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1.
The emergence and spread of NDM-1-producing Enterobacteriaceae have resulted in a worldwide public health risk that has affected some provinces of China. China is an exceptionally large country, and there is a crucial need to investigate the epidemic of bla
NDM-1-positive Enterobacteriaceae in our province. A total of 186 carbapenem-resistant Enterobacteriaceae isolates (CRE) were collected in a grade-3 hospital in Zhejiang province. Carbapenem-resistant genes, including bla
KPC, bla
IMP, bla
VIM, bla
OXA-48 and bla
NDM-1 were screened and sequenced. Ninety isolates were identified as harboring the bla
KPC-2 genes, and five bla
NDM-1-positive isolates were uncovered. XbaI-PFGE revealed that three bla
NDM-1-positive K. pneumoniae isolates belonged to two different clones. S1-PFGE and southern blot suggested that the bla
NDM-1 genes were located on IncX3-type plasmids with two different sizes ranging from 33.3 to 54.7 kb (n=4) and 104.5 to 138.9 kb (n=1), respectively, all of which could easily transfer to Escherichia coli by conjugation and electrotransformation. The high-throughput sequencing of two plasmids was performed leading to the identification of a smaller 54-kb plasmid, which had high sequence similarity with a previously reported pCFNDM-CN, and a larger plasmid in which only a 7.8-kb sequence of a common gene environment around bla
NDM-1 (bla
NDM-1-trpF- dsbC-cutA1-groEL-ΔInsE,) was detected. PCR mapping and sequencing demonstrated that four smaller bla
NDM-1 plasmids contained a common gene environment around bla
NDM-1 (IS5-bla
NDM-1-trpF- dsbC-cutA1-groEL). We monitored the CRE epidemic in our hospital and determined that KPC-2 carbapenemase was a major risk to patient health and the IncX3-type plasmid played a vital role in the spread of the bla
NDM-1 gene among the CRE. 相似文献
2.
Background
Spread of the bla NDM-1 gene that encodes the New Delhi metallo-β-lactamase (NDM-1) in Enterobacteriaceae is a major global health problem. Plasmids carrying bla NDM-1 from two different multi-drug resistant Klebsiella pneumonia isolates collected in Singapore were completely sequenced and compared to known plasmids carrying bla NDM-1.Methodology/Principal Findings
The two plasmids, pTR3 and pTR4, were transferred to Escherichia coli recipient strain J53 and completely sequenced by a shotgun approach using 3-kb paired-end libraries on 454. Although the K. pneumoniae strains were unrelated by molecular typing using PFGE and MLST, complete sequencing revealed that pTR3 and pTR4 are identical. The plasmid sequence is similar to the E. coli NDM-1-encoding plasmid p271A, which was isolated in Australia from a patient returning from Bangladesh. The immediate regions of the bla NDM-1 gene in pTR3/4 are identical to that of p271A, but the backbone of our plasmid is much more similar to another IncN2 plasmid reported recently, pJIE137, which contained an additional 5.2-kb CUP (conserved upstream repeat) regulon region in comparison to p271A. A 257-bp element bounded by imperfect 39-bp inverted repeats (IR) and an incomplete version of this element flanking the 3.6-kb NDM-1-encoding region were identified in these plasmids and are likely to be the vestiges of an unknown IS.Conclusions
Although the hosts are not epidemiologically linked, we found that the plasmids bearing the bla NDM-1 gene are identical. Comparative analyses of the conserved NDM-1-encoding region among different plasmids from K. pneumoniae and E. coli suggested that the transposable elements and the two unknown IR-associated elements flanking the NDM-1-encoding region might have aided the spreading of this worrisome resistance determinant. 相似文献3.
Increasing reports of multidrug resistance conferred by conjugative plasmids of Enterobacteriaceae necessitate a better understanding of their evolution. One such group is the narrow-host-range IncI1 plasmid type, known for their ability to carry genes encoding resistance to extended-spectrum beta lactamases. The focus of this study was to perform comparative sequencing of IncI1 plasmids from porcine enterotoxigenic Escherichia coli (ETEC), isolated irrespective of antimicrobial susceptibility phenotype. Five IncI1 plasmids of porcine ETEC origin and one IncI1 plasmid from a Salmonella enterica serovar Kentucky isolate from a healthy broiler chicken were sequenced and compared to existing IncI1 plasmid sequences in an effort to better understand the overall genetic composition of the IncI1 plasmid lineages. Overall, the sequenced porcine ETEC IncI1 plasmids were divergent from other sequenced IncI1 plasmids based upon multiple means of inferred phylogeny. High occurrences of IncI1 and IncA/C plasmid-associated genes and the blaTEM and blaCMY-2 beta lactamase genes were observed among porcine ETEC. However, the presence of blaTEM and blaCMY-2 did not strongly correlate with IncI1 plasmid possession, suggesting that these plasmids in porcine ETEC are not primarily associated with the carriage of such resistance genes. Overall, this work suggests a conservation of the IncI1 plasmid backbone among sequenced plasmids with a single locus for the acquisition of accessory genes, such as those associated with antimicrobial resistance. Furthermore, the high occurrence of IncI1 and IncA/C plasmids among clinical E. coli from commercial swine facilities is indicative of extensive horizontal gene transfer among porcine ETEC. 相似文献
4.
Background
The current spread of the gene encoding the metallo-ß-lactamase NDM-1 in Enterobacteriaceae is linked to a variety of surrounding genetic structures and plasmid scaffolds.Methodology
The whole sequence of plasmid pGUE-NDM carrying the bla NDM-1 gene was determined by high-density pyrosequencing and a genomic comparative analysis with other bla NDM-1-negative IncFII was performed.Principal Findings
Plasmid pGUE-NDM replicating in Escherichia coli confers resistance to many antibiotic molecules including β-lactams, aminoglycosides, trimethoprim, and sulfonamides. It is 87,022 bp in-size and carries the two β-lactamase genes bla NDM-1 and bla OXA-1, together with three aminoglycoside resistance genes aacA4, aadA2, and aacC2. Comparative analysis of the multidrug resistance locus contained a module encompassing the bla NDM-1 gene that is actually conserved among different structures identified in other enterobacterial isolates. This module was constituted by the bla NDM-1 gene, a fragment of insertion sequence ISAba125 and a bleomycin resistance encoding gene.Significance
This is the first characterized bla NDM-1-carrying IncFII-type plasmid. Such association between the bla NDM-1 gene and an IncFII-type plasmid backbone is extremely worrisome considering that this plasmid type is known to spread efficiently, as examplified with the worldwide dissemination of bla CTX-M-15-borne IncFII plasmids. 相似文献5.
The multidrug-resistant rate of Klebsiella pneumoniae has risen rapidly worldwide. To better understand the multidrug resistance situation and molecular characterization of Klebsiella pneumoniae, a total of 153 Klebsiella pneumoniae isolates were collected, and drug susceptibility test was performed to detect its susceptibility patterns to 13 kinds of antibiotics. Phenotypic tests for carbapenemases ESBLs and AmpC enzyme-producing strains were performed to detect the resistance phenotype of the isolates. Then PCR amplification and sequencing analysis were performed for the drug resistance determinants. The results showed that 63 strains harbored bla
CTX-M gene, and 14 strains harbored bla
DHA gene. Moreover, there were 5 strains carrying bla
KPC gene, among which 4 strains carried bla
CTX-M, bla
DHA and bla
KPC genes, and these 4 strains were also resistant to imipenem. Our data indicated that drug-resistant Klebsiella pneumoniae were highly prevalent in the hospital. Thus it is warranted that surveillance of epidemiology of those resistant isolates should be a cause for concern, and appropriate drugs should be chosen. 相似文献
6.
Eric T. Sumrall Elizabeth B. Gallo Aaron Oladipo Aboderin Adebayo Lamikanra Iruka N. Okeke 《PloS one》2014,9(10)
The plasmid-encoded quinolone resistance gene qnrS1 was recently found to be commonly associated with ciprofloxacin resistance in Nigeria. We mapped the qnrS1 gene from an Escherichia coli isolate obtained in Nigeria to a 43.5 Kb IncX2 plasmid. The plasmid, pEBG1, was sufficient to confer ciprofloxacin non-susceptibility, as well as tetracycline and trimethoprim resistance, on E. coli K-12. Deletion analysis confirmed that qnrS1 accounted for all the ciprofloxacin non-suceptibility conferred by pEBG1 and tetracycline and trimethoprim resistance could be attributed to tetAR and dfrA14 genes respectively. While it contained a complete IncX conjugation system, pEBG1 was not self-transmissible likely due to an IS3 element inserted between the pilX5 and pilX6 genes. The plasmid was however efficiently mobilizable. pEBG1 was most similar to another qnrS1-bearing IncX2 plasmid from Nigeria, but both plasmids acquired qnrS1 independently and differ in their content of other resistance genes. Screening qnrS1–positive isolates from other individuals in Nigeria revealed that they carried neither pEBG1 nor pNGX2-QnrS1 but that IncX plasmids were prevalent. This study demonstrates that the IncX backbone is a flexible platform that has contributed to qnrS1 dissemination in Nigeria. 相似文献
7.
Plasmid and Host Strain Characteristics of Escherichia coli Resistant to Extended-Spectrum Cephalosporins in the Norwegian Broiler Production 总被引:1,自引:0,他引:1
Solveig S?lver?d Mo Jannice Schau Sletteme?s Einar Sverre Berg Madelaine Norstr?m Marianne Sunde 《PloS one》2016,11(4)
Escherichia coli resistant to extended-spectrum cephalosporins have been detected in the Norwegian broiler production, despite the fact that antimicrobial agents are rarely used. The genetic mechanism responsible for cephalosporin resistance is mainly attributed to the presence of the blaCMY-2 gene encoding a plasmid-mediated AmpC-beta-lactamase (pAmpC). The aim of this study was to characterize and compare blaCMY-2 containing Escherichia coli isolated from the intestinal flora of broilers and retail chicken meat (fillets) to identify possible successful clones and/or resistance plasmids widespread in the Norwegian broiler production. Methods used included PCR based phylotyping, conjugation experiments, plasmid replicon typing, pulsed-field gel electrophoresis, multiple locus variable-number tandem-repeats analysis and whole genome sequencing. The nucleotide sequence of an IncK plasmid carrying blaCMY-2 was determined. Intestinal isolates displayed a higher degree of genetic diversity than meat isolates. A cluster of genetically related isolates belonging to ST38, phylogroup D, carrying blaCMY-2 containing IncK plasmids was identified. Furthermore, genes encoding plasmid stability systems (relBE/stbDE and pndAC) were identified on the IncK plasmid. Single nucleotide polymorphism (SNP) analysis of a subset of isolates confirmed a close genetic relationship within the two most prevalent STs. The IncK plasmids within these two STs also shared a high degree of similarity. Cephalosporin-resistant E. coli with the same genetic characteristics have been identified in the broiler production in other European countries, and the IncK plasmid characterized in this study showed close homology to a plasmid isolated from retail chicken meat in the Netherlands. The results indicate that both clonal expansion and horizontal transfer of blaCMY-2 containing plasmids contribute to dissemination of cephalosporin resistant E. coli in the broiler production. The presence of plasmid stability systems may explain why the IncK plasmid containing blaCMY-2 is maintained and disseminated in the Norwegian broiler production in absence of selection pressure from the use of antimicrobial agents. 相似文献
8.
《Genomics》2020,112(2):1182-1191
Enterobacter bugandensis is a recently described species that has been largely associated with nosocomial infections. We report the genome of a non-clinical E. bugandensis strain, which was integrated with publicly available genomes to study the pangenome and general population structure of E. bugandensis. Core- and whole-genome multilocus sequence typing allowed the detection of five E. bugandensis phylogroups (PG-A to E), which contain important antimicrobial resistance and virulence determinants. We uncovered several extended-spectrum β-lactamases, including blaCTX-M-55 and blaNDM-5, present in an IncX replicon type plasmid, described here for the first time in E. bugandensis. Genetic context analysis of blaNDM-5 revealed the resemblance of this plasmid with other IncX plasmids from other bacteria from the same country. Three distinctive siderophore producing operons were found in E. bugandensis: enterobactin (ent), aerobactin (iuc/iut), and salmochelin (iro). Our findings provide novel insights on the lifestyle, physiology, antimicrobial, and virulence profiles of E. bugandensis. 相似文献
9.
《Genomics》2021,113(4):2171-2176
BackgroundRecent reports have established the emergence and dissemination of extensively drug resistant (XDR) H58 Salmonella Typhi clone in Pakistan. In India where typhoid fever is endemic, only sporadic cases of ceftriaxone resistant S. Typhi are reported. This study aimed at elucidating the phylogenetic evolutionary framework of ceftriaxone resistant S. Typhi isolates from India to predict their potential dissemination.MethodsFive ceftriaxone resistant S. Typhi isolates from three tertiary care hospitals in India were sequenced on an Ion Torrent Personal Genome Machine (PGM). A core genome single-nucleotide-polymorphism (SNP) based phylogeny of the isolates in comparison to the global collection of MDR and XDR S. Typhi isolates was built. Two of five isolates were additionally sequenced using Oxford Nanopore MinION to completely characterize the plasmid and understand its transmission dynamics within Enterobacteriaceae.ResultsComparative genomic analysis and detailed plasmid characterization indicate that while in Pakistan (4.3.1 lineage I) the XDR trait is associated with blaCTX-M-15 gene on IncY plasmid, in India (4.3.1 lineage II), the ceftriaxone resistance is due to short term persistence of resistance plasmids such as IncX3 (blaSHV-12) or IncN (blaTEM-1B + blaDHA-1).ConclusionConsidering the selection pressure exerted by the extensive use of ceftriaxone in India, there are potential risks for the occurrence of plasmid transmission events in the predominant H58 lineages. Therefore, continuous monitoring of S. Typhi lineages carrying plasmid-mediated cephalosporin resistant genes is vital not just for India but also globally. 相似文献
10.
Alessandra Carattoli Salome N. Seiffert Sybille Schwendener Vincent Perreten Andrea Endimiani 《PloS one》2015,10(5)
IntroductionblaOXA-48, blaNDM-1 and blaCTX-M-3 are clinically relevant resistance genes, frequently associated with the broad-host range plasmids of the IncL/M group. The L and M plasmids belong to two compatible groups, which were incorrectly classified together by molecular methods. In order to understand their evolution, we fully sequenced four IncL/M plasmids, including the reference plasmids R471 and R69, the recently described blaOXA-48-carrying plasmid pKPN-El.Nr7 from a Klebsiella pneumoniae isolated in Bern (Switzerland), and the blaSHV-5 carrying plasmid p202c from a Salmonella enterica from Tirana (Albania).MethodsSequencing was performed using 454 Junior Genome Sequencer (Roche). Annotation was performed using Sequin and Artemis software. Plasmid sequences were compared with 13 fully sequenced plasmids belonging to the IncL/M group available in GenBank.ResultsComparative analysis of plasmid genomes revealed two distinct genetic lineages, each containing one of the R471 (IncL) and R69 (IncM) reference plasmids. Conjugation experiments demonstrated that plasmids representative of the IncL and IncM groups were compatible with each other. The IncL group is constituted by the blaOXA-48-carrying plasmids and R471. The IncM group contains two sub-types of plasmids named IncM1 and IncM2 that are each incompatible.ConclusionThis work re-defines the structure of the IncL and IncM families and ascribes a definitive designation to the fully sequenced IncL/M plasmids available in GenBank. 相似文献
11.
Annemieke Smet Filip Van Nieuwerburgh Tom T. M. Vandekerckhove An Martel Dieter Deforce Patrick Butaye Freddy Haesebrouck 《PloS one》2010,5(6)
Background
CTX-M-producing Escherichia coli strains are regarded as major global pathogens.Methodology/Principal Findings
The nucleotide sequence of three plasmids (pEC_B24: 73801-bp; pEC_L8: 118525-bp and pEC_L46: 144871-bp) from Escherichia coli isolates obtained from patients with urinary tract infections and one plasmid (pEC_Bactec: 92970-bp) from an Escherichia coli strain isolated from the joint of a horse with arthritis were determined. Plasmid pEC_Bactec belongs to the IncI1 group and carries two resistance genes: bla TEM-1 and bla CTX-M-15. It shares more than 90% homology with a previously published bla CTX-M-plasmid from E. coli of human origin. Plasmid pEC_B24 belongs to the IncFII group whereas plasmids pEC_L8 and pEC_L46 represent a fusion of two replicons of type FII and FIA. On the pEC_B24 backbone, two resistance genes, bla TEM-1 and bla CTX-M-15, were found. Six resistance genes, bla TEM-1, bla CTX-M-15, bla OXA-1, aac6''-lb-cr, tetA and catB4, were detected on the pEC_L8 backbone. The same antimicrobial drug resistance genes, with the exception of tetA, were also identified on the pEC_L46 backbone. Genome analysis of all 4 plasmids studied provides evidence of a seemingly frequent transposition event of the bla CTX-M-15-ISEcp1 element. This element seems to have a preferred insertion site at the tnpA gene of a bla TEM-carrying Tn3-like transposon, the latter itself being inserted by a transposition event. The IS26-composite transposon, which contains the bla OXA-1, aac6''-lb-cr and catB4 genes, was inserted into plasmids pEC_L8 and pEC_L46 by homologous recombination rather than a transposition event. Results obtained for pEC_L46 indicated that IS26 also plays an important role in structural rearrangements of the plasmid backbone and seems to facilitate the mobilisation of fragments from other plasmids.Conclusions
Collectively, these data suggests that IS26 together with ISEcp1 could play a critical role in the evolution of diverse multiresistant plasmids found in clinical Enterobacteriaceae. 相似文献12.
N. Sun Y.Y. Gu J. Wang L. Zhang F.F. Chen J.X. Zhang W.P. Wang X.J. Li 《Letters in applied microbiology》2022,74(2):220-227
Duplex polymerase chain reaction with lateral flow dipsticks (duplex PCR-LFD) was developed for the simultaneous detection of beta-lactamase Klebsiella pneumoniae carbapenemase (blaKPC) and beta-lactamase New Dehli metallo-beta-lactamase (blaNDM) genes in body fluid samples. This method was validated using well-characterized isolates. The assessment of the specificity of duplex PCR-LFD showed that there was no cross-reactivity with other targets. The detection limit of the duplex PCR-LFD assay was 20 CFU per ml for blaKPC and blaNDM. Among 177 sterile body fluid samples tested by the duplex PCR-LFD assay, 40 were blaKPC-positive and five were blaNDM-positive. The results obtained from 122 corresponding Gram-negative bacteria which were isolated from these clinical samples and tested by duplex PCR-LFD assay showed that there were 37 strains carrying blaKPC genes in 40 blaKPC-positive samples and three strains carrying blaNDM genes in five blaNDM-positive samples. Statistical analysis indicated that there was no significant difference between the direct detection of blaKPC and blaNDM genes in clinical sterile body fluid samples and their corresponding clinical isolates. Therefore, duplex PCR-LFD can be effective for the simultaneous detection of blaKPC and blaNDM in clinical isolates and directly from clinical samples, which may be helpful for the administration of appropriate antimicrobial treatment. 相似文献
13.
Chao-Ju Chen Tsu-Lan Wu Po-Liang Lu Ying-Tsong Chen Chang-Phone Fung Yin-Ching Chuang Jung-Chung Lin L. Kristopher Siu 《PloS one》2014,9(8)
Objective
Two plasmids carrying bla NDM-1 isolated from carbapenem-resistant Klebsiella pneumoniae (CR-KP) and carbapenem-resistant Escherichia coli (CR-EC) were sequenced. CR-KP and CR-EC were isolated from two Taiwanese patients without travel histories.Methods
Complete sequencing of the plasmids (pLK75 and pLK78) was conducted using a shotgun approach. Annotation of the contigs was performed using the RAST Server, followed by manual inspection and correction.Results
These similar plasmids were obtained from two patients with overlapping stays at the same hospital. The pLK75 and pLK78 plasmids were 56,489-bp and 56,072-bp in length, respectively. Plasmid annotation revealed a common backbone similar to the IncN plasmid pR46. The regions flanking the bla NDM-1 genes in these plasmids were very similar to plasmid pNDM-HU01 in Japan, which contains a complex class 1 integron located next to an ISCR1 element. The ISCR1 element has been suggested to provide a powerful mechanism for mobilising antibiotic resistance genes.Conclusion
Two indigenous NDM-1-producing Enterobacteriaceae cases were identified for the first time in Taiwan, highlighting the alarming introduction of NDM-1-producing Enterobacteriaceae in this region. 相似文献14.
Objective
To investigate the local epidemiology of Klebsiella penumoniae carrying bla CTX-M-15 in southern China and to characterize the genetic environment of bla CTX-M-15.Methods
PCR and DNA sequencing were used to detect and characterize the genetic contexts of bla CTX-M-15. The clonal relatedness of isolates carrying bla CTX-M-15 was determined by pulse-field gel electrophoresis. Conjugative plasmids carrying bla CTX-M-15 were obtained by mating and were further subject to restriction analysis and replicon typing.Results
A total of 47CTX-M-15 ESBL-producing isolates of K. pneumoniae were collected from nine hospitals in China from October 2007 to October 2008. Isolates were clustered into various clonal groups. The local spread of bla CTX-M-15 was mainly mediated by one major conjugative plasmid as determined by S1-PFGE and restriction analysis. A 90-kb plasmid belonging to incompatible group FII was the major carrier of bla CTX-M-15 in K. pneumoniae. Except bla TEM-1, the resistance genes such as bla SHV, bla DHA-1, bla OXA-1, qnrB, qnrS, aac(3)-II, and aac(6′)-Ib were not found in the plasmid. In the comparing of conjugative gene sequence, it is 100% identical with the plasmid pKF3–94, which was found in K. pneumonia from Zhejiang province of china previously.Conclusions
bla CTX-M-15 was prevalent in K. pneumonia of southern China. The dissemination of bla CTX-M-15 appeared to be due to the horizontal transfer of a 90-kb epidemic plasmid. 相似文献15.
Hee Young Kang Jungmin Kim Sung Yong Seol Yoo Chul Lee Je Chul Lee Dong Taek Cho 《Journal of microbiology (Seoul, Korea)》2009,47(1):68-75
In this study, we identified extended-spectrum β-lactamase (ESBL) and plasmid-mediated AmpC β-lactamase which were associated
with 16S rRNA methylase gene on the conjugative plasmid. Among 82 clinical isolates of Enterobacteriaceae that carry 16S rRNA methylase gene (64 strains, armA, and 18 strains, rmtB), bla
SHV-12 was detected either alone or combined with bla
DHA-1, bla
CTX-M-3, and bla
CTX-M-14 in 30 strains carrying armA and 6 strains carrying rmtB. The bla
CTX-M-3 was detected in 13 of 64 strains carrying armA but no strains carrying rmtB. Whereas bla
CTX-M-14 was detected in 15 of 18 strains carrying rmtB but only 2 of 64 strains carrying armA. Overall, bla
SHV-12 and bla
CTX-M-14 was the most common ESBL gene which was associated with armA and rmtB, respectively. In addition, we found that bla
CTX-M-3 localized with armA on the same IncL/M plasmid and bla
CTX-M-14 localized with rmtB on the same IncA/C plasmid. Restriction fragment length polymorphism of conjugative plasmids and pulsed-field gel electrophoresis
of genomic DNAs revealed that intercellular horizontal transfer of conjugative plasmid and clonal transmission have been occurred
at the same time. 相似文献
16.
Nathalie Tijet Prameet M. Sheth Olga Lastovetska Catherine Chung Samir N. Patel Roberto G. Melano 《PloS one》2014,9(12)
Due to the lack of detailed reports of Klebsiella pneumoniae carbapenemase (KPC)-producing enterobacteria in Ontario, Canada, we perform a molecular characterization of KPC-producing Enterobacteriaceae submitted to the provincial reference laboratory from 2008 to 2011. Susceptibility profiles were accessed by E-test. Molecular types of isolates were determined by pulse-field gel electrophoresis (PFGE) and multilocus sequence typing. Screening of ß-lactamase genes was performed by multiplex PCR and alleles were identified by DNA sequencing. The genetic platform of bla
KPC gene was analyzed by PCR. Plasmid replicons were typed using PCR-based typing approach. KPC-plasmids were also evaluated by S1 nuclease-PFGE and Southern blot. Thirty unique clinical isolates (26 Klebsiella pneumoniae, 2 Enterobacter cloacae, 1 Citrobacter freundii and 1 Raoultella ornithinolytica) were identified as bla
KPC positive: 4 in 2008, 3 in 2009, 10 in 2010 and 13 in 2011. The majority exhibited resistance to carbapenems, cephalosporins and fluoroquinolones and two isolates were also resistant to colistin. The isolates harbored bla
KPC-2 (n = 23) or bla
KPC-3 (n = 7). bla
TEM-1 (n = 27) was commonly detected and occasionally bla
OXA-1 (n = 3) and bla
CTX-M-15 (n = 1). As expected, all K. pneumoniae isolates carried bla
SHV-11. bla
KPC genes were identified on Tn4401a (n = 20) or b (n = 10) isoforms, on plasmids of different sizes belonging to the incompatibility groups IncFIIA (n = 19), IncN (n = 3), IncI2 (n = 3), IncFrep (n = 2) and IncA/C (n = 1). The occurrence of KPC ß-lactamase in Ontario was mainly associated with the spread of the K. pneumoniae clone ST258. 相似文献
17.
Background
Gram-negative multidrug-resistant (MDR) bacteria are major causes of nosocomial infections, and antibiotic resistance in these organisms is often plasmid mediated. Data are scarce pertaining to molecular mechanisms of antibiotic resistance in resource constrained areas such as Iraq.Methodology/Principal Findings
In this study, all MDR Enterobacteriaceae (n = 38) and randomly selected non-MDR counterparts (n = 41) isolated from patients, healthcare workers and environmental surfaces in a newly opened hospital in Iraq were investigated to characterize plasmids found in these isolates and determine their contribution to antibiotic resistance. Our results demonstrated that MDR E. coli and K. pneumoniae isolates harbored significantly more (≥3) plasmids compared to their non-MDR counterparts, which carried ≤2 plasmids (p<0.01). Various large plasmids (∼52 to 100 kb) from representative isolates were confirmed to contain multiple resistance genes by DNA microarray analysis. Aminoglycoside (acc, aadA, aph, strA/B, and ksgA), β-lactam (bla TEM1, bla AMPC, bla CTX-M-15, bla OXA-1, bla VIM-2 and bla SHV), sulfamethoxazole/trimethoprim (sul/dfr), tetracycline (tet) and chloramphenicol (cat) resistance genes were detected on these plasmids. Additionally, multiple plasmids carrying multiple antibiotic resistance genes were found in the same host strain. Genetic transfer-associated genes were identified on the plasmids from both MDR and non-MDR isolates. Seven plasmid replicon types (FII, FIA, FIB, B/O, K, I1 and N) were detected in the isolates, while globally disseminated IncA/C and IncHI1 plasmids were not detected in these isolates.Conclusions/Significance
This is the first report of the characteristics of the plasmids found in Enterobacteriaceae isolated following the opening of a new hospital in Iraq. The information provided here furthers our understanding of the mechanisms of drug resistance in this specific region and their evolutionary relationship with other parts of world. The large plasmids, carrying resistance genes and transfer-associated genes, may be potential factors for regional dissemination of antibiotic resistance. 相似文献18.
[目的] 研究克雷伯氏菌与多复制子抗性质粒间的关系,分析细菌携带多复制子质粒对抗生素环境的响应机制。[方法] 以2018-2020年分离的56株不同来源克雷伯氏菌(Klebsiella sp.)分离株为研究对象,利用微量肉汤稀释法评估其多重耐药表型,对分离菌株进行全基因组测序(WGS),通过细菌全基因组关联分析(BGWAS)技术和比较基因组学方法深入解析多复制子抗性质粒形成的机制。[结果] 耐药表型分析发现野生动物来源的菌株具有更广的耐药谱系,总体Klebsiella sp.对氨苄西林表现出很高的耐药率(80.36%),尤其是马来穿山甲来源菌株对头孢类抗生素高度耐受,同时对氯霉素、左氧氟沙星和复方新诺明等药物耐受,基因组分析发现这些菌株携带了抗性质粒和更多的抗生素抗性基因。进一步对69个质粒序列分析,发现有28个质粒为多复制子质粒,主要携带blaCTX-M-15、blaCTX-M-14、blaCTX-M-55、blaOXA-1和blaTEM-1等β-内酰胺酶基因。细菌携带质粒类型分析认为Klebsiella pneumoniae可能是多复制子质粒的重要宿主,质粒骨架与结构分析发现多复制子质粒多由2个或2个以上单个质粒融合而成,携带此类质粒的菌株不仅获得了更广的耐药表型,而且在全球传播扩散分布逐年增加,因此产生对抗生素环境更强的适应性。[结论] 多重耐药性细菌呈现的表型与携带的多复制子质粒有关,相比较下多复制子质粒比非多复制子质粒有更强的抗性基因携带能力,或许是细菌在强大的抗生素压力下产生的重要响应机制。本研究对于未来探索细菌抗性基因的传播扩散机制具有重要意义。 相似文献
19.
Johnson TJ Bielak EM Fortini D Hansen LH Hasman H Debroy C Nolan LK Carattoli A 《Plasmid》2012,68(1):43-50
IncX plasmids are narrow host range plasmids of Enterobactericeae that have been isolated for over 50years. They are known to encode type IV fimbriae enabling their own conjugative transfer, and to provide accessory functions to their host bacteria such as resistance towards antimicrobial agents and biofilm formation. Previous plasmid-based replicon typing procedures have indicated that the prevalence of IncX plasmids is low among members of the Enterobacteriaceae. However, examination of a number of IncX-like plasmid sequences and their occurrence in various organisms suggests that IncX plasmid diversity and prevalence is underappreciated. To address these possible shortcomings, we generated additional plasmid sequences of IncX plasmids of interest and compared them to the genomes of all sequenced IncX-like plasmids. These comparisons revealed that IncX plasmids possess a highly syntenic plasmid backbone, but that they are quite divergent with respect to nucleotide and amino acid similarity. Based on phylogenetic comparisons of the sequenced IncX plasmids, the IncX plasmid group has been expanded to include at least four subtypes, IncX1-IncX4. A revised IncX plasmid replicon typing procedure, based upon these sequences and subtypes, was then developed. Use of this revised typing procedure revealed that IncX plasmid occurrence among bacterial populations is much more common than had previously been acknowledged. Thus, this revised procedure can be used to better discern the occurrence of IncX type plasmids among enterobacterial populations. 相似文献
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