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- JANEWANGJK55
- those expressing a carbapenems phenotype plasmids often also carry genes encoding resistance to other commonly used antimicrobial drug classes (including aminoglycosides, cephalosporins, chloramphenicols, or fluoroquinolones).
- JANEWANGJK55
- Conjugation experiments were carried out using a broth mating protocol. (Ref) E. coli J53
- JANEWANGJK55
- In714= Salmonella enterica; Aeromonas hydrophila; IncP-1epsilon plasmids; K. p; E. coli
In27= Salmonella, E. coli, Klebsiella pneumoniae, Acinetobacter baumannii.
- JANEWANGJK55
- In Enterobacteriaceae, transposon Tn** appeared to be the main vehicle for dissemination of blaNDM-1.
IncX3-type plasmids have spread around our province, and it has been a threat in the dissemination of the blaNDM-1 gene among Enterobacteriaceae strains in China.
Interestingly, the backbone of *** is organized similarly to the backbone of IncX plasmids, which were thought to be narrow host range plasmids of Enterobacteriaceae, but the ability of transfer to Pseudomonas aeruginosa has been demonstrated. The first blaNDM-1-harboring IncX3 plasmid, pNDM-HN380, was reported in 2012 from a K. pneumonia isolate discovered in China.27
- JANEWANGJK55
- Moreover, the pKOX3-P4-IMP also showed similarity to one plasmid from K. oxytoca, pKOX105 (GenBank no. HM126016). The pKOX105 was highly related to the p9 and p12 plasmids from K. pneumoniae and K. oxytoca strains at a New York City hospital in 2005 carrying blaKPC-2 and blaKPC-3, respectively.35
- JANEWANGJK55
- (BlaIMP-4 and qnrS1 genes and their organizations)
The immediate ***-bp region flanking *** was nearly identical (>99% identity) among the three plasmids, and another -3-kb region downstream was also identical between *** and ***, indicating a potential common origin (Fig. *). The Tn3 element upstream of the *** region in *** and *** was not found in ****.
Several qnrS1-carrying plasmids have been described in the literature and have publicly available nucleotide sequences. These plasmids range in size and belong to various incompatibility groups including IncN, IncI1, IncX1 and IncX2. Comparative sequence analysis of available qnrS1 plasmids revealed that the genetic architecture surrounding the qnrS1 gene is identical between *** and ***, and they additionally sharing a high sequence identity with the qnrS1 genetic region in other partial plasmid sequences, including *** from Shigella flexneri and ** from Salmonella **.
Genomic analysis of *** revealed homologs of multiple genes that promote pathogenicity in other pathogens. These include bla*** genes. More recently, the *** has been demonstrated to promote *** in E. coli ***, Salmonella spp.. In clinical isolates of K. pneumonia, cultured from a liver abscess in a human, genes involved in ***. The p3 also contains genes involved in ***, previously found in some clinical isolates of K. pneumonia, as well as genes encoding ***. In silico analysis also reveals ***genes present in the genome of *** that show partial homology to known toxins and toxin transporters previously identified in other pathogenic bacteria, including ***. Further investigation is needed to determine the biological relevance of these toxin homologs in K. oxytoca pathogenesis.
- JANEWANGJK55
- Conjugation test have been performed using E. coli J53 (Azr) as a recipient, with which no transconjugant could be obtained (data not shown).
- JANEWANGJK55
- has disseminated among multiple enterobacterial species (E. coli, K. pneumoniae, C. freundii and E. cloacae) originating from patients with epidemiological links to multiple geographic areas in China.
emphasize
IncN plasmids have been reported in association with the most prevalent ESBL, metallo- and non-metallo-carbapenemase and plasmid-mediated quinolone resistance genes, including the emerging KPC-2 and KPC-3 carbapenem resistance genes. (2010-JAC-IncN pKOX105)
According to the type of associated resistance, genes previously localized on IncX plasmids included: b-lactams (TEM-1, TEM-52, SHV-1), quinolones (qnrS1), amonoglycoisdes (aphA1), olaquindox (oqxAB) and bleomycin (blmS). (2012-EMI-Novel IncX3)
Although differences exist in the variable regions of these plasmids, their backbones are generally well conserved and probably encode factors that promote their success. These include multiple systems to protect the plasmid from restriction, to ensure stable plasmid inheritance along with other features yet to be defined. It is clear, however, that these plasmids have been moving beyond the bacterial species, promoting the successful dissemination of carbapenem resistance in *** setting.
The b-lactamase hydrolysis profile of NDM-1 is similar to that of IMP-1 and VIM-2, the more commonly encountered metallo-carbapenemases, but with slower rates of hydrolysis. (2011-CID-8.8-A carb from NDM-1).
The plasmids contained a large number of antimicrobial/heavy metal resistance and plasmid maintenance genes, which may have explained their persistence. No obvious environmental/human reservoir was found. There was no evidence of transmission of outbreak plasmids to other Gram-negative clinical isolates, although blaNDM variants were present in other isolates in different genetic contexts. WGS can effectively define complex antimicrobial resistance epidemiology. Infection control may be effective in terminating outbreaks caused by particular strains, even in areas with widespread resistance.
The identification of *** plasmid expands the repertoire of the coexistence of *** in plasmids carried by various species of the family Enterobacteriaceae in different countries.
Only reported in other bacteira species, May K. oxytoca as a reservoir for the carbapenemases.
Thus, the *** b-lactamase is likely being disseminated among species of Enterobacteriaceae through both conjugal plasmid transfer and transposition.
Our findings underline the importance of continuous microbiological and molecular surveillance with regard to further dissemination of genes in uncommon bacteria species.
Multiple insertion sequence elements were found scattered throughout ***, and these may facilitate the dissemination of the antimicrobial resistance determinants.
The sequence of the immediate region surrounding the KPC-2 in P-5 is nearly identical (**%) to those of ** from *** and p*** from ***, the two other ***-carrying plasmids reported to date, indication a potential common origin.
This is another feature of *** that differs from those of *** and ***, both of which have been reported to be conjugative. However, the region containing *** in *** appears to be a composite transposon bounded by two flanking *** elements in a head-to-tail arrangement which may be responsible for the mobility of *** (Fig. *). The putative transposase and reverse transcriptase genes and the hypothetical insertion sequence (IS) genes at the vicinity of *** may also facilitate its spread.
KPC-2 was initially isolated from S. enterica serotype Cubana (GenBank accession number AF481906).41 KPC-2 differs from KPC-1 by a single amino acid substitution, namely S174G.
Comparison of the genetic environment of bla genes
We therefore hypothesized that *** gene was embedded on a highly mobile and conserved genetic element, which was contributing to the spread and the apparent success of ** across the Enterobacteriaceae in this setting.
These plasmids from different *** appear to have evolved to acquire similar gene clusters on multiple occasions, suggesting possible plasmid-mediated convergent evolution success.
structure was 100% similar to a region consisting of ***-bp partial sequence in p*** from *** (GenBank no. ***). 5050-bp
BLASTn comparison revealed a novel plasmid scaffold.
IS1328-Tn3926, Tn21-tnpR, Intl1, aac(6’)-lb-cr, OXA-10, aadA1, qacEDeltal, sul1, hp,
Although the roles of these largely uncharacterized K. oxytoca genes have not been fully elucidated, the high homology between the proteins suggests some type of transportation role that warrants future functional validation.
In addition, various isolates of the IncN, IncL/M, IncFII and IncH groups have been identified in different coutries.
Comparative analysis showed that *** does not resemble any of the *** plasmids. Only the *** region was conserved, and the shared sequence ranged from *** to *** bp in length (Fig. 1b).
IS26 and Tn3 elements were associated with many rearrangements (discussed below).
Several of the proteins encoded by the *** plasmid are identical to those known to confer resistance to chloramphenicol (catA2), trimethoprim (dfrA1 and dfrA12), streptomycin (strA and strB), sulfonamide (sul1 and sul2) in other bacterial species. The homology of the **-kb region to these known sequences is truncated by flanking IS elements. Its common occurrence suggests that the sul2-strA-strB region is a highly diffused genetic trait which can be transferred between the chromosomes and plasmids of different bacteria.
The sul2 and the strA and strB genes, are localized in an approximately **-kb region, which closely resembles that of the broad-host-range plasmid RSF1010, and the MDR transposon-like element of Vibrio cholera. The homology of the **-kb region to these known sequences is truncated by flanking IS elements. Its common occurrence suggests that the IS110-sul2-strA-strB region is highly diffused genetic trait which can be transferred between the chromosomes and plasmids of different bacteria.
- JANEWANGJK55
- and bracketed by two copies of insertion sequence ISKpn19, which could form a composite transposon with the potential to mobilize blaKPC-2.
- JANEWANGJK55
- Analysis of the genetic environment of these three genes has demonstrated that IS** and IS*** are involved in the spread of the ** genes, while the transposable elements IS26, ** might contribute to the dissemination of the *** gene.
