Genetic variation of the ompA and 16S rRNA genes of Riemerella anatipestifer.

The genetic diversity of the 16S rRNA and ompA genes of Riemerella anatipestifer was investigated. A 16S rRNA gene-based PCR was able to amplify all 18 Taiwanese strains and 10 reference strains. The identity of 16S rRNA sequence of these strains and seven other sequences retrieved from GenBank was 95.0-100.0%. The percentage identity of the ompA sequence of the 15 Taiwanese strains and eight reference strains amplified in this study and two other sequences retrieved from GenBank was 88.1-100.0%. Phylogenetic analysis based on the 16S rRNA gene showed that all the R. anatipestifer strains fell into a single cluster. It is concluded that the 16S rRNA gene-based PCR is suitable for the screening of R. anatipestifer infections. Phylogenetic analysis of the ompA of R. anatipestifer resulted in three different clusters, while seven clusters were found when the derived amino acid sequence was the basis of analysis. No apparent cluster was found using the criteria of host, isolate serotype, the year or location of isolation.