In cities across the globe, the majority of wastewater - that includes drug resistant and pathogenic bacteria among other contaminants - is released into streams untreated. This water is often subsequently used for irrigation of pastures and produce. This use of wastewater-contaminated streams allows antibiotic-resistant bacteria to potentially cycle back to humans through agricultural products. In this study, we investigated the prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolated from produce and irrigation water across 17 provinces of Ecuador. A total of 117 vegetable samples, 119 fruit samples, and 38 irrigation water samples were analyzed. Results showed that 11% of the samples were positive for E. coli including 11 irrigation water samples (29%), and samples of 13 vegetables (11%), and 11 fruits (9%). Among the 165 E. coli isolates cultured, 96 (58%) had the ESBL phenotype, and 58% of ESBL producing E. coli came from irrigation water samples, 11% from vegetables, and 30% from fruits. The bla CTX-M - 55, bla CTX-M 65, and bla CTX-M 15 genes were the most frequently found gene associated with the ESBL phenotype and coincided with the bla CTX-M alleles associated with human infections in Ecuador. Three isolates had the mcr-1 gene which is responsible for colistin resistance. This report provides evidence of the potential role of irrigation water in the growing antimicrobial resistance crisis in Ecuador.
Keywords: CTX-M; ESBL E. coli; Extended-spectrum beta-lactamase (ESBL); fresh produce; irrigation water.
Copyright © 2021 Montero, Irazabal, Cardenas, Graham and Trueba.