| Dissemination of Cephalosporin Resistance Genes between Escherichia coli Strains from Farm Animals and Humans by Specific Plasmid Lineages. | | Dissemination of Cephalosporin Resistance Genes between Escherichia coli Strains from Farm Animals and Humans by Specific Plasmid Lineages. | de Been M, Lanza VF, de Toro M, Scharringa J, Dohmen W, Du Y, Hu J, Lei Y, Li N, Tooming-Klunderud A, Heederik DJ, Fluit AC, Bonten MJ, Willems RJ, de la Cruz F, van Schaik W. PLoS Genet. 2014 Dec 18;10(12):e1004776. doi: 10.1371/journal.pgen.1004776. | 2014-12-17T23:00:00Z | <p style="text-align:justify;"><span class="ms-rteThemeFontFace-1 ms-rteFontSize-2"><span class="ms-rteThemeForeColor-2-5 ms-rteThemeFontFace-1 ms-rteFontSize-2" style="font-weight:bold;">Abstract</span><br></span></p><div style="color:#000000;font-family:arial, helvetica, clean, sans-serif;text-align:justify;"><p style="margin-bottom:0.5em;font-size:1.04em;"><span class="ms-rteThemeFontFace-1 ms-rteFontSize-2">Third-generation cephalosporins are a class of β-lactam antibiotics that are often used for the treatment of human infections caused by Gram-negative bacteria, especially Escherichia coli. Worryingly, the incidence of human infections caused by third-generation cephalosporin-resistant E. coli is increasing worldwide. Recent studies have suggested that these E. coli strains, and their antibiotic resistance genes, can spread from food-producing animals, via the food-chain, to humans. However, these studies used traditional typing methods, which may not have provided sufficient resolution to reliably assess the relatedness of these strains. We therefore used whole-genome sequencing (WGS) to study the relatedness of cephalosporin-resistant E. coli from humans, chicken meat, poultry and pigs. One strain collection included pairs of human and poultry-associated strains that had previously been considered to be identical based on Multi-Locus Sequence Typing, plasmid typing and antibiotic resistance gene sequencing. The second collection included isolates from farmers and their pigs. WGS analysis revealed considerable heterogeneity between human and poultry-associated isolates. The most closely related pairs of strains from both sources carried 1263 Single-Nucleotide Polymorphisms (SNPs) per Mbp core genome. In contrast, epidemiologically linked strains from humans and pigs differed by only 1.8 SNPs per Mbp core genome. WGS-based plasmid reconstructions revealed three distinct plasmid lineages (IncI1- and IncK-type) that carried cephalosporin resistance genes of the Extended-Spectrum Beta-Lactamase (ESBL)- and AmpC-types. The plasmid backbones within each lineage were virtually identical and were shared by genetically unrelated human and animal isolates. Plasmid reconstructions from short-read sequencing data were validated by long-read DNA sequencing for two strains. Our findings failed to demonstrate evidence for recent clonal transmission of cephalosporin-resistant E. coli strains from poultry to humans, as has been suggested based on traditional, low-resolution typing methods. Instead, our data suggest that cephalosporin resistance genes are mainly disseminated in animals and humans via distinct plasmids.</span><br></p></div> | <p><span style="color:#474f51;font-family:"yanone kaffeesatz";font-size:18px;background-color:#ffffff;">[</span><a href="http://www.ncbi.nlm.nih.gov/pubmed/25522320" style="color:#ed391b;margin:0px;padding:0px;border:0px;font-stretch:inherit;font-size:18px;line-height:inherit;font-family:"yanone kaffeesatz";vertical-align:baseline;background-color:#ffffff;">pubmed</a><span style="color:#474f51;font-family:"yanone kaffeesatz";font-size:18px;background-color:#ffffff;">]</span><br></p> | 71 | | |
