Prevalence of Shiga toxin-producing Escherichia Coli O157 in Moroccan food and antimicrobial resistance profiles of the strains isolated.

Abstract

Foods contaminated with Shiga toxin-producing Escherichia coli (STEC) are implicated in serious outbreaks. The present study investigated the prevalence of stx1, stx2, eae, and rfbEO157 genes by real-time PCR in enrichment broths of ground beef, artisanal dairy products, lettuce, spinach, turkey, chicken and bivalve mollusks sold in northern Morocco, the isolation of STEC O157 from positive enrichment broths and determination of antimicrobial resistance profiles of the isolates. The screening results revealed that amongst 620 samples analyzed, 82 enrichment broths (13.23%) were stx + (stx1 or/and stx2) eae- rfbEO157-, 77 out of 620 enrichment broths (12.42%) were stx + eae + rfbEO157-, and 73 out of 620 enrichment broths (11.77%) were stx + eae + rfbEO157 + . The food matrix most contaminated was ground beef 33/140 (23.57%), followed by dairy 27/140 (19.29%), poultry 8/140 (5.71%), leafy vegetables 4/100 (4.00%) and then bivalve mollusks 1/100 (1.00%). 14 STEC O157 isolates were isolated from 4 positive samples (4/73; 5.5%) (multiple isolates were recovered from each positive sample). Antibiotic susceptibility testing showed that the STEC O157 isolates were resistant to at least 4 of the 20 antimicrobials tested. All isolates were resistant to amoxicillin/clavulanic acid, 11/14 (78.6%) were resistant to streptomycin, 10/14 (71.4%) were resistant to tobramycin, 9/14 (64.3%) were resistant to ertapenem and piperacillin, 8/14 (57.1%) were resistant to cefotaxime and 7/14 (50.0%) were resistant to ampicillin and ceftazidime. All isolates were sensitive to amikacin, ceftazidime/avibactam, gentamicin, imipenem, nitrofurantoin and trimethoprim/sulfamethoxazole. Results indicate food producers and sellers may need further training in good hygiene rules, highlighting the importance of implementing strict quality control to ensure food safety.