ISOLATION, IDENTIFICATION AND ANTIBIOGRAM OF SALMONELLA FROM DIARRHOEIC CALVES IN SYLHET SADAR UPAZILLA

Abstract

The study was conducted for the isolation, identification and antibiogram study of Salmonella from rectal swab of diarrhoeic calves collected from different dairy farms at Sylhet Sadar Upazilla. A total of 80 rectal swabs were tested; of which 16 (20%) samples were culture positive for Salmonella. All of the isolates revealed similar morphological, cultural and biochemical characteristics. The isolates produced raised, rounded/circular, smooth, glistening, opaque, colorless, transparent/translucent colonies with black center on SS agar; colorless, smooth, pale and transparent and raised colonies on MacConkey agar; pale pink colored colonies on BGA; colorless/pale colonies without metallic sheen on the EMB agar, and colourless colonies on VRB agar. They fermented dextrose, maltose and mannitol; produced acid and gas, but did not ferment lactose and sucrose. On TSI agar slant, Salmonella showed expected result. The isolates of Salmonella were Methyl red and Citrate Utilization test positive; indole and Voges-Proskauer test negative. In antibiogram study among the 16 isolates of Salmonellae, 16 (100%) were highly sensitive to Ceftriaxone. 68.75% were highly, 12.5% were moderately, 6.25% were less sensitive, and 12.5% were resistance to Cephalexin. 56.25% were highly, 25% were moderately sensitive, and 18.75% were resistance to Gentamycin. 43.75% were highly, 25% were moderately, 12.5% were less sensitive, and 18.75% were resistance to Cotrimazole. 25% were highly, 18.75% were moderately, 43.75% were less sensitive, and 12.5% were resistance to Chloramphenicol, 18.75% were highly, 43.75% were moderately, 25% were less sensitive, and 12.5% were resistance to Amoxicillin, 6.25% were highly, 31.25% were moderately, 18.75% were less sensitive, and 43.75% were resistance to Ampicillin, 50% were moderately, 31.25% were less sensitive, and 18.75% were resistance to Erythromycin, 31.25% were moderately, 18.75% were less sensitive, and 50% were resistance to Nalidixic acid, 100% of the isolates were resistance to Penicillin and Bacitracin. Our study suggests that, Salmonella with antibiotic resistance is circulating among the cattle population in Sylhet Sadar Upazilla, many of the isolates were found multi-drug resistant. As Salmonella is a leading member of the Enterobacteriaceae, it may exchange its resistance criteria to other members of the family. Therefore, continuous monitoring and judicious use of antibiotic must be implemented. Salmonella has huge zoonotic importance that is why veterinarians should be more stringent in applying the proper antibiotic in treating animals.