The study was intended for molecular detection of E. coli isolated from raw cow's milk. A total of 20 milk samples were collected from different upazila markets of Jamalpur, Tangail, Kishoreganj and Netrokona districts of Bangladesh. Milk samples were cultured onto various culture media for the isolation of bacteria. The isolated bacteria were identified by studying staining characteristics, cultural properties on different selective media, biochemical tests, catalase and coagulase test, and finally by PCR. Out of 20 samples, 15 (75%) milk samples were found positive for E. coli. 15 Escherichia coli isolates were amplified by 16S rRNA gene based PCR. Antimicrobial sensitivity test was carried out to ascertain the susceptibility of the organism to various antibiotics. Its results showed that the E. coli isolates were resistant to amoxycillin (86.67%) and erythromycin (73.33%) but sensitive to azithromycin (53.33%), ciprofloxacin (86.67%), gentamicin (86.67%), norfloxacin (80%) and streptomycin (66.67%).

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, Kishoreganj 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.