A novel transposon Tn7540 carrying bla(NDM-9) and fosA3 in chromosome of a pathogenic multidrug-resistant Salmonella enterica serovar Indiana isolated from human faeces. - Related Documents




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151501.0000A 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
542410.9995The large plasmid carried class 1 integrons mediated multidrug resistance of foodborne Salmonella Indiana. Salmonella enterica serovar Indiana (S. Indiana) has aroused widespread concern as an important zoonotic pathogen. The molecular mechanism of multidrug resistance (MDR) in S. Indiana is not known and should be assessed. We aim to investigate the molecular mechanism of MDR and the importance of large plasmids carried class 1 integrons in the MDR of foodborne S. Indiana. Class 1 integrons in 48 S. Indiana isolates and 200 isolates of 7 other Salmonella serotypes were detected by polymerase chain reaction (PCR). To analyze the antimicrobial resistance genes (ARGs) of two S. Indiana isolates, designated S. Indiana 15 and S. Indiana 222, next-generation sequencing (NGS) was performed, and the resulting sequences were compared with the complete nucleotide sequences of S. Indiana D90 and S. Indiana C629. Comparative functional analysis was conducted between the intI1 (1,014 bp) of S. Indiana 222 and the intI1 (699 bp) of S. Indiana 15. Plasmid conjugation transfer analysis was performed to analyze the horizontal gene transfer of the integrons-related resistance genes with integron-positive and integron-negative Salmonella isolates. 64.58% of S. Indiana isolates carried class 1 integrons, which was significantly higher than that of other Salmonella serotypes (p < 0.001). The NGS results showed that the S. Indiana 15 and S. Indiana 222 isolates carried a large plasmid with a class 1 integron and multiple ARGs, similar to S. Indiana D90 and S. Indiana C629. Two integrases found in S. Indiana isolates belong to class 1 integrases and could integrate resistance genes into specific integration sites of the integrons. The conjugation frequency of intI1 (1,014 bp) was 6.08 × 10(-5), which was significantly higher than that of intI1 (699 bp) (p < 0.01). The large plasmids carrying a class 1 integron and the number of ARGs were strongly correlated (p < 0.001). The conjugation frequency of integron-positive S. Indiana recipient isolates was significantly higher than that of integron-negative recipient isolates (p < 0.05). S. Indiana containing large plasmids carrying a class 1 integron more easily captured resistance genes from other bacteria (S. Enteritidis and S. Derby), which could be an important cause of the emerging pandemic of MDR clones. Graphical abstractS. Indiana containing large plasmids carrying a class 1 integron more easily captured resistance genes from other bacteria (S. Enteritidis and S. Derby), which could be an important cause of the emerging pandemic of MDR clones.202236312970
151920.9995Epidemiology and resistance mechanisms of tigecycline- and carbapenem-resistant Enterobacteriaceae in China: a multicentre genome-based study. OBJECTIVES: To elucidate the molecular epidemiology of tigecycline and carbapenem-resistant Enterobacteriaceae isolates and mechanisms of tigecycline resistance. METHODS: We gathered 31 unduplicated strains of tigecycline-resistant Enterobacteriaceae from six hospitals nationwide. Antimicrobial susceptibility testing, phenotypic detection, and PCR identification were performed first, followed by homology analysis using MLST and PFGE. Conjugation transfer experiments using resistance gene plasmids were carried out, and the conjugates' growth curves were examined. All strains were sequenced using the Illumina HiSeq technology, and we identified a strain KP28 carrying a complete gene cluster tmexCD2-toprJ2. Then, its plasmid was further constructed using the PacBio platforms to complete the frame. The genetic connection of the tmexCD2-toprJ2 gene cluster carried by KP28 was established using core genome analyses. RESULTS: All 31 tigecycline-resistant Enterobacteriaceae strains (TG-CRE) were multidrug resistant. PFGE classified strains of CRKP, CRECL, and CRKAE into 16 distinct spectra, 6 distinct spectra, and 3 distinct spectra. MLST results showed a high concentration of ST11 in CRKP strains and a predominance of ST116 in CRECL strains, suggesting possible clonal transmission or selective dominance. The findings of the plasmid conjugation assay revealed that three strains expressing carbapenem resistance genes were effectively transmitted to the recipient cell E. coli EC600. WGS data revealed that these 31 strains include 79 resistance genes, with one strain (KP28) carrying the whole tigecycline resistance gene cluster, tmexC2D2-toprJ2. This resistance gene is contained in a large IncHI5 plasmid, which is difficult to transfer. CONCLUSION: The overall carriage rate of the tmexC2D2-toprJ2 gene cluster was found to be low among the five Chinese hospitals investigated. Conversely, tet(A) mutations were present in most of the strains. Bacteria with the carbapenem resistance genes bla (KPC) and bla (NDM) are vulnerable to horizontal transmission. Increasing the risk of transmission of antibiotic-resistant genes.202540400686
152130.9995Fusion plasmid carrying the colistin resistance gene mcr of Escherichia coli isolated from healthy residents. OBJECTIVES: The extensive spread of colistin resistance represents an enormous concern to infectious disease treatment, because colistin is one of the few effective antibiotics against multidrug-resistant bacterial infections, including carbapenem-resistant bacteria. This dissemination can be caused by plasmid transfer containing the colistin resistance gene mcr. Therefore, the plasmid host range affects horizontal gene transfer. This study reports a fusion plasmid of different incompatibility types, which could easily expand the plasmid host range, allowing widespread mcr prevalence in the microbial community. METHODS: Genome sequences of colistin-resistant Escherichia coli isolates from stool specimens of healthy human residents in Ecuador were determined using the DNBSEQ and MinION platforms. Hybrid genome assembly was performed using Unicycler, and the genomes were annotated using DFAST. Genome analysis was performed using the Geneious Prime software. RESULTS: Two colistin-resistant E. coli strains isolated separately from different residents presented mcr-carrying plasmids with fused different incompatibility types, IncFIA, IncHIIA, and IncHIIB. The phylogenies of these host bacteria were different. The sizes of the mcr-carrying fusion plasmids pLR-06 and pLR-50 with the full Tn6330 mcr-transposon were 260 Kbp and 198 Kbp, respectively. Both fusion plasmids possessed other resistance genes, including tet(B), tet(M), bla(TEM-1b), sul3, cmlA1, aadA1, aadA2, fosA3, and dfrA12. CONCLUSION: This is the first report of a fusion plasmid comprising different incompatibility types with mcr from colistin-resistant E. coli strains isolated from community residents. The mcr fusion plasmid may play a crucial role in achieving horizontal mcr transmission and the evolution of the multidrug resistance plasmid among hosts.202235705132
151740.9994Co-occurrence of blaNDM-1, rmtC, and mcr-9 in multidrug-resistant Enterobacter kobei strain isolated from an infant with urinary tract infection. OBJECTIVES: The co-emergence of mcr and carbapenem resistance genes in Gram-negative bacteria is a serious problem. This study aims to clarify the genetic characteristic of one novel multidrug-resistant Enterobacter kobei EC1382 with mcr-9 causing urinary tract inflammation in an infant. METHODS: Antimicrobial drug susceptibility testing was performed for this isolate using the broth microdilution method. Whole-genome sequencing was performed using the Illumina PacBio RS II platform and HiSeq platform, and the antimicrobial resistance genes, mobile elements, and plasmid replicon types were identified. Conjugation analysis was performed using Escherichia coli C600 as recipients. RESULTS: Enterobacter kobei EC1382 was resistant to carbapenem, aminoglycoside, and cephalosporin. Twenty-five antimicrobial resistance genes were identified, including genes conferring resistance to carbapenem (blaNDM-1), colistin (mcr-9), and aminoglycosides (rmtC). The blaNDM-1 gene, accompanied by bleMBL and rmtC located downstream of an ISCR14 element, was detected in the IncFII(Yp) type plasmid pEC1382-2. Interestingly, although E. kobei EC1382 was susceptible to colistin, it had three identical mcr-9 genes (two in the chromosome and one in the IncHI2-type plasmid pEC1382-1). The backbone (∼12.2-kb genetic fragment) of these mcr-9 (flanked by IS903B and IS481-IS26) regions were conserved in this strain, and they were found to be present in various bacteria as three types, implying a silent distribution. CONCLUSIONS: To the best of our knowledge, this is the first study to demonstrate the coexistence of blaNDM-1, rmtC, and mcr-9 in E. kobei. The silent prevalence of mcr-9 in bacteria may be a threat to public health.202337062506
152050.9994Colistin resistance in Salmonella and Escherichia coli isolates from a pig farm in Great Britain. OBJECTIVES: The objective of this study was to characterize colistin-resistant bacteria isolated from pigs on a farm in Great Britain following identification of a plasmid-borne colistin resistance mechanism in Escherichia coli from China. METHODS: Phenotypic antimicrobial susceptibility testing was undertaken by broth dilution and WGS was performed to detect the presence of genes encoding resistance and virulence. Transferable colistin resistance was investigated by conjugation. RESULTS: Two E. coli and one Salmonella Typhimurium variant Copenhagen were shown to be MDR, including resistance to colistin, with one E. coli and the Salmonella carrying the mcr-1 gene; all three harboured chromosomal mutations in genes conferring colistin resistance and both E. coli harboured β-lactamase resistance. The Salmonella mcr-1 plasmid was highly similar to pHNSHP45, from China, while the E. coli mcr-1 plasmid only had the ISApII and mcr-1 genes in common. The frequency of mcr-1 plasmid transfer by conjugation to recipient Enterobacteriaceae from Salmonella was low, lying between 10(-7) and 10(-9) cfu/recipient cfu. We were unable to demonstrate mcr-1 plasmid transfer from the E. coli. Plasmid profiling indicated transfer of multiple plasmids from the Salmonella resulting in some MDR transconjugants. CONCLUSIONS: Identification of the mcr-1 gene in Enterobacteriaceae from pigs confirms its presence in livestock in Great Britain. The results suggest dissemination of resistance through different horizontally transferable elements. The in vitro transfer of multiple plasmids carrying colistin and other resistances from the Salmonella isolate underlines the potential for wider dissemination and recombination.201627147305
206760.9994Genetic characterization of three qnrS1-harbouring multidrug-resistance plasmids and qnrS1-containing transposons circulating in Ho Chi Minh City, Vietnam. Plasmid-mediated quinolone resistance (PMQR) refers to a family of closely related genes that confer decreased susceptibility to fluoroquinolones. PMQR genes are generally associated with integrons and/or plasmids that carry additional antimicrobial resistance genes active against a range of antimicrobials. In Ho Chi Minh City (HCMC), Vietnam, we have previously shown a high frequency of PMQR genes within commensal Enterobacteriaceae. However, there are limited available sequence data detailing the genetic context in which the PMQR genes reside, and a lack of understanding of how these genes spread across the Enterobacteriaceae. Here, we aimed to determine the genetic background facilitating the spread and maintenance of qnrS1, the dominant PMQR gene circulating in HCMC. We sequenced three qnrS1-carrying plasmids in their entirety to understand the genetic context of these qnrS1-embedded plasmids and also the association of qnrS1-mediated quinolone resistance with other antimicrobial resistance phenotypes. Annotation of the three qnrS1-containing plasmids revealed a qnrS1-containing transposon with a closely related structure. We screened 112 qnrS1-positive commensal Enterobacteriaceae isolated in the community and in a hospital in HCMC to detect the common transposon structure. We found the same transposon structure to be present in 71.4 % (45/63) of qnrS1-positive hospital isolates and in 36.7 % (18/49) of qnrS1-positive isolates from the community. The resulting sequence analysis of the qnrS1 environment suggested that qnrS1 genes are widely distributed and are mobilized on elements with a common genetic background. Our data add additional insight into mechanisms that facilitate resistance to multiple antimicrobials in Gram-negative bacteria in Vietnam.201526272054
189570.9994Comparative Genome Analysis of Livestock and Human Colistin-Resistant Escherichia coli Isolates from the Same Household. BACKGROUND: Emergence and dissemination of colistin-resistant bacteria that harbor mobile colistin resistance (mcr) genes pose a dire challenge for the treatment of intractable infections caused by multidrug-resistant bacteria. Current findings on colistin-resistant bacteria in both humans and livestock of the same households highlight the need to identify the dissemination mechanisms of colistin-resistant bacteria. METHODS: In this study, a comparative genome analysis of colistin-resistant Escherichia coli isolates from livestock and humans of the same household was performed to clarify the possible dissemination mechanism of mcr genes among bacteria. Pulsed-field gel electrophoresis and whole-genome sequencing followed by sequence typing of the isolates were performed for assessment of the samples. RESULTS: The study revealed that two colistin-resistant E. coli isolates, one each from a pig and a chicken, were phylogenetically similar but not identical to the human isolates obtained from the same household. The comparative genome analysis revealed that the chicken isolate and a human isolate shared the same IncHl2 plasmid harboring the mcr transposon (mcr-1-PAP2). The pig isolate and the other human isolate retained the mcr-1 transposon on the chromosome, with the pig isolate carrying the complete mcr transposon (ISApl1-mcr-1-PAP2-ISApl1) and the human isolate carrying the incomplete mcr transposon (ISApl1-mcr-1-PAP2). CONCLUSION: The results of the study confirm the distribution of colistin-resistant bacteria and subsequent transmission of the resistance gene-carrying transposon between livestock and humans of the same household. To the best of our knowledge, this is the first report on genomic analysis of colistin-resistant E. coli isolates obtained from livestock and residents of the same household.202133688219
586780.9994Molecular analysis of florfenicol-resistant Pasteurella multocida isolates in Germany. OBJECTIVES: Three florfenicol-resistant Pasteurella multocida isolates from Germany, two from swine and one from a calf, were investigated for the genetics and transferability of florfenicol resistance. METHODS: The isolates were investigated for susceptibility to antimicrobial agents and plasmid content. Florfenicol resistance plasmids carrying the gene floR were identified by transformation and PCR. Plasmids were mapped, and a novel plasmid type was sequenced completely. PFGE served to determine the clonality of the isolates. RESULTS: In one porcine and the bovine P. multocida isolate, florfenicol resistance was associated with the plasmid pCCK381 previously described in a bovine P. multocida isolate from the UK. The remaining porcine isolate harboured a new type of floR-carrying plasmid, the 10 226 bp plasmid pCCK1900. Complete sequence analysis identified an RSF1010-like plasmid backbone with the mobilization genes mobA, mobB and mobC, the plasmid replication genes repA, repB and repC, the sulphonamide resistance gene sul2 and the streptomycin resistance genes strA and strB. The floR gene area was integrated into a region downstream of strB, which exhibited homology to the floR flanking regions found in various bacteria. PFGE revealed that the floR-carrying P. multocida strains from Germany were unrelated and also different from the UK strain. CONCLUSIONS: After the UK and France, floR-mediated florfenicol resistance has now also been identified in target bacteria from Germany. PFGE data and the analysis of plasmids strongly suggested that the spread of florfenicol resistance is due to the horizontal transfer of plasmids rather than the clonal dissemination of a resistant P. multocida isolate.200818786941
152590.9994Genetic 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
5455100.9994Two novel plasmids harbouring the multiresistance gene cfr in porcine Staphylococcus equorum. BACKGROUND: The emergence and transmission of the multidrug resistance gene cfr have raised public health concerns worldwide. OBJECTIVES: Multidrug-resistant Staphylococcus equorum isolates can pose a threat to public health. In this study, we have characterised the whole-genome of one Staphylococcus equorum isolate harbouring two distinct cfr-carrying plasmids. METHODS: Antimicrobial susceptibility testing was performed by broth microdilution. Genomic DNA was sequenced using both the Illumina HiSeq X Ten and Nanopore MinION platforms. De novo hybrid assembly was performed by Unicycler. Genomic data were assessed by in silico prediction and bioinformatic tools. RESULTS: Staphylococcus equorum isolate SN42 exhibited resistance or high MICs to linezolid, erythromycin, tetracycline, oxacillin, clindamycin, virginiamycin, tiamulin, chloramphenicol and florfenicol. It carried two cfr-harbouring plasmids: the RepA N-family plasmid pSN42-51 K and the Inc18-family plasmid pSN42-50 K. These two plasmids exhibited low structural similarities to the so far reported cfr-carrying plasmids. Both plasmids harboured an arsenic resistance operon, copper and cadmium resistance genes as well as the lincosamide-pleuromutilin-streptogramin A resistance gene lsa(B). In addition, plasmid pSN42-51 K carried two erm(B) genes for macrolide-lincosamide-streptogramin B resistance, the streptomycin resistance gene ant(6)-Ia as well as mercury resistance genes while pSN42-50 K was associated with the heavy metal translocating P-type ATPase gene hmtp. The co-carriage and co-existence of these antimicrobial resistance and heavy metal resistance genes increases the likelihood of co-selection of the cfr-carrying plasmids. CONCLUSION: This is the first report of S. equorum carrying two distinct cfr-carrying plasmids, underscoring the need for ongoing surveillance to address the potential dissemination of multi-drug resistance in bacteria from food-producing animals to ensure food safety and public health.202439362467
1887110.9994Complete Genetic Analysis of Plasmids Carrying mcr-1 and Other Resistance Genes in Avian Pathogenic Escherichia coli Isolates from Diseased Chickens in Anhui Province in China. Antimicrobial resistance associated with colistin has emerged as a significant concern worldwide, threatening the use of one of the most important antimicrobials for treating human disease. This study aimed to investigate the prevalence of colistin-resistant avian-pathogenic Escherichia coli (APEC) and shed light on the possibility of transmission of mcr-1 (mobilized colistin resistance)-positive APEC. A total of 72 APEC isolates from Anhui Province in China were collected between March 2017 and December 2018 and screened for the mcr-1 gene. Antimicrobial susceptibility testing was performed using the broth dilution method. Pulsed-field gel electrophoresis, Southern blot analysis, and conjugation assay were performed to determine the location and conjugative ability of the mcr-1 gene. Whole-genome sequencing and analysis were performed using Illumina MiSeq and Nanopore MinION platforms. Three APEC isolates (AH25, AH62, and AH65) were found to be positive for the mcr-1 gene and showed multidrug resistance. The mcr-1 genes were located on IncI2 plasmids, and conjugation assays revealed that these plasmids were transferrable. Notably, strains AH62 and AH65, both belonging to ST1788, were collected from different places but carried the same drug resistance genes and shared highly similar plasmids. This study highlights the potential for a possible epidemic of mcr-1-positive APEC and the urgent need for continuous active monitoring.IMPORTANCE In this study, three plasmids carrying mcr-1 were isolated and characterized from APEC isolates from Anhui Province in China. The mcr-1 genes were located on IncI2 plasmids, and these plasmids were transferrable. These three IncI2 plasmids had high homology with the plasmids harbored by pathogenic bacteria isolated from other species. This finding showed that IncI2 plasmids poses a risk for the exchange of genetic material between different niches. Although colistin has been banned for use in food-producing animals in China, the coexistence of the broad-spectrum β-lactamase and mcr-1 genes on a plasmid can also lead to the stable existence of mcr-1 genes. The findings illustrated the need to improve the monitoring of drug resistance in poultry systems so as to curb the transmission or persistence of multidrug-resistant bacteria.202133853876
1524120.9994Characterization of a Novel mcr-8.2-Bearing Plasmid in ST395 Klebsiella pneumoniae of Chicken Origin. The emergence of mobile colistin resistance mcr genes undermines the efficacy of colistin as the last-resort drug for multi-drug resistance infections and constitutes a great public health concern. Plasmids play a critical role in the transmission of mcr genes among bacteria. One colistin-resistant Klebsiella pneumoniae strain of chicken origin was collected and analyzed by antimicrobial susceptibility testing, PCR, conjugation assay and S1-PFGE. Whole-genome sequencing (WGS) approach combining Illumina and MinION platforms was utilized to decipher the underlying colistin resistance mechanism and genetic context. A novel mcr-8.2-bearing plasmid p2019036D-mcr8-345kb with 345 655 bp in size encoding various resistance genes including floR, sul1, aadA16, aadA2, bla (CTX-M-27), bla (DHA-1), tet(D), dfrA12 and qnrB4 was identified responsible for the colistin resistance phenotype. Plasmid comparison has shown that the mcr-8.2-bearing plasmid differed from other reported plasmids positive for mcr-8.2 but shared the same core mcr-8.2-bearing conserved region. This study demonstrates the emergence of mcr-8.2-bearing K. pneumoniae of animal origin is a potential risk to humans.202032606828
5422130.9994Analysis of Resistance to Florfenicol and the Related Mechanism of Dissemination in Different Animal-Derived Bacteria. Bacterial resistance to antibiotics has become an important concern for public health. This study was aimed to investigate the characteristics and the distribution of the florfenicol-related resistance genes in bacteria isolated from four farms. A total of 106 florfenicol-resistant Gram-negative bacilli were examined for florfenicol-related resistance genes, and the positive isolates were further characterized. The antimicrobial sensitivity results showed that most of them (100, 94.33%) belonged to multidrug resistance Enterobacteriaceae. About 91.51% of the strains carried floR gene, while 4.72% carried cfr gene. According to the pulsed-field gel electrophoresis results, 34 Escherichia coli were subdivided into 22 profiles, the genetic similarity coefficient of which ranged from 80.3 to 98.0%. The multilocus sequence typing (MLST) results revealed 17 sequence types (STs), with ST10 being the most prevalent. The genome sequencing result showed that the Proteus vulgaris G32 genome consists of a 4.06-Mb chromosome, a 177,911-bp plasmid (pG32-177), and a 51,686-bp plasmid (pG32-51). A floR located in a drug-resistant region on the chromosome of P. vulgaris G32 was with IS91 family transposase, and the other floR gene on the plasmid pG32-177 was with an ISCR2 insertion sequence. The cfr gene was located on the pG32-51 flanked by IS26 element and TnpA26. This study suggested that the mobile genetic elements played an important role in the replication of resistance genes and the horizontal resistance gene transfer.202032903722
1523140.9994The characterization of an IncN-IncR fusion plasmid co-harboring bla(TEM-40), bla(KPC-2), and bla(IMP-4) derived from ST1393 Klebsiella pneumoniae. Plasmids, as important genetic elements apart from chromosomes, often carry multiple resistance genes and various mobile genetic elements, enabling them to acquire more exogenous genes and confer additional resistance phenotypes to bacteria. Various carbapenem resistance genes are often located on IncN plasmids, and several reports have linked fusion plasmids to IncN plasmids. Therefore, this study aims to explore the emergence, molecular structure characteristics, and resistance features mediated by IncN fusion plasmids carrying multiple carbapenem resistance genes. In this study, species identification was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). Polymerase chain reaction (PCR) was employed to detect the presence of carbapenem resistance genes in the strains. PCR-based replicon typing (PBRT) was used to identify IncN plasmids. Plasmids were analyzed through S1-nuclease pulsed-field gel electrophoresis (S1-PFGE), Southern blotting, conjugation experiments, and stability tests. Whole-genome sequencing (WGS) and antimicrobial susceptibility testing (AST) were conducted to characterize the target strains. Four strains containing IncN plasmids were identified: two Klebsiella pneumoniae, one Escherichia coli, and one Enterobacter cloacae, all harboring carbapenem resistance genes. Among them, two IncN plasmids (pFAHZZU7605-KPC-IMP and pFAHZZU7865-IMP) contained blaIMP-4 and exhibited similar molecular structure characteristics. Notably, the pFAHZZU7605-KPC-IMP plasmid harbored both IncN and IncR replicons. We hypothesize that the pFAHZZU7605-KPC-IMP fusion plasmid resulted from the recombination of a pFAHZZU7865-IMP-like plasmid and an IncR-like plasmid. Further analysis of the plasmid's genetic elements revealed that insertion sequences ISKpn19 and ISKpn27 played crucial roles in the plasmid recombination and fusion process. In clinical settings, plasmids carrying different resistance genes can undergo fusion, mediated by genetic elements, thereby expanding the resistance spectrum of host bacteria. Hence, it is essential to enhance the monitoring and research of transposable elements to control the spread of multidrug-resistant bacteria.202439496788
1886150.9994Comparative genomic analysis of Colistin resistant Escherichia coli isolated from pigs, a human and wastewater on colistin withdrawn pig farm. In this study, genomic and plasmid characteristics of Escherichia coli were determined with the aim of deducing how mcr genes may have spread on a colistin withdrawn pig farm. Whole genome hybrid sequencing was applied to six mcr-positive E. coli (MCRPE) strains isolated from pigs, a farmworker and wastewater collected between 2017 and 2019. Among these, mcr-1.1 genes were identified on IncI2 plasmids from a pig and wastewater, and on IncX4 from the human isolate, whereas mcr-3 genes were found on plasmids IncFII and IncHI2 in two porcine strains. The MCRPE isolates exhibited genotypic and phenotypic multidrug resistance (MDR) traits as well as heavy metal and antiseptic resistance genes. The mcr-1.1-IncI2 and IncX4 plasmids carried only colistin resistance genes. Whereas, the mcr-3.5-IncHI2 plasmid presented MDR region, with several mobile genetic elements. Despite the MCRPE strains belonged to different E. coli lineages, mcr-carrying plasmids with high similarities were found in isolates from pigs and wastewater recovered in different years. This study highlighted that several factors, including the resistomic profile of the host bacteria, co-selection via adjunct antibiotic resistance genes, antiseptics, and/or disinfectants, and plasmid-host fitness adaptation may encourage the maintenance of plasmids carrying mcr genes in E. coli.202336991093
1516160.9994Draft genome sequence of mcr-1-mediated colistin-resistant Escherichia coli ST359 from chicken carcasses in Northeastern Brazil. OBJECTIVES: Considering that polymyxin is a drug of last resort in the treatment of humans infected by multidrug-resistant bacteria, the occurrence of plasmid-mediated colistin resistance mcr gene among Gram-negative bacteria in foods must be investigated. We present herein the draft genome sequence of a phenotypically colistin-resistant Escherichia coli carrying mcr-1 in chicken carcasses from a public market. METHODS: Total genomic DNA from the strain was sequenced by means of the Illumina MiSeq. The assembled contigs were annotated and manually curated. In silico analyses were performed to detect significant epidemiologic (serotyping and MLST) and structural features related plasmids identification, virulence and resistome. RESULTS: The ST359 E. coli strain presented a conserved 747 bp mcr-1 gene within a 9431 kb contig compatible with the IncX4 plasmid, which has been identified as a key vector for the global dissemination of mcr determinants among Enterobacteriacea. Other genes encoding for multidrug resistance such as bla(CTX-M-2) and bla(TEM-1B), and the virulence factors astA, cma, gad, iroN, ipfA, mchF were also detected. CONCLUSION: We reported a draft genome of a colistin-resistant E. coli ST359 associated with an IncX4 plasmid containing the gene mcr-1. The genomic data can be useful in epidemiological and evolutionary investigations on the spread of colistin-resistance among Enterobacteriacea in the food chain.202032927113
5423170.9994Characterization of mobile genetic elements in multidrug-resistant Bacteroides fragilis isolates from different hospitals in the Netherlands. OBJECTIVES: Five human clinical multidrug-resistant (MDR) Bacteroides fragilis isolates, including resistance to meropenem and metronidazole, were recovered at different hospitals in the Netherlands between 2014 and 2020 and sent to the anaerobic reference laboratory for full characterization. METHODS: Isolates were recovered from a variety of clinical specimens from patients with unrelated backgrounds. Long- and short-read sequencing was performed, followed by a hybrid assembly to study the presence of mobile genetic elements (MGEs) and antimicrobial resistance genes (ARGs). RESULTS: A cfxA gene was present on a transposon (Tn) similar to Tn4555 in two isolates. In two isolates a novel Tn was present with the cfxA gene. Four isolates harbored a nimE gene, located on a pBFS01_2 plasmid. One isolate contained a novel plasmid carrying a nimA gene with IS1168. The tetQ gene was present on novel conjugative transposons (CTns) belonging to the CTnDOT family. Two isolates harbored a novel plasmid with tetQ. Other ARGs in these isolates, but not on an MGE, were: cfiA, ermF, mef(EN2), and sul2. ARGs harboured differed between isolates and corresponded with the observed phenotypic resistance. CONCLUSIONS: Novel CTns, Tns, and plasmids were encountered in the five MDR B. fragilis isolates, complementing our knowledge on MDR and horizontal gene transfer in anaerobic bacteria.202337001724
1890180.9994Emergence and Characterization of Tigecycline Resistance Gene tet(X4) in ST609 Escherichia coli Isolates from Wastewater in Turkey. Emergence of pathogens harboring tigecycline resistance genes incurs great concerns. Wastewater is recognized as the important reservoir of antimicrobial resistance genes. Here we characterized the phenotypes and genotypes of bacteria carrying tet(X4) from wastewater in Turkey for the first time. Four tet(X4)-positive Escherichia coli isolates were identified and characterized by PCR, Sanger sequencing, antimicrobial susceptibility testing, conjugation assays, Illumina sequencing, nanopore sequencing and bioinformatic analysis. Four tet(X4)-harboring isolates were multidrug-resistant (MDR) bacteria and the tet(X4) gene was nontransferable in four isolates. Genetic analysis revealed that tet(X4) genes in four isolates were located on plasmids co-harboring two replicons IncFIA(HI1) and IncFIB(K). However, none of the four plasmids carried genes associated with horizontal transfer of plasmids. The coexistence of bla(SHV-12)-bearing IncX3-type plasmid and tet(X4)-harboring plasmid was also found in one isolate. These findings indicate that continuous surveillance of the tet(X4)-bearing isolates in different environments worldwide should be strengthened. IMPORTANCE The emergence of tigecycline resistance genes in humans and animals in China seriously threatens the clinical utility of tigecycline, but the molecular epidemiology of tigecycline-resistant bacteria in other countries remained largely unknown. Therefore, it is necessary to learn the prevalence and molecular characteristics of bacteria carrying tigecycline resistance genes, particularly the mobilizable tet(X4), in other countries. In the study, we first described the presence and molecular characteristics of the tet(X4)-positive E. coli isolates from wastewater in Turkey. Four tet(X4)-bearing isolates belonged to ST609, an E. coli clone commonly found from humans, animals and the environment. These findings highlight the importance of monitoring the tet(X4) gene in different settings globally.202235863037
1897190.9994Plasmid-based replicon typing: Useful tool in demonstrating the silent pandemic of plasmid-mediated multi-drug resistance in Enterobacterales. BACKGROUND: Multi-drug resistant Enterobacterales increasingly isolated in hospital settings have a significant impact on therapy and overall treatment costs. Conjugative plasmids carrying relevant resistance genes have been described as the most frequent mechanism of acquisition and spread of resistance. PCR-based replicon typing (PBRT) is a method for plasmid identification and incompatibility typing which helps detect the presence of plasmid families in these bacteria. This study was undertaken to provide an insight into the prevalence of resistance plasmids in MDR Enterobacterales in our tertiary care setting. METHODS: A selection of one hundred multi-drug resistant Enterobacterale isolates sourced from clinical samples were subjected to PCR-based replicon typing. RESULTS: A total of 21 plasmid replicon types were detected from 85% of the isolates out of the 28 families described in literature. Majority of the isolates (54%) showed three or more replicons. IncF was the most frequent plasmid family detected with FIA being the most common replicon type (43%) followed by FII (29%) and FIB (28%) replicons. Among the IncX plasmid family, X3 replicon was the commonest (14%). IncF and IncX plasmid families are known to carry a large spectrum of resistance genes. CONCLUSION: The presence of these plasmids engenders emergent steps to be taken for prevention of their transmission in the form of strict infection control measures in the hospital and adoption of novel methods of plasmid curing to eliminate the plasmids from these organisms rendering them susceptible to the currently used antimicrobials.202540463599