Shiga Toxin Producing Escherichia coli (STEC) in Food Producing Animals from Trinidad and Tobago

Abstract

Aims: To determine the occurrence of Shiga toxin producing Escherichia coli (STEC) in faecal samples from representative food-producing bovine animals in Trinidad and Tobago. Study Design: This was a prospective cross sectional observational laboratory based study. Place and Duration of Study: Bovine faecal samples were collected from selected food animal farms located in the twin island of Trinidad and Tobago and processed at the Microbiology laboratories at the Veterinary School, Faculty of Medical Sciences, The University of the West Indies Campus, from March to May 2014. Materials and Methods: 205 cattle faecal samples collected from 12 animal farms across Trinidad & Tobago were analyzed for E. coli bacteria. Using conventional and molecular microbiology laboratory techniques, 160 recovered E. coli isolates from these samples were then screened for possession of the intimin (eae), Shiga toxin 1 (stx1) and Shiga toxin 2 (stx2) genes. Results: Shiga toxin producing E. coli (STEC) genes were detected in 9.4% (15/160) of E. coli isolates analyzed by molecular methods. Overall, 1.3% of the isolates were positive for the intimin (eae) gene; 6.6% for stx1 and 7.3% for stx2 toxins genes. All detected STEC positive isolates, however did not belong to any of the most known O serogroups associated with Shiga toxin genes; and were also all negative for Locus of Enterocyte Effacement (LEE) genes (espA, tir and escN). Conclusion: There is low occurrence of E. coli producing stx1 and stx2 (STEC) genes in Trinidad and Tobago. STEC in the country is not associated with the seven most common serogroups or the LEE genes. This information has never been reported in Trinidad and Tobago before and therefore present a novel contribution to the epidemiology of STEC in the country and Caribbean region.