Characterizing the Multidrug Resistance of non-O157 Shiga Toxin-ProducingEscherichia coliIsolates from Cattle Farms and Abattoirs

Abstract

Non-O157 Shiga toxin-producing Escherichia coli (STECs) are not as well characterized as O157 STEC cases, despite their similar prevalence in many countries. Hence, the objective of this study was to investigate the phenotypic and genotypic basis of multidrug resistance (MDR) in non-O157 STEC farm- and abattoir-sourced isolates and assess the potential dissemination of these MDR profiles in vitro. Susceptibility testing to 20 antimicrobials was performed on 146 non-O157 STECs isolated from farm and abattoir environments. Eighty-seven percent of non-O157 STEC isolates were multidrug resistant to antimicrobials used during veterinary and agricultural practice. Antimicrobial resistance was significantly higher in abattoir isolates compared with the farm isolates (p < 0.05). Corresponding resistance determinants and integrons were investigated by polymerase chain reaction, with the predominant resistance determinants detected being floR, ampC, tet(A), bla, and sul1. This is the first report of tet(G) in a non-O157 STEC isolate. Class 1 integrons were detected in 17 isolates. Resistance to ampicillin, cephalothin, chloramphenicol, kanamycin, neomycin, sulfonamides, trimethoprim, and tetracycline was associated with transferable plasmids belonging to incompatibility groups IncP, IncB/O, and IncFIB. Most MDR non-O157 STECs (90%) isolated in this study belong to phylogenetic groups A and B1. These findings suggest that MDR non-O157 STECs are emerging as a result of nonpathogenic E. coli acquiring virulence and resistance genes. This may convey a certain competitive advantage in the colonization of cattle when antimicrobial selective pressures are present, thereby leading to an increase in contamination of food with MDR non-O157 STECs.

Antibiotic‐resistant Shiga toxin‐producing Escherichia coli: An overview of prevalence and intervention strategies

“…In another study conducted in the Eastern Cape Province of South Africa, 31.7% of O157 isolated from dairy cattle faecal samples demonstrated resistance to multiple antimicrobial agents by the disc‐diffusion method and all O157 isolates were found to harbour antibiotic resistance genes, the most frequent being tetA (tetracycline resistance), strA (streptomycin resistance) , bla AmpC (penicillin and cephalosporin resistance) and bla CMY‐1 (cephalosporin resistance; Iweriebor, Iwu, Obi, Nwodo, & Okoh, ). Multidrug‐resistant STEC have also been isolated from feedlot cattle in Canada (Rehman, Carrillo, Malouin, & Diarra, ), abattoirs in Ireland (Kennedy et al, ), beef and dairy products in Egypt (Ahmed & Shimamoto, ), from calf in Brazil (Antonio et al, ) as well as in pork and chicken meat in South Korea (Park et al, ).…”

“…Seven O157 isolates harbouring bla CMY‐2 , obtained from clinical samples at the Osaka Prefecture, Japan, had antibiotic resistance genes encoded on a IncI1 plasmid that has high transmissibility across bacterial species (Kawahara et al, ). In Ireland, multidrug‐resistant (MDR) non‐O157 STEC isolated from cattle farms and abattoirs were found to carry Class 1 integrons with antibiotic resistance genes embedded on plasmids (Kennedy et al, ). The presence of these mobile genetic elements (plasmids, integrons) in STEC may contribute towards the acquisition/dissemination of antibiotic resistance genes among these human pathogens.…”

“…Multidrug-resistant STEC have also been isolated from feedlot cattle in Canada (Rehman, Carrillo, Malouin, & Diarra, 2017), abattoirs in Ireland (Kennedy et al, 2017), beef and dairy products in Egypt (Ahmed & Shimamoto, 2015), from calf in Brazil (Antonio et al, 2003) as well as in pork and chicken meat in South Korea (Park et al, 2015).…”

Prediction, Diversity, and Genomic Analysis of Temperate Phages Induced From Shiga Toxin-Producing Escherichia coli Strains

“…Shiga toxin-producing Escherichia coli (STEC) has been associated with numerous foodborne outbreaks around the world and causes severe illnesses, such as hemorrhagic colitis, bloody diarrhea, and hemolytic-uremic syndrome (Nüesch-Inderbinen et al, 2018). STEC can be easily disseminated and can cause human illness through direct contact with animal feces, contaminated irrigation water, and fecal-oral contamination of food items (Guy et al, 2014;Colello et al, 2016;Kennedy et al, 2017;Probert et al, 2017;Browne et al, 2018). E. coli O157:H7 was the first STEC strain discovered and was associated with contaminated burger patties in 1982; it has recently been related to leafy green outbreaks in multiple states (Juska et al, 2000;CDC, 2018).…”

Supershed Escherichia coli O157:H7 Has Potential for Increased Persistence on the Rectoanal Junction Squamous Epithelial Cells and Antibiotic Resistance

“…For instance, European countries have used macrolides like azithromycin in STEC treatment in early stages of human infection without any induction of Shiga toxin expression but the mph(A) gene that confers resistance to azithromycin could prevent successful application of this therapy [39]. Most common AR genes observed in STEC are isolated from humans, blaTEM-1, strA, strB, sul1, sul2, dfrA, and tet(A) [40], while floR, ampC, tet(A), blaTEM, and sul1 have been identified in bovine STEC isolates recovered from farms and abattoirs [41]. In addition, resistance to antibiotics like ampicillin, gentamicin, streptomycin, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole has been associated with the presence of class 1 integrons [42].…”