Multidrug resistant Escherichia coli from fresh produce sold by street vendors in South African informal settlements

The aim of this study was to assess the prevalence of commensal and pathogenic Escherichia coli on informally sold fresh produce in South Africa, who harbour and express antimicrobial resistance genes and therefore pose indirect risks to public health. The majority (85.71%) of E. coli isolates from spinach, apples, carrots, cabbage and tomatoes, were multi-drug resistant (MDR). Resistance to Aminoglycoside (94.81%), Cephalosporin (93.51%), Penicillin (93.51%) and Chloramphenicol (87.01%) antibiotic classes were most prevalent. Antibiotic resistance genes detected included bla(TEM) (89.29%), tetA (82.14%), tetB (53.57%), tetL (46.43%), sull (41.07%), sull (51.79%), aadAl a (58.93%) and strAB (51.79%). A single isolate was found to harbour eae virulence factor. Moreover, E. coil isolates were grouped into the intra-intestinal infectious phylogenetic group E (28.57%), the rare group C (26.79%), the generalist group B1 (21.43%) and the human commensal group A (16.07%). Presence of MDR E. coil represents a transmission route and significant human health risk.

Automated summary

The majority of E. coli isolates from informally sold fresh produce in South Africa were multi-drug resistant, with high prevalence of resistance to Aminoglycoside, Cephalosporin, Penicillin, and Chloramphenicol antibiotics. Various antibiotic resistance genes were detected, with some isolates also carrying virulence factors. E. coli isolates were grouped into different phylogenetic groups, indicating a significant human health risk.