Prevalence of sorbitol non-fermenting Shiga toxin-producingEscherichia coliin Black Bengal goats on smallholdings

Abstract

SUMMARYA cross-sectional survey was carried out in Bangladesh with the sampling of 514 Black Bengal goats on smallholdings to determine the presence of sorbitol non-fermenting (SNF) Shiga toxin-producingE. coli(STEC). Swab samples collected from the recto-anal junction were plated onto cefixime and potassium tellurite added sorbitol MacConkey (CT-SMAC) agar, a selective medium for STEC O157 serogroup, where this serogroup and other SNF STEC produce colourless colonies. The SNFE. coli(SNF EC) isolates obtained from the survey were investigated by PCR for the presence of Shiga toxin-producing genes,stx1andstx2, and two other virulence genes,eaeandhlyAthat code for adherence factor (intimin protein) and pore-forming cytolysin, respectively. The SNF EC isolates were also assessed for the presence of therfbO157gene to verify their identity to O157 serogroup. The results revealed that the proportions of goats carrying SNF EC isolates andstx1andstx2genes were 6·2% (32/514) [95% confidence interval (CI) 4·4–8·7)], 1·2% (95% CI 0·5–2·6) and 1·2% (95% CI 0·5–2·6), respectively. All the SNF STEC tested negative forrfbO157, hlyAandeaegenes. The risk for transmission of STEC from Black Bengal goats to humans is low.