Microbiological screening and antibiotics responsiveness of pathogenic bacteria isolated from pond cultivated pangas fishes (Pangasius hypothallus) in Bangladesh

Pangas fish (Pangasius hypophthalmus) is one of the most cultivated fishes in Bangladesh and exposed to various infectious diseases including bacterial diseases. An attempt was done to determine the most infectious bacterial pathogens and antibiotics susceptibilities of isolated bacterial pathogens. There are 52 infected pangas fishes that were collected from different ponds in the Mymensingh district for one year. The physicochemical parameters of water samples of fishes were noted, and it was found that the parameters did not show any significant impact on the disease development of pangas. Aeromonas spp (27%), Flavobacterium spp (25%), Edw ar dsiella spp (23%), Vibrio spp (2%), Enterococcus spp (2%), Pseudomonas sp (2%) were found from different body parts of pangas fish and rest of the isolates were normal flora. The antibiotic susceptibility test was performed by following KirbyBauer disc diffusion method, and it was found that the antibiotic susceptibility patterns of the bacterial pathogen differed slightly. Edw ar dsiella spp (67%) and Vibrio spp showed the most sensitivity to ciprofloxacin while other pathogens such as Aeromonas spp (57%), Flavobacterium spp (69%), and Enterococcus spp exerted the highest sensitivity to Levofloxacin. Additionally, 100% resistant cases were observed to amoxicillin by most of the isolates except Flavobacter spp (85%). Conclusively, levofloxacin was found as the most sensitive antibiotic (41%) for pathogens, but the isolates showed the most resistance against amoxicillin (41%) among all antibiotics. Multiple drugs resistant to Pseudomonas spp were also found, which paves the way to widen the use of the range of antibiotics and /or synergistic application of the most potential antibiotics.