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United States Department of Agriculture

Agricultural Research Service

Research Project: Molecular Biology of Human Pathogens Associated with Food

Location: Produce Safety and Microbiology Research

Title: Antimicrobial resistance in Escherichia coli O157 and non-O157 isolated from feces of domestic farm animals in Culiacan, Mexico

Authors
item Amezquita, Bianca -
item Chaidez, Cristobal -
item Quiñones, Beatriz
item Jimenez, Maribel -
item Lugo, Ofelia -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 21, 2014
Publication Date: N/A

Technical Abstract: Antimicrobial resistance in E. coli O157 and non-O157 strains is a matter of increasing concern, and the association with some virulence traits in the same bacteria remains unclear. Inappropriate antimicrobial use in human and animal therapy has been associated with selective pressure in enteric microorganisms to acquire resistance. Animals may act as reservoirs of antibiotic resistant bacteria that can be transmitted to humans, or vice versa, by direct contact or indirectly, via the food chain. The aim of this study was to investigate the antimicrobial resistance profile of E. coli O157 and non-O157 isolated from feces of domestic animals of Culiacan, Mexico. Methods: Animal feces were collected during one year of sampling. Two different isolation methods were used to recover E. coli O157 and non-O157 strains. The first sampling method was without immunomagnetic separation (IMS) and the second one was with IMS. The strains were examined by PCR for presence of O-antigen, H-antigen. Antimicrobial resistance patterns were determined by the Kirby-Bauer disk diffusion method and 15 antibiotics were tested, according to the Clinical and Laboratory Standards Institute procedure. Results: A total of thirty E. coli O157:H7 and non-O157 strains were analyzed. It was observed that 70% (21/30) of the bacteria in the study, showed resistance to at least one of the antimicrobial agents tested, and in some cases resistance to more than one antibiotic was observed. It was found that 84% (11/13) of the E. coli O157 were resistant to at least one antibiotic. Moreover, 59% (10/17) of resistant bacteria belonging to the serotype O8:H19, O15:NT , O20:H4 , O73:H4 , O75:H8 and O111:H8. From the 15 antibiotics tested, E. coli O157 and non-O157 strains were most commonly resistant to ampicillin, cephalotin and cefoperazone. A total of 14 resistance profiles were obtained, and generally, no relationship was observed within resistance profile and serotypes or sampling sites. Conclusions: The presence of several E. coli serotypes with antimicrobial resistance may indicate the bacterial ability to acquire genetic antimicrobial resistant determinants and highlights the need for appropriate use of antimicrobials in this agricultural region in Mexico.

Last Modified: 10/21/2014
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