Prevalence and antibiotic resistance profiles of diarrheagenic Escherichia coli strains isolated from food items in northwestern Mexico

• Published in: International journal of food microbiology 2013-06, Vol.164 (1), p.36-45
• Main Authors: Canizalez-Roman, Adrian, Gonzalez-Nuñez, Edgar, Vidal, Jorge E., Flores-Villaseñor, Héctor, León-Sicairos, Nidia
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Antibiotic resistance; antibiotics; bacteriology; beverages; Biological and medical sciences; Biosurveillance; cell culture; children; coliform bacteria; dairy products; developed countries; diarrhea; Diarrheagenic; Drug Resistance, Microbial; E. coli; enterohemorrhagic Escherichia coli; enteroinvasive Escherichia coli; enteropathogenic Escherichia coli; enterotoxigenic Escherichia coli; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli - physiology; Escherichia coli Infections - microbiology; Food; Food industries; Food Microbiology; Fundamental and applied biological sciences. Psychology; ice; Mexico; polymerase chain reaction; Prevalence; surveys; tourists; travel; water pollution
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2013.03.020

Diarrheogenic Escherichia coli (DEC) strains are an important cause of intestinal syndromes in the developing world mainly affecting children. DEC strains often infect tourists from developed countries traveling to Mexico, causing so-called “traveler diarrhea”. DEC strains are typically transmitted by contaminated food and water; however, the prevalence of these strains in food items that are produced, consumed and sometimes exported in northwestern Mexico has not been evaluated. In this study, we conducted a large microbiological survey of DEC strains in 5162 food items and beverages consumed throughout Sinaloa state during 2008 and 2009. We developed a panel of eight sequential PCR reactions that detected the presence of all DEC categories, including typical or atypical variants. Thermotolerant coliforms (also known as fecal coliforms) and E. coli were detected by conventional bacteriology in 13.4% (692/5162) and 7.92% (409/5162) of food items, respectively. Among 409 E. coli isolates, 13.6% (56/409) belonged to DEC strains. Dairy products (2.8%) were the most contaminated with DEC, while DEC strains were not detected in beverages and ice samples. The pathogenic type that was most commonly isolated was EPEC (78.5%), followed by EAEC (10.7%), STEC (8.9%) and ETEC (1.7%). EHEC, DAEC and EIEC strains were not detected. Approximately 80% of EPEC and EAEC strains were classified as atypical variants; they did not adhere to a culture of HEp-2 cell. Of the isolated DEC strains, 66% showed resistance to at least one commonly prescribed antibiotic. In conclusion, the presence of DEC strains in food items and beverages available in northwestern Mexico is low and may not represent a threat for the general population or those traveling to tourist areas. •We report a new scheme of eight sequential PCR reactions to identify DEC strains.•DEC strains were detected in ~1% from food items in northwestern Mexico.•Dairy products (2.8%) were most frequently contaminated by DEC strains.•More than half DEC strains show resistance to at least one antibiotic.