Characterization of tet(M) and tet(G) Genes among Tetracycline-resistant Aeromonas spp. Isolated from Imported Ornamental Fishes

Abstract

In this study, the molecular structures of tet(M) and tet(G) carried by tetracycline (Tc) resistant bacteria in intestinal microflora from the imported ornamental fish were characterized and compared with each other depend on the imported countries. Of the total isolates, approximately 8.9% of the Ent-lac+ (lactose fermentative bacteria on coliform media) Tc resistant isolates in fish from three different countries , Singapore, Taiwan and Brazil, were appeared to contain tet(M). Three representative isolates of different countries, Aeromonas spp. JSM-1 (Singapore), JTM-1 (Taiwan) and JBM-1 (Brazil), were isolated and analyzed the molecular structures of tet(M) gene. Interestingly, partial sequence of tet(M) genes (1099 bp) in JBM-1 (Brazil) showed 99.5% homology with the tet(M) found in the Vibrio spp. RV16 isolate, obtained from marine fish in Korea and known to carry Tn1545 parent type of tet(M). In contrast, tet(M) gene in JSM-1 and JTM-1 showed mosaic structure of Tn1545 and Tn916, and 100% homology with each other. It may suggest the presence of various characteristics in terms of tet(M) gene structure. The determined sequence of the tet(G) from Aeromonas spp. JSG-1 and JBG-1 isolated from Singapore and Indonesia ornamental fish respectively showed similar nucleotide sequence homology but revealed a few nucleotide changes in comparison with the sequence of the prototype tet(G) gene (S52437 in GenBank).

Ornamental fish: a potential source of pathogenic and multidrug-resistant motile Aeromonas spp.

“…Resistance to oxytetracycline (100%) and tetracycline (51%) was observed in the ornamental guppy, and tetA (65%), tetE (25%) and tetB (15%) were observed among the isolates (Hossain et al 2019b). The tetracycline resistance, tetM and tetG genes were detected in ornamental fish-borne motile Aeromonas isolates from Singapore, Taiwan and Brazil (Park et al 2012). Tetracycline resistance genes (tetA, tetD and tetE) were identified in goldfish-borne motile Aeromonas spp.…”

“…isolated from ornamental fish and their carriage water. Park et al (2012) identified Tn1545 parent type tetM in tetracycline-resistant motile Aeromonas spp. isolated from imported ornamental fish in Korea.…”

“…The tetracycline resistance, tetM and tetG genes were detected in ornamental fish‐borne motile Aeromonas isolates from Singapore, Taiwan and Brazil (Park et al . 2012). Tetracycline resistance genes ( tetA , tetD and tetE ) were identified in goldfish‐borne motile Aeromonas spp.…”