Co-carrying of KPC-2, NDM-5, CTX-M-3 and CTX-M-65 in three plasmids with serotype O89: H10 Escherichia coli strain belonging to the ST2 clone in China

Emergence of multidrug-resistant E. coli ST8346 isolates carrying three distinct plasmids with NDM-5, KPC-2, and OXA-181

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 blaNDM-5, blaKPC-2, and/or blaOXA-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. blaNDM-5, blaKPC-2, and blaOXA-181 were located on separate plasmids. Plasmids harboring blaNDM-5 showed genetic similarities to blaNDM-5-bearing IncF plasmids in the United Kingdom. The IncA/C plasmids harboring blaKPC-2 had identical sequences resembling a plasmid from a K. pneumoniae strain in Taiwan, except for the blaKPC-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 blaNDM-5, blaKPC-2, and blaOXA-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.

Genomic Characterization of Escherichia coli Co-Producing KPC-2 and NDM-5 Carbapenemases Isolated from Intensive Care Unit in a Chinese Hospital

Background: Around the world, carbapenemase-producing Escherichia coli is becoming more prevalent. The purpose of this research was to analyze the whole plasmid sequences from YL03 isolates of the E. coli strain that produce both KPC-2 and NDM-5 carbapenemases. Materials and Methods: Whole-genome sequencing (WGS) and analysis of E. coli strain YL03, which was isolated from a wound sample, was performed by Illumina Novaseq 6000 and Pacific Biosciences Sequel (PacBio, Menlo Park, CA) sequencers. Following that, the WGS results were used to predict and analyze the YL03 genome composition and function. A complete gene sequence for YL03 with the accession number CP093551 has been uploaded to GenBank. Results: The results showed that YL03 co-carried five resistance genes, which included blaKPC-2, blaNDM-5, blaTEM-1B, blaCTX-M-14, and mdf(A). Furthermore, three resistance plasmids were found in YL03: pYL03-KPC, pYL03-NDM, and pYL03-CTX. Among them, the 53 kb-long pYL03-KPC plasmid belonging to the IncP, carried the replicase gene (repA) and the carbapenemase gene (blaKPC-2). The blaKPC-2 gene was flanked by a composite transposon-like element (Tn3-[Tn3] tnpR-ISKpn27 blaKPC--ISKpn6). Conclusions: The YL03 strain co-carried blaKPC-2 and blaNDM-5 and had a unique multidrug resistance plasmid containing blaKPC-2.

Characterisation of a Novel Hybrid IncFIIpHN7A8:IncR:IncN Plasmid Co-Harboring blaNDM-5 and blaKPC-2 from a Clinical ST11 Carbapenem-Resistant Klebsiella pneumoniae Strain

Purpose

We aimed to characterize a novel blaNDM-5 and blaKPC-2 co-carrying hybrid plasmid from a clinical carbapenem-resistant Klebsiella pneumoniae (CRKP) strain.

Methods

Antimicrobial susceptibility was determined by the broth microdilution method. Plasmid size and localization were estimated using S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) and Southern blotting. Plasmid transfer ability was evaluated by conjugation experiments. Whole genome sequencing (WGS) was performed using Illumina NovaSeq6000 and Oxford Nanopore MinION platforms. Genomic characteristics were analyzed using bioinformatics methods.

Results

Strain ZY27320 was a multidrug-resistant (MDR) clinical ST11 K. pneumoniae strain that confers high-level resistance to carbapenems (meropenem, MIC 128 mg/L; imipenem, MIC 64 mg/L) and ceftazidime/avibactam (MIC >128/4 mg/L). Both S1-PFGE-Southern blotting and whole genome sequencing revealed that the carbapenemase genes blaKPC-2 and blaNDM-5 were carried by the same IncFIIpHN7A8:IncR:IncN hybrid plasmid (pKPC2_NDM5). Conjugation experiments indicated that pKPC2_NDM5 was a non-conjugative plasmid.

Conclusion

This is the first report of a hybrid plasmid carrying both carbapenemase genes blaNDM-5 and blaKPC-2 in a clinical K. pneumoniae ST11 isolate that confers resistance to both ceftazidime/avibactam and carbapenems, thereby presenting a serious threat to treatment in clinical practice.

Molecular epidemiological characteristics of carbapenem-resistant Klebsiella pneumoniae among children in China

Klebsiella pneumoniae infection and antimicrobial resistance among children are major concerns. The occurrence of hypervirulent K. pneumoniae (hvKp) infections is gradually increasing worldwide, and disinfectant resistance is also being reported. Carbapenem- and disinfectant-resistant hvKp infection has made clinical treatment and nosocomial infection control among children increasingly challenging. In this study, whole-genome sequencing was conducted among 34 Carba NP-positive carbapenem-resistant K. pneumoniae (CRKP) strains, and the distribution of antibiotic resistance genes, virulence genes and disinfectant resistance genes was determined. Eleven distinct STs were identified, and most of them were ST11 (58.8%). Among the carbapenem resistance genes, KPC-2 was predominant (61.8%), followed by NDM-1 (26.5%) and IPM-4 (11.8%), and no other carbapenemase genes were found. Twelve virulence genes were investigated. All 34 CRKP strains carried the following virulence genes: rcsA/B, entA, fimA/H and mrkA/D. The gene iucB was present in only 3 (8.9%) CRKP strains. The positive detection rates of the iroN and ybtA genes were 94.1% and 64.7%, respectively. None of the strains was found to carry the rmpA and iroB genes. Two disinfectant resistance genes were investigated in this study. Twenty-one (61.8%) strains carried both the qacE and cepA disinfectant resistance genes, 13 (38.2%) CRKP strains carried only the cepA gene, and no strains with only the qacE gene was detected. The correlations among virulence, drug resistance and disinfectant tolerance showed that the virulence and disinfectant resistance genes were distinct among several types of carbapenemase-producing CRKP strains.

Study of intestinal microbial flora of local chickens to investigate the effect of probiotics Bacillus subtilis and Bacillus coagulans on the expression of ctxM and luxS pathogenic genes in isolates of Escherichia coli

Background and objective: Antibiotics are widely used worldwide. However, due to the emergence of antibiotic resistance in a wide range of microorganisms, their use worldwide has failed. Probiotics are suggested as complementary and alternative medicine. The present study aimed to investigate the effects of probiotics isolated from local chickens on the expression of luxS and ctxM genes in resistant Escherichia coli.

Materials and methods: 300 fecal samples were taken from patients referring to Imam Khomeini Hospital in Tehran during May–September 2016 and Escherichia coli samples were isolated using specific culture media and biochemical tests and then the presence of luxS and ctxM genes were identified using PCR with specific primers. In order to extract the probiotics forming spores, the intestinal contents of 10 poultry that had not used any antibiotics and probiotics were cultured, isolated, and identified using biochemical and PCR methods. Commercial strains of Bacillus subtilis and Bacillus coagulans were purchased to compare their effects with native bacteria. These strains were then co-cultured with resistant Escherichia coli strains containing ctxM and luxS genes. Real-time PCR was used to evaluate the effect of these probiotics on gene expression

Results: The results indicated that 40 isolates (7.5%) of Escherichia coli were obtained from the 300 fecal samples. Thirteen samples (32.5%) were outpatients and 27 (67.5%) were inpatients. All isolates were isolated from men and women aged 21–62. Four Escherichia coli strains were isolated from patients carrying ctxM and luxS genes. Isolation of Bacillus coagulans and Bacillus subtilis from samples was confirmed by biochemical and molecular experiments. The commercial and native strains of Bacillus coagulans reduced the expression of the luxS and ctxM genes by 3.60, 3.30, 1.58, and 2.70 times respectively. Also, the commercial and native strains of Bacillus subtilis decreased the expression of the luxS and ctxM genes by 1.37, 1.10, 2.20, and 2.80 times respectively. The results of statistical analysis showed a significant relationship between the presence of native and commercial probiotics in culture and reduced expression of ctxM and luxS genes.

Conclusion: According to the results, supplements of Bacillus coagulans and Bacillus subtilis increase the effect of antibiotics resistance in Escherichia coli by reducing the expression of resistance genes.

Antimicrobial resistant bacteria recovered from retail ground meat products in the US include a Raoultella ornithinolytica co-harboring blaKPC-2 and blaNDM-5

Retail beef and pork, including processed products, can serve as vehicles for the zoonotic foodborne transmission of pathogens and antimicrobial resistant bacteria. However, processed and seasoned products like sausages, are not often included in research and surveillance programs. The objective of this study was to investigate retail ground beef and pork, including processed products, for the presence of common foodborne pathogens and antimicrobial resistant bacteria. We purchased 763 packages of fresh and fully cooked retail meat products during 29 visits to 17 grocery stores representing seven major grocery chains located in west and central Ohio. Each package of meat was evaluated for contamination with methicillin-resistant Staphylococcus aureus (MRSA), Salmonella spp., Enterobacteriaceae expressing extended-spectrum cephalosporin resistance, and carbapenemase-producing organisms (CPO). Only 3 of the 144 (2.1%) packages of fully cooked meat products contained any of these organisms, 1 with an extended-spectrum β-lactamase-producing (ESBL) Enterobacteriaceae and 2 with CPO. Among the 619 fresh meat products, we found that 85 (13.7%) packages were contaminated with MRSA, 19 (3.1%) with Salmonella, 136 (22.0%) with Enterobacteriaceae expressing an AmpC (blaCMY) resistance genotype, 25 (4.0%) with Enterobacteriaceae expressing an ESBL (blaCTX-M) resistance genotype, and 31 (5.0%) with CPO, primarily environmental organisms expressing intrinsic carbapenem resistance. However, one CPO, a Raoultella ornithinolytica, isolated from pork sausage co-harbored both blaKPC-2 and blaNDM-5 on IncN and IncX3 plasmids, respectively. Our findings suggest that fresh retail meat, including processed products can be important vehicles for the transmission of foodborne pathogens and antimicrobial resistant bacteria, including those with epidemic carbapenemase-producing genotypes.

Detection of multi-drug resistance and AmpC β-lactamase/extended-spectrum β-lactamase genes in bacterial isolates of loggerhead sea turtles (Caretta caretta) from the Mediterranean Sea

Sea turtles are useful sentinels to monitor the dissemination of antimicrobial resistance (AMR) in the marine coastal ecosystems. Forty Gram negative bacteria were isolated from wounds of 52 injured Caretta caretta, living in the Mediterranean Sea. Bacteria were identified using 16S rRNA gene sequencing and tested for susceptibility to 15 antibiotics. In addition, NGS amplicon sequencing was performed to detect the presence of AmpC β-lactamase genes (bla_AmpC) and extended-spectrum β-lactamase (ESBL) genes (bla_CTX-M,bla_SHV,bla_TEM). Seventy-five percent of the isolates (30/40 isolates) exhibited multidrug resistance (MDR) phenotypes and 32.5% (13/40 isolates) were confirmed to be positive for at least one gene. The variants of ESBLs genes were bla_CTX-M-3,bla_TEM-236 and bla_SHV-12. Variants of the bla_AmpCβ-lactamase gene i.e., bla_ACT-24, bla_ACT-2, bla_ACT-17, bla_DHA-4 and bla_CMY-37, were also detected. In addition, 4 isolates were found simultaneously harboring CTX and AmpC genes while 2 strains harbored 3 genes (bla_{ACT-2+TEM-236+SHV-12}, and bla_{CTX-M-3+ACT-24+TEM-236}).

Nosocomial infection by Klebsiella pneumoniae among neonates: a molecular epidemiological study

BACKGROUND

Nosocomial infection by Klebsiella pneumoniae (Kp) and drug resistance of Kp among neonates is a major concern. Hypervirulent K. pneumoniae (hvKp) infections are gradually increasing worldwide. Carbapenem-resistant hvKp infection has brought challenges to clinical treatment.

AIM

To evaluate the changes in drug resistance trends of Kp strains in neonatal intensive care unit (NICU) nosocomial infections, to analyse drug resistance genes and virulence genes of carbapenem-resistant K. pneumoniae (CRKP) and to identify whether these CRKP strains are hvKp.

METHODS

A total of 80 neonates with Kp nosocomial infections from 2013 to 2018 were retrospectively studied. Drug susceptibility testing was performed on 80 Kp strains, among which the 12 CRKP strains were further studied.

FINDINGS

Kp accounted for 26.9% of nosocomial infections in the NICU. CRKP strains accounted for 15.0%. Among the 80 nosocomial infection Kp strains, CRKP strains accounted for 33.3% and 53.3% in 2017 and 2018 respectively. One of the 12 CRKP strains was positive in the drawing test. The 12 CRKP strains were divided into four complete genome sequence types: cgST1 (N = 2), cgST2 (N = 1), cgST3 (N = 1), and cgST4 (N = 8). Among genes that mediated carbapenem resistance, strains of cgST4 carried NDM-5, strains of cgST2 and cgST3 carried NDM-1, and strains of cgST1 carried IMP-4. None of the 12 CRKP strains carried rmpA/rmpA2 (highly related with hvKp).

CONCLUSION

Nosocomial infections of CRKP among neonates are becoming common, but no hvKp was found among the CRKP strains in this study.

High incidence and characteristic of PRRSV and resistant bacterial Co-Infection in pig farms

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and resistant bacterial co-infection is a serious threat to pig farms. This study was aimed to determine the characteristics of the co-infection of PRRSV with resistant bacterial strains in pig farms. The presence of the PRRSV orf5 gene was confirmed by RT-PCR from 395 samples. Bacterial strains were isolated from PRRSV positive samples. Antimicrobial drug susceptibility was determined by the Kirby-Bauer method. Resistant genes were determined by PCR amplification and sequencing. The whole genome of carbapenems resistant E.coli was sequenced and analyse. A total of 75 samples were PRRSV positive, and 45 different orf5 sequences were finally determined. Phylogenetic analysis showed that 45 sequences are clustered into four groups, including JXA1-like, NADC30-like, GD-QY2-like, and CH-1a-like viruses. Twenty-one samples were identified with PRRSV and amoxicillin resistance bacterial co-infection, and 23 were found with amoxicillin resistance (including 15 Escherichia coli, 3 Klebsiella pneumoniae, 2 Haemophilus parasuis, 1 Actinobacillus pleuropneumoniae, 1 Pasteurella multocida, and 1 Proteus mirabilis). All bacterial strains were resistant to the most commonantibiotics and were carriers of a large number of resistance genes. Whole-genome sequencing of E. coli ScEc7 yielded 113 scaffolds of genome DNA, one IncX3 plasmid pScEc7-NDM-5 (46,161 bp) and one IncF plasmid pScEc7-CTX-M (129,978 bp). It carries19 resistance genes, 8 virulence factors, and several mobile genetic elements. The results obtained let us to concluded that: (1) Co-infection is common in pig farms. (2) The orf5 gene continues to undergo its sequences divergence. (3) The bacterial carrying diverse resistance genes were resistant to most of the commonly used antibiotics. (4) Carbapenems resistant isolate has a large number of resistance genes, virulence factors, and MGEs. Therefore, continuous study of the characteristic of PRRSV and resistant bacterial co-infection is necessary for healthy pig aquaculture.

Molecular characterization of a novel bla CTX-M-3-carrying Tn6741 transposon in Morganella morganii isolated from swine

Introduction. The bla _CTX-M-3 gene has rarely been reported in Morganella morganii strains and its genetic environment has not yet been investigated.Aim. To identify the bla _CTX-M-3 gene in M. morganii isolated from swine and characterize its genetic environment.Methodology. A M. morganii isolate (named MM1L5) from a deceased swine was identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and subjected to antimicrobial susceptibility testing. The bla genes were detected and then the genetic location and environment of bla _CTX-M-3 were investigated by Southern blot and PCR mapping, respectively. The M. morganii bla _CTX-M-3 gene was cloned and expressed in Escherichia coli.Results. Isolate MM1L5 harboured the bla _CTX-M-3 and bla _TEM-1 genes. The bla _CTX-M-3 gene, located on the chromosome, was co-carried with an IS26 and bla _TEM-1 gene by a novel 6361 bp IS26-flanked composite transposon, designated Tn6741. This transposon consisted of a novel bla _CTX-M-3-containing module, IS26-ΔISEcp1-bla _CTX-M-3-Δorf477-IS26 (named Tn6710), and a bla _TEM-1-containing module, IS26-Δorf477-bla _TEM-1-tnpR-IS26, differing from previous reports. Phylogenetic analysis showed a significant variation based on the sequence of Tn6741, as compared to those of other related transposons. Interestingly, although the cloned bla _CTX-M-3 gene could confer resistance to ceftiofur, cefquinome, ceftriaxone and cefotaxime, one amino acid substitution (Ile-142-Thr) resulted in a significant reduction of resistance to these antimicrobials.Conclusion. This is the first time that bla _CTX-M-3 has been identified on a chromosome from a M. morganii isolate. Furthermore, the bla _CTX-M-3 gene was located with an IS26 element and bla _TEM-1 gene on a novel IS26-flanked composite transposon, Tn6741, suggesting that Tn6741 might act as a reservoir for the bla _CTX-M-3 and bla _TEM-1 genes and may become an important vehicle for their dissemination among M. morganii.

Co-Occurrence of the bla KPC-2 and Mcr-3.3 Gene in Aeromonas caviae SCAc2001 Isolated from Patients with Diarrheal Disease

Purpose

To characterize the genetic feature of a multi-drug-resistant Aeromonas caviae strain isolated from the diarrhea sample of a 45-year-old male patient with acute diarrhea.

Materials and Methods

Whole-genome of the A. caviae strain SCAc2001 was sequenced via the Illumina system, followed by a series of bioinformatic analyses to describe the genetic feature.

Results

The genome sequence of A. caviae SCAc2001 was assembled into 340 scaffolds (305 of them were > 1000 bp in length and 4,487,370 bp in total) with an average G+C content of 61.09%. Phylogenetic analysis showed that the A. caviae SCAc2001 strain was highly similar to the A. caviae strain R25-2 and T25-39. Resistome analysis identified that A. caviae SCAc2001 carried 13 antimicrobial resistance genes, including β-lactams (bla_KPC, bla_CTX-M-14, bla_TEM-1, bla_OXA-10, bla_OXA-427, bla_VEB-3 and bla_MOX-6), aminoglycosides (aadA1), fluoroquinolones (aac(6ʹ)-Ib-cr), phenicol resistance (catB3), sulfonamide (sul1), trimethoprim (dfrA5) and colistin resistance (mcr-3.3).And also, A. caviae ScAc2001 carried 54 putative virulence genes including the type IV pilus, fimbria, flagellarthe, and hemolysin A encoding genes, and 12 pathogen–host interactions (PHI) genes. There were also four genomic islands and eight prophages in the genome of A. caviae ScAc2001. In addition, A. caviae SCAc2001 also carried three secondary metabolism products coding clusters including nonribosomal peptide synthetases (nrps), hserlactone and bacteriocin.

Conclusion

A. caviae ScAc2001 carries many resistance genes, a variety of virulence factors, PHI genes and four genomic islands and eight prophages, which poses a severe threat to infectious diseases control strategies, diagnosis methods and clinical treatment.

Whole-Genome Analysis of Two Copies of bla NDM-1 Gene Carrying Acinetobacter johnsonii Strain Acsw19 Isolated from Sichuan, China

Purpose

To characterize the genetic feature of the carbapenems resistant Acinetobacter johnsonii strain Acsw19 isolated from municipal sludge. This strain was found to carry two copies of bla _NDM-1, cmlB1-like gene, and bla _OXA-211-like gene along with other 8 antimicrobial resistance genes, 3 plasmids, 15 genomic islands and 8 prophages.

Methods

A carbapenem-resistant Acinetobacter johnsonii strain Acsw19 isolated from municipal sludge was subjected to whole-genome sequencing (WGS) via the PacBio and Illumina MiSeq platforms. Thereafter, the characteristic was analyzed by a series of bioinformatics software.

Results

The results showed that the genome of Acsw19 was consisted of a 3,433,749 bp circular chromosome and 3 circular plasmids, pAcsw19-1 (11,161 bp), pAcsw19-2 (351,885 bp) and pAcsw19-3 (38,391bp), respectively. Resistome analysis showed that Acsw19 carried 12 antimicrobial resistance genes, including 6 [cmlB1-like, bla _NDM-1, bla _OXA-58, aph (3')-VIa, msr(E) and mph(E)] in the plasmid pAcsw19-2 and 6 (bla _OXA-211-like, bla _NDM-1, aph(3")-Ib, aph(6)-Id, sul2, and floR) in the chromosome genome. Specifically, the cmlB1-like gene shared 86.33%, 71.7% and 71.9% similarities with the cmlB1, cmlA4 and cmlA8 gene, and the bla _OXA-211-like gene shared 94.4%, 95.39% and 96.36% similarities with bla _OXA-211, bla _OXA-643 and bla _OXA-652, at the nucleotide level, respectively. Phylogenetic analysis showed that the bla _OXA-211-like gene and cmlB1-like gene had the closest evolutionary relationship with bla _OXA-643 and cmlB1, respectively. These results indicated that the bla _OXA-211-like and cmlB1-like genes identified in the current study should be the novel variant resistance genes.

Conclusion

Carrying of two copies of bla _NDM-1, cmlB1-like, bla _OXA-211-like and along with other 8 antimicrobial resistance genes, 3 plasmids, 15 genomic islands and 8 prophages Acinetobacter johnsonii strain might increase the possibility of spreading of resistance genes.

Diversity and frequency of resistance and virulence genes in bla KPC and bla NDM co-producing Klebsiella pneumoniae strains from China

Background

Emergence of bla_KPC and bla_NDM co-producing Klebsiella pneumoniae strains have led to the limited therapeutic options for clinical treatment. Understanding the diversity and frequency of resistance and virulence genes of these isolates is of great significance.

Purpose

The aim of this study is to research the diversity and frequency of resistance and virulence genes in the bla_KPC and bla_NDM co-producing Klebsiella pneumoniae strains.

Methods and Results

In this study, 117 K. pneumonia strains were isolated from China, and among of which, 24 were found to be bla_KPC and bla_NDM co-producing with significant resistance against almost all the commonly used antibiotics. Additionally, 4 strains were hypermucoviscous and 8 showed high serum resistance. Overall, bla_SHV, bla_CTX-M, tetA and sul1 resistance genes found in 100% of the isolates, followed by bla_TEM (95.8%), oqxA/B (91.7%), qnrB (87.5%), aac(6’)Ib-cr (83.3%), bla_DHA (79.2%), rmtB (66.7%), qnrS (54.2%), cat(54.2%), floR (50.0%), sul2 (45.8%) cmlA (20.8%)andbla_CMY (8.33%), respectively. What’ more, seven bla_CTX-M subtypes [bla_CTX-M-14 (n=18), bla_CTX-M-3(n=11), bla_CTX-M-65 (n=4), bla_CTX-M-15 (n=3), bla_CTX-M-28 (n=2), bla_CTX-M-55 (n=2), bla_CTX-M-22 (n=1)] and six bla_SHV subtypes [bla_SHV-12(n=16), bla_SHV-11 (n=4), bla_SHV-2a(n=1), bla_SHV-1(n=1), bla_SHV-38(n=1) and bla_SHV-28(n=1)] were detected. The frequency of virulence genes was as follows: 100% for entB, ybtS and irp, 95.8% for mrkD, 91.66% for fimH, 79.2% for iutA, 62.5% for iroBCDE, aerobactin and kfu, 66.7% for allS, 45.8% for wcaG, 37.5% for rmpA, 20.8% for pagO and 16.7% for magA.

Conclusion

From this study, we concluded that the bla_KPC and bla_NDM co-producing Klebsiella pneumoniae strains have a high diversity and frequency of resistance and virulence genes. This study may offer hospitals important information about the control of infections caused by bla_KPC and bla_NDM co-producing Klebsiella pneumoniae.

Characterization of an NDM-5 carbapenemase-producing Escherichia coli ST156 isolate from a poultry farm in Zhejiang, China

BACKGROUND

The emergence of carbapenem-resistant Enterobacteriaceae strains has posed a severe threat to public health in recent years. The mobile elements carrying the New Delhi metallo-β-lactqtamase (NDM) gene have been regarded as the major mechanism leading to the rapid increase of carbapenem-resistant Enterobacteriaceae strains isolated from clinics and animals.

RESULTS

We describe an NDM-5-producing Escherichia coli strain, ECCRA-119 (sequence type 156 [ST156]), isolated from a poultry farm in Zhejiang, China. ECCRA-119 is a multidrug-resistant (MDR) isolate that exhibited resistance to 27 antimicrobial compounds, including imipenem and meropenem, as detected by antimicrobial susceptibility testing (AST). The complete genome sequence of the ECCRA-119 isolate was also obtained using the PacBio RS II platform. Eleven acquired resistance genes were identified in the chromosome; four were detected in plasmid pTB201, while six were detected in plasmid pTB202. Importantly, the carbapenem-resistant gene blaNDM-5 was detected in the IncX3 plasmid pTB203. In addition, seven virulence genes and one metal-resistance gene were also detected. The results of conjugation experiments and the transfer regions identification indicated that the blaNDM-5-harboring plasmid pTB203 could be transferred between E. coli strains.

CONCLUSIONS

The results reflected the severe bacterial resistance in a poultry farm in Zhejiang province and increased our understanding of the presence and transmission of the blaNDM-5 gene.