Occurrence and distribution of tetracycline resistance determinants and their pollution profi le in selected aquaculture environments in Sri Lanka

Abstract

Tetracycline (TET) has been extensively used in aquaculture for chemotherapy against various fi sh diseases. The contamination levels in 16 aquaculture farms in Sri Lanka were analyzed using high performance liquid chromatography (HPLC). The presence of antibiotic-resistant bacteria was identified using the 16SrRNA gene sequencing and the corresponding antibiotic resistant genes (ARGs) were screened at each location using the PCR method. The concentration of TET in the aquaculture farm samples ranged between 0.001± 0.001 - 0.112± 0.017 ppm. Bacillus and Staphylococcus were recorded as the most dominant resistant bacterial genera against TET. Acinetobacter sp., Achromabacter sp., Staphylococcus sp., Micrococcus sp. were also identifi ed as resistant bacteria. In the present study, tet (M) and tet (A) were the abundant resistance genes (11/16 isolates), followed by tet (S) (5/16) and tet (B) (4/16). It was found that tet (M) is one of the most widely distributed tetracycline resistance determinants in the aquacu lture environment in Sri Lanka.