Dataset Information

ISEcp1B-mediated transposition of blaCTX-M in Escherichia coli.

ABSTRACT: Several expanded-spectrum beta-lactamase bla(CTX-M) genes are associated with ISEcp1-like elements in Enterobacteriaceae. We found that ISEcp1B was able to mobilize the adjacent bla(CTX-M-19) gene by a transpositional mechanism in Escherichia coli by recognizing a variety of DNA sequences as right inverted repeats.

SUBMITTER: Poirel L

PROVIDER: S-EPMC538921 | biostudies-literature | 2005 Jan

REPOSITORIES: biostudies-literature

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ISEcp1B-mediated transposition of blaCTX-M in Escherichia coli.

Poirel Laurent L Lartigue Marie-Frédérique MF Decousser Jean-Winoc JW Nordmann Patrice P

Antimicrobial agents and chemotherapy 20050101 1

Several expanded-spectrum beta-lactamase bla(CTX-M) genes are associated with ISEcp1-like elements in Enterobacteriaceae. We found that ISEcp1B was able to mobilize the adjacent bla(CTX-M-19) gene by a transpositional mechanism in Escherichia coli by recognizing a variety of DNA sequences as right inverted repeats. ...[more]

PMID: 15616333

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Project description:The genome of the cyanobacterium Synechocystis sp. strain PCC6803 has nine kinds of insertion sequence (IS) elements, of which ISY100 in 22 copies is the most abundant. A typical ISY100 member is 947 bp long and has imperfect terminal inverted repeat sequences. It has an open reading frame encoding a 282-amino-acid protein that appears to have partial homology with the transposase encoded by a bacterial IS, IS630, indicating that ISY100 belongs to the IS630 family. To determine whether ISY100 has transposition ability, we constructed a plasmid carrying the IPTG (isopropyl-beta-D-thiogalactopyranoside)-inducible transposase gene at one site and mini-ISY100 with the chloramphenicol resistance gene, substituted for the transposase gene of ISY100, at another site and introduced the plasmid into an Escherichia coli strain already harboring a target plasmid. Mini-ISY100 transposed to the target plasmid in the presence of IPTG at a very high frequency. Mini-ISY100 was inserted into the TA sequence and duplicated it upon transposition, as do IS630 family elements. Moreover, the mini-ISY100-carrying plasmid produced linear molecules of mini-ISY100 with the exact 3' ends of ISY100 and 5' ends lacking two nucleotides of the ISY100 sequence. No bacterial insertion elements have been shown to generate such molecules, whereas the eukaryotic Tc1/mariner family elements, Tc1 and Tc3, which transpose to the TA sequence, have. These findings suggest that ISY100 transposes to a new site through the formation of linear molecules, such as Tc1 and Tc3, by excision. Some Tc1/mariner family elements leave a footprint with an extra sequence at the site of excision. No footprints, however, were detected in the case of ISY100, suggesting that eukaryotes have a system that repairs a double strand break at the site of excision by an end-joining reaction, in which the gap is filled with a sequence of several base pairs, whereas prokaryotes do not have such a system. ISY100 transposes in E. coli, indicating that it transposes without any host factor other than the transposase encoded by itself. Therefore, it may be able to transpose in other biological systems.

Project description:An increase in the prevalence of commensal Escherichia coli carrying blaCTX-M genes among dairy cattle was observed between 2008 and 2012 in Washington State. To study the molecular epidemiology of this change, we selected 126 blaCTX-M-positive and 126 blaCTX-M-negative isolates for determinations of the multilocus sequence types (MLSTs) and antibiotic resistance phenotypes from E. coli obtained during a previous study. For 99 isolates, we also determined the blaCTX-M alleles using PCR and sequencing and identified the replicon types of blaCTX-M-carrying plasmids. The blaCTX-M-negative E. coli isolates comprised 76 sequence types (STs) compared with 32 STs in blaCTX-M-positive E. coli isolates. The blaCTX-M-positive E. coli isolates formed three MLST clonal complexes, accounting for 83% of these isolates; 52% of blaCTX-M-negative E. coli isolates clustered into 10 clonal complexes, and the remainder were singletons. Overall, blaCTX-M-negative E. coli isolates had more diverse genotypes that were distinct to farms, whereas blaCTX-M-positive E. coli isolates had a clonal population structure and were widely disseminated on farms in both regions included in the study. Plasmid replicon types included IncI1 which predominated, followed by IncFIB and IncFIA/FIB. blaCTX-M-15 was the predominant CTX-M gene allele, followed by blaCTX-M-27 and blaCTX-M-14 There was no significant association between plasmid replicon types and bacterial STs, and neither clonal complexes nor major plasmid groups were associated with two discrete dairy-farming regions of Washington State.IMPORTANCE Infections caused by extended-spectrum ?-lactamase (ESBL)-producing Escherichia coli occur globally and present treatment challenges because of their resistance to multiple antimicrobial drugs. Cattle are potential reservoirs of ESBL-producing Enterobacteriaceae, and so understanding the causes of successful dissemination of blaCTX-M genes in commensal bacteria will inform future approaches for the prevention of antibiotic-resistant pathogen emergence.

Project description:Conserved IncI1 and IncHI1 plasmids carrying blaCTX-M-1 have been found circulating in chickens and horses from continental Europe, respectively. In Canada, blaCTX-M-1 is overwhelmingly the most common blaCTX-M variant found in Escherichia coli from chicken and horses and can be recovered at lower frequencies in swine, cattle, and dogs. Whole-genome sequencing has identified a large genetic diversity of isolates carrying this variant, warranting further investigations into the plasmids carrying this gene. Therefore, the objective of this study was to describe the genetic profiles of blaCTX-M-1 plasmids circulating in E. coli from Canadian domestic animals and compare them to those recovered in animals in Europe. Fifty-one blaCTX-M-1 positive E. coli isolates from chicken (n = 14), horses (racetrack horses n = 11; community horses n = 3), swine (n = 7), turkey (n = 6), dogs (n = 5), beef cattle (n = 3), and dairy cattle (n = 2) were selected for plasmid characterization. Sequences were obtained through both Illumina and Oxford Nanopore technologies. Genomes were assembled using either Unicycler hybrid assembly or Flye with polishing performed using Pilon. blaCTX-M-1 was found residing on a plasmid in 45 isolates and chromosomally located in six isolates. A conserved IncI1/ST3 plasmid was identified among chicken (n = 12), turkey (n = 4), swine (n = 6), dog (n = 2), and beef cattle (n = 2) isolates. When compared against publicly available data, these plasmids showed a high degree of similarity to those identified in isolates from poultry and swine in Europe. These results suggest that an epidemic IncI1/ST3 plasmid similar to the one found in Europe is contributing to the spread of blaCTX-M-1 in Canada. A conserved IncHI1/FIA(HI1)/ST2 plasmid was also recovered from nearly all racetrack horse isolates (n = 10). Although IncHI1/ST2 plasmids have been reported among European horse isolates, IncHI1/ST9 plasmids appear to be more widespread. Further studies are necessary to understand the factors contributing to these plasmids' success in their respective populations.

Dataset Information

ISEcp1B-mediated transposition of blaCTX-M in Escherichia coli.

Publications

ISEcp1B-mediated transposition of blaCTX-M in Escherichia coli.

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