Evaluación de la resistencia antimicrobiana de Enterobacterias aisladas a partir de vegetales de la ciudad de Riobamba

Abstract

The monitoring of hygienic conditions throughout the food production chain aims to prevent the transmission of pathogenic microorganisms. The safety of raw vegetables and fruits is being affected by the presence of Enterobacteriaceae that possess complex mechanisms of antimicrobial resistance and virulence. In Riobamba (Ecuador) it was found that a high percentage of the vegetables shipped in the city's markets harbor Escherichia coli, Klebsiella spp. and Enterobacter spp., bacteria that show a considerable amount of multi-resistance patterns to different antibiotics. The antibiotic resistance by phenotypic evaluation detected high rates of resistance to the clinically-important beta-lacta antibiotic ampicillin and trimethoprim sulfamethoxazole. The molecular detection of antibiotic resistance genes detected de presence of beta-lactamases blaCTX-M and blaTEM, as well as carbapenemases blaCMY and blaSHV, that were considered emerging resistance mechanisms. On the other hand, the evaluation of virulence genes of diarrheagenic E. coli revealed the presence of enterohemorrhagic E. coli (EHEC) and enteroadherent E. coli (EAEC) pathotypes in some isolates. Although its finding is not numerous, the presence of this pathotypes is of concern due to the great frequency with which the EHEC variant appears in reports of foodborne diseases. Considering this result, the vegetables marketed in the city of Riobamba may constitute a potential route of dissemination of pathogenic bacteria and antimicrobial resistance through food chain.