Molecular characterization, antibiotic resistant pattern and biofilm forming potentiality of bacterial community associated with Ompok pabda fish farming in southwestern Bangladesh

Abstract

Ompok pabda is gaining popularity in the aquaculture industry due to its increasing demand; however research on microbial diversity and antibiotic susceptibility remains limited. The present study was designed to identify the bacterial pathogens commonly found in the pabda farming system with their biofilm forming potential and antibiotic susceptibility. Different bacterial strains were isolated from water, sediments and gut, gill of pabda fish and the isolates were identified based on their morphological traits, biochemical and molecular analysis. Antibiotic susceptibilities, antibiotic resistance gene determination and biofilm formation capabilities were evaluated by disc diffusion method, PCR amplification and Microtiter plate (MTP) assay, respectively. The respective isolates of gill and gut of pabda aquaculture and their environments were: Exiguobacterium spp. (25%), Enterococcus spp. (20%), Bacillus spp. (10%), Acinetobacter spp. (10%), Enterobacter spp. (10%), Aeromonas spp. (10%), Lactococcus spp. (5%), Klebsiella spp (5%) and Kurthia spp. (5%). Antibiotic resistance frequencies were found to be relatively high, especially for trimethoprim (95%), sulfafurazole (75%), ampicillin (60%), amoxicillin-clavulanic acid (55%), and cephradine (50%). 30% isolates were categorized as DR bacteria followed by 30% isolates were MDR bacteria and 40% were classified as XDR bacteria. Moreover, 4 antibiotic resistant genes were detected with sul1 (30%), dfrA (10%), tetC (40%), and qnrA (5%) of isolates. Based on the microtiter plate method, 20%, 25%, and 30% of isolates were found to produce strong, moderate, and weak biofilms, respectively. The findings suggest that biofilm forming bacterial strains found in O. pabda fish farm may be a potential source of numerous antibiotic-resistant bacteria. The study sheds new light on antibiotic resistance genes, which are typically inherited by bacteria and play an important role in developing effective treatments or control strategies.