Genomic diversity of Riemerella anatipestifer associated with outbreaks of New Duck disease in India

Abstract

Riemerella anatipestifer causes New Duck disease in poultry, primarily in domestic ducks. The present study confirms the occurrence of genetically diverse isolates of R. anatipestifer in the ducks of India. Isolation of R. anatipestifer was attempted from 13 suspected outbreaks of duck septicaemia in different regions of Kerala, India and 6 isolates could be obtained, namely KAL–1, KNB-1, KML-1, KML-2, KML-3, and KTL-1. All the isolates were subjected to specific 16S rRNA gene based PCR and sequencing, which revealed 99 % similarity to R. anatipestifer strain ATCC 11845 ribosomal RNA partial sequence. Molecular fingerprinting of the isolates by ERIC-PCR produced 10–12 bands per isolate ranging in size from 150 bp to 2000 bp. The phylogenetic analysis of these fingerprints revealed that the variants obtained from commercial flocks are genetically more diverse compared to the variant associated with outbreak in an organized instructional farm.