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- JANEWANGJK55
- Including pS455-p2, four plasmids were identified from S455, which carried 24 antimicrobial resistance genes. Interestingly, com
WGS revealed that the S. Indiana S455
showed considerable homology to pHNSHP45 from E. coli and pSCS23 from S. Albany. Interestingly, compara the largest plasmid pS455-p1 of S455 showed pHNSHP45-2, respectively. In the strain SHP45 from which mcr-1 was first discovered.
- JANEWANGJK55
- Two large plasmids, denoted as plasmid pS455-1 (222, 458 bp) and pS455-2 (60, 540 bp), pS455-3 (38, 906 bp), pS455-4 (8, 815 bp).
A novel IS261-Tn21 cassette was co-located with blaCTX-M-65 on the IncHI2/HI2A/Y/N plasmid pS455-1. The latter was also found to encode 20 other antimicrobial resistance genes.
A phage P1-like region was also identified and lysogenised into the antibiotic resistance-containing domain in plasmid pSLK172-1.
- JANEWANGJK55
- The ISApl1 element is consistently absent in front of the mcr-1 gene on the most IncX4 plasmids (23,24), implying diversified conjugation-aided mechanisms for the transfer of the plasmid-borne mcr-1 gene. (2017-feng-mBio-MCR-2)
- JANEWANGJK55
- However, little information about S. enterica serovar Indiana was available until this serotype was obtained from a food animal and showed resistance to multiple antimicrobial agents from 2010 in China (Yan et al., 2010). Since then, isolation of S. Indiana increased rapidly and became a prevalent serotype in China (Gong et al., 2016a).
- JANEWANGJK55
- ** were resistant to multiple antimicrobials including ESCs and fluoroquinolones which are often antimicrobials of choice for treating salmonellosis. Resistance to cefotaxime could be explained by the presence of IncHI2/IncN plasmids carrying blaCTX-M-9G genes. OqxAB genes on IncHI2 plasmids.
- JANEWANGJK55
- In conclusion, our findings report on the characterization of a novel disrupted mcr-1 co-located with blaCTX-M-14 on a 370-kbp plasmid. The latter likely occurred through a process of illegitimate recombination. Whether future exposure to colistin will result in the recovery an intact mcr-1 gene, in to E. coli SLK172 remains to be determined. Functional experiments should further clarify the nature of how mcr-1 transposes and its origins, a strategy that would have implications for our current understanding of how the dissemination of these important resistance genes occurs.
- JANEWANGJK55
- This study describes the first complete sequencing of one S. Indiana strain S455 with four plasmids, coproducing. The comparison analysis described in the current study revealed that ***. Dissemination of IncHI2 and IncI2 plasmids containing additional resistance genes including mcr-1, NDM, CTX-M, oqxAB, among Salmonella spp. as well as other species of Enterobacteriaceae represents a great hurdle to effective treatment of bacterial infections.
- JANEWANGJK55
- The study further confirms that the mcr-1 gene may efficiently spread among most enterobacterial species, with variable frequencies depending on the recipient strains/species, rather than on the plasmid types.
- JANEWANGJK55
- There is a need to monitor the spread of the mcr-1 gene between E. coli on one hand and MDR S. enterica strains on the other hand, since it may possibly give rise to pandrug-resistant isolates such as those producing MCR-1, ESBLs and carbapenemases.
been widely reported globally This is indicating the
Comparative analysis was firstly carried out using these sequences to query the NCBI reference database in order to identify any previously characterized episomal structures.
were identified and which contributed to the expression of a MDR phenotype.
Our results indicate that the multi-resistant serotype Indiana are of high prevalence among food-producing animals in China. CTX-M type ESBLs have been widely reported globally for many years and there is a strong linkage between their emergence and increasing quinolone resistance in the Enterobacteriaceae (Lavilla et al., 2008). The co-existence or co-transfer of PMQR genes in ESBLs and expecially in CTX-M-producing isolates has been also previously described (Liu 2013; Jiang 2014; yang 2015). These may promote the development of multidrug-resistant isolates under selective pressure of the quinolone and/or cephalosporin (Liu 2013).
Multi-drug resistant S. enterica serotype Typhimurium and Indiana and especially CTX-M-producing isolates were predominant among food-producing animals in China. Untypeable and IncN/IncFIB/IncP/IncA/C/IncHI2 resistant plasmids harboring blaCTX-M genes and clonal spread of strains were both responsible for dissemination of resistant Salmonella isolates.
Plasmid sequences were examined to identify their backbone structure along with genotypes of importance to public health (Figure 1).
Genome comparisons of *** indicate that
Consequently, these genes are unlikely to be recent acquisitions ….
- JANEWANGJK55
- The plasmid profiles of the donor and transconjugants were determined by S1-nuclease pulsed-field gel electrophoresis (S1-PFGE) and PCRs were also performed to confirm the presence of the mcr-1 gene following transfer.
- JANEWANGJK55
- First report of Klebsiella oxytoca strain simultaneously producing NDM-1, IMP-4 and KPC-2 carbapenemases
- JANEWANGJK55
- Draft for Dog1 CY69 CQ9, 81 and 89
from three earlier studies, 265 E. coli isolates collected from 2000 food samples of the national food surveillance in 2014, 93 E. coli isolates from healthy pigs between May, 2011 and August, 2012 in China, 69 E. coli isolates from sick dogs between June to August, 2016 in China, and 114 E. coli isolates from chicken markets during July to September 2016.
- JANEWANGJK55
- Briefly, the procedure included a lysis step of the bacterial cells embedded in agarose plugs followed by digestion with 8 U S1 nuclease at 37oC for 30 min. Finally, each plasmid sample was resolved by PFGE in a Chef-Mapper® XA System (BioRad, U.S.). Each DNA band was considered a unit length of linear plasmid (Barton and others 1995).
- JANEWANGJK55
- selected for conjugation experiments and analyzed individually for their ability to transfer colistin resistance gene to a plasmid-free recipient, E. coli 26R 793 (rifampicin-resistant). Conjugation experiments were carried out using a broth mating protocol. Transconjugants were selected on the agar plates containing colistin (2 mg/liter) and rifampicin (100 mg/liter). Susceptibility tests were again performed, to confirm plasmid transfer, followed by S1 nuclease-PFGE, PBRT and PCR (as described).
- JANEWANGJK55
- Accession numbers were assigned as follows
To assess the genomic background of the isolates Genomic DNA of four isolates (F81/F89/Dog1/CY69) were sequenced using the Illumina HiSeq 2500 platform (Illumina, San Diego, CA, USA) generating 90 bp paired-end reads from a library with an average insert size of 500 bp and a total amount of quality-filtered raw sequence of over 550 Mbp per isolate. Reads were assembled de novo using SOAPdenovo v2.04 (Luo and others 2012). The core-genome based phylogeny was determined by Harvest Suite and a maximum composite likelihood phylogentic tree was generated by MEGA version 6 software using E. coli MG1655 as reference.
