Diversity of Non-O157 Shiga Toxin-Producing Escherichia coli Isolated from Cattle from Central and Southern Chile.
Leonela DíazSebastian GutierrezAndrea I Moreno-SwittLuis Pablo HervéChristopher Hamilton-WestNora Lía PadolaPaola NavarreteAngélica Reyes-JaraJianghong MengNarjol González-EscalonaMagaly ToroPublished in: Animals : an open access journal from MDPI (2021)
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.
Keyphrases
- escherichia coli
- antimicrobial resistance
- bioinformatics analysis
- genome wide
- genome wide identification
- klebsiella pneumoniae
- genetic diversity
- biofilm formation
- genome wide analysis
- endothelial cells
- dna methylation
- clinical trial
- transcription factor
- staphylococcus aureus
- candida albicans
- cystic fibrosis
- zika virus
- pseudomonas aeruginosa
- dengue virus
- pluripotent stem cells