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153500.9798Complete Genome Sequencing of Acinetobacter baumannii AC1633 and Acinetobacter nosocomialis AC1530 Unveils a Large Multidrug-Resistant Plasmid Encoding the NDM-1 and OXA-58 Carbapenemases. Carbapenem-resistant Acinetobacter spp. are considered priority drug-resistant human-pathogenic bacteria. The genomes of two carbapenem-resistant Acinetobacter spp. clinical isolates obtained from the same tertiary hospital in Terengganu, Malaysia, namely, A. baumannii AC1633 and A. nosocomialis AC1530, were sequenced. Both isolates were found to harbor the carbapenemase genes bla(NDM-1) and bla(OXA-58) in a large (ca. 170 kb) plasmid designated pAC1633-1 and pAC1530, respectively, that also encodes genes that confer resistance to aminoglycosides, sulfonamides, and macrolides. The two plasmids were almost identical except for the insertion of ISAba11 and an IS4 family element in pAC1633-1, and ISAba11 along with relBE toxin-antitoxin genes flanked by inversely orientated pdif (XerC/XerD) recombination sites in pAC1530. The bla(NDM-1) gene was encoded in a Tn125 composite transposon structure flanked by ISAba125, whereas bla(OXA-58) was flanked by ISAba11 and ISAba3 downstream and a partial ISAba3 element upstream within a pdif module. The presence of conjugative genes in plasmids pAC1633-1/pAC1530 and their discovery in two distinct species of Acinetobacter from the same hospital are suggestive of conjugative transfer, but mating experiments failed to demonstrate transmissibility under standard laboratory conditions. Comparative sequence analysis strongly inferred that pAC1633-1/pAC1530 was derived from two separate plasmids in an IS1006-mediated recombination or transposition event. A. baumannii AC1633 also harbored three other plasmids designated pAC1633-2, pAC1633-3, and pAC1633-4. Both pAC1633-3 and pAC1633-4 are cryptic plasmids, whereas pAC1633-2 is a 12,651-bp plasmid of the GR8/GR23 Rep3-superfamily group that encodes the tetA(39) tetracycline resistance determinant in a pdif module.IMPORTANCE Bacteria of the genus Acinetobacter are important hospital-acquired pathogens, with carbapenem-resistant A. baumannii listed by the World Health Organization as the one of the top priority pathogens. Whole-genome sequencing of carbapenem-resistant A. baumannii AC1633 and A. nosocomialis AC1530, which were isolated from the main tertiary hospital in Terengganu, Malaysia, led to the discovery of a large, ca. 170-kb plasmid that harbored genes encoding the New Delhi metallo-β-lactamase-1 (NDM-1) and OXA-58 carbapenemases alongside genes that conferred resistance to aminoglycosides, macrolides, and sulfonamides. The plasmid was a patchwork of multiple mobile genetic elements and comparative sequence analysis indicated that it may have been derived from two separate plasmids through an IS1006-mediated recombination or transposition event. The presence of such a potentially transmissible plasmid encoding resistance to multiple antimicrobials warrants vigilance, as its spread to susceptible strains would lead to increasing incidences of antimicrobial resistance.202133504662
519910.9793Whole genome sequencing uncovers a novel IND-16 metallo-β-lactamase from an extensively drug-resistant Chryseobacterium indologenes strain J31. BACKGROUND: Chryseobacterium indologenes is an emerging opportunistic pathogen in hospital-acquired infection, which is intrinsically resistant to most antimicrobial agents against gram-negative bacteria. In the purpose of extending our understanding of the resistance mechanism of C. indologenes, we sequenced and analyzed the genome of an extensively antibiotic resistant C. indologenes strain, isolated from a Chinese prostate cancer patient. We also investigated the presence of antibiotic resistance genes, particularly metallo-β-lactamase (MBL) genes, and performed a comparative genomic analysis with other Chryseobacterium species. RESULTS: 16s rRNA sequencing indicated the isolate belongs to C. indologenes. We assembled a total of 1095M bp clean-filtered reads into 171 contigs by de novo assembly. The draft genome of C. indologenes J31 consisted of 5,830,795 bp with a GC content of 36.9 %. RAST analysis revealed the genome contained 5196 coding sequences (CDSs), 28 rRNAs, 81 tRNAs and 114 pseudogenes. We detected 90 antibiotic resistance genes from different drug classes in the whole genome. Notably, a novel bla(IND) allele bla(IND-16) was identified, which shared 99 % identity with bla(IND-8) and bla(IND-10). By comparing strain J31 genome to the closely four related neighbors in the genus Chryseobacterium, we identified 2634 conserved genes, and 1449 unique genes. CONCLUSIONS: In this study, we described the whole genome sequence of C. indologenes strain J31. Numerous resistance determinants were detected in the genome and might be responsible for the extensively antibiotic resistance of this strain. Comparative genomic analysis revealed the presence of considerable strain-specific genes which would contribute to the distinctive characteristics of strain J31. Our study provides the insight of the multidrug resistance mechanism in genus Chryseobacterium.201627785154
185320.9793Dissemination dynamics of colistin resistance genes mcr-9 and mcr-10 across diverse Inc plasmid backbones. BACKGROUND: The polymyxin antibiotic colistin is used as a final line of treatment for life threatening infections caused by multidrug resistant and carbapenem-resistant Gram-negative bacteria. Mobile colistin resistance genes mcr-9 and mcr-10 are increasingly detected in Enterobacteriaceae but their epidemiology is poorly understood. METHODS: The genetic characteristics of mcr-9 and mcr-10, being the only mobile colistin resistance genes detected in a local population of Enterobacter species isolated from bloodstream infections in Dartmouth Hitchcock Medical Center, USA, were elucidated and contextualized against a global dataset of mcr-9/10-bearing plasmids using genomic and phylogenetic tools. RESULTS: Seven out of 59 Enterobacter isolates carry either an mcr-9 or mcr-10 on a plasmid with distinct single and multiple replicon configurations, including IncFIB(pECLA), IncFIB(K), IncFIA(HI1)-IncFIB(K), IncFIB(pECLA)--IncFII(pECLA) and IncFIB(K)--IncFII(pECLA), whereas two genomes harbor mcr-9 on their chromosome. Global contextualization reveals that allelic variants of mcr-9 and mcr-10 are widely disseminated across diverse Inc-type plasmids, transcending geographic and taxonomic boundaries. Plasmid-borne genes conferring resistance to other antimicrobial agents, such as aminoglycoside, tetracycline and trimethoprim, tend to co-occur with mcr-9.1 and mcr-9.2 alleles. CONCLUSIONS: Findings from this study enhance our understanding of the plasmid backgrounds of mcr-9 and mcr-10, their associated antimicrobial resistance gene carriage and co-occurrence. This knowledge may be critical to inform scalable and effective public health interventions aimed at preserving the efficacy of colistin.202540999001
523630.9793Genome characterization of a multi-drug resistant Escherichia coli strain, L1PEag1, isolated from commercial cape gooseberry fruits (Physalis peruviana L.). INTRODUCTION: Foodborne infections, which are frequently linked to bacterial contamination, are a serious concern to public health on a global scale. Whether agricultural farming practices help spread genes linked to antibiotic resistance in bacteria associated with humans or animals is a controversial question. METHODS: This study applied a long-read Oxford Nanopore MinION-based sequencing to obtain the complete genome sequence of a multi-drug resistant Escherichia coli strain (L1PEag1), isolated from commercial cape gooseberry fruits (Physalis peruviana L.) in Ecuador. Using different genome analysis tools, the serotype, Multi Locus Sequence Typing (MLST), virulence genes, and antimicrobial resistance (AMR) genes of the L1PEag1 isolate were determined. Additionally, in vitro assays were performed to demonstrate functional genes. RESULTS: The complete genome sequence of the L1PEag1 isolate was assembled into a circular chromosome of 4825.722 Kbp and one plasmid of 3.561 Kbp. The L1PEag1 isolate belongs to the B2 phylogroup, sequence type ST1170, and O1:H4 serotype based on in silico genome analysis. The genome contains 4,473 genes, 88 tRNA, 8 5S rRNA, 7 16S rRNA, and 7 23S rRNA. The average GC content is 50.58%. The specific annotation consisted of 4,439 and 3,723 genes annotated with KEEG and COG respectively, 3 intact prophage regions, 23 genomic islands (GIs), and 4 insertion sequences (ISs) of the ISAs1 and IS630 families. The L1PEag1 isolate carries 25 virulence genes, and 4 perfect and 51 strict antibiotic resistant gene (ARG) regions based on VirulenceFinder and RGI annotation. Besides, the in vitro antibiotic profile indicated resistance to kanamycin (K30), azithromycin (AZM15), clindamycin (DA2), novobiocin (NV30), amikacin (AMK30), and other antibiotics. The L1PEag1 isolate was predicted as a human pathogen, matching 464 protein families (0.934 likelihood). CONCLUSION: Our work emphasizes the necessity of monitoring environmental antibiotic resistance, particularly in commercial settings to contribute to develop early mitigation techniques for dealing with resistance diffusion.202439104589
541740.9792Molecular characteristics of oxazolidinone resistance in enterococci from a multicenter study in China. BACKGROUND: Linezolid-resistant enterococci pose great challenges in clinical practice. The aim of this study is to study the mechanisms underlying the resistance and genetic environment of antimicrobial resistance gene of linezolid-resistant enterococci. RESULTS: The linezolid MICs of 16 enterococci were 4 mg/L to 16 mg/L. Four strains belonged to multi-drug resistant (MDR) bacteria. The sequence types (STs) of 13 enterococci strains performed WGS were diverse: 3 ST476, 1 ST86, ST116, ST480, ST59, ST416, ST21, ST67, ST16, ST585 and ST18. None of them carried multi-drug resistance gene cfr. Only one strain had the G2658 T mutation of target 23S rRNA gene. Thirteen (13/16, 81.3%) strains harbored the novel oxazolidinone resistance gene optrA. WGS analysis showed that the optrA gene was flanked by sequence IS1216E insertion in 13 strains, and optrA was adjacent to transposons Tn558 in two strains and Tn554 in one strain. The optrA gene was identified to be co-localized with fexA, the resistance genes mediated florfenicol resistance in 13 strains, and ermA1, the resistance genes mediated erythromycin resistance in 9 strains, indicating that linezolid-resistant strains may be selected due to non-oxazolidinone antibiotics (i.e. macrolides and florfenicol) usage. CONCLUSION: Our findings demonstrate the high diversity of optrA-carrying genetic platforms. The mobile genetic elements (MGEs) may play an important role in the dissemination of optrA into the enterococci isolates of human origin. The genetic evidence of transferable feature and co-selection of optrA should be gave more attention in clinical practice.201931299904
151550.9792A novel transposon Tn7540 carrying bla(NDM-9) and fosA3 in chromosome of a pathogenic multidrug-resistant Salmonella enterica serovar Indiana isolated from human faeces. OBJECTIVES: Emergence of multidrug-resistant (MDR) Salmonella enterica serovar Indiana has raised global concern. Mobile genetic elements (MGEs) play vital roles in accelerating the dissemination of resistance genes in bacteria communities. The study aims to improve our understanding of the underlying resistance mechanisms and characterize the MGEs in a MDR S. Indiana isolate. METHODS: Here, we report the characteristics of a MDR pathogenic S. Indiana isolate. The antimicrobial susceptibility pattern of S. Indiana QT6365 was determined. The genomic structure of the chromosome and the plasmid, serotype, and multi-locus sequence type were analysed by whole genome sequencing. The circular form derived from IS26-flanked transposon was confirmed by reverse polymerase chain reaction and sequencing. RESULTS: S. Indiana QT6365 exhibited resistance to all tested antimicrobials except for aztreonam, amikacin, polymyxin, and tigecycline, was defined as MDR, and belonged to ST17. S. Indiana QT6365 was closely related with food resource S. Indiana C629 with similar resistance gene profiles. Multiple resistance genes are mainly carried by a novel transposon Tn7540 located on the chromosome and an IncHI2/HI2A/N plasmid. Sequence analysis and the formed circular intermediate suggested Tn7540 might be generated through homologous recombination by IS26-bounded translocatable units (IS26-fosA-IS26-intI1-dfrA12-aadA2-sul1-ISCR1-bla(NDM-9)-IS26). CONCLUSIONS: To the best of our knowledge, this is the first report of the novel chromosomal transposon possessing bla(NDM-9) and fosA3 in S. Indiana isolated from human specimen, which might facilitate the dissemination of resistance genes and should arouse serious awareness.202336854357
545460.9792Identification of an Enterococcus faecium strain isolated from raw bovine milk co-harbouring the oxazolidinone resistance genes optrA and poxtA in China. Oxazolidinones are potent antimicrobial agents used to treat human infections caused by multidrug-resistant Gram-positive bacteria. The growing resistance to oxazolidinones poses a significant threat to public health. In August 2021, a linezolid-resistant Enterococcus faecium BN83 was isolated from a raw milk sample of cow in Inner Mongolia, China. This isolate exhibited a multidrug resistance phenotype and was resistant to most of drugs tested including linezolid and tedizolid. PCR detection showed that two mobile oxazolidinones resistance genes, optrA and poxtA, were present in this isolate. Whole genome sequencing analysis revealed that the genes optrA and poxtA were located on two different plasmids, designated as pBN83-1 and pBN83-2, belonging to RepA_N and Inc18 families respectively. Genetic context analysis suggested that optrA gene on plasmid pBN83-1 was located in transposon Tn6261 initially found in E. faecalis. Comprehensive analysis revealed that Tn6261 act as an important horizontal transmission vector for the spread of optrA in E. faecium. Additionally, poxtA-bearing pBN83-2 displayed high similarity to numerous plasmids from Enterococcus of different origin and pBN83-2-like plasmid represented a key mobile genetic element involved in movement of poxtA in enterococcal species. The presence of optrA- and poxtA-carrying E. faecium in raw bovine milk represents a public health concern and active surveillance is urgently warranted to investigate the prevalence of oxazolidinone resistance genes in animal-derived food products.202438718528
172170.9791Convergence of MCR-8.2 and Chromosome-Mediated Resistance to Colistin and Tigecycline in an NDM-5-Producing ST656 Klebsiella pneumoniae Isolate From a Lung Transplant Patient in China. We characterized the first NDM-5 and MCR-8.2 co-harboring ST656 Klebsiella pneumoniae clinical isolate, combining with chromosomal gene-mediated resistance to colistin and tigecycline. The K. pneumoniae KP32558 was isolated from the bronchoalveolar lavage fluid from a lung transplant patient. Complete genome sequences were obtained through Illumina HiSeq sequencing and nanopore sequencing. The acquired resistance genes and mutations in chromosome-encoded genes associated with colistin and tigecycline resistance were analyzed. Comparative genomic analysis was conducted between mcr-8.2-carrying plasmids. The K. pneumoniae KP32558 was identified as a pan-drug resistant bacteria, belonging to ST656, and harbored plasmid-encoded bla(NDM-5) and mcr-8.2 genes. The bla(NDM-5) gene was located on an IncX3 type plasmid. The mcr-8.2 gene was located on a conjugative plasmid pKP32558-2-mcr8, which had a common ancestor with another two mcr-8.2-carrying plasmids pMCR8_020135 and pMCR8_095845. The MIC of KP32558 for colistin was 256 mg/L. The mcr-8.2 gene and mutations in the two-component system, pmrA and crrB, and the regulator mgrB, had a synergistic effect on the high-level colistin resistance. The truncation in the acrR gene, related to tigecycline resistance, was also identified. K. pneumoniae has evolved a variety of complex resistance mechanisms to the last-resort antimicrobials, close surveillance is urgently needed to monitor the prevalence of this clone.202235899054
198980.9791Prevalence and characterization of IncQ1α-mediated multi-drug resistance in Proteus mirabilis Isolated from pigs in Kunming, Yunnan, China. BACKGROUND: Proteus mirabilis is a conditionally pathogenic bacterium that is inherently resistant to polymyxin and tigecycline, largely due to antibiotic resistance genes (ARGs). These ARGs can be horizontally transferred to other bacteria, raising concerns about the Inc plasmid-mediated ARG transmission from Proteus mirabilis, which poses a serious public health threat. This study aims to investigate the presence of Inc plasmid types in pig-derived Proteus mirabilis in Kunming, Yunnan, China. METHODS: Fecal samples were collected from pig farms across six districts of Kunming (Luquan, Jinning, Yiliang, Anning, Songming, and Xundian) from 2022 to 2023. Proteus mirabilis isolates were identified using IDS and 16S rRNA gene sequencing. Then, positive strains underwent antimicrobial susceptibility testing and incompatibility plasmid typing. Multi-drug-resistant isolates with positive incompatibility plasmid genes were selected for whole-genome sequencing. Resistance and Inc group data were then isolated and compared with 126 complete genome sequences from public databases. Whole-genome multi-locus sequence typing, resistance group analysis, genomic island prediction, and plasmid structural gene analysis were performed. RESULTS: A total of 30 isolates were obtained from 230 samples, yielding a prevalence of 13.04%. All isolates exhibited multi-drug resistance, with 100% resistance to cotrimoxazole, erythromycin, penicillin G, chloramphenicol, ampicillin, and streptomycin. Among these, 15 isolates tested positive for the IncQ1α plasmid repC gene. The two most multi-drug-resistant and repC-positive strains, NO. 15 and 21, were sequenced to compare genomic features on Inc groups and ARGs with public data. Genome analysis revealed that the repC gene was primarily associated with IncQ1α, with structural genes from other F-type plasmids (TraV, TraU, TraN, TraL, TraK, TraI, TraH, TraG, TraF, TraE/GumN, and TraA) also present. Strain NO. 15 carried 33 ARGs, and strain NO. 21 carried 38 ARGs, conferring resistance to tetracyclines, fluoroquinolones, aminoglycosides, sulfonamides, peptides, chloramphenicol, cephalosporins, lincomycins, macrolides, and 2-aminopyrimidines. CONCLUSION: The repC gene is primarily associated with IncQ1α, with structural genes from other F-type plasmids. A comparison with 126 public genome datasets confirmed this association.202439850143
540590.9790Characterization of florfenicol resistance genes in the coagulase-negative Staphylococcus (CoNS) isolates and genomic features of a multidrug-resistant Staphylococcus lentus strain H29. BACKGROUND: With the wide use of florfenicol to prevent and treat the bacterial infection of domestic animals, the emergence of the florfenicol resistance bacteria is increasingly serious. It is very important to elucidate the molecular mechanism of the bacteria's resistance to florfenicol. METHODS: The minimum inhibitory concentration (MIC) levels were determined by the agar dilution method, and polymerase chain reaction was conducted to analyze the distribution of florfenicol resistance genes in 39 CoNS strains isolated from poultry and livestock animals and seafood. The whole genome sequence of one multidrug resistant strain, Staphylococcus lentus H29, was characterized, and comparative genomics analysis of the resistance gene-related sequences was also performed. RESULTS: As a result, the isolates from the animals showed a higher resistance rate (23/28, 82.1%) and much higher MIC levels to florfenicol than those from seafood. Twenty-seven animal isolates carried 37 florfenicol resistance genes (including 26 fexA, 6 cfr and 5 fexB genes) with one carrying a cfr gene, 16 each harboring a fexA gene, 5 with both a fexA gene and a fexB gene and the other 5 with both a fexA gene and a cfr gene. On the other hand, all 11 isolates from seafood were sensitive to florfenicol, and only 3 carried a fexA gene each. The whole genome sequence of S. lentus H29 was composed of a chromosome and two plasmids (pH29-46, pH29-26) and harbored 11 resistance genes, including 6 genes [cfr, fexA, ant(6)-Ia, aacA-aphD, mecA and mph(C)] encoded on the chromosome, 4 genes [cfr, fexA, aacA-aphD and tcaA] on pH29-46 and 1 gene (fosD) on pH29-26. We found that the S. lentus H29 genome carried two identical copies of the gene arrays of radC-tnpABC-hp-fexA (5671 bp) and IS256-cfr (2690 bp), of which one copy of the two gene arrays was encoded on plasmid pH29-46, while the other was encoded on the chromosome. CONCLUSIONS: The current study revealed the wide distribution of florfenicol resistance genes (cfr, fexA and fexB) in animal bacteria, and to the best of our knowledge, this is the first report that one S. lentus strain carried two identical copies of florfenicol resistance-related gene arrays.202133413633
5203100.9790Draft genome sequence analysis of a novel MLST (ST5028) and multidrug-resistant Klebsiella quasipneumoniae subsp. similipneumoniae (Kp4) strain 456S1 isolated from a pig farm in China. OBJECTIVES: The avian breeding industry is an important element in exposing bacteria to antibiotics. As one of the major animal welfare and economic problems for the poultry industry, multidrug-resistant Klebsiella spp. have become a substantial source of antibiotic resistance genes. In the present work, we reported the draft genome sequence of a novel multilocus sequence type (MLST) (ST5028) Klebsiella quasipneumoniae subsp. similipneumoniae (Kp4) strain 456S1, which was isolated from a pig farm in China with broad-spectrum antimicrobial activities. METHODS: Classical microbiological methods were applied to isolate and identify the strain, genomic DNA was sequenced using an Illumina HiSeq platform, and the reads were de novo assembled into contigs using CLC Genomics Workbench. The assembled contigs were annotated, and whole-genome sequencing (WGS) analysis was performed. RESULTS: WGS analysis revealed that the genome of strain 456S1 comprised a circular chromosome of 5,419,059 bp (GC content, 57.8%), harbouring 12 important antibiotic resistance genes: aac(6')-ib-cr, aadA16, floR, dfrA27, fosA, tet(D), blaOKP-B-3, oqxA, oqxB, qnrB6, sul1 and arr-3. The Klebsiella quasipneumoniae subsp. similipneumoniae (Kp4) 456S1 was also found to belong to a novel sequence type (ST5028) determined by MLST. CONCLUSION: The genome sequence reported herein will provide useful information for antibiotic resistance and pathogenic mechanisms in Klebsiella quasipneumoniae and will be a reference for comparative analysis with genomic features among different sources of clinically important multidrug-resistant strains, especially among bacteria of animal and human origin.202133516893
1511110.9790Characterization of an Extensively Drug-Resistant Salmonella Kentucky ST198 Co-Harboring cfr, mcr-1 and tet(A) Variant from Retail Chicken Meat in Shanghai, China. The emergence of extensively drug-resistant (XDR) foodborne pathogens poses grave threats to food safety. This study characterizes the genome of an XDR Salmonella Kentucky isolate (Sal23C1) co-harboring cfr, mcr-1 and tet(A) from Shanghai chicken meat in 2022, which was the only isolate co-harboring these three key resistance genes among 502 screened Salmonella isolates. Genomic analysis revealed that the multidrug resistance gene cfr, which confers resistance to phenicols, lincosamides, oxazolidinones, pleuromutilins and streptogramin A, was identified within a Tn3-IS6-cfr-IS6 structure on the transferable plasmid p3Sal23C1 (32,387 bp), showing high similarity to the Citrobacter braakii plasmid pCE32-2 (99% coverage, 99.98% identity). Concurrently, the mcr-1 gene resided in a pap2-mcr-1 structure on the transferable IncI2 plasmid p2Sal23C1 (63,103 bp). Notably, both genes could be co-transferred to recipient bacteria via conjugative plasmids at frequencies of (1.15 ± 0.98) × 10(-6). Furthermore, a novel ~79 kb multidrug resistance region (MRR) chromosomally inserted at the bcfH locus was identified, carrying fosA3, mph(A), rmtB, qnrS1 and bla(CTX-M-55). Additionally, a novel Salmonella Genomic Island 1 variant (SGI1-KI) harbored aadA7, qacEΔ1, sul1 and the tet(A) variant. The acquisition of these antibiotic resistance genes in this isolate enhanced bacterial resistance to 21 antimicrobials, including resistance to the critical last-resort antibiotics tigecycline and colistin, which left virtually no treatment options for potential infections. Taken together, this is the first comprehensive genomic report of an XDR poultry-derived Salmonella Kentucky isolate co-harboring cfr, mcr-1 and the tet(A) variant. The mobility of these resistance genes, facilitated by IS6 elements and conjugative plasmids, underscores significant public health risks associated with such isolates in the food chain.202540941142
1493120.9790Coexistence of blaKPC-2 and blaNDM-1 in one IncHI5 plasmid confers transferable carbapenem resistance from a clinical isolate of Klebsiella michiganensis in China. OBJECTIVES: This study firstly identified an IncHI5 plasmid pK254-KPC_NDM co-carrying two different class carbapenemase genes blaKPC-2 and blaNDM-1 in Klebsiella michiganensis K254. METHODS: The strain K254 was sequenced by high-throughput genome sequencing. A detailed genomic and phenotypic characterization of pK254-KPC_NDM was performed. RESULTS: pK254-KPC_NDM displayed the conserve IncHI5 backbone and carried a resistant accessory region: Tn1696-related transposon Tn7414 containing blaKPC-2 and blaNDM-1. A sequence comparison was applied to a collection of four Tn1696-related transposons (Tn7414-Tn7417) harbouring carbapenemase genes. For all these four transposons, the blaNDM-1 was carried by Tn125 derivatives within three different mobile genetic elements. Tn7414 further acquired another carbapenemase gene, blaKPC-2, because of the integration of the local blaKPC-2 genetic environment from Tn6296, resulting in the high-level carbapenem resistance of K. michiganensis K254. The conjugal transfer and plasmid stability experiments confirmed that pK254-KPC_NDM could be transferred intercellularly and keep the stable vertical inheritance in different bacteria, which would contribute to the further dissemination of multiple carbapenemase genes and enhance the adaption and survival of K. michiganensis under complex and diverse antimicrobial selection pressures. CONCLUSION: This study was the first to report the K. michiganensis isolate coharbouring blaKPC-2 and blaNDM-1 in the Tn1696-related transposon in IncHI5 plasmid. The emergence of novel transposons simultaneously carrying multiple carbapenemase genes might contribute to the further dissemination of high-level carbapenem resistance in the isolates of the hospital settings and pose new challenges for the treatment of nosocomial infection.202337714378
1518130.9789Genomic characterisation of an mcr-1 and mcr-3-producing Escherichia coli strain isolated from pigs in France. OBJECTIVES: Colistin is considered a last-resort antibiotic against carbapenem-resistant isolates. Currently, this antibiotic is facing the emergence of mobilised colistin resistance (mcr) genes, which confer colistin resistance. This study conducted genomic characterisation of an atypical multidrug-resistant Escherichia coli harbouring two mcr genes in France. Samples collected from a pig farm in Avignon (Vaucluse department) were subjected to molecular screening targeting mcr variants. METHODS: Samples were cultured on selective Lucie-Bardet-Jean-Marc-Rolain medium. Growing bacteria were identified using MALDI-TOF, followed by antibiotic susceptibility testing. Whole-genome sequencing and bioinformatic genome analysis were performed. RESULTS: Selective culture of stools revealed the presence of an E. coli strain named Q4552 harbouring mcr-1.1 and mcr-3.5 genes, which is also resistant to 14 antibiotics. Genome sequencing and assembly yielded a complete and circular chromosome and eight different plasmids. Sequence analysis demonstrated an integration of a mobile genetic element carrying mcr-1.1 in the chromosome, whereas mcr-3.5 was in the plasmid and its resistome was composed of 22 resistance genes. The Q4552 strain was identified as an ST-843 clone that belonged to the clonal complex Cplx-568 and is the only ST type of this cplx-568 that has been isolated from animals, humans, and the environment. CONCLUSION: We report the first co-occurrence of mcr-1 and mcr-3 genes in France from a pathogenic E. coli isolated from a pig. Because this clone (ST-843) has been reported in zoonotic transmissions, programs to monitor the bacterium are urgently required to avoid its spread and zoonotic transmission to humans.202235085790
5418140.9789Detection of optrA in the African continent (Tunisia) within a mosaic Enterococcus faecalis plasmid from urban wastewaters. OBJECTIVES: Oxazolidinone resistance is a serious limitation in the treatment of MDR Enterococcus infections. Plasmid-mediated oxazolidinone resistance has been strongly linked to animals where the use of phenicols might co-select resistance to both antibiotic families. Our goal was to assess the diversity of genes conferring phenicol/oxazolidinone resistance among diverse enterococci and to characterize the optrA genetic environment. METHODS: Chloramphenicol-resistant isolates (>16 mg/L, n = 245) from different sources (hospitals/healthy humans/wastewaters/animals) in Portugal, Angola and Tunisia (1996-2016) were selected. Phenicol (eight cat variants, fexA, fexB) or phenicol + oxazolidinone [cfr, cfr(B), optrA] resistance genes were searched for by PCR. Susceptibility (disc diffusion/microdilution), filter mating, stability of antibiotic resistance (500 bacterial generations), plasmid typing (S1-PFGE/hybridization), MLST and WGS (Illumina-HiSeq) were performed for optrA-positive isolates. RESULTS: Resistance to phenicols (n = 181, 74%) and phenicols + oxazolidinones (n = 2, 1%) was associated with the presence of cat(A-8) (40%, predominant in hospitals and swine), cat(A-7) (29%, predominant in poultry and healthy humans), cat(A-9) (2%), fexB (2%) and fexA + optrA (1%). fexA and optrA genes were co-located in a transferable plasmid (pAF379, 72 918 bp) of two ST86 MDR Tunisian Enterococcus faecalis (wastewaters) carrying several putative virulence genes. MICs of chloramphenicol, linezolid and tedizolid were stably maintained at 64, 4 and 1 mg/L, respectively. The chimeric pAF379 comprised relics of genetic elements from different Gram-positive bacteria and origins (human/porcine). CONCLUSIONS: To the best of our knowledge, we report the first detection of optrA in an African country (Tunisia) within a transferable mosaic plasmid of different origins. Its identification in isolates from environmental sources is worrisome and alerts for the need of a concerted global surveillance on the occurrence and spread of optrA.201729029072
5487150.9789Rapid Transmission and Divergence of Vancomycin-Resistant Enterococcus faecium Sequence Type 80, China. We investigated genomic evolution of vancomycin-resistant Enterococcus faecium (VREF) during an outbreak in Shenzhen, China. Whole-genome sequencing revealed 2 sequence type 80 VREF subpopulations diverging through insertion sequence-mediated recombination. One subpopulation acquired more antimicrobial resistance and carbohydrate metabolism genes. Persistent VREF transmission underscores the need for genomic surveillance to curb spread.202540305388
1525160.9789Genetic Characterization of Enterobacter hormaechei Co-Harboring bla (NDM-1) and mcr-9 Causing Upper Respiratory Tract Infection. PURPOSE: With the spread of multiple drug-resistant bacteria, bla (NDM-1) and mcr-9 have been detected in various bacteria worldwide. However, the simultaneous detection of bla (NDM-1) and mcr-9 in Enterobacter hormaechei has been rarely reported. This study identified an E. hormaechei strain carrying both bla (NDM-1) and mcr-9. We investigated the genetic characteristics of these two resistance genes in detail, elucidating various potential mechanisms by which they may be transmitted. METHODS: Bacterial genomic features and possible origins were assessed by whole-genome sequencing (WGS) with Illumina and PacBio platforms and phylogenetic analysis. Subsequent investigations were performed, including antimicrobial susceptibility testing and multilocus sequence typing (MLST). RESULTS: We isolated an E. hormaechei strain DY1901 carrying both bla (NDM-1) and mcr-9 from the sputum sample. Susceptibility testing showed that the isolate was multidrug-resistant. Multiple antibiotic resistance genes and virulence genes are widely distributed in DY1901. S1-PFGE, Southern blotting, and plasmid replicon typing showed that DY1901 carried four plasmids. The plasmid carrying mcr-9 was 259Kb in size and belonged to IncHI2, while the plasmid carrying bla (NDM-1) was 45Kb in length and belonged to IncX3. CONCLUSION: The E. hormaechei strain isolated in this study has a broad antibiotic resistance spectrum, posing a challenge to clinical treatment. Plasmids carrying mcr-9 are fusion plasmids, and those taking NDM are widely disseminated in China, suggesting that we should conduct routine genomic surveillance on such plasmids to curb the spread of drug-resistant bacteria in the region.202236068833
1508170.9789First Detection and Genomic Insight into mcr-1 Encoding Plasmid-Mediated Colistin-Resistance Gene in Escherichia coli ST101 Isolated from the Migratory Bird Species Hirundo rustica in Thailand. Background: This study aimed to investigate the occurrence of mcr-1 encoding plasmid-mediated colistin-resistance gene in Escherichia coli isolated from migratory birds in Thailand. Materials and Methods: A total of 178 cloacal swabs from migratory birds was sampled and isolated from 2016 to 2017 in Nan, Trang, and Bangkok, Thailand. The multiplex polymerase chain reaction was used to screen the resistance genes. After screening, a disk diffusion assay and the minimum inhibitory concentration were investigated. The draft genome sequence of isolate 2A85589 was obtained using an Illumina HiSeq X-Ten platform. The genome was assembled using SPAdes 3.0.0. Antimicrobial resistance genes were identified using ResFinder 3.1. Results: We reported E. coli ST101 of isolate 2A85589, an mcr-1-carrying resistance gene isolated from the migratory bird species Hirundo rustica in Thailand. The draft genome of 2A85589 was 4,621,016 bp in size. IncHI1A plasmid was identified using PlasmidFinder with high coverage. In silico analysis detected the presence of eight putative acquired resistance genes, namely blaTEM-1B, mcr-1, mef(A), mef(B), QnrS1, sul3, tet(A), and tet(B), which conferred resistance to β-lactam, colistin, macrolide, quinolone, sulfonamide, and tetracycline. Conclusion: This study underlines the potential risk of the environmental contamination of mcr-1-carrying E. coli isolated from the migratory bird. The long range migration of birds can result in dissemination of mcr-1-carrying bacteria globally. Therefore, plasmid-mediated colistin is an urgent need to be addressed in both human and veterinary medicine for disease control and prevention.201931334682
2001180.9788Identification of plasmids co-carrying cfr(D)/optrA and cfr(D2)/poxtA linezolid resistance genes in two Enterococcus avium isolates from swine brain. Oxazolidinones are critically important antibiotics to treat human infections caused by multidrug-resistant bacteria, therefore the occurrence of linezolid-resistant enterococci from food-producing animals poses a serious risk to human health. In this study, Enterococcus avium 38157 and 44917 strains, isolated from the brain of two unrelated piglets, were found to carry the linezolid resistance genes cfr(D)-optrA, and cfr(D2)-poxtA, respectively. Whole genome sequencing analysis of E. avium 38157 revealed that the genes were co-located on the 36.5-kb pEa_cfr(D)-optrA plasmid showing high identity with the pAT02-c of Enterococcus faecium AT02 from pet food. The optrA region, was 99% identical to the one of the pAv-optrA plasmid from a bovine Aerococcus viridans strain, whereas the cfr(D) genetic context was identical to that of the plasmid 2 of E. faecium 15-307.1. pEa_cfr(D)-optrA was not transferable to enterococcal recipients. In E. avium 44917 a cfr(D)-like gene, named cfr(D2), and the poxtA gene were co-located on the transferable 42.6-kb pEa-cfr(D2)-poxtA plasmid 97% identical to the Tn6349 transposon of the human MRSA AOUC-0915. The cfr(D2) genetic context, fully replaced the Tn6644 that in S. aureus AOUC-0915 harbor the cfr gene. In conclusion, this is, the best of our knowledge, the first report of the new cfr(D2) gene variant. The occurrence of plasmids co-carrying two linezolid resistance genes in enterococci from food-producing animals needs close surveillance to prevent their spread to human pathogens.202337116421
1531190.9788Emergence of Plasmids Co-Harboring Carbapenem Resistance Genes and tmexCD2-toprJ2 in Sequence Type 11 Carbapenem Resistant Klebsiella pneumoniae Strains. OBJECTIVES: To characterize two plasmids co-harboring carbapenem resistance genes and tmexCD2-toprJ2 in carbapenem-resistant Klebsiella pneumoniae (CRKP) strains. METHODS: Two clinical CRKP strains were isolated and characterized by antimicrobial susceptibility testing, conjugation assays, whole-genome sequencing, and bioinformatics analysis. RESULTS: The two CRKP strains NB4 and NB5 were both resistant to imipenem, meropenem and tigecycline. Whole-genome sequencing revealed that two CRKP strains belonged to the ST11 type and carried multiple resistance genes. The tmexCD2-toprJ2 clusters in both strains were located on the IncFIB(Mar)-like/HI1B-like group of hybrid plasmids, which co-harbored the metallo-β-lactamase gene bla(NDM-1). In addition, the co-existence of bla(NDM-1) and bla(KPC-2) and the presence of tmexCD2-toprJ2 in CRKP strain NB5 was observed. CONCLUSIONS: In this study, tmexCD2-toprJ2 gene clusters were identified in two NDM-1-producing CRKP ST11 strains. These gene clusters will likely spread into clinical high-risk CRKP clones and exacerbate the antimicrobial resistance crisis. In addition, we detected the co-occurrence of bla(NDM-1), bla(KPC-2) and tmexCD2-toprJ2 in a single strain, which will undoubtedly accelerate the formation of a "superdrug resistant" bacteria. Hence, effective control measures should be implemented to prevent the further dissemination of such organisms in clinical settings.202235646740