Microbial Resistance to Antibiotics and Biofilm Formation of Bacterial Isolates from Different Carp Species and Risk Assessment for Public Health

The aim of this research was to investigate the effects of biofilm on antibiotic resistance of the bacterial isolates present in fish meat and to assess the risk of antibiotic residues for public health. Common carp, silver carp and grass carp fishes were purchased from retail stores for an in vitro biofilm investigation and a drug-resistant pattern determination. In all samples, up to 10(4) CFU/g of bacteria, such as Escherichia coli, Aeromonas hydrophila, Shewanella putrefaciens, Vibrio spp. and Staphylococcus spp., were observed. Isolates from the samples and their biofilms were subjected to an antibiogram assay using antibiotics such as amoxicillin, ampicillin, cefotaxime, ciprofloxacin, chloramphenicol, gentamicin, streptomycin, tetracycline and trimethoprim. Obtained results showed that some of the isolates were sensitive to antibiotics and some were resistant. Results of LC-MS/MS analysis showed that antibiotics residues were present in fish samples in the range between 4.9 and 199.4 µg/kg, with a total sum of 417.1 µg/kg. Estimated daily intake (EDI) was established to be 0.274 μg/kg of body weight/day for men and 0.332 μg/kg of body weight/day for women, with an acceptable daily intake (ADI) of 8.5 and 7.0 µg/kg of body weight/day for men and women, respectively. The results of the present study, therefore, highlight the safe consumption of fresh fish.