Antimicrobial Resistance Profiles and Tetracycline Resistance Genes of Escherichia coli in Mediterranean Mussel and Sea Snails Collected from the Eastern Black Sea (Turkey)

Abstract

Aquatic environments are often affected by and exposed to anthropogenic pollutants includingantimicrobials used as disease prevention and feed additives. Antimicrobial resistance is a major problem both in animaland in human health worldwide. In this study, Mediterranean mussel (Mytilus galloprovincialis) and Sea snail (Rapanavenosa) samples were collected seasonally from the coastline of Black Sea. A total of 54 Escherichia coli were isolatedfrom Mediterranean mussel and Sea snail collected from the coast of Artvin, Rize, Trabzon and Giresun, Turkey.Antimicrobial resistance and the presence of tetracycline (tet) resistance genes (tetA, tetB, tetC, tetD, and tetE) in E.coli isolates were investigated. Antimicrobial susceptibility test determined that 83.3 % of the isolates exhibitedresistance to sulfamethoxazole. Resistance to ampicillin and aztreonam was as 66.7 % and 37.0 % among the testedantimicrobials, respectively. The lowest resistant antimicrobial was florfenicol (1.9 %). tetC resistance gene wasdetected in more than 50% of the isolates. Among the tet resistance genes, tetC was found in the most common genefollowed by tetB, tetA, tetE, and tetD. At least one tet gene was detected in 88% of the isolates, and 46% of the isolateshad two or more tet genes. The presence of tet resistance genes in E. coli in aquatic environments indicates that theseisolates may be a reservoir of tet resistance genes. They may also exhibit an important role in the spread of genes amongthe pathogenic and non-pathogenic bacteria.