Isolation and identification of Escherichia coli from diarrhoeic calves^#

Neonatal calf diarrhoea is the most common cause of morbidity and mortality in pre-weaned dairy calves, causing huge economic and productivity losses to dairy industry worldwide. Escherichia coli is the most important bacterial cause of diarrhoea in calves during the first week of life. The present study was planned to know the incidence of colibacillosis in diarrheic calves. A total of 25 diarrhoeic calves below one month of age, irrespective of sex and breed, kept at private dairy farms as well as animals of individual holdings in and around Bikaner were included in the study. Faecal samples were collected per rectum and microscopically examined to rule out for any helminthic infestation. Same faecal samples were used for bacterial culture examination and for isolation and identification of E. coli through bacteriological methods and PCR. The confirmation of E. coli isolates was done by using biochemical test kits (Hi Enterobacteriaceae identification kit KB003) where out of 25 faecal samples, 22 (88%) were found positive for E. coli. Out of 22, E. coli isolates thus identified, 16 (72.7%) isolates were further confirmed as ETEC K99 strains. It can be concluded from the present study that K99 bearing enterotoxigenic E. coli is the important cause of diarrhea in calves in and around Bikaner city of Rajasthan.