Distribution of an Oxytetracycline Resistance Determinant tet(34) among Marine Bacterial Isolates of a Vibrio species

Abstract

The distribution of tet(34) was examined among oxytetracycline (OTC) resistant Vibrio strains isolated from Japan, Korea and the Philippines. tet(34) was detected in 10 isolates (6 in fish, 4 in seawater) from Japan and Korea, suggesting that it is widely distributed among fish and seawater bacteria in these countries. Ninety-eight percent of the Vibrio strains in the Philippines were sensitive to OTC, but none of the 60 isolates from the Philippines. The minimum inhibitory concentration (MIC) of OTC-resistant isolates increased 2 to 8 fold in the presence of Mg2+, and MICs were higher in the Japanese and Korean isolates than the Philippine isolates. The MIC for furaltadone (FD) was low in Japanese (23.9%) isolates at over 3.1 μg/ml and high in Korean (50%) and Philippine (56.7%) isolates. This was probably due to the different frequency of use of FD in these countries. Sequences of 16S rDNA of tet(34)-positive isolates were 100% identical, suggesting that tet(34) is conveyed in a particular Vibrio species. © 2003, Japanese Society of Microbial Ecology & The Japanese Society of Soil Microbiology. All rights reserved.