Prevalence and characteristics of extended-spectrum β-lactamases-producing Escherichia coli from broiler chickens at different day-age

Abstract

Commensal Escherichia coli from the poultries have been considered as reservoirs of extended-spectrum β-lactamases ( ESBL )-encoding genes. Between May 2018 and March 2019, a total of 340 E. coli isolates were obtained from apparently healthy broiler chickens from 20 to 40 D old, distributed in 17 small-scale commercial farms. Finally, 45 isolates (8 from 20-day-old broiler chickens, 14 from 30-day-old ones, and 23 from 40-day-old ones) were identified as ESBL producers, which were further investigated to shed light on the virulence gene profiles, phylogenetic groups, and multilocus sequence types and to detect the ESBL plasmid-mediated quinolone resistance determinant ( PMQR ) genes as well as the mutations in the quinolone resistance-determining regions ( QRDR ) of gyrA and parC . Molecular analysis showed that phylogenic group A and B1 accounted for 66.7% of the ESBL producers. The overall occurrence of virulence genes ranged from 5.1% ( cva ) to 86.7% ( papC ). Twenty (44.4%) ESBL producers were considered as biofilm producers with moderate or heavy biofilm formation. The most predominant specific CTX-M subtype was bla CTX-M-14 (n = 19), followed by bla CTX-M-9 (n = 17), bla CTX-M-55 (n = 9), bla CTX-M-15 (n = 6), bla CTX-M-1 (n = 5), and bla CTX-M-65 (n = 4). Additionally, PMQR genes were identified in 86.7% of ESBL producers, qnrS (n = 21) was the most dominant PMQR gene, followed by the aac(6′)-Ib-cr (n = 15), qnrB (n = 12), and qnrA (n = 9), and all of them co-expressed with β-lactamase genes. All PMQR-positive isolates harbored simultaneously at least 1 mutation in the QRDR of gyrA and parC . Forty-five ESBL producers were assigned to 33 sequence types, and the most frequent sequence types ( STs ) was ST10 (n = 5) and followed by ST95 (n = 3). Additionally, ST302, ST88, ST410, ST187, and ST23 were represented by 2 ESBL producers, respectively, and the remaining ones exhibited diverse ST. Moreover, the prevalence of ESBL producers, the biofilm-forming ability, and the occurrence of the QRDR mutations among the E. coli isolates were characterized by gradually increased with advancing age of broiler chickens.

Genetic Diversity of Escherichia coli Coharboring mcr-1 and Extended Spectrum Beta-Lactamases from Poultry

“…In the present study, ST23 was reported in one isolate which harbored mcr -1. The ST23 was previously reported by China which harbored ESBL-resistant genes including bla CTX-M , bla TEM , and bla SHV [ 45 ]. Generally, it is fact that mcr genes have been identified on diverse STs in E. coli isolated from human, animal, and food samples suggesting the dissemination of genes successfully through the mobile genetic element (MGE) and plasmid rather than dissemination of specific clones of E. coli [ 46 ].…”

Prevalence and Characterization of ESBL/AmpC Producing Escherichia coli from Fresh Meat in Portugal

“…Of note, the four CTX-M-65 producers co-harbored qnrS and aac(6′)-Ib-cr [ 72 ]. Studies in China in Enterobacteriaceae ESBL producers identified strains co-harboring two and three PMQR-encoding mechanisms simultaneously [ 76 , 101 ]. Although uncommon, in Europe, some Enterobacteriaceae strains from animals, food, and the environment co-harboring two PMQR encoding genes, were found, although not mentioning they were ESBL producers [ 20 ].…”

Successful Treatment of Severe Post-craniotomy Meningitis Caused by an Escherichia coli Sequence Type 410 Strain Coharboring blaNDM–5 and blaCTX–M–65

“…bla CTX – M – 65 gene is widely found in E. coli isolated from food-producing animals and no sequence type related to the widespread popularity of CTX-M-65-type ESBL has been found. Previous study showed that E. coli ST410 encoding bla CTX – M – 65 had been obtained from healthy broiler chickens ( Liu et al, 2020 ). It is very likely that poultry will be sources of bla CTX – M – 65 and transfer this resistant gene to human via food supply chain.…”