Identification and antimicrobial sensitivity profiling of bacteria isolated from cultured catfish shing (Heteropneustes fossilis)

Abstract

The cultivated species of catfish (Heteropneustes fossilis), also known as "Shing" has a delectable flavor, a high market value, a high nutritional and therapeutic value, and a high iron and calcium content. In Bangladesh, the shing (H. fossilis) fish is one of the most sought-after, popular, and extremely valuable indigenous species. The purpose of this research was to isolate bacterial pathogens from infected shing (H. fossilis) fish and determine their antibiotic sensitivity. In total, 76 medically infected shing fish were collected by the cultivators from their own ponds in the Jashore district, in southern Bangladesh. Disease-causing bacteria were found in 62 (81.5%) of the infected fish, while normal flora were found in 14 (18.5%) of the 76 samples. There were 62 pathogenic bacterial isolates found, and Aeromona spp., Pseudomonas spp., Streptococcus spp., Flavobacterium spp. and Vibrio spp. were the main causes of disease in the sick fish. Among the species of bacteria that were isolated, the prevalence of the largest pathogens, Aeromonas spp. was 34 (51.4%) and the prevalence of the second largest, Pseudomonas spp. was 13 (20.3%). The other isolates were comprised of the following species: Streptococcus spp. 9 (9.4%), Flavobacterium spp. 4 (5.4%) and Vibrio spp. 2 (4.1%). The farming of shing (H. fossilis) fish has been increased rapidly all around the country. Therefore, bacterial infections may reduce the production of fish in ponds. In this research, bacterial strains showed a high degree of sensitivity to ciprofloxacin (77%) and levofloxacin (54%). Significantly, oxytetracycline (52%) enrofloxacin (45%) and erythromycin (45%) were the intermediate/moderate sensitive antibiotics. All the strains were found to be resistant to amoxicillin 57/62 (92%) and neomycin 42/62 (68%). The findings of this research will be beneficial to fish farmers in the treatment of bacterial infections in fish, as these diseases are caused by microorganisms. The PCR method might be studied further as a means of identifying all bacterial cultures, which would require additional research.