Prevalence of AmpC, ESBL, and colistin resistance genes in Enterobacterales isolated from ready-to-eat food in Algeria

Antimicrobial resistance among bacteria present in ready-to-eat foods is an emerging concern. Hence, this study investigated the presence of extended-spectrum and AmpC β-lactamases (ESBL/AmpC)-producing Enterobacterales (ESBL-E) and the dissemination of mcr-1 in ESBL-E from ready-to-eat food samples (RTE) in Algeria . RTE food samples ( n = 204) were aseptically collected and selectively cultured using MacConkey agar. The isolates were screened for ESBL production using the DDST test, confirmed ESBL-E isolates were identified using different conventional methods and MALDI-TOF MS, antibiotic susceptibility was determined using the disc diffusion and broth microdilution assay, ESBL-E isolates were analyzed for colistin and ESBL/AmpC encoding genes by PCR, and food samples were analyzed by univariate and multiple logistic regression. Overall, 48 (17.4%) of the 276 Enterobacterales were confirmed as ESBL producers, with a high prevalence in soups (40%), salads (25%), and cream-filled pastries (23.8%) . Antibiotic susceptibility testing revealed that all the ESBL-E isolates were found multi-drug resistant. PCR revealed that bla TEM , bla CTX-M , bla CMY-2 , bla OXA-1 , and bla SHV were the most frequently detected. bla CTX-M-9 and bla CTX-M-1 were the predominant CTX-M types. Furthermore, four isolates were positive for mcr-1 ; three of them harbored the colistin resistance gene and ESBL/AmpC genes (2 E. cloacae and 1 S. enterica ). To the best of our knowledge, this is the first report that detects the presence of the mcr-1 gene in ESBL-E strains isolated from RTE foods in Algeria. These findings suggest an urgent need for strict policies that prevent the spread and transmission of ESBL-E in food.