Isolation, Identification and Antimicrobial Sensitivity Profile of Salmonella Isolates from Diarrheic Calves in Sebeta Town Dairy Farms, Central Ethiopia

Abstract

A cross-sectional study was conducted in dairy farms Sebeta town from November 2018- May 2019 with a purposive sampling method to isolate, identify Salmonella isolates from diarrheic calves. The samples were examined for the presence of Salmonella following the conventional techniques of ISO standard and using OMNILOG bacterial identification system, GEN III microplate for confirmation and sub species identification. Out of 116 fecal samples examined for the isolation of Salmonella, of which 8 (6.89%) were positive. Among potential risk factors considered, flock size (P=0.010), calves age (P=0.023), body condition (P=0.019), colostrum feeding (P=0.023), bedding (P=0.017), calves kept in their pens with a frequency of change of bedding material (P=0.016), and feeding up to weaning (P=0.054) were closely linked with the occurrence of Salmonella infection. In conclusion, this study shows Salmonella could be considered as a potential causative agent of diarrhea in calves. Among 8 isolates of Salmonella, all showed 100% susceptibility for sulphamethoxazole+trimethoprim and polymixin B, 87% to ampicillin, chloramphenicol, and tetracycline as well as 75% to gentamicin. However, only one isolate showed mono drug (tetracycline) resistance. Therefore, improved management practices and appropriate antibiotic treatment of diarrheic calves should be employed to prevent the spread of Salmonella infection occurring in healthy animals at Sebeta and other similar farms in Ethiopia.