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Abstract Antimicrobial resistance (AMR) is an emerging problem in the aquaculture sector. Further, it connects livestock and human health through possible horizontal gene transfer. In the present study, 258 bacterial isolates were recovered from ornamental fish samples collected from fish farms in Chennai, Madurai and Tiruvarur districts of Tamil Nadu. 16S rRNA sequencing of the isolates revealed the presence of 86 different bacterial strains in the infected fish samples. The highest diversity index was observed in the Goldfish sample (1.99) collected from Tiruvarur, followed by Flower horn (1.98) sample from Chennai. All the bacterial isolates were susceptible to ciprofloxacin and sulphafurazole. The highest resistance was recorded against oxytetracycline, followed by bacitracin, tetracycline and ampicillin. Some of the bacterial isolates exhibited resistance against the new-generation antibiotic, cefepime. Resistance to new generation antibiotics indicates the need for surveillance and monitoring programs to control the indiscriminate use of antibiotics in aquaculture and develop new generation antibiotics. The highest MAR index was recorded in P. vulgaris(0.79) from Guppy (Tiruvarur). MAR index values, ≥ 0.20 exhibited by the bacterial strains isolated from different locations in Tamil Nadu indicate the abusive use of the antimicrobials. Class 1 and Class 2 integrons were detected in the genomic and plasmid DNA of 71 and 3 isolates, respectively. The findings of the present study indicate that ornamental fish may act as the reservoir of MAR bacteria and threaten the human and animal health through dissemination ARGs via horizontal gene transfer.
Hemamalini et al. (Fri,) studied this question.