DETECTION OF PASTEURELLA-MULTOCIDA-SPECIFIC DNA IN TURKEY FLOCKS BY USE OF THE POLYMERASE CHAIN-REACTION

A polymerase. chain reaction (PCR)-based assay using primers construct ed to amplify tile gene (psl) encoding the P6-like protein (Psl) of Pa steurella multocida was developed. After Southern blotting and hybridi zation with psl, the assay (PCR-H) was found to be specific (it did no t detect a variety of other avian bacterial pathogens) and sensitive ( detected greater than or equal to 10 IZ multiocida organisms or greate r than or equal to 24 femtograms of extracted P. multoicda DNA). Sampl es were collected from the oropharynx of randomly selected birds house d on premises that had recently experienced an outbreak of avian chole ra (outbreak farms) or from birds housed on premises that had nor repo rted an outbreak of this disease during the preceding 12 mo (control f arms). The PCR-H assay detected 11 infected turkeys out of a total of 178 sampled on six outbreak farms as compared with isolation of P. mul tocida from 23 turkeys by using mouse inoculation. Neither method dete cted P. multocida in samples collected from 174 turkeys sampled on six control farms. Statistical analysis using the Kappa test demonstrated that the results of the two tests showed poor agreement from five out break flocks (K = 0, 0, 0, 0.35, 0.47) and strong agreement from one o utbreak flock (IC = 0.89). Combined results from the outbreak flocks s howed poor agreement (K = 0.49) between the two methods.