Jersinioza ryb lososiowatych - charakterystyka czynnika etiologicznego i metody jego identyfikacji

Yersinia ruckeri, a Gram-negative rod belonging to Enterobacteriaceae family, genus Yersinia, is a causative agent of yersiniosis of salmonids. The size of the active growth cells are 0.75 × 1.0 µm - 3 µm. The presence of flagella are connected with motile ability but non motile bacterium are isolated more frequently. The biochemical characteristics of Y. ruckeri strains are rather homogenous. Y. ruckeri rods in in vitro examination are characterized as quite sensitive to medicines. All of the Polish isolates were sensitive to oxytetracycline, flumeqine and enrofloxacin. Classical bacteriological methods are mainly used for the diagnostics of yersinisis. Tryptone soya agar or 5% blood agar are carried out for the isolation of the microorganism. Selective and facultative mediums such as Furones medium, ROD or Waltman-Shotts media are also used. Identification of the isolated strains is performed by the characteristics of their biochemical properties, after which an analysis of the obtained profiles is done. Commercial API 20E kits are used in the examination of biochemical characteristic of the isolates but it is necessary for the results of the identification to be always supplemented by complementary tests. The plate agglutination test and PCR are carried out as a confirmation of identification of Y. ruckeri rods. This last method, on account of its high sensitivity, is useful in the detection of asymptomatic carriers of bacterium Y. ruckeri.