Enterotoxigenic E. coli (ETEC) is the major cause of diarrhoea in neonatal animals. This study determined the prevalence, serological diversity, virulence gene profile and in-vitro antibiogram of ETEC isolates from diarrhoeic faeces of calves and lambs. The prevalence rate of ETEC in lambs was recorded 18.46 % with O8 as predominant serotype. However, in calves the prevalence rate was recorded 8.57 % with O15 and O26 as predominant serotypes. The antibiogram screening showed differential susceptibility pattern among ETEC isolates with highest resistance to ampicillin and highest sensitivity to enrofloxacin. In the present study, for the first time it was reported that the diarrhoea in calves and lambs occur due to virulent gene est not due to elt gene, which was absent in all the isolates.

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Salmonella isolates should be distinguished as it may assist in tracing the source of an outbreak and monitoring trends in antimicrobial resistance associated with a particular type. The specific detection of these Salmonella serotypes is therefore extremely important in order to attribute an isolate to a previously known epidemic outbreak. The present investigation was to isolate and identify S. Gallinarum, to study variation in the profile of outer membrane proteins (OMPs) and to determine in vitro antibiogram of S. Gallinarum in poultry. A total of 228 faecal samples and 22 visceral samples suspected for Salmonellosis were collected, of these 15 samples (6.0%) were found positive for S. Gallinarum. In the present study, rfbS gene sequence was helpful in the serotype-specific detection of S. Gallinarum giving a 187 bp product. Salmonella Gallinarum crude protein extracts determined by SDSPAGE showed migration of OMPs as several bands at approximate moleculer weights of appx. 45 kDa, 55 kDa, 64 kDa, 65 kDa, 74 kDa, 110 kDa, 120 kDa, 135 kDa, 150 kDa,155 kDa, 200 kDa and above 200 kDa. The study indicated a definite variation in the profile of OMPs of various Salmonella Gallinarum strains with major OMPs in the range of appx 80-100 kDa which could be the target for vaccine production. All the isolates tested against 14 antimicrobial agents showed variable susceptibility pattern with highest resistance to nalidixic acid, ampicillin and sulphadiazine and sensitivity to chloramphenicol, gentamicin and enrofloxacin.