key O-serogroups (O103, O111, O26, and O157). Resistance was most prevalent against colistin (39.6%) and streptomycin (20.6%), with 8.6% of isolates exhibiting multidrug resistance (MDR). Additionally, 19 isolates showed ESBL-producing phenotypes, and resistance genes for colistin, phenicols, aminoglycosides, and carbapenems were detected. The presence of STEC and MDR strains in both rodents and poultry highlights a high pathogenic potential and a serious zoonotic risk to public health, necessitating enhanced surveillance. Full article

Background: Eravaycline is a novel fully synthetic fluorocycline that is currently approved for complicated intra-abdominal infections. However, it is sometimes also used off-label in tertiary care centers for other infection sites as an antibiotic of last resort due to its broad spectrum of activity and efficacy against Enterobacterales, including multidrug-resistant pathogens like extended spectrum β-lactamase (ESBL) producers or carbapenem-resistant Enterobacterales, as well as all Gram-positive organisms including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin- and linezolid-resistant Enterococcus faecium (VRE). Methods: We retrospectively included a total of 78 patients from Austria and Udine who received eravacycline between April 2023 and August 2024 to evaluate the real-world efficacy of eravacycline in various infection sites and pathogens using descriptive statistics. Results: Eravacycline was most commonly used in intra-abdominal infections (44.9%), followed by pneumonia (12.8%) and infections of unknown origin (7.7%). Escherichia coli, including ESBL producers, was the most common pathogen (24.4%), followed by Enterococcus spp. (12.8%) and Klebsiella pneumoniae (12.8%). Clinical cure was achieved in 65% of patients, whereas microbiological cure was documented in 46%; source control was attained in 48.7%, and 16.7% died within 30 days. A total of 48% of patients required intensive care. Conclusions: Eravacycline represents a possible therapeutic option for a wide range of pathogens, but its use must be evaluated in the context of infection site and severity. Full article

In 2023, the European Centre for Disease Prevention and Control surveillance report highlighted an increasing number of carbapenem-resistant Escherichia coli isolates carrying the less common bla_NDM-5 variant in Europe. The aim of this study was to investigate the molecular epidemiology of NDM-producing (New Delhi metallo-β-lactamase) E. coli isolates collected in Croatia over a one-year period. A total of 160 carbapenemase-producing E. coli isolates were reported through national surveillance in Croatia between March 2023 and March 2024. Whole-genome sequencing was performed on 22 NDM-producing E. coli isolates. Phylogenetic analysis identified 17 sequence types, indicating high diversity and polyclonal spread. High variability in resistome profiles and co-occurrence of resistance genes across multiple antimicrobial classes indicate multidrug resistance. The predominant bla_NDM variant was bla_NDM-1 (77.27%), followed by bla_NDM-5 (22.73%). Co-occurrence of bla_NDM with extended-spectrum β-lactamase (ESBL) encoding genes was detected in 12/22 isolates (54.55%). Plasmid analysis identified 22 different replicon types, with IncFII (54.54%) and IncA/C2 (45.45%) being the most frequent. Our findings provide insights into the molecular epidemiology of NDM-producing E. coli at the national level, highlighting the presence of the bla_NDM-5 variant. These results emphasize the need for genomic surveillance and strengthened infection control strategies to better understand and limit its spread. Full article