Antimicrobial Drug Resistance in Fish Pathogens

Abstract

In the 1970s several reports of drug resistance in fish pathogens from Japanese fish farms linked antibiotic resistance to fish farming. In this report, the devastating effect of acquired sulfonamide resistance in the treatment of furunculosis was demonstrated in clinical trials. A. salmonicida strains from Norway, including 10 isolates of sulfonamide-resistant atypical strains representing the various groups of a typical A. salmonicida isolated in Norway, were screened for occurrence of class 1 integrons and sulfonamide resistance genes. In this study A. salmonicida isolates from Switzerland, Finland, France, Japan, Scotland, and the United States were also studied. The study also characterized a third R plasmid of about 70 kb found in two A. hydrophila isolates in 1974 in the United States. It is also of particular interest that one of the R plasmids of E. tarda is very similar to the R plasmids of P. damselae subsp. piscicida. Infections with multiple-drug-resistant V. anguillarum occurred in farmed ayu in Japan in 1973. Several studies demonstrate transfer of R plasmids from fish pathogens to E. coli recipients. In many ways, fish pathogens represent possible intermediate vectors for shipping antibiotic resistance genes between the environment and human beings for further recombination.