ARS | Publication request: Rapid genotyping assays for the identification and differentiation of Yersinia ruckeri biotype 2 strains

Submitted to: Letters in Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 25, 2011
Publication Date: July 18, 2011
Citation: Welch, T.J. 2011. Rapid genotyping assays for the identification and differentiation of Yersinia ruckeri biotype 2 strains. Letters in Applied Microbiology. DOI: 10.1111/j.1472-765X.2011.03114.x.

Interpretive Summary: Enteric Redmouth Disease (ERM) outbreaks have recently been reported in fish populations that had previously been immersion vaccinated against this disease thus suggesting vaccine failure. The bacterial isolates responsible for these outbreaks have been identified as strains of Y. ruckeri that lack both flagellar motility and phospholipase activity and have been classified as Y. ruckeri biotype 2 (BT2). Recent analysis of BT2 Y. ruckeri isolates circulating in the United States and Europe identified the genetic basis for the BT2 phenotype and demonstrated that the BT2 phenotype has emerged independently at least four times. This manuscript describes novel DNA-based assays for the identification of specific lineages of BT2 Y. ruckeri. These assays are rapid and simple to perform allowing the unambiguous identification of specific BT2 lineages which will be critical for the development and evaluation of improved vaccines or other management practices aimed at controlling BT2 isolates.

Technical Abstract: Novel assays for the identification and differentiation of biotype 2 phenotype-causing alleles among emerging strains of Yersinia ruckeri are presented. Assays were validated against isolates previously genotyped by DNA sequencing. The methods employed are simple to perform and interpret and thus could be directly applied in veterinary diagnostic laboratories.