Antibiotic Resistance Profiling of Bacterial Pathogens Isolated from Different Tissues of Indian Major Carp (Labeo rohita)

Infectious diseases caused by bacterial pathogens are increasing in freshwater aquaculture. Freshwater fishes including Labeo rohita collected from aquafarms serve as the reservoirs of antibiotic-resistant bacterial pathogens that can cause serious disease outbreaks. The study aimed to identify the prevalent pathogenic bacterial strains isolated from different tissues of Labeo rohita to elucidate their antimicrobial resistance profiles. Bacterial pathogens were isolated from gills, cecum and skin of Labeo rohita collected from aquafarms in Padampur, Bargarh district, Odisha. Biochemical characterization of bacterial isolates was carried out followed by identification using 16s rRNA ribotyping. Antibiotic resistant profiling was performed using Kirby-Bauer’s method and analyzed using WHONET software, which showed wide variations among the bacterial isolates. Phylogenetic analysis revealed that bacterial isolates exhibited close similarity to Aeromonas hydrophila, Aeromonas caviae, Enterobacter cloacae, Enterobacter mori, Providencia stuartii, Escherichia coli and Mammaliicoccus sciuri. The study revealed that Aeromonas hydrophila, Enterobacter mori and Aeromonas caviae were resistant to ampicillin/sulbactum whereas Enterobacter cloacae showed resistance to cefoxitin. E. coli and Providencia stuartii revealed multidrug resistance profiles. Differential pattern of resistance was exhibited by Mammaliicoccus sciuri against penicillin, linezolid, tetracycline, oxacillin and cefoxitin. Identification of multidrug resistant bacterial strains have substantiated the discovery of tailored antimicrobial strategies and further genetic investigation to elucidate the underlying resistance mechanisms.