Virulence and antimicrobial resistance profiles of Shiga toxin-producing Escherichia coli from river water and farm animal feces near an agricultural region in Northwestern Mexico

Authors: AMEZQUITA-LOPEZ, BIANCA - AUTONOMOUS UNIVERSITY OF SINALOA; SOTO-BELTRAN, MARCELA - AUTONOMOUS UNIVERSITY OF SINALOA; Lee, Bertram; BON-HARO, EDGAR - AUTONOMOUS UNIVERSITY OF SINALOA; LUGO-MELCHOR, OFELIA - CENTRO DE INVESTIGACIÓN Y ASISTENCIA EN TECNOLOGÍA Y DISEÑO DEL ESTADO DE JALISCO; Quinones, Beatriz

Submitted to: Microbiology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2024
Publication Date: 3/8/2024
Citation: Amezquita-Lopez, B.A., Soto-Beltran, M., Lee, B.G., Bon-Haro, E.F., Lugo-Melchor, O.Y., Quinones, B. 2024. Virulence and antimicrobial resistance profiles of Shiga toxin-producing Escherichia coli from river water and farm animal feces near an agricultural region in Northwestern Mexico. Microbiology Research. 15(1):385-403. https://doi.org/10.3390/microbiolres15010026.
DOI: https://doi.org/10.3390/microbiolres15010026

Interpretive Summary: The increased consumption of fresh produce in the United States (U.S.) has contributed to a demand for year-round availability, and import trade agreements supply products that are out of season. Consequently, Mexico has become a leading supplier of agricultural products ($43 billion) to the U.S., suppling over 65% of the total value of U.S. fresh produce imports. In Northwestern Mexico, the Culiacan Valley is an important agricultural region for various fresh produce commodities to be exported to the U.S., and the most important horticultural crops are tomatoes, peppers, and cucumbers. Published findings on the epidemiology of in-field contamination in the agricultural Culiacan Valley revealed runoff occurs from rural farms into seasonal streams. In particular, livestock near agricultural fields and water for irrigation are thus considered as potential key routes of transmission STEC O157 and non-O157 strains, harboring virulence and antimicrobial resistance genes. Given that livestock are found in streams near agricultural fields, these animal reservoirs are potential point sources of contamination and transport of zoonotic STEC. In the present study, feces from domestic farm animals were collected from sites in close proximity to surface waterways, which can then lead to the transport of these foodborne pathogens eventually into irrigation/holding ponds and directly into agricultural fields. The ultimate goal was to identify the primary quantitative sources of zoonotic STEC to assist in the focused development of pathogen control efforts for preventing specific STEC populations to prevail in the watersheds and agricultural fields for export produce.

Technical Abstract: Shiga toxin-producing Escherichia coli (STEC) are zoonotic enteric pathogens linked to human gastroenteritis worldwide. To aid the development of pathogen control efforts, the present study characterized the genotypic diversity and pathogenic potential of STEC recovered from sources near agricultural fields in Northwest Mexico. Samples were collected from irrigation river water and domestic animal feces in farms proximal to agricultural fields and were subjected to enrichment followed by immunomagnetic separation and plating on selective media for the recovery of the STEC isolates. Comparative genomic analyses indicated that the recovered STEC with the clinically relevant serotypes O157:H7, O8:H19, and O113:H21 had virulence genes repertoires associated with host cell adherence, iron uptake and effector protein secretion. Subsequent phenotypic characterization revealed multidrug resistance against aminoglycoside, carbapenem, cephalosporin, fluoroquinolone, penicillin, phenicol, and tetracycline, highlighting the need for improved surveillance on the use of antimicrobials. The present study indicated for the first time that river water in the agricultural Culiacan Valley in Mexico is a relevant key route of transmission for STEC O157 and non-O157 with a virulence potential. In addition, feces from domestic farm animals near surface waterways can act as potential point sources of contamination and transport of diverse STEC with clinically relevant genotypes.