Diagnosis of Bordetellosis in Pigs from North East India by PCR

Abstract

Bordetella bronchiseptica is an etiologic agent of bronchopneumonia and progressive atrophic rhinitis (PAR) in swine. Both toxigenic and nontoxigenic B. bronchiseptica strains have been associated with bronchopneumonia. Monitoring and investigation of outbreaks involving these bacteria require sensitive and accurate identification and reliable determination of the isolates. In the present study, we report the development, optimization and performance characteristics of polymerase chain reaction (PCR) for B. bronchiseptica strains. A total of 47 isolates of B. bronchiseptica were biochemically identified from 90 pigs suffering from bronchopneumonia maintained in a semi intensive rearing system of organized piggery in Meghalaya. PCR was employed with filamentous hemagglutinin toxin genes (fhaB and fhaC) and fimbrial toxin genes (fim2 and fim3) primers to identify the specific toxin types of B. bronchiseptica. All the 47 isolates were positive for all the toxin genes. The specifity of designed primer pairs was tested by screening some common bacterial species related to the respiratory tract namely, Pasteurella multocida, Staphylococcus aureus and Streptococcus spp. No DNA amplifications of the organisms tested could be seen in the specificity test. Amplicon mobility in agarose gels indicates the amplicons are highly stable. The data presented, establish this PCR as a reliable method for identification and study of adhesins of B. bronchiseptica that may greatly simplify investigations of swine bronchopneumonia and PAR for Indian isolates.