Isolation, Characterisation and biofilm production of e.coli from mackerel (rastrelliger Kanagurta)

Fish and fishery products are of great importance for human nutrition worldwide and provide clear health benefits. Fish can act as a source of food borne pathogens and may be a potential source of infection. A study was undertaken to find out the incidence and characterization of E.coli in fishes, determine biofilm production and antibiotic resistance of isolates. A total of 100.0 raw mackerel fish (Rastrelliger kanagurta) was collected from different markets in and around Puducherry. Fifty two (52.0%) isolates of E.coli were recovered from 100.0 samples. Among the 52.0 isolates 38.0 (73.07%) were found to produce biofilm on modified congo red agar. All the 52.0 isolates were subjected for antibiotic resistant profile test. Of the 52.0 E. coli isolates characterized, all (100.0%) of the isolates displayed sensitivity towards norfloxacin (10 μg), sulphametoxazole/trimethroprim (25 μg) and chloramphenicol (30 μg). On the other hand, resistance was observed against ampicilin (34.3%), tetracycline (22.5%) and Amphotericin B (10.8%). The result indicates that there is an increased prevalence of E.coli mainly due to contamination of the fishes during processing and also from an environment.