Isolation of Pathogenic and Non-pathogenic Microbial Stains from Different Types of Sea Fish Samples and their Quality Assessment with Antibiogram Properties

Aims: The contamination of sea fish and seafood by bacteria of fecal origin along with various pathogenic drug-resistant microorganisms are widely documented as the cause of several human diseases. Our present studies aim to determine the comparative microbiological quality among raw, cooked and cooked-frozen fish along with antimicrobial profiling of those isolated pathogenic and non-pathogenic microbes with potential drug modelling and increasing the awareness of taking unnecessary antibiotics. The objective of the present study was to investigate the status of fish in cold condition after cooking.

Methodology: We collected a total of four sea fish species (Rupchada, Koral, Tuna, and Poma) from the local shops in Dhaka city. Raw, cooked, and frozen fish samples were analyzed for the existence of pathogenic bacteria through conventional cultural techniques and the confirmatory biochemical identification procedures. Kirby-Bauer disk diffusion method was performed to demonstrate the antibiotic susceptibility pattern of isolated microorganisms.

Results: Total viable bacteria were present in all four fish samples in raw, cooked, and frozen condition up to 8.5 log CFU/ml. Most of the raw fish samples were found to harbour a vast population of microorganisms up to 7 log CFU/ml, including fecal coliforms. Several specific bacterial species like Escherichia coli, Klebsiella spp., Salmonella spp., Shigella spp., Staphylococcus spp., Pseudomonas spp. and Vibrio spp. were noticed to be present in raw samples. The microbial loads were reduced in cooked samples, and the status was static in frozen samples. The study of antibiogram showed several pathogenic isolates to be drug-resistant against second-line drugs.

Conclusion: Thus, the incidence of fecal coliforms in raw fish may be considered as a severe threat to public health upon consumption of such fishes. Such a prevalence of pathogens in the studied fish samples, including antibiotic-resistant strains of pathogenic microorganisms, can lead to severe public health risk and are the significant findings of this study.