Browsing by Author "Reyes-Jara A."

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    Diversity of non-o157 shiga toxin-producing escherichia coli isolated from cattle from central and southern chile
    (MDPI AG, 2021) Díaz L.; Gutierrez S.; Navarrete P.; Reyes-Jara A.; Toro M.; Moreno-Switt A.I.; Moreno-Switt A.I.; Hervé L.P.; Hamilton-West C.; Hervé L.P.; Padola N.L.; Navarrete P.; Meng J.; González-Escalona N.
    © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Cattle are the main reservoir of Shiga toxin-producing Escherichia coli (STEC), one of the world’s most important foodborne pathogens. The pathogen causes severe human diseases and outbreaks. This study aimed to identify and characterize non-O157 STEC isolated from cattle feces from central and southern Chile. We analyzed 446 cattle fecal samples and isolated non-O157 STEC from 12.6% (56/446); a total of 93 different isolates were recovered. Most isolates displayed β-glucuronidase activity (96.8%; 90/93) and fermented sorbitol (86.0%; 80/93), whereas only 39.8% (37/93) were resistant to tellurite. A subgroup of 30 representative non-O157 STEC isolates was selected for whole-genome sequencing and bioinformatics analysis. In silico analysis showed that they grouped into 16 different sequence types and 17 serotypes; the serotypes most frequently identified were O116:H21 and O168:H8 (13% each). A single isolate of serotype O26:H11 was recovered. One isolate was resistant to tetracycline and carried resistance genes tet(A) and tet(R); no other isolate displayed antimicrobial resistance or carried antimicrobial resistance genes. The intimin gene (eae) was identified in 13.3% (4/30) of the genomes and 90% (27/30) carried the stx2 gene. A phylogenetic reconstruction demonstrated that the isolates clustered based on serotypes, independent of geographical origin. These results indicate that cattle in Chile carry a wide diversity of STEC potentially pathogenic for humans based on the presence of critical virulence genes.