In vitro antimicrobial susceptibility of Photobacterium damselae subsp piscicida to 15 different antimicrobial agents

The in vitro susceptibilities of 145 Photobacterium dantselae subsp. piscic ida strains, isolated from different geographical regions, against 15 major fish farming antimicrobial agents were assessed using a disc diffusion met hod. Ninety-nine percent of all isolates were sensitive to florfenicol and trimethoprime-sulfamethoxazole, 93% of the strains were resistant to erythr omycin. Based on the antimicrobial susceptibility, the P. damselae subp. pi scicida isolates could be distinguished from each other. While all American and European isolates were sensitive to kanamycin, 49% of the Japanese iso lates were resistant to it. Moreover the results clearly indicated increasi ng resistance to a variety of antibiotics, particular in Japan, but also in some Mediterranean countries. (C) 2001 Elsevier Science B.V. All rights re served.