Studies on the prevalence of Riemerella anatipestifer in the upper respiratory tract of clinically healthy ducklings and characterization of untypable strains

A total of 44 bacterial strains obtained from 49 clinically healthy ducklin gs of different ages originating from four different farms were identified as members of the species Riemerella anatipestifer (RA) using conventional biochemical test methods. Numerical analysis of the whole-cell fatty acid p atterns of these isolates resulted in two different clusters, one of which showed a similar pattern to that of the type strain of RI L. Strains having a different fatty acid methyl esters (FAME)-profile (cluster II) were desi gnated P, anatipestifer-like (RA-like). Sequencing of 16S rRNA genes of RA- like field isolates revealed 99 % identity to RA. The significance of these observations are discussed. The present findings document for the first ti me that RA seems to represent a normal part of the pharyngeal flora of heal thy Pekin ducks.