MOLECULAR DETECTION AND CHARACTERIZATION OF SALMONELLA SPP. ISOLATED FROM FRESH FISHES SOLD IN SELECTED UPAZILA MARKETS OF BANGLADESH

Abstract

Aquatic environments are the major reservoirs of Salmonella. Therefore, fishery products have been recognized as a major carrier of food-borne organism. Fish is known to harbor bacteria of public health significance. Aquatic environments are known to influence the bacterial loads in the harvested fish. The present work was undertaken for molecular detection and characterization of Salmonella species isolated from fresh fishes sold in different markets of Jamalpur,Tangail, Kishorganj and Netrokona districts of Bangladesh. The isolates were identified by their morphological, cultural and biochemical characteristics with standard reference organisms, and molecular methods. Out of 20 pangas fish (Pangasius spp.) samples the number of samples found to be positive for Salmonella spp was 14 (70%); of 20 koi fish (Anabas spp.) samples this number was 17 (85%); and of 20 tilapia fish (Oreochromis spp.) samples it was 15 (75%). All the isolates of Salmonella were confirmed by targeting genus specific histidine transport operon gene. Antimicrobial susceptibility test was performed to know the susceptibility and resistance patterns of the isolates to different antimicrobial agents. Results of antimicrobial susceptibility test shows that 40 (86.95%) isolates were found to be resistant to azithromycin, 42 (91.30%) were resistant to erythromycin. On the other hand all isolates were 100% susceptible to ciprofloxacin and gentamicin, 38 (82.62%) were susceptible to norfloxacin, 40 (86.95%) were susceptible to streptomycin.