Molecular analysis of Pasteurella multocida strains isolated from fowl cholera infection in backyard chickens

To characterize Pasteurella isolated from backyard chickens using whole cell protein lysate profiles and random amplified polymorphic DNA (RAPD) techniques to show their genetic relationship because Pasteurella multocida (P. multocida) is an important cause of fatal infections in backyard chickens.

Twenty one P. multocida isolates were recovered previously from clinical cases of fowl cholera belonging to individual owners and phenotypically analyzed using biochemical tests and serotyping were used for the genetic characterization.

Phylogenetic study based on both methods revealed that the recovered population of P. multocida isolated from backyard chickens differs markedly, constituting a well-separated cluster and appearance of 3 distinguishing lineages with greater discrimination shown by RAPD-PCR that resulted in two suclusters in cluster A and three subclusters in cluster B and were related greatly with capsular serogroups for the examined strains. The whole cell protein revealed the presence of dominant protein bands at approximately 41 and 61 kDa in all of the examined isolates that may be a virulent proteins share in the increasing of its pathogenicity. Clear distinctive bands ranged from 123 to 1554 bp.

Based on the previous findings, there are three spreading clusters that may indicate the association of a small number of P. multocida variants with the majority of cases suggesting that certain clones of P. multocida are able to colonize the examined backyard chickens. Also, the ease and rapidity of RAPD-PCR support the use of this technique as alternative to the more labour-intensive SDS-PAGE system for strain differentiation and epidemiological studies of avian P. multocida. Further application of RAPD technology to the examination of avian cholera outbreaks in commercially available flocks may facilitate more effective management of this disease by providing the potential to investigate correlations of P. multocida genotypes, to identify affiliations between bird types and bacterial genotypes, and to elucidate the role of specific bird species in disease transmission.