Dominant plasmids carrying extended‐spectrum β‐lactamases bla_CTX‐M genes in genetically diverse Escherichia coli from slaughterhouse and urban wastewaters

Abstract

Wastewater treatment plants (WWTP) receiving effluents from food-producing animals and humans may contribute to the spread of extended-spectrum β-lactamases (ESBL)-carrying plasmids. This study was designed to investigate extended-spectrum cephalosporin resistant Escherichia coli strains, CTX-M distributions and the genetic lineage of bla -carrying plasmids from urban and slaughterhouse wastewaters. The level of extended-spectrum cephalosporin-resistant E. coli in slaughterhouse wastewater entering the WWTP was negligible compared with that of urban wastewater. The bla gene was predominant in slaughterhouse wastewater whereas diverse bla genes were encountered in urban wastewater and WWTP outlet. Characterization of the main CTX-M-producing E. coli isolates by antibiotic resistance phenotyping, genotyping and typing of plasmids carrying bla genes revealed that bla and bla genes were harboured by the predominant bla IncI1/ST3 and bla F31:A4:B1 plasmids, which were recovered from unrelated E. coli genotypes in both slaughterhouse and urban wastewaters. This study highlighted the spread of predominant bla and bla plasmid lineages in diverse E. coli genotypes from humans and food-producing animals, their mixing in WWTP and final release into the aquatic environment. This could have a serious negative impact on public health and requires further evaluation.

Prevalence of Beta-Lactam and Quinolone/Fluoroquinolone Resistance in Enterobacteriaceae From Dogs in France and Spain—Characterization of ESBL/pAmpC Isolates, Genes, and Conjugative Plasmids

“…Among the ESBL genes identified in Enterobacteriaceae isolated from different dogs in the two countries, the bla CTX−M−1 gene was exclusively located on the specific conjugative IncI1/ST3 plasmid. Although this study is the first to identify bla CTX−M−1 on IncI1/ST3 plasmid in Spain, such a combination has recently been reported in France in healthy urban dogs (5), in both diseased and healthy humans (33) but also in food-producing animals and the environment (22, 34). The bla CTX−M−1 on IncI1/ST3 plasmid was detected in four different E. coli ST, including ST38 and ST602 which have frequently been identified in different situations (human pathogens or not, livestock, environment) but are only rarely found in dogs.…”

“…After bacterial DNA extraction with a DNeasy blood and tissue kit (Qiagen, Hilden, Germany), the bla TEM , bla SHV , bla CTX−M , bla CMY−2 , genes were detected by PCR and sequenced using specific previously-described primers (22, 23). Sequences were analyzed by the BLAST Internet services (www.ncbi.nlm.nih.gov/BLAST).…”