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Developing simple, inexpensive, fast, sensitive, and specific probes for antibiotic-resistant bacteria is crucial for the management of urinary tract infections (UTIs). We here propose a paper-based sensor for the rapid detection of β-lactamase-producing bacteria in the urine samples of UTI patients. By conjugating a strongly electronegative group -N + (CH 3 ) 3 with the core structures of cephalosporin and carbapenem antibiotics, two visual probes were achieved to respectively target the extended-spectrum/AmpC β-lactamases (ESBL/AmpC) and carbapenemase, the two most prevalent factors causing antibiotic resistance. By integrating these probes into a portable paper sensor, we confirmed 10 and 8 cases out of 30 clinical urine samples as ESBL/AmpC- and carbapenemase-positive, respectively, demonstrating 100% clinical sensitivity and specificity. This paper sensor can be easily conducted on-site, without resorting to bacterial culture, providing a solution to the challenge of rapid detection of β-lactamase-producing bacteria, particularly in resource-limited settings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The main mechanism that causes resistance to carbapenem, one of the most potent antibiotic available, in Enterobacterales bacterial isolates, is due to Klebsiella pneumoniae carbapenemase (KPC) production by the bacterium. KPC is spread worldwide, requiring laboratories to be capable of identifying this enzyme, however some methods can be expensive for small laboratories, especially in developing countries. Therefore, the development of methods with low cost of reagents for the detection of KPC enzyme is necessary. The objective of this study was to evaluate the detection of KPC enzyme by MALDI-TOF MS from inactivated bacteria impregnated in filter paper. A total of 129 Enterobacterales isolates were impregnated in filter paper, and after 7 days at room temperature, they were subjected to a protein extraction protocol and spectra acquisition, in triplicates, by MALDI-TOF MS. The spectra were evaluated and KPC was identified according to the presence of a peak of 28,712.62 ± 27.80 m/z. Considering the presence of the KPC peak in at least one spectrum of the triplicates, this method presented 60.8% sensitivity and 96.4% specificity. However, considering the presence of KPC peak in at least two spectra of the triplicate, a specificity of 100% was achieved. The detection of KPC enzyme from inactivated bacteria impregnated in filter paper can be used as a method to confirm the presence of KPC, which could be very significant for small laboratories with limited resources., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The emergence of antimicrobial resistance (AMR) in pathogenic bacteria, expedited by the overuse and misuse of antibiotics, necessitates the development of a rapid and pan-territorially accessible diagnostic protocol for resistant bacterial infections, which would not only enable judicious prescription of drugs, leading to infection control but also augment AMR surveillance. In this study, we introduce for the first time a " turn-on " terbium (Tb 3+ ) photoluminescence assay supported on a paper-based platform for rapid point-of-care (POC) detection of β-lactamase (BL)-producing bacteria. We strategically conjugated biphenyl-4-carboxylic acid ( BCA ), a potent Tb 3+ sensitizer, with cephalosporin to engineer a BL substrate CCS , where the energy transfer to terbium is arrested. However, BL, a major resistance element produced by bacteria resistant to β-lactam antibiotics, triggers a spontaneous release of BCA , empowering terbium sensitization within a supramolecular scaffold supported on paper. The remarkable optical response facilitates quick assessment with a binary answer, and the time-gated signal acquisition ensues improved sensitivity with a detection limit as low as 0.1 mU/mL. Furthermore, to ensure accessibility, particularly in resource-limited areas, we have developed an in loco imaging device as an affordable alternative to high-end instruments. The integration of the assay with the device readily identified the BL-associated drug-resistant strains in the mimic urinary tract infection samples within 2 h, demonstrating its excellent potential for in-field translation. We believe that this rapid paper-based POC assay, coupled with the in loco device, can be deployed anywhere, especially in developing regions, and will enable extensive surveillance on antibiotic-resistant infections.

Rapid and accurate detection of carbapenemase-producing Enterobacteriaceae (CPE) is important for preventing their spread in health care settings. We compared the performance of the Carba NP (CNP) test using the CLSI tube method with that using a modified paper strip method for the detection of carbapenemases in 390 Enterobacteriaceae isolates. The isolates were identified by Hong Kong's carbapenem-resistant Enterobacteriaceae surveillance program in 2016 and comprised 213 CPE and 177 carbapenemase-negative Enterobacteriaceae isolates. Molecular genotype was used as the reference. The test results were read at different time points for the CLSI method (1 min, 5 min, 1 h, and 2 h) and strip method (1 min and 5 min). The strip CNP and CLSI CNP tests correctly detect carbapenemase production in 93% and 93% of KPC producers, 100% and 38% of IMI producers, 94% and 85% of IMP producers, 98% and 90% of NDM producers, and 29% and 12% of OXA producers, respectively. Overall, the strip method has superior sensitivity to the CLSI method (86% versus 75%, respectively; P < 0.001, McNemar test). The specificity of both methods was 100%. By the CLSI method, 27%, 14%, 29%, and 6% of the CPE isolates were positive at 1 min, 5 min, 1 h, and 2 h, respectively. In contrast, by the strip method, 76% of the CPE isolates were positive at 1 min, and an additional 10% were positive at 5 min. In conclusion, the Carba NP test by use of the modified strip method has a higher sensitivity and a shorter assay time than that those by use of the CLSI tube method., (Copyright © 2017 American Society for Microbiology.)

Carbapenemase-producing Enterobacteriaceae (CPE) isolates have now emerged worldwide. We therefore modified the phenotypic Carba NP test by use of a filter paper strip for easily and rapidly identifying CPE in routine laboratory. A collection of 56 CPE and carbapenemase-producing Pseudomonas spp. isolates (including 28 NDM-1, 11 IMP-14a, 1 IMP-1, 1 IMP-4, 1 IMP-9, 1 IMP-15, 4 VIM-2, 1 VIM-1, 1 IMP-14a with VIM-2, 3 OXA-48, 3 OXA-181 and 1 KPC-2 producers) and 41 non-CPE isolates (including 19 ESBL, 7 pAmpC, 3 AmpC, 9 ESBL with pAmpC and 3 non-ESBL & non-AmpC producers) as confirmed by the PCR methods were tested by the paper strip method using pharmaceutical imipenem/cilastatin as a substrate. Bacterial colonies of each isolate were applied directly on filter paper strips dropped with either imipenem-phenol red (test strip) or phenol red solution alone (control strip). The reaction was read within 5 min. This test failed to detect 3 OXA-181, 2 OXA-48 and 3 IMP-14a producers (85.7 % sensitivity), whereas no false positives were seen (100 % specificity). Further evaluation of the paper strip test in 267 CPE screening-positive isolates from three hospitals by their medical technologists showed 92.0 % sensitivity (100 % for NDM producers) and 100 % specificity compared with the PCR methods. Because of its ease, rapidness and cost effective, the paper strip test has a potential for routine CPE testing in low-resource laboratories particularly in areas with high prevalence of NDM enzymes, leading to appropriate antimicrobial therapy and infection control strategy.

Background: Rapid detection of carbapenemase-producing gram-negative bacilli (GNB) is required for optimal treatment of infected patients. We developed and assessed a new disk carbapenemase test (DCT)., Methods: Paper disks containing 0.3 mg of imipenem and bromothymol blue indicator were developed, and the performance of the DCT were evaluated by using 742 strains of GNB with or without carbapenemases., Results: The paper disks were simple to prepare, and the dried disks were stable at -20°C and at 4°C. The DCT detected 212 of 215 strains (98.6% sensitivity with 95% confidence interval [CI] 96.0-99.5%) of GNB with known class A (KPC and Sme) and class B (NDM, IMP, VIM, and SIM) carbapenemases within 60 min, but failed to detect GES-5 carbapenemase. The DCT also detected all two Escherichia coli isolates with OXA-48, but failed to detect GNB with OXA-232, and other OXA carbapenemases. The DCT showed 100% specificity (95% CI, 99.2-100%) in the test of 448 imipenem-nonsusceptible, but carbapenemase genes not tested, clinical isolates of GNB., Conclusions: The DCT is simple and can be easily performed, even in small laboratories, for the rapid detection of GNB with KPC, NDM and the majority of IMP, VIM, and SIM carbapenemases.

Resistance to β-lactam antibiotics in Gram-negative bacteria is commonly associated with production of β-lactamases, including extended-spectrum β-lactamases (ESBLs) and carbapenemases belonging to different molecular classes: those with a catalytically active serine and those with at least one active-site Zn 2+ to facilitate hydrolysis. To counteract the hydrolytic activity of these enzymes, combinations of a β-lactam with a β-lactamase inhibitor (BLI) have been clinically successful. However, some β-lactam-BLI combinations have lost their effectiveness against prevalent Gram-negative pathogens that produce ESBLs, carbapenemases or multiple β-lactamases in the same organism. In this Review, descriptions are provided for medically relevant β-lactamase families and various BLI combinations that have been developed or are under development. Recently approved inhibitor combinations include the inhibitors avibactam and vaborbactam of the diazabicyclooctanone and boronic acid inhibitor classes, respectively, as new scaffolds for future inhibitor design.

This study was conducted to isolate and identify extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales in conventional and organic chicken meats, which were sold in Turkey. A total of 200 raw chicken meat sample (100 conventional and 100 organic) were used as material. Classic culture technique based on chromogenic method was used for the isolation of bacteria, and the identification was performed with VITEK MS. Phenotypic ESBL production was detected by combined disc diffusion method. Gene regions responsible for ESBL production were determined by PCR. MIC values of isolates were detected by VITEK 2. Phenotypic ESBL-producing Enterobacterales were detected in 46% of conventional chicken meats and in 22% of organic chicken meats. Of the 115 isolates obtained, 97 (84%) were Escherichia coli, 12 (10%) were Klebsiella pneumoniae, four (3·48%) were Serratia fonticola, one (0·87%) was Rahnella aquatilis, and one (0·87%) was Serratia liquefaciens. PCR analysis revealed that 109 of 115 isolates (94·78%) contained at least one of the bla CTX-M , bla TEM , and bla SHV genes. Of the 115 ESBL-producing isolates, 103 (89·57%) were found resistant to at least one antibiotic except for the β-lactam group. The contamination level of ESBL-producing Enterobacterales was higher in conventional chicken meats (P < 0·001)., (© 2021 The Society for Applied Microbiology.)

According to the World Health Organization, bacterium Acinetobacter baumannii is the first on the critical priority list of pathogens in urgent need for new antibiotics. The increasing resistance of A. baumannii to the last-line treatment options, including carbapenems, is a global problem. We report the molecular epidemiology of 12 carbapenem-resistant clinical isolates of A. baumannii collected from hospitalised patients in three neighbouring countries in Southeast Europe: Croatia, Serbia, and Bosnia and Herzegovina, giving an insight into the molecular characterisation and evolutionary history of the acquisition of resistance genes. Besides the blaOXA-23 gene, the endemic presence of OXA-72 oxacillinase of the same origin for more than a decade as the leading mechanism of carbapenem resistance in Southeast Europe was confirmed. To the best of our knowledge, this is the first paper that investigates and analyses the phylogenetic association of the most common mechanisms of resistance to carbapenems in clinical isolates of A. baumannii originating from three neighbouring countries in Southeast Europe.

Background: Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-KP) has become one of the most important contemporary pathogens, especially in endemic areas., Aims: To provide practical suggestion for physicians dealing with the management of KPC-KP infections in critically ill patients, based on expert opinions., Sources: PubMed search for relevant publications related to the management of KPC-KP infections., Contents: A panel of experts developed a list of 12 questions to be addressed. In view of the current lack of high-level evidence, they were asked to provide answers on the bases of their knowledge and experience in the field. The panel identified several key aspects to be addressed when dealing with KPC-KP in critically ill patients (preventing colonization in the patient, preventing infection in the colonized patient and colonization of his or her contacts, reducing mortality in the infected patient by rapidly diagnosing the causative agent and promptly adopting the best therapeutic strategy) and provided related suggestions that were based on the available observational literature and the experience of panel members., Implications: Diagnostic technologies could speed up the diagnosis of KPC-KP infections. Combination treatment should be preferred to monotherapy in cases of severe infections. For non-critically ill patients without severe infections, results from randomized clinical trials are needed for ultimately weighing benefits and costs of using combinations rather than monotherapy. Multifaceted infection control interventions are needed to decrease the rates of colonization and cross-transmission of KPC-KP., (Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

The radiolabeled drug 99mTc-tazobactam (99mTc-TZB) was developed and assessed as an infection imaging agent in Pseudomonas aeruginosa and Salmonella enterica infection-induced animal models by comparing with inflammation induced animal models. Radiosynthesis of 99mTc-TZB was assessed while changing ligand concentration, reducing agent concentration, pH, and reaction time while keeping radioactivity constant (~370 MBq). Percent labeling of the resulting complex was measured using paper chromatography and instant thin layer chromatography. The analysis of the 99mTc-TZB complex indicated >95% labeling yield and electrophoresis revealed complex is neutral in nature. The biodistribution study also showed predominantly renal excretion; however liver, stomach, and intestine also showed slight tracer agent uptake. The agent significantly accumulated in Pseudomonas aeruginosa and Salmonella enterica infection induced tissues 3.58 ± 0.26% and 2.43 ± 0.42% respectively at 1 hour postinjection. The inflamed tissue failed to uptake noticeable activity at 1 hour time point. The scintigraphic study results were found in accordance with biodistribution pattern. On the basis of our preliminary results, the newly developed 99mTc-TZB can be used to diagnose bacterial infection and to discriminate between infected and inflamed tissues. [ABSTRACT FROM AUTHOR]

Akkermansia muciniphila, a member of the Verrucomicrobiota phylum, is recognized as a key gut microbe and has emerged as a potential next-generation probiotic. Assessment of antibiotic resistance in probiotics is a prerequisite for their application, while very few is studied in Akkermansia species. To address this, eight representative class A β-lactamases (36.90 %-41.30 % identity with known β-lactamases) from the Akkermansia species were screened and found to increase the minimum inhibitory concentration (MIC) of Escherichia coli to β-lactams (2-1024 fold). Secondly, four β-lactamases were successfully purified and identified as extended-spectrum β-lactamase because they exhibited hydrolase activity against β-lactams from penicillin, cephalosporins, and monobactam classes. Based on predicted three-dimensional structure, we hypothesized and validated that serine at 51 position was catalytic amino acid. Thirdly, the genomic context analysis revealed the absence of mobile genetic elements or other antibiotic resistance genes surrounding β-lactamase genes, suggesting they may not be transferable. This study provides a foundational basis for the safety evaluation of Akkermansia species as probiotics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The emergence of RND efflux pump gene cluster tmexCD-toprJ threats the clinical use of tigecycline as a last-resort antibiotic. Co-existence of extended spectrum β-lactamases and tmexCD-toprJ can accelerate the emergence of multidrug resistant or extensively drug-resistant Pseudomonas aeruginosa, leading to the production of high-risk clones. This study identified a novel gene cluster, tmexC6D6.2-toprJ1b, on the chromosome of a high-risk ST233 XDR P. aeruginosa from Chinese retail chicken samples. Genetic feature analysis revealed that a tnfxB6-tmexC6D6.2-toprJ1b-strBA-floR-tet(G)-IS6100-sul1-aadA2-int1-intA structure formed a putative transposition unit. tmexC6D6.2-toprJ1b shared high similarity at the nucleotide level with other tmexCD-toprJ gene clusters. tnfxB6 regulator was located downstream from the tmexC6D6.2-toprJ1b gene cluster and it did not affect bacterial resistance phenotype. The expression of tmexC6D6.2-toprJ1b could reduce the growth of E. coli and bring a moderate fitness cost. Further studies are needed to decipher the mechanism of the silencing of tnfxB6 in mediating the high-level resistance of tmexC6D6.2-torpJ1b and continuously monitor the coexistence of the novel tmexCD-toprJ gene cluster and the ESBLs-related resistance genes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Animal food products are important sources of zoonotic agents, increasing the risk of exposure to antibiotic-resistant bacteria from farm to fork. Therefore, we aimed to detect and fully characterise Extended-Spectrum Beta-Lactamase (ESBL)-producing E. coli from the poultry sector in a One Health approach. From December 2021 to March 2022, 48 chicken meat samples were collected from 16 establishments in La Rioja (Northern Spain). Antibiotic susceptibility testing was assessed by the disk-diffusion method. Forty E. coli isolates were recovered from 33 of the 48 chicken meat samples tested (68.8%) when plated on MacConkey-agar. In addition, six ESBL-E. coli (6/48, 12.5%) were obtained on cefotaxime-supplemented MacConkey-agar, which were Whole-Genome Sequenced. A large diversity of clones and ESBL genes was observed, namely ST1140-E/bla CTX-M-32 (n = 1), ST752-A/bla TEM-52 (n = 1), ST117-B2/bla CTX-M-1 /bla SHV-12 (n = 2), ST10-A/bla SHV-12 (n = 1) and ST223-B1/bla SHV-12 (n = 1). Three IncI1-plasmids (pST3-CC3) were found carrying the bla SHV-12 /bla CTX-M-1 /bla CTX-M-32 genes in two genetic environments: i) IS26-smc-glpR-bla SHV-12 -IS26; and ii) wbuC-bla CTX-M-32 /bla CTX-M-1 -ISEcp1. The bla TEM-52 gene was carried on a P1-like phage-plasmid flanked by an IS4-mediated composite transposon. An IncHI2 plasmid harboured a bla SHV-12 gene flanked by an IS26-mediated composite transposon but also additional genes conferring resistance to aminoglycosides, chloramphenicol, and sulphonamides. To analyse the cross-sectoral relatedness of our ESBL-E. coli isolates, our six genomes were mapped with publicly available genomes (n = 2588) related to the STs detected, revealing that one of our genomes (X3078-ST117) displayed strong similarities (34-40 allelic differences) with few genomes belonging to ST117 from the poultry sector from Germany and USA. This study demonstrated that the proportion of ESBL-E. coli is still high in chicken meat in Spain. In addition, the ST117 clone and the IncI1-bla CTX-M-1-32 /bla SHV-12 plasmids might represent successful clones and plasmids adapted to the chicken host., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

To prevent foodborne illness, adequate cleaning and disinfection (C&D) is essential to remove pathogenic bacteria from the slaughter environment. The aim of this study was to determine the presence of Campylobacter spp., Listeria monocytogenes, and extended-spectrum beta-lactamase-producing Escherichia coli (ESBL E. coli) before and after C&D in slaughterhouses. Samples from food- and non-food contact surfaces taken before and after C&D in one red meat and one poultry slaughterhouse were analyzed for the target bacteria. Whole-genome sequencing and antimicrobial susceptibility testing were performed. In total, 484 samples were analyzed. Campylobacter spp. were isolated from 13.0% to 15.5% of samples before C&D in the red meat and poultry slaughterhouse, respectively. Listeria monocytogenes was isolated before C&D in 12.5% and 5.2% of samples in the red meat and poultry slaughterhouse, respectively. It was noted that C. jejuni was detected on multiple surfaces and that L. monocytogenes showed potential persistence in one slaughterhouse. After C&D, L. monocytogenes was found in one sample. ESBL E. coli was not detected either before or after C&D. These findings show the possibility to remove pathogenic bacteria from slaughter and meat processing facilities, but also indicate that deficiencies in slaughter hygiene pose a risk of cross-contamination of meat., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: To compare outcomes of ceftriaxone to AmpC-stable therapies in patients with bacteremia caused by low-risk AmpC harboring Enterobacterales., Methods: IRB-approved, retrospective cohort of hospitalized patients ≥18 years old with Serratia marcescens, Morganella morganii, or Providencia spp. bacteremia from 1/1/2017-2/28/2024. Patients were compared by definitive therapy with ceftriaxone vs AmpC-stable therapy (cefepime, carbapenem). The primary endpoint was 30-day all-cause mortality; secondary endpoints were clinical failure and development of ceftriaxone resistance., Results: 163 patients were included; 33.1 % received ceftriaxone, 66.9 % AmpC-stable therapies. 30-day all-cause mortality was 9.3 % ceftriaxone vs 10.1 % AmpC stable patients (P = 0.87); ceftriaxone definitive therapy was not associated with 30-day all-cause mortality (adjOR, 0.79; 95 %CI, 0.23-2.3). There were no differences in clinical failure (9.3 % vs 21.1 %, P = 0.059) or relapsing infection (5.6 % vs 9.3 %, P = 0.55) between ceftriaxone and AmpC-stable treated patients., Conclusions: Patients treated with definitive ceftriaxone for low-risk AmpC Enterobacterales bacteremia had similar outcomes to AmpC stable therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objectives: In vitro activity of β-lactam enhancer/β-lactam combination zidebactam/cefepime was evaluated against carbapenem- and colistin-resistant Klebsiella pneumoniae isolates., Methods: Non duplicate K. pneumoniae (n=185), resistant to colistin as well as non-susceptible to carbapenems were collected (2018-2019) at two large tertiary care hospitals in India. Colistin resistance-conferring genes mcr1 and mcr3 were screened among 123 of 185 randomly-selected isolates. These isolates were also subjected to multi-locus sequence typing (MLST). Additionally, alterations in mgrB were screened in 109 of these 123 isolates. All the study isolates were screened for presence of carbapenemases genes. MICs of zidebactam/cefepime, colistin, carbapenems, ceftazidime/avibactam, imipenem/relebactam, amikacin and piperacillin/tazobactam were determined by reference CLSI broth dilution method., Results: Among the isolates, 65.4% (121/185) carried bla OXA-48-like gene and 27.6% isolates (51/185) carried dual carbapenemase genes; bla OXA-48-like and bla NDM . Of the remainder, 8 isolates carried bla NDM and 5 isolates lacked carbapenemases gene despite being carbapenem-resistant. None of the isolates showed presence of mcr1 and mcr3. Out of 109 isolates analysed for mgrB, 36 showed mutational changes. The MLST profile revealed at least 14 unique sequence types with ST231 being the dominant clone. All the isolates showed colistin MICs >2 mg/L and were non-susceptible to carbapenems. Zidebactam/cefepime demonstrated potent activity with MIC 50 and MIC 90 of 1 and 2 mg/L, respectively. MIC 90 s of amikacin, ceftazidime/avibactam and imipenem/relebactam were >32 mg/L., Conclusion: Zidebactam/cefepime combination was highly active against multi-clonal, carbapenem-non-susceptible and colistin-resistant K. pneumoniae isolates producing OXA-48-like (Ambler class D) or/and NDM (Ambler class B) carbapenemases, thus potentially offering a valuable treatment options for infections caused by such pan-drug resistant resistotypes. Though, zidebactam is not an inhibitor of class B and D β-lactamases, potent activity of zidebactam/cefepime combination is attributable to β-lactam enhancer mechanism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

The increasing challenge of carbapenem antibiotics resistance caused by Pseudomonas aeruginosa is one of the global healthcare problems. P. aeruginosa is a significant opportunistic infection. For epidemiological reasons, identifying resistance genes is essential, and it is also desirable to quickly identify the techniques for producing carbapenemase enzymes. So, the study aims to determine the prevalence of beta-lactamase encoding genes (blaIMP, blaVIM, bla GIM, and bla SPM) phenotypically and genotypically in P. aeruginosa isolates to address the epidemiological spread of these genes in Baghdad city. The study identified P. aeruginosa isolates from various clinical sources by chemical characterization and VITEK 2 system, the antibiogram test, phenotypic screening carbapenem resistance by Combined disk synergy test (CDST), and conventional PCR were used to detect presence of VIM, IMP, SPM, and GIM genes. Bacterial susceptibility testing revealed (40 %) of isolates were resistant to Imipenem and (85 %) of them positive to CDST. Genotypic screening on phenotypic Metallo-β-lactamase isolates showed that (100 %) isolates contained blaVIM genes, blaGIM genes (88 %), whereas (65 %) isolates carried blaSPM genes. In this investigation, there was no evidence of blaIMP among carbapenem-resistant isolates. The study appeared high prevalence of multi-drug resistance P. aeruginosa isolates that produce carbapenemase enzymes and having β-lactamase genes in local hospitalized patients compared to global ratio. Expanding the sample size and types of enzymes screening in MDR P. aeruginosa should be the main focus in the future research., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Sawsan M. Kareem reports administrative support was provided by Mustansiriyah University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Hospital wastewater is a reservoir for the environmental spread of clinically relevant antimicrobial-resistant bacteria and resistance genes. The aim of this study was to quantify total Escherichia coli, extended-spectrum β-lactamase (ESBL)-producing E. coli, and carbapenemase-producing organisms (CPOs) and perform whole-genome sequencing-based characterization of these bacterial isolates in hospital wastewater samples collected bimonthly in Japan from January to November 2021. Total E. coli counts were 8.1 × 10 3 -8.8 × 10 4 colony-forming units (CFU)/mL. ESBL-producing E. coli were detected in the sampling months of January, March, May, and July, with the ratio of ESBL-producing E. coli to total E. coli being remarkably highest (95 %) in July. In contrast, DHA-1 Ambler class C β-lactamase (AmpC)-producing E. coli was detected in September and November, accounting for 28 % and 3 % of total E. coli counts, respectively. All 140 ESBL-producing E. coli isolates harbored the bla CTX-M genes, with bla CTX-M-14 being the most common genotype (94.3 %), the vast majority of which were associated with the human virulent B2-O25b: H4-ST131-fimH30R/non-Rx. In September, E. coli clade I-O8:H33-ST3910-fimH1074 was primarily associated with bla DHA-1 . Among 26 representative CPO isolates, Aeromonas caviae (34.6 %) and A. hydrophila subsp. hydrophila (30.8 %) were dominant. The most frequently detected carbapenemase gene was bla IMP-1 (57.7 %), followed by bla GES-24 (34.6 %) and bla GES-4 (7.7 %). Estimated bacterial counts of CPOs ranged from 4.0 × 10 -1 to 4.7 × 10 3  CFU/mL over the six sampling months. bla IMP-1 -positive A. hydrophila subsp. hydrophila ST860, which was repeatedly detected over the five sampling months, accounted for the highest total number of this bacterial clone (79 %). Overall, this study provides insights into the overwhelming presence and persistence of E. coli B2-O25b:H4-ST131-H30R/non-Rx with bla CTX-M-14 and Aeromonas spp. with bla IMP-1 in hospital wastewater, and the change in the dynamics of resistance gene prevalence from bla CTX-M -positive E. coli to bla DHA-1 -positive E. coli., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The mcr-type gene encodes the main plasmid-mediated mechanism of colistin resistance and has been reported in several bacterial species obtained from different sources. Anthropogenic activities in the environment favor the evolution of antimicrobial resistance. Indeed, mcr-1-positive Escherichia coli strains were susceptible to non-polymyxins antimicrobials, but now emerging as multidrug-resistant (MDR) lineages. In this regard, hundreds of surface water and agricultural soil samples were screened for the presence of E. coli carrying the mcr-type genes and mcr-1-positive strains were subjected to in-depth genomic analysis. Almost all colistin-resistant strains were classified as MDR, highlighting those obtained from soils that showed resistance to extended-spectrum cephalosporins and carbapenems. International and high-risk clones of E. coli were identified, with ST10 and ST1720 shared between water and soil samples. Resistome analysis showed a broad resistome (AMR, metal tolerance, and biocide resistance). The mcr-1.1 and mcr-1.26 allelic variants were detected on IncX4 and IncI2 plasmids. Curiously, mcr-1-positive E. coli strains from agricultural soils harbored plasmid-mediated bla CTX-M-1 , bla CTX-M-8 , or bla KPC-2 genes. Virulome analysis demonstrated traits of a high putative virulence potential, with the presence of extraintestinal pathogenic E. coli. Comparative analysis revealed the persistence and dissemination of plasmid-mediated antimicrobial resistance genes in genetically diversity E. coli strains at the human-animal-environmental interface. These findings demonstrate a possible emerging AMR trend with the convergence of resistance to colistin and broad-spectrum β-lactams in environmental-derived E. coli strains., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background & Aims: The alarming rise of antibiotic resistance presents a substantial and worrisome issue within the context of biliary obstruction, specifically in the treatment of cholangitis. This abovementioned scenario underscores the critical importance of addressing extended spectrum β-lactamase (ESBL) producers in the biliary system to adequately tackle cholangitis using third-generation cephalosporins. Hence, we aimed to determine the frequency of ESBL and carbapenemases among biliary Escherichia coli and Klebsiella pneumoniae isolated from patients with biliary obstruction., Methods: In this cross-sectional study, bile samples were collected via aspiration from patients diagnosed with biliary obstruction during the endoscopic retrograde cholangiopancreatography (ERCP) procedure. Subsequent culturing of these samples was performed, followed by phenotypic and molecular assessments for the detection of ESBL- and carbapenemase-producing strains of E. coli and K. pneumoniae., Results: Approximately 23.5 % of patients with biliary obstruction harbored biliary ESBL-producers, with the majority (70.2 %) being diagnosed with cholangitis. Moreover, 2.1 % of patients had biliary carbapenemase-producing K. pneumoniae strains. Molecular analysis confirmed the high prevalence of bla CTX-M and bla TEM in E. coli, and bla TEM and bla SHV in K. pneumoniae. Additionally, the presence of biliary K. pneumoniae harboring bla KPC , bla NDM , and bla IMP was observed., Conclusion: Our study reveals a noteworthy observation that over half of patients experiencing biliary obstruction harbor ESBL-producing bacteria in their biliary tract. Notably, we discovered a significant link between ESBL producers and the risk of cholangitis. These findings raise important concerns regarding the suitability of employing third-generation cephalosporins as initial treatment for cholangitis and other similar biliary infections., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Purpose: Phenotypic methods have been proposed for the detection of carbapenemase production. These tests can have slower turnaround times. With the sensitivity-based algorithm described by Gill et al. will be possible to detect the carbapenemase., Methods: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates from three hospitals between January 2017 and December 2021 were included. The modified carbapenemase-inactivation-method(mCIM) and two algorithms were used, defined as "primary algorithm, i.e. ceftazidime and cefepime non-susceptible in addition to imipenem or meropenem resistance" and "secondary algorithm, i.e. ceftolozane/tazobactam non-susceptible in addition to imipenem or meropenem resistance". PCR testing was performed on all isolates., Results: 256 CRPA isolates were included in the study. When the primary or secondary algorithm criteria were applied, there were 173 isolates that met one or both of them. Of these, 29 were CIM-positive isolates., Conclusion: In our study, the use of the algorithm reduced the need for CIM testing by 32 %., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Pseudomonas aeruginosa exhibits significant antibiotic resistance facilitated by both intrinsic and acquired mechanisms, prominently through Pseudomonas-derived cephalosporinase (PDC), serine Ambler class C β-lactamases encoded by the AmpC. AmpC, involved in the peptidoglycan recycling pathway, is regulated by genes such as ampD, ampR, and ampG, leading to increased expression and resistance to various beta-lactams. PDCs are classified into three main types: classical class C β-lactamases, extended-spectrum class C β-lactamases (ESAC β-lactamases), and inhibitor-resistant class C β-lactamases. This study aimed to identify prevalent PDC variants and its genetic characteristics in Indian and global P. aeruginosa isolates, focusing on their role in β-lactam resistance. Analyzing PDC sequences from 111 P. aeruginosa isolates collected at Christian Medical College (CMC), Vellore, we found the ESAC allele PDC-447 to be the most widespread among Indian isolates, present in 18 % of carbapenem-resistant and 11 % of carbapenem-susceptible strains. Global and Indian isolates PDC variants were validated using the NCBI PathogenWatch database, and the sequenced PDC region compared to PDC-1. PDC-398 and PDC-397 followed in prevalence among carbapenem-resistant isolates, while PDC-5 (ESAC) and PDC-1 (classical class C) were common in carbapenem-susceptible strains. A global analysis of 19,478 genomes revealed significant prevalence of ESAC variants such as PDC-3 (17.28 %) and PDC-5 (12.91 %), alongside classical class C beta-lactamases like PDC-8 (10.65 %). Indian isolates exhibited distinct patterns with PDC-3 and PDC-5 prevailing at 19.84 % and 10 %, respectively. Mutations in the omega loop, H-helix, and R2 region of PDCs were linked to enhanced antibiotic resistance, particularly the T105A mutation in the H-helix region. These findings underscore the complexity of antimicrobial resistance mechanisms in P. aeruginosa and highlight the need for novel therapeutic strategies and continuous surveillance to manage infections by this versatile pathogen. Understanding the prevalence and genetic characteristics of PDC variants is crucial for effective treatment strategies against P. aeruginosa and combating antibiotic resistance., Competing Interests: Declaration of competing interest Dr. Balaji Veeraraghavan reports financial support was provided by Christian Medical College Vellore. Dr. Balaji Veeraraghavan reports financial support was provided by Indian Council of Medical Research. Dr. Balaji Veeraraghavan reports a relationship with Christian Medical College Vellore that includes: employment. Dr. Balaji Veeraraghavan has patent pending to NA. NA If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: E. coli ST8346 is a unique strain associated with the potential carriage of multiple carbapenemases. Three unique E. coli ST8346 isolates were identified, each concurrently harboring multiple carbapenemases, including bla NDM-5 , bla KPC-2 , and/or bla OXA-181 . This study aimed to characterize the genetic and plasmid structures of these isolates to understand their transmission and resistance mechanisms., Methods: Antibiotic resistance profiles, genetic relatedness, and plasmid structures were determined using antibiotic susceptibility testing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), S1 nuclease PFGE, and long-read sequencing., Results: All the strains were carbapenem resistant. PFGE revealed close genetic relationships among the isolates, despite the lack of geographical or epidemiological connections. bla NDM-5 , bla KPC-2 , and bla OXA-181 were located on separate plasmids. Plasmids harboring bla NDM-5 showed genetic similarities to bla NDM-5 -bearing IncF plasmids in the United Kingdom. The IncA/C plasmids harboring bla KPC-2 had identical sequences resembling a plasmid from a K. pneumoniae strain in Taiwan, except for the bla KPC-2 region, which matched a strain from China, indicating a hybrid plasmid., Conclusion: This study is the first to identify and characterize the coexistence of bla NDM-5 , bla KPC-2 , and bla OXA-181 in E. coli ST8346 isolates. The spread appears to be due to independent acquisition events. We identified the putative origins of these plasmids and detected a possible recombination event in a novel IncA/C plasmid. These findings emphasize the importance of ongoing surveillance and further investigations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objectives: Wet hospital environments have been documented as potential reservoirs for Carbapenemase-producing Enterobacteriaceae (CPE), possibly contributing to outbreaks among inpatients. Our objectives were to assess the prevalence of CPE reservoirs in a hospital's wet environments and to investigate the contamination of adjacent dry surfaces., Methods: From March to August 2023, we conducted a cross-sectional study in two hospital wards experiencing ongoing large outbreaks. Sampling of the environment was undertaken in two distinct phases. During phase 1, 38 shower drains and 38 toilet bowls, defined as the wet environment, were sampled using swabs. Phase 2 consisted in sampling adjacent dry surfaces, using wipes in rooms that had tested positive during phase 1. Samples were plated on a selective medium (chromID®CARBASMART, bioMérieux). Species were identified using the matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) technique. Carbapenemases were detected by OKNVI RESIST-5® (CORIS BioConcept)., Results: From the 38 patient rooms, 76 samples were taken during phase 1. All in all, 33 (86.8%) rooms presented at least one CPE reservoir in the wet environment; there were 32 (84.2%) contaminated shower drains and six (15.8%) contaminated toilet bowls. Among 57 identified CPEs, the most frequent strain was Enterobacter cloacae VIM (13, 22.8%). During phase 2, 11 (8.3%) out of 132 samples tested positive for CPE. Enterobacter cloacae complex VIM accounted for six (54.5%) of the CPE strains., Conclusion: These findings suggest that the wet hospital environments were broadly contaminated with CPE, mostly Enterobacter cloacae VIM. The spread of CPE from wet environments to dry surfaces seemed limited., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

To improve the understanding of antimicrobial resistance (AMR) in migratory birds derived-Enterobacter cloacae (E. cloacae) complex and its spread at the human-bird-environment interface, we isolated 11 strains of third-generation cephalosporin-resistant E. cloacae from 1003 specimens from 29 migratory bird species over two years in Chongming, Shanghai, China. The comprehensive analysis incorporated second- and third-generation sequencing techniques and extensive bioinformatic analysis. Four human-associated E. cloacae sequence types (STs), including ST432, ST412, ST1, and ST639, were found in migratory birds. We confirmed that the bla CMH-4 and bla CMH-6 genes were the major genotypes of the β-lactamase resistance genes in E. cloacae found in migratory birds. In addition, a thorough genomic analysis was performed on a global collection of 398 E. cloacae isolates carrying the bla CMH gene from 46 different countries. China had the highest proportion with 19.10 % (76/398), followed by Singapore with 18.34 % (73/398), Nigeria with 15.83 % (63/398), and the USA with 14.07 % (56/398). The first transmission of E. cloacae carrying bla CMH-4 and bla CMH-6 was defined around 1894 and 1549, respectively. Time-based phylogenetic analysis revealed that host jumps among humans, birds, and the environment led to the emergence of modern strains with ESBL- and carbapenem-resistant genes from about 2004 to 2016. The detection rate of insertion sequences (IS) of E. cloacae carrying bla CMH from human sources is higher than that from migratory bird sources, which is related to the different genetic environments caused by antibiotic selective pressure. It is crucial to have a comprehensive understanding of the characteristics exhibited by bla CMH producing E. cloacae in different ecological environments. Our results contribute to the effective monitoring and implementation of proactive strategies to reduce the spread of multidrug-resistant E. cloacae., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Aim: This study aimed to analyze the prevalence, phenotypes, and carriage of resistance genes of carbapenem-resistant Klebsiella michiganensis strains isolated in our hospital., Method: ology: Four K. michiganensis strains were collected from January 2015 to December 2023. Antimicrobial susceptibility was tested using 21 antibiotics with the BD Phoenix™ M50 System. Whole-genome sequencing of the four strains was performed on an Illumina NovaSeq 6000 platform. Species identification was performed using Kleborate software, sequence type (ST) was performed using MLST, and prediction of antibiotic resistance genes and virulence genes were performed using ABRicate. PlasmidFinder was used to search for plasmids. Whole genome data from 211 strains of carbapenem-resistant K. michiganensis were downloaded from the NCBI database; together with the strains in this study, these data were used to construct an phylogenetic tree using genome single nucleotide polymorphisms (SNP)., Results: Antimicrobial susceptibility showed that K. michiganensis was highly resistant to β-lactams. For the three carbapenems, strain WF0046 was only resistant to ertapenem, while WF0047, WF0052, and WF0053 were resistant to all three carbapenems tested. The four strains of K. michiganensis only showed complete sensitivity to polymyxin E and tigecycline. The four K. michiganensis strains were found to have 43 resistance genes, and all carried carbapenem resistance genes; WF0046 carried the carbapenem resistance gene bla IMP-4 , while the other three strains carried bla NDM-1 . Among the other resistance genes, β-lactam resistance genes were predicted most (11 types), followed by eight types of aminoglycoside resistance genes. Of the strains characterized in this study, WF0046 belonged to ST158, WF0047 belonged to ST40, WF0052 belonged to ST533, and WF0053 belonged to ST13. These four strains, along with 211 carbapenem-resistant K. michiganensis strains downloaded from NCBI, were divided into five clades; WF0052 belonged to clade A, WF0046 belonged to clade C, and WF0047 and WF0053 both belonged to clade D. The four strains had relatively distant genetic relationships; WF0046, WF0047, and WF0053 were closely related to strains of human origin from other regions of China, while WF0052 was genetically close with a strain of K. michiganensis isolated in the United States., Conclusion: The strains of K. michiganensis from our hospital were resistant to multiple antibiotics, and all strains carried carbapenem resistance genes along with multiple other antibiotic resistance genes. The phylogenetic results showed that these four strains had distant genetic relationships and different ST types, indicating that they came from different sources and the possibility of polyclonal transmission., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Antimicrobial resistance (AMR) is a major global public threat, now largely reported in natural environments. Seabirds are carriers of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E. coli), but different foraging and breeding behaviour could impact ESBL-E. coli circulation. We compared the prevalence and genetic determinants of ESBL-E. coli from resident Kelp gulls (Larus dominicanus, Ld), migratory Franklin's gulls (Larus pipixcan, Lp), and endemic Peruvian pelicans (Pelecanus thagus, Pt) from the Humboldt Current Ecosystem (HCE) of central Chile. From 2020 to 2022, we collected 699 fresh faecal samples (Ld = 449, Lp = 116, Pt = 134), and isolated 271 ESBL-E. coli (39 %). Whole-genome-sequencing (WGS) was performed on 85 E. coli selected isolates to identify their Sequence Type (ST), AMR genes, virulence genes, mobile genetic elements (MGE), and to assess potential interspecies transmission. ESBL-genes were detected in the remaining ESBL-E. coli isolates by PCR. ESBL-E. coli prevalence in Ld (46 % [CI: 42-51 %]) and Pt (34 % [CI: 27-43 %]) was higher than in Lp (15 % [CI: 9-22 %]). WGS revealed 41 ESBL-E. coli STs including pandemic clones ST10, ST58, ST131 and ST410. The blaCTX-M-1 and blaCTX-M-15 genes were the most prevalent among ESBL genes, and were mostly associated with MGE IncI1-I(Alpha) and ISEc9. We also report the pAmpC blaCMY-2 gene associated to MGE Inc1-I(Alpha) and IS640 in two E. coli from a Ld and a Lp. Eight ESBL-E. coli of the same ST were shared by at least two seabird species, including ST10 (Ld and Pt); ST88, ST410 and ST617 (Pt and Lp); ST38, ST58, ST131, and SST1722 (three species). Single nucleotide polymorphism (SNP) phylogenetic analyses of ST38, ST617 and ST1722 showed a low difference of SNPs between STs found in different seabird species, suggesting ESBL-E. coli clonal exchanges. Our results highlight ESBL-E. coli dissemination across seabirds of the HCE, including species that unusually forage on human waste like pelicans., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The widespread dissemination of carbapenem-resistant bacteria in wastewater systems, particularly from clinical sources, poses a significant public health risk. This study assessed the concentrations and distributions of extracellular DNA (exDNA) and intracellular DNA (iDNA) harboring carbapenemase genes in wastewater from six tertiary care hospitals in Germany. We collected a total of 36 samples, comprising six biological replicates from each hospital, and analysed them using quantitative real-time PCR (qPCR) and digital PCR (dPCR). The analysis targeted seven carbapenemase genes: bla NDM , bla KPC , bla IMP , bla VIM , bla OXA-23-like , bla OXA-48-like , and bla OXA-58-like across both DNA fractions. Our results revealed significant variability in the concentrations of exDNA and iDNA across the sampling sites, with iDNA typically present at higher concentrations. Using NanoDrop One spectrophotometry and the Qubit dsDNA kit, exDNA concentrations ranged from 2.7 to 7.7 ng/mL, while Qubit recorded lower values between 1.1 and 4.0 ng/mL. Conversely, iDNA concentrations were markedly higher, spanning from 42.3 to 191.7 ng/mL with NanoDrop and 12.0 to 46.5 ng/mL with Qubit, highlighting the variability between DNA types and quantification methods. Despite its lower concentrations, exDNA comprised up to 18.2 % of total DNA, highlighting its potential role in the horizontal transfer of antimicrobial resistance genes (ARGs). The study detected target ARGs in both DNA fractions at all sites, with notable differences in their concentrations; iDNA consistently exhibited higher levels of ARGs, with the highest concentrations reaching 10.57 ± 0.20 log gene copies per liter (GC/L) for bla VIM in iDNA and 6.96 ± 0.72 log GC/L for bla IMP in exDNA. dPCR demonstrated greater sensitivity than qPCR, especially effective for detecting low-abundance targets like bla OXA-23-like in the exDNA fraction. Additionally, qPCR's susceptibility to inhibition and contamination emphasizes the superior robustness of dPCR. This research highlights the need for improved monitoring and the implementation of advanced treatment technologies to mitigate ARG dissemination in wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Following a one-health approach, we sought to determine reservoirs of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-PE), other than Escherichia coli or Klebsiella pneumoniae complex species (i.e., low-abundant species), and their associated ESBL genes and plasmid-replicon profiles., Methods: From 06/2017-05/2019, ESBL-PE isolates were recovered from clinical samples routinely collected at the University Hospital Basel (Basel, Switzerland), as well as from wastewater and foodstuffs collected monthly at predefined locations throughout the city of Basel. Whole-genome sequencing was performed for characterization of ESBL-PE isolates., Results: Among 1634 isolates recovered, 114 (7%) belonged to 17 low-abundant ESBL-PE species. Seven species originated from more than one compartment, mainly from clinical and wastewater samples (6/17). Sixteen different ESBL genes were identified, with bla CTX-M-15 (27%), bla FONA-6 (23%) and bla SHV-12 (16%) being most frequent. The bla CTX-M-1 gene was the only ESBL gene recovered from all three compartments. Putative plasmids constituted 60% of ESBL gene-containing contigs, while chromosomes comprised 40%. Foodstuff isolates showed the highest proportion (91%, 41/45) of ESBL genes located on chromosomes, whereas wastewater isolates had the highest proportion (95%, 37/39) of putative plasmids. Multi-replicon combinations were identified in 81% of the isolates. Epidemiological links were found among some clinical and wastewater isolates., Conclusions: The dominance of bla CTX-M-15 among low-abundant ESBL-PE species supports its species-independent transmission potential beyond the E. coli and K. pneumoniae complex, and bla CTX-M-1 may be transmitted between strains recovered from different compartments. The substantial overlap between low-abundant ESBL-PE present in wastewater and clinical samples supports the utility of wastewater surveillance for antibiotic resistance monitoring., Competing Interests: Declaration of competing interest Sarah Tschudin-Sutter reports financial support was provided by Swiss National Science Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Carbapenem-resistant Klebsiella pneumoniae producing metallo-β-lactamase poses a major public health threat worldwide. Imipenemase often coexists with other resistance genes leading to the formation of multidrug-resistant bacteria. In this study, we describe the microbiological and genomic characteristics of the hypervirulent carbapenem-resistant K. pneumoniae ST20-K23 strain KPN945 harboring bla IMP-4 and qnrS1 . The minimum inhibitory concentration of KPN945 against antimicrobials was determined by the broth microdilution method. The virulence of KPN945 was evaluated through string test, serum killing resistance, and Galleria mellonella larvae infection models. The transferability of pKPN945B was assessed using a conjugation test. The genome sequence characteristics of KPN945 were analyzed through whole genome sequencing, and a phylogenetic tree was constructed to evaluate the prevalence of imipenemase. Our findings showed that KPN945 was non-susceptible to β-lactam antibiotics, highly resistant to serum killing, and highly lethal to G. mellonella larvae. The fusion plasmid pKPN945B carried by the isolate KPN945 belonged to the IncR incompatibility group and harbored multiple drug resistance genes such as bla IMP-4 , bla CTX-M-14 , qnrS1 , and sul2 . The most important point is that the IncR plasmid is a novel plasmid that arose by the accretion of parts from different plasmids, making it transferable and with a fitness cost. Globally, bla IMP-4 is the most prevalent imipenemase subtype, with the highest isolation rates in Asia, particularly China. The spread of bla IMP-4 , especially the emergence of transferable plasmids, deserves our vigilance and prevention. Additionally, we should pay attention to the formation of hypervirulent K. pneumoniae mediated by non-virulent plasmids., Importance: Up to now, IncR replicons carrying bla have not been reported, and the IncR plasmids described in previous studies have been found to be non-transferrable to other bacteria through conjugation. Moreover, there have been no extensive phylogenetic analyses of strains carrying blaIMP in the published papers. The lack of data in these studies is noteworthy because blaIMP appears in the novel transferable fusion plasmid IncR. Although the IncR plasmid has no tra operon, it can still be transferred to IMP-4 have not been reported, and the IncR plasmids described in previous studies have been found to be non-transferrable to other bacteria through conjugation. Moreover, there have been no extensive phylogenetic analyses of strains carrying blaIMP in the published papers. The lack of data in these studies is noteworthy because blaIMP appears in the novel transferable fusion plasmid IncR. Although the IncR plasmid has no tra operon, it can still be transferred to Escherichia coli EC600 or Klebsiella pneumoniae ATCC13883 (RIF R ) without high fitness cost, but it only affects the MIC of imipenem. bla IMP integrates with other resistance mechanisms leading to the formation of multidrug-resistant strains. Notably, the high prevalence of bla IMP-4 in Asia and the presence of bla IMP-4 on novel transferable IncR plasmids suggest the urgent need to monitor the emergence of such plasmids and control their spread., Competing Interests: The authors declare no conflict of interest.

The emergence of carbapenem-resistant bacteria especially carbapenem-resistant Escherichia coli (CREC) in food animals poses a serious threat to food safety and public health. Reports about the dissemination of carbapenem-resistant bacteria along the food animal production chain are scattered and mainly focus on swine and chicken. Abuse of antibiotics in duck farms is common especially in China which has the largest duck production industry, however, the CREC transmission between farmed ducks and slaughtered meats remains unclear and the role of slaughterhouse in disseminating CREC among duck meats remains largely unknown. Herein, we collected 251 fecal samples from five typical duck farms along with 125 slaughtered meat samples (25 from each farm) in the corresponding slaughterhouse in Anhui Province, China, in December 2018. All samples were screened for CREC isolates which were analyzed for the presence of carbapenemase genes and colistin resistance gene mcr. The resistance profiles, transferability, pulsed-field gel electrophoresis (PFGE), whole-genome sequencing and phylogenetic analysis of the CREC isolates from both ducks and meats were further characterized. This is the first report presenting the high prevalence of bla NDM -positive CREC isolates in ducks from duck farms (57.8 %) and slaughtered meats (33.6 %) in the corresponding slaughterhouse. Among the 203 bla NDM -positive CREC isolates obtained in this study, 19.2 % harbored mcr-1 and all CREC isolates showed resistance to nearly all currently available antibiotics (except tigecycline). Of note, mcr-1 was found in 17.8 % of the meat-derived CREC carrying bla NDM . Based on the PFGE analysis, clonal spread of bla NDM -positive CREC including some also carrying mcr-1 was found between farmed ducks and slaughtered duck meats even from different farms. Special attention should be paid to the clonal dissemination of meat-derived CREC within the slaughterhouse, which contributed to the high prevalence of bla NDM in slaughtered meats. Additionally, horizontal transmission mainly mediated by transferable bla NDM-5 -bearing IncX3 plasmids, untypable bla NDM-1 -bearing plasmids and mcr-1-bearing IncHI2 plasmids further facilitated the rapid spread of such multidrug-resistant strains. Notably, the bla NDM -bearing plasmids and mcr-1-bearing plasmids in CREC from meats were highly similar to those from animals and humans. More worryingly, the phylogenomic analysis showed that CREC isolates from both ducks and corresponding meats clustered with previously reported human CREC isolates carrying mcr-1 in different geographical areas including China. These findings further prove that the CREC and resistance plasmids in farmed ducks could transmit to meats even from different farms via the slaughterhouse and then trigger infections in humans. The high prevalence and clonal transmission of CREC isolates including those also carrying mcr-1 between ducks and meats are alarming, and urgent control measures are required to reduce the dissemination of such organisms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The intensification of livestock farming has led to the widespread use of massive amounts of antibiotics worldwide. Poultry production, including white meat, eggs and the use of their manure as fertiliser, has been identified as one of the most crucial reservoirs for the emergence and spread of resistant bacteria, including E. coli in poultry as an important opportunistic pathogen representing the greatest biological hazard to human and wildlife health. Thus, this study aimed to analyse E. coli in the faecal carriage of healthy poultry flocks and to investigate the phenotypic and genotypic characteristics of antimicrobial resistance, including integrons genes and phylogenetic groups. A total of 431 cloacal swabs from apparently healthy poultry from four regions in Eastern Algeria from December 2021 to October 2022. 360 E. coli were isolated; from broilers (n = 151), broiler breeders (n = 91), laying hens (n = 72), and breeding hens (n = 46). Among this, 281 isolates exhibited multidrug resistance (MDR) phenotype, 17 of the 360 E. coli isolates exhibited ESBL, and one isolate exhibited both ESBL/pAmpC. A representative collection of 183 among 281 MDR E. coli was selected for further analysis by PCR to detect genes encoding resistance to different antibiotics, and sequencing was performed on all positive PCR products of bla CTX-M and bla CMY-2 genes. Phylogenetic groups were determined in 80 E. coli isolates (20 from each of the four kinds of poultry). The bla CTX-M gene was found in 16 (94.11 %) ESBL-producing E. coli isolates within 11 strains co-expressing the bla SHV gene and 8 strains co-expressing the bla TEM gene. Sequence analysis showed frequent diversity in CTX-M-group-1, with bla CTX-M-15 being the most predominant (n = 11), followed by bla CTX-M-1 (n = 5). The bla CMY-2 gene was detected only in one ESBL/pAmpC isolate. Among the 183 tested isolates, various antimicrobial resistance genes were found (number of strains) bla TEM (n = 121), bla SHV (n = 12), tetA (n = 100), tetB (n = 29), sul1(n = 67), sul2 (n = 32), qnrS (n = 45), qnrB (n = 10), qnrA (n = 1), catA1(n = 13), aac-(6')-Ib (n = 3). Furthermore, class 1 and class 2 integrons were found in 113 and 2 E. coli, respectively. The isolates were classified into multiple phylogroups, including A (35 %), B1 (27.5 %), B2 and D each (18.75 %). The detection of integrons and different classes of resistance genes in the faecal carriage of healthy poultry production indicates that commensal E. coli could potentially act as a reservoir for antimicrobial resistance, posing a significant One Health challenge encompassing the interconnected domains of human, animal health and the environment. Here, we present the first investigation to describe the diversity of bla CTX-M producing E. coli isolates with widespread detection of CTX-M-15 and CTX-M-1 in healthy breeders (Broiler and breeding hens) in Eastern Algeria., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Extended-spectrum β-lactamases (ESBLs)-producing E. coli have been proposed as an indicator bacterium for antimicrobial resistance (AMR) surveillance within a OneHealth framework. However, it is important to understand the effects and potential biases ESBL-selection has on E. coli populations. Utilising whole genome sequencing, this study compared 80 ESBL-selected E. coli isolates with 201 non-selected isolates from Australian wastewater. The findings revealed significant variations between these cohorts in genetic diversity, AMR profiles, and carriage of virulence-associated genes (VAGs), plasmids, and the transmissible Locus of Stress Tolerance (tLST), a genomic island that imparts resistance to extreme heat and chlorination. The study highlights the predominance of certain sequence types (STs), particularly ST131 (75 % clade A), in ESBL-selected isolates (40 % vs 2 %) and overall the ESBL-selected isolates were largely multidrug-resistant (MDR), predominantly carrying genes for resistance to aminoglycosides, extended-spectrum β-lactams, fluoroquinolone, macrolides, sulphonamides/trimethoprim, and tetracyclines. The ESBLs identified were almost exclusively bla CTX-M genes, most commonly bla CTX-M-15  > bla CTX-M-27  > bla CTX-M-14 . These were predominately carried on IncF plasmids or chromosomally (always ISEcp1 associated), in equal numbers. In contrast, 80 % of non-selected isolates carried no acquired ARGs, and none carried bla CTX-M genes. In both cohorts, extraintestinal pathogenic E. coli (ExPEC) was the dominate pathotype (35 % total) with few (4 % total) intestinal pathogenic E. coli pathotypes identified (aEPEC > ETEC > EAEC). Nevertheless, some clinically important genes were only identified in the non-selected group, namely tigecycline-resistance gene tet(X4) and AmpC ESBL bla CMY-2 . Additionally, the presence of tLST, associated with higher metal resistance gene carriage (Ag, As, Cu, Hg, Ni), in a substantial portion of non-selected isolates (20 % vs 0 %), underscores environmental pressures shaping bacterial populations in wastewater ecosystems. These insights are important for developing comprehensive, less biased genomic surveillance strategies to understand and manage public health threats posed by pathogenic E. coli and AMR., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Dissemination of antimicrobial resistance in food animals is a One Health concern, but sheep production has been overlooked. This study aimed to explore the dissemination of Escherichia coli resistant to extended-spectrum cephalosporins (ESC) in feedlot lambs. Two pens were sampled on two occasions, and carcasses and other mammals living around were also tested. E. coli were recovered and antibiotic resistance determined. bla CTX-M/CMY genes and their genetic localization were characterized. Whole genome sequencing (WGS) was performed to confirm clonal relationship. The most prevalent ESC-resistance genes in the 108 E. coli isolates were bla CTX-M-55 (53.7 %), bla CTX-M-2 (14.8 %) and bla CMY-2 (13.9 %). Most bla CTX-M-55 genes were found on the chromosome, but IncA/C, IncHI1, IncHI2 and IncF plasmids were also identified. Genetic diversity was observed even though ST6448 was by far the most frequent ST. WGS analysis showed high similarity among isolates recovered from feedlot lambs, animals in the surroundings and lambs' carcasses, proving the clonal and plasmidic dissemination., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. None., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Fresh produce is usually consumed raw or minimally processed, making it a potential vehicle for the transmission of antimicrobial-resistant (AMR) microorganisms to humans. The objective of the study was to assess the occurrence of extended-spectrum ß-lactamase (ESBL)- and carbapenemase-producing Enterobacterales (ESBL-E and CPE), respectively, in 118 fresh herbs and 101 bagged salads collected at retail level in Switzerland and to characterize the isolates' phenotypic and genotypic properties using culture-based methods and whole genome sequencing (WGS). Of the fresh herbs, 6/118 contained ESBL-E and 7/118 yielded CPE. Of the salads, 13/101 contained ESBL-E and 1/101 CPE. Antimicrobial susceptibility testing (AST) identified 9/29 isolates as multidrug-resistant (MDR). ESBL-E were Escherichia coli (n = 6), Klebsiella pneumoniae (n = 4) Enterobacter chuandaensis (n = 1), and Kluyvera spp. (n = 1) carrying ß-lactamase (bla) genes belonging to the cefotaximase-München (bla CTX-M )-groups, Proteus spp. (n = 1) containing Hôpital-Universitaire-de-Genève-bla (bla hugA ), Raoultella ornithinolytica (n = 1) carrying sulfhydryl reagent variable bla (bla SHV ), and Serratia fonticola (n = 7) carrying S. fonticula bla (bla FONA ) genes. CPE were Enterobacter asburiae (n = 1) E. cloacae (n = 6) and E. vonholyi (n = 1) carrying imipenemase bla (bla IMI ) genes. Several K. pneumoniae sequence types (STs) were identified (ST967, ST628, ST219, and ST1823), which have been linked to human disease and nosocomial outbreaks. They carried bla CTX-M-15 on plasmids detected globally in environmental and clinical samples. E. coli (ST10, ST48, ST609, ST2040, ST6215 and ST3580) and enterotoxigenic E. coli (ETEC) ST2040 carrying bla CTX-M-15 were found. E. cloacae (ST820 and ST1516) with bla IMI-1 have been found previously in clinical settings and community outbreaks. The occurrence and consumption of fresh produce containing MDR ESBL-E and CPE pose substantial public health risks and raise significant food safety concerns., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: There is a high diversity of beta-lactamases in gram negative pathogens, making them difficult to treat. In the presence of OXA-1 and ampC, PTZ is no longer clinically relevant when treating Enterobacterales expressing ESBLs. Further, MBL infections are often treated with the combination of ceftazidime/avibactam with aztreonam. . It has recently been reported that NDM-expressing E. coli isolates co-harboring PBP3 insert develops resistance to this triple combination., Methods: A pentaplex PCR is developed and validated to simultaneously detect bla CTX-M , bla OXA-1 , bla CMY , bla NDM , and the PBP3 insert in whole genome sequenced E. coli and K. pneumoniae isolates. In addition, the isolates chosen for pentaplex PCR evaluation were tested for their minimum inhibitory concentrations (MICs) against piperacillin/tazobactam, cefoperazone/sulbactam (C/S), ertapenem, imipenem, meropenem, ceftazidime/avibactam, aztreonam/avibactam, cefepime/taniborbactam, and cefiderocol., Results: The developed pentaplex PCR showed 100 % reproducibility with the antimicrobial resistance profile generated from whole genome sequenced data. PTZ and C/S are not effective against ESBL and/or OXA-1 expressing E. coli and K. pneumoniae isolates and do not offer any activity against CMY co-producers. Further, the combined effect of CMY, NDM and PBP3 inserts impacts aztreonam/avibactam activity and reduces the susceptibility to 40 % in E. coli isolates. While, aztreonam/avibactam showed potent activity against NDM-expressing K. pneumoniae isolates. Importantly, cefepime/taniborbactam and cefiderocol showed limited activity against NDM-expressing E. coli and K. pneumoniae isolates., Conclusion: The pentaplex PCR was effective in detecting four beta-lactamases (bla CTX-M , bla OXA-1 , bla CMY , bla NDM ) as well as PBP3 inserts. It is expected that using pentaplex PCR as a diagnostic test for resistance detection in clinical practice will improve patient outcomes by providing prompt and targeted treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

The present study aimed to determine the presence of Klebsiella pneumoniae and Escherichia coli with extended-spectrum β-lactamase (ESBL)s property from treated wastewater effluents. Treated effluent samples were collected from two major water treatment plants which located at Avaniyapuram and Sakkimangalam, Madurai, Tamil Nadu, India. Among the 51 isolates, 56.86 % represented E. coli (18 from Avaniyapuram and 11 from Sakkimangalam) and 43.14 % were K. pneumoniae (7 from Avaniyapuram and 15 from Sakkimangalam). Based on the ESBL propensity, E. coli was overrepresented in the present study. All the isolates turned positive for ESBL, while 5.88 % of K. pneumoniae and 7.84 % of E. coli were positive for carbapenemases. Further, K. pneumoniae isolates from both sites showed 100 % resistance to beta-lactams, with resistance to other antibiotics such as tetracycline and meropenem. E. coli isolates were 100 % resistant to ceftazidime and cefuroxime, and 88.9 % were resistant to amoxicillin/clavulanate and ceftriaxone. The MAR indices observed in the present study for E. coli and K. pneumoniae were above the threshold value of 0.2 suggested a high risk of environmental contamination. These findings highlighted the need for routine surveillance at appropriate intervals for the presence of ESBL producing pathogens and other MDR pathogens in the environment to provide proper clinical management, develop various counter measures and policies to address and halt the spread of such potential threats., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Antimicrobial resistance is a critical global health issue, significantly contributing to patient mortality. Recent antibiotic developments have aimed to counteract carbapenemase-producing Enterobacterales; however, the impact of their use on the emergence of antibiotic resistance is unknown. This study investigates the first case of a non-carbapenemase-producing, pan-β-lactam-resistant Escherichia coli strain from a patient previously treated with ceftolozane-tazobactam and cefiderocol., Methods: This study describes the clinical progression of a 39-year-old ICU patient who developed multiple infections, culminating in the isolation of a pan-β-lactam-resistant E. coli strain (EC554). The resistance profile was characterised through MIC determination, whole-genome sequencing, the use of the β-lactam inactivation method, RT-qPCR, efflux pump inhibition assays, outer membrane protein analysis, and bla TEM transformation., Findings: The EC554 isolate displayed resistance to all tested β-lactams and β-lactam-β-lactamase inhibitor combinations. Whole-genome sequencing revealed four plasmids in EC554, with the only β-lactamase gene being blaTEM-252 on the pEC554-PBR-X1-X1 plasmid. We found that the extremely resistant phenotype was attributable to a combination of different mechanisms: a high expression of TEM-252, efflux pump activity, porin loss, and PBP3 mutations., Interpretation: The findings illustrate the complex interplay of multiple resistance mechanisms in E. coli, highlighting the potential for high-level resistance even without carbapenemase production. This study underscores the importance of comprehensively characterising resistance mechanisms in order to inform effective treatment strategies and mitigate the spread of resistant strains., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Herein, we first isolated two MCR-9- and KPC-2-co-producing K. pneumoniae isolates. Notably, we observed a fusion event between the chromosome and plasmid, mediated by IS903B, in these two strains. This cointegration of chromosomes and plasmids introduces a new mode of transmission for antimicrobial resistance genes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This study conducted a four-month monitoring of carbapenem resistance in a broiler breeding farm in China. A total of 185 carbapenem-resistant bacterial isolates were obtained from 2298 cloacal swabs from broiler breeders and their offspring within a production cycle. The detection rate of carbapenem-resistant isolates was higher during the brooding period. Whole-genome sequencing (WGS) was performed on 133 isolates based on sampling stages, including 113 carbapenem-resistant Enterobacterales (CRE) isolates and 20 Stenotrophomonas pavanii isolates, which have intrinsic resistance to carbapenems. A total of 69 antibiotic resistance genes (ARGs), including bla NDM-1 , mcr-1, and bla NDM-5 , were identified among the sequenced CRE isolates. Notably, bla NDM-5 (92.0 %, 104/113) was the primary contributor to carbapenem resistance. CRE isolates from the same breeding stage exhibited close genomic relationships, and the bla NDM-5 genes were observed in similar genetic backgrounds, indicating the transmission of CRE strains and bla NDM-5 during the broiler breeding process. No CRE was isolated from 0 d broiler offspring, suggesting that broiler breeders were not the direct source of CRE in their offspring. Tracing the feeding process revealed that brooder and rearing houses were likely key factors in the cross-transmission of CRE between broiler breeders and their offspring. CRE pose a significant threat to public health and food safety. China is one of the world's leading poultry producing and consuming countries. This study provided insights into the epidemiological trends and key transmission nodes of carbapenem resistance and CRE within the broiler breeding process, which could help the control of antibiotic resistance and bacterial infections in the broiler industry., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Purpose: Carbapenem-resistant Enterobacterales (CRE) are a global concern due to their high mortality rates and limited therapeutics. CRE-caused bloodstream infections (BSIs) are challenging to manage, especially in healthcare settings. This study aimed to investigate the predictors of mortality in BSI patients caused by CRE., Methods: A single center prospective study to examine the characteristics of BSI caused by CRE in a large academic hospital over 15 months. The main outcomes were microbiological characteristics and clinical outcomes of patients at 28 days based on a step-wise regression analysis., Results: A total of 76 episodes of BSI due to CRE were included. The study found that the most common type of carbapenemase was OXA-48 (69.7 %, n = 53), followed by the co-existence of OXA-48 and MBL (26.3 %, n = 20), with Klebsiella pneumoniae being the most common (90 %, n = 69). Patients with OXA-48-BSI were more likely to have a urinary source of infection, while patients with MBL-BSI were more likely to have a non-urinary source of infection. All cases (100 %) had medical devices. Around 30.3 % of patients received effective empirical treatment, while 61.8 % received adequate therapy at 48 h. The overall mortality rate was 42.1 % (n = 32), and the main predictors of mortality in this study were the presence of sepsis and inadequate initial therapy, while age >65 predicted mortality in the linear regression but not the stepwise regression model., Conclusion: CRE-BSIs are a serious health threat. The study highlights the need for preventive strategies focused on high-risk patients and proper device management to reduce BSI., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

The worldwide dissemination of New Delhi metallo-β-lactamase-1 (NDM-1), which mediates resistance to almost all clinical β-lactam antibiotics, is a major public health problem. The global distribution, species, sources, and potential transfer risk of bla NDM-1 -carrying bacteria are unclear. Results of a comprehensive analysis of literature in 2010-2022 showed that a total of 6002 bla NDM-1 carrying bacteria were widely distributed around 62 countries with a high trend in the coastal areas. Opportunistic pathogens or pathogens like Klebsiella sp., Escherichia sp., Acinetobacter sp. and Pseudomonas sp. were the four main species indicating the potential microbial risk. Source analysis showed that 86.45 % of target bacteria were isolated from the source of hospital (e.g., Hospital patients and wastewater) and little from surface water (5.07 %) and farms (3.98 %). A plasmid-encoded bla NDM-1 Acinetobacter sp. with the resistance mechanisms of antibiotic efflux pump, antibiotic target change and antibiotic degradation was isolated from the wastewater of a typical tertiary hospital. Insertion sequences (IS3 and IS30) located in the adjacent 5 kbp of bla NDM-1 -ble MBL gene cluster indicating the transposon-mediated horizontal gene transfer risk. These results showed that the worldwide spread of bla NDM-1 -carrying bacteria and its potential horizontal gene transfer risk deserve good control., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Changzheng Cui reports financial support was provided by Science and Technology Commission of Shanghai Municipality. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)