Prevelance of Yersinia ruckeri in salmonid fish in Poland and the phenotype characteristics of isolates [Polish]

摘要

The aim of the study was to isolate Yersinia ruckeri from salmonid fish cultured in Poland. Fish from 25 farms were tested and the isolated bacteria were characterized morphologically and biochemically and identified using the APILAB Plus system. Serological affinity among Y. ruckeri isolates was determined by agglutination and ELISA tests. Pathogenicity was determined by challenge tests. Thirty six isolates originating from 14 rainbow trout farms were identified as Y. ruckeri. These isolates varied in some biochemical tests and in motility. The study determined that Polish Y. ruckeri isolates belong to two biotypes: 58% of the isolates were motile and hydrolyzed Tween 80 (biotype 1) and 42% of the isolates demonstrated negative reactions in these tests (biotype 2). A relationship between ONPG, sorbitol fermentation and V-P tests was found within biotype 1 which allowed two biogroups to be separated. ONPG+/sorbitol-/V-P- isolates were classified as biogroup 1 and ONPG-/sorbitol+/V-P+ isolates as biogroup 2. Twenty six isolates (72%) were pathogenic for rainbow trout. All pathogenic isolates were homogenous serologically but did not react with the anti Y. ruckeri serotype I serum.