Determination and transferability of plasmid-mediated antibiotic resistance genes of the bacteria isolated from rainbow trout

Abstract

Antibiotic resistance and the presence of resistance genes (ARGs) were investigated in the bacteria isolated from rainbow trout (Oncorhynchus mykiss) from different trout farms located in Turkey. The most frequent types of antibiotic resistance were towards β‐lactams (cephalothin [70% of bacterial isolates], amoxicillin [63%], ampicillin [62%], ticarcillin [56%], aztreonam [51%]), macrolide [erythromycin, 68%] and sulphonamide [sulphamethoxazole, 51%]. Of bacterial isolates, 51% were multiple drug resistant (MDR), while 35% of the isolates were extensively drug resistant (XDR). None of isolates were pandrug resistant (PDR). The most common ARGs were ampC (36%) and sul1 (24%). The class 1 integron gene cassette was detected in 51% of the bacteria. There was a strong positive correlation between the antibiotic resistance rate and the presence of ARGs (r2 = .932). Gene encodes blaCTX‐M1, one of the extended spectrum beta‐lactamase enzymes, was first described in Aeromonas caviae, Photobacterium damselae, Pseudomonas luteola and Burkholderia cepacia. It was determined that 35% of the bacteria harboured at least one plasmid. Plasmid‐mediated ARGs were identified to be tetracyclines (tetA, tetB, tetC, tetD), sulphonamides (sul1, sul3) and β lactams (ampC, blapse). Thus, results suggest that ARG contamination situation deliberates resistance to tetracycline, aminoglycoside, chloramphenicol and sulphonamide. Therefore, the presence and activity of ARGs in fish and in environmental bacteria may play an important role in the spread of resistance genes among bacteria by transposition or integron gene cassettes.

Antimicrobial activity oftrans-cinnamic acid and commonly used antibiotics against important fish pathogens and nonpathogenic isolates

“…Contrary to our study, Capkin et al . () found that C . freundii, a rainbow trout isolate, was susceptible to erythromycin.…”

“…Similar to our study, it was found that A. hydrophila and A. sobria , an intestinal isolates of rainbow trout, were susceptible to chloramphenicol, while they showed resistance of 25–73% to streptomycin and erythromycin (Capkin et al . ). Likewise, it was reported that there were strains resistant to streptomycin among A. veronii strains isolated from trout farms and strains resistant to erythromycin isolated from tilapia fish and aquaculture ambient (Akinbowale et al .…”

“…However, A. veronii , an intestinal isolate of rainbow trout, was susceptible to streptomycin and erythromycin in the research reported by Capkin (Capkin et al . ).…”

“…) and 4% (Capkin et al . ). In different studies, antibiogram results of Y. ruckeri strains with regard to chloramphenicol and vancomycin are consistent with our study.…”

“…) and 88% (Capkin et al . ). It was also reported in previous studies that Y. ruckeri strains isolated from fish may exhibit different susceptibilities to antibiotics (de Grandis and Stevenson ; Vuillaume and Brun ).…”