Pathogenicity And Antibiogram Of Escherichia Coli Isolated From Diarrhoeic Cow Calves

Abstract

Thirty two isolates of Escherichia coli recovered from diarrhoeic samples in cow calves were tested for virulence factors by a battery of in vivo (pathogenicity and enterotoxigenicity) and in vitro methods. Four isolates (12.50%) belonging to O88, O97, O98 and O159 serogroups proved fatal to Swiss albino mice on intraperitoneal inoculation of whole bacterial culture. Similarly the cell free filtrate of 4 (12.50%) isolates, belonging to O14, O88, O110 and O138 serogroups caused death of mice within 6 to 20 hours post intravenous inoculation (hpi) of intravenous inoculation. None of the isolates produced STa or LT enterotoxins in suckling mouse and mouse paw oedema test, respectively. Five (15.63%) isolates were found resistant towards the lytic action of cow calf serum, whereas 10 (31.25%) were sensitive and 17 (53.12%) intermediate sensitive to serum. The in vitro sensitivity of the isolates to antimicrobial drugs was found 100% to ciprofloxacin and sulphadiazine, followed by ceftriaxone and ceftriaxone/tazobactum (96.88%), cefotaxime (71.90%), amoxyclav (68.75%) and amikacin (46.9%).