Dataset Information

Sequence of closely related plasmids encoding bla(NDM-1) in two unrelated Klebsiella pneumoniae isolates in Singapore.

ABSTRACT: BACKGROUND: Spread of the bla(NDM-1) gene that encodes the New Delhi metallo-?-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.

SUBMITTER: Chen YT

PROVIDER: S-EPMC3490853 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Sequence of closely related plasmids encoding bla(NDM-1) in two unrelated Klebsiella pneumoniae isolates in Singapore.

Chen Ying-Tsong YT Lin Ann-Chi AC Siu L Kristopher LK Koh Tse Hsien TH

PloS one 20121106 11

<h4>Background</h4>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).<h4>Methodology/principal findings</h4>The two plasmids, pTR3 and pTR4, were transferred to Escherichia coli recipient strain J53 and complet ...[more]

PMID: 23139815

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Project description:Objective:Regional dissemination is the major cause of the widespread prevalence of a plasmid-encoding NDM-1 enzyme. We investigated the drug resistance, joint efficiency, and gene environment of a Klebsiella pneumoniae strain carrying bla NDM-1 gene. Materials and Methods:Carbapenem-non-susceptible strains were analyzed using the VITEK 2 Compact. Strains carrying bla NDM-1 were identified using polymerase chain reaction and sequencing. Antimicrobial susceptibility testing and plasmid conjugation experiments were then conducted. Strains carrying bla NDM-1 were subjected to Southern blot analysis. After the gene mapping of bla NDM-1, library construction, and sequencing, plasmids were subsequently spliced and genotyped using the software Glimmer 3.0, and then analyzed using Mauve software. Results:Among 1735 carbapenem-non-susceptible strains, 54 strains of bla NDM-1-positive bacteria were identified, which consisted of 44 strains of K. pneumoniae, 8 strains of Acinetobacter baumannii and 2 strains of Escherichia coli. Strains carrying bla NDM-1 had a resistance rate of more than 50% in most antibiotics. Plasmid conjugation between strains carrying bla NDM-1 and E. coli strain J53 had a success rate of 50%. Southern blot analysis indicated that each strain had multiple plasmids containing bla NDM-1. Among the five plasmids containing bla NDM-1 in K. pneumoniae for sequencing, two plasmids with complete sequences were obtained. The findings were as follows: (i) The p11106 and p12 plasmids were highly similar to pNDM-BTR; (ii) the p11106 and p12 plasmids showed differences in the 20-30 kb region (orf00032-orf00043) from the other six plasmids; and (iii) bla NDM-1 was located at orf00037, while ble was found at orf00038. Two tnpA genes were located in the upstream region, and orf00052 (tnpA) in the 36 kb region was in the downstream sequence. Conclusion:bla NDM-1-containing bacteria exhibit multidrug resistance, which rapidly spreads and is transferred through efficient plasmid conjugation; the multidrug resistance of these bacteria may be determined by analyzing their drug-resistant plasmids. The presence of ble and tnpA genes suggests a possible hypothesis that bla NDM-1 originates from A. baumannii, which is retained in K. pneumoniae over a long period by transposition of mobile elements.

Project description:NDM-5 carbapenemase was mainly identified in Escherichia coli, while the rapid transmission of bla NDM-5 among Enterobacteriaceae has raised serious public attention. This study identified 14 NDM-5-producing Klebsiella pneumoniae isolates from 107 carbapenem-resistant K. pneumoniae isolates, recovered from blood, urine, and normally sterile body fluids of pediatric patients from January 2016 to December 2018. All NDM-5-producing isolates were highly resistant to ?-lactams, while tigecycline and polymyxin B exhibited excellent antimicrobial activity. These 14 strains belonged to 9 different sequence types (STs) and displayed various pulsed-field gel electrophoresis (PFGE) patterns, suggesting that they were not clonally related. S1-PFGE followed by Southern blotting showed that the bla NDM-5 gene was located on an ?46-kb IncX3 plasmid in all strains. All bla NDM-5-carrying plasmids were successfully transferred into recipient E. coli J53. PCR-based sequencing demonstrated that all of the bla NDM-5-carrying plasmids shared highly similar backbones, with nucleotide sequence identity of >99%. Moreover, this plasmid displayed high sequence similarity to the previously reported epidemic IncX3 bla NDM-5-carrying plasmids, with dynamic changes observed only in bla NDM-5-surrounding elements. Interestingly, the IncX3 bla NDM-5-carrying plasmids showed strong stability in clinical isolates when cultured in antibiotic-free medium. However, after the conjugation inhibitor linoleic acid was added, a gradual increase in the level of IncX3 plasmid loss could be observed. Clinical isolates displayed 10% to 15% bla NDM-5-carrying plasmid loss after coculture with linoleic acid for 5?days. These results showed that the IncX3 plasmid facilitated the dissemination of bla NDM-5 among multiclonal K. pneumoniae strains in children and that conjugal transfer contributed significantly to IncX3 plasmid stability within K. pneumoniae IMPORTANCE The emergence and spread of New Delhi metallo-?-lactamase (NDM)-producing Enterobacteriaceae have been a serious challenge to public health, and NDM-5 shows increased resistance to carbapenems compared with other variants. NDM-5 has been identified mostly in E. coli but has rarely been described in K. pneumoniae and other Enterobacteriaceae isolates. Here, we present the dissemination of highly similar 46-kb IncX3 bla NDM-5-carrying plasmids among multiclonal K. pneumoniae strains in children, highlighting the horizontal gene transfer of bla NDM-5 among K. pneumoniae strains via the IncX3 plasmid. Moreover, the IncX3 bla NDM-5-carrying plasmids displayed strong stability in clinical strains when cultured in antibiotic-free medium, and the plasmid maintenance was attributed partly to conjugal transfer. Plasmid conjugation is mediated by the type IV secretion system (T4SS), and T4SS is conserved among all epidemic IncX3 bla NDM-5-carrying plasmids. Therefore, combining conjugation inhibition and promotion of plasmid loss would be an effective strategy to limit the conjugation-assisted persistence of IncX3 bla NDM-5-carrying plasmids.

Project description:Municipal wastewater treatment facilities are considered to be "hotspots" for antibiotic resistance, since they conjoin high densities of environmental and fecal bacteria with selective pressure in the form of sub-therapeutic concentrations of antibiotics. Discharged effluents and biosolids from these facilities can disseminate antibiotic resistant genes to terrestrial and aquatic environments, potentially contributing to the increasing global trend in antibiotic resistance. This phenomenon is especially pertinent when resistance genes are associated with mobile genetic elements such as conjugative plasmids, which can be transferred between bacterial phyla. Fluoroquinolones are among the most abundant antibiotic compounds detected in wastewater treatment facilities, especially in biosolids, where due to their hydrophobic properties they accumulate to concentrations that may exceed 40 mg/L. Although fluoroquinolone resistance is traditionally associated with mutations in the gyrA/topoisomerase IV genes, there is increasing evidence of plasmid-mediated quinolone resistance, which is primarily encoded on qnr genes. In this study, we sequenced seven qnr-harboring plasmids from a diverse collection of Klebsiella strains, isolated from dewatered biosolids from a large wastewater treatment facility in Israel. One of the plasmids, termed pKPSH-11XL was a large (185.4 kbp), multi-drug resistance, IncF-type plasmid that harbored qnrB and 10 additional antibiotic resistance genes that conferred resistance to five different antibiotic families. It was highly similar to the pKPN3-like plasmid family that has been detected in multidrug resistant clinical Klebsiella isolates. In contrast, the six additional plasmids were much smaller (7-9 Kbp) and harbored a qnrS -type gene. These plasmids were highly similar to each other and closely resembled pGNB2, a plasmid isolated from a German wastewater treatment facility. Comparative genome analyses of pKPSH-11XL and other pKPN3-like plasmids concomitant to phylogenetic analysis of housekeeping genes from host Klebsiella strains, revealed that these plasmids are limited to a predominantly human-associated sub-clade of Klebsiella, suggesting that their host range is very narrow. Conversely, the pGNB2-like plasmids had a much broader host range and appeared to be associated with Klebsiella residing in natural environments. This study suggests that: (A) qnrB-harboring multidrug-resistant pKPN3-like plasmids can endure the rigorous wastewater treatment process and may therefore be disseminated to downstream environments; and (B) that small qnrS-harboring pGNB2-like plasmids are ubiquitous in wastewater treatment facilities and are most likely environmental in origin.

Project description:Carbapenem-resistant Klebsiella pneumoniae (CRKP), which harbors the bla NDM plasmid, has been reported extensively and is considered a global threat clinically. However, characterization and comparisons of bla NDM-1-carrying and bla NDM-5-harboring IncX3-type plasmids in CRKP are lacking. Here, we systematically compared the differences in the characteristics, genetic backgrounds, transferability, and fitness costs between bla NDM-1-carrying and bla NDM-5-carrying plasmids in K. pneumoniae isolates. Fifteen NDM-producing CRKP isolates were recovered from 1376 CRKP isolates between 2019 and 2021, of which 4 were positive for bla NDM-1 and 11 were positive for bla NDM-5. All strains were highly resistant to carbapenem but remained susceptible to tigecycline and colistin. Core-genome-based phylogenetic analyses revealed that these strains were not clonally related. Whole-genome sequencing showed that bla NDM-1 and bla NDM-5 were located on ~54 kb and ~46 kb IncX3-type plasmids, respectively. The backbone, genetic context, and fitness cost of the bla NDM-1-bearing plasmid were highly similar to those of the bla NDM-5-carrying plasmid, but the transferability of the bla NDM-1-positive plasmid was greater than that of the bla NDM-5-positive plasmid. In conclusion, the transmission of bla NDM-1 or bla NDM-5 is mainly disseminated by plasmids rather than clonal spread. The high transfer frequency of the IncX3 plasmid facilitates the prevalence and dissemination of NDM-KP among Enterobacteriaceae. IMPORTANCE The emergence of NDM-producing Klebsiella pneumoniae is a severe challenge to public health. The widespread presence of bla NDM-1 and bla NDM-5 in Enterobacteriaceae has aroused broad concern. In this study, we performed molecular characterization of bla NDM-1-carrying and bla NDM-5-harboring IncX3-type plasmids in carbapenem-resistant Klebsiella pneumoniae (CRKP) and compared their phenotypes between strains with different bla NDM subtype. Our findings highlight the importance of IncX3-type plasmids in the transfer of the bla NDM-1 and bla NDM-5 genes and demonstrate that the bla NDM-1 plasmid possesses higher transfer ability. These data will provide important insights into carbapenem resistance gene transfer via plasmids and their further spread in clinical settings.

Dataset Information

Sequence of closely related plasmids encoding bla(NDM-1) in two unrelated Klebsiella pneumoniae isolates in Singapore.

Publications

Sequence of closely related plasmids encoding bla(NDM-1) in two unrelated Klebsiella pneumoniae isolates in Singapore.

Similar Datasets

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