Determination of antibiotic resistance genes in Escherichia coli isolated from Mediterranean mussel and sea snail in Eastern Black Sea

In this study, antibiotic resistance level, resistance gene presence and transferable of resistance in Escherichia coli isolated from sea snail (Rapana venosa) and Mediterranean mussel (Mytilus galloprovincialis) collected from Eastern Black Sea were investigated by conventional and molecular methods. The highest resistance in bacteria to tested antibiotics was determined as sulfamethoxazole and the lowest resistance to florfenicol. The multiple antibiotic resistance (MAR) index of bacteria was calculated as 0.28 for all isolates. The highest MAR value was calculated in Trabzon stations with 0.34 and the lowest value was 0.18 with bacteria isolated from Artvin stations. While 98.1% ampC gene was detected in 54 isolates, the lowest sul3 gene was found to be 3.7% among tested genes. Conjugation experiments have shown that 10 of 24 plasmid-containing bacteria are capable of transferring their plasmids to the recipient strain. The presence of resistance genes in the original strain was investigated in the obtained transconjugant bacteria. Some of the detected genes were confirmed by DNA sequence analysis. Resistance to antibiotics in bacteria is of ecological importance worldwide. It is known that bacteria containing this resistance gene play an important role in spreading resistance genes between pathogen and/or non-pathogenic bacteria.