Detection of enterotoxigenic K99 (F5) and F41 from fecal sample of calves by molecular and serological methods

Enterotoxigenic Escherichia coli (ETEC) is one of the major causes of neonatal calf diarrhea. Almost all ETEC bacteria are known to adhere to receptors on the small intestinal epithelium via their fimbriae, (F5 (K99) and F41).This study was undertaken to investigate the phenotypic and genotypic screening of virulence genes in E. coli K99 and F41. During January 2008 to December 2009, 298 diarrheic neonatal calves at 1–30 days old were studied by multiplex PCR, isolation, and serological grouping. Of the 298 diarrheic samples, 268 E. coli were isolated, of which 16 samples (5.3%) were positive for having the F5 (K99) fimbrial gene by PCR while all of the E. coli isolates also carried F41 fimbrial genes. Twenty-five percent of the isolates were proven not to be toxigenic as they did not possess the STa enterotoxin gene.