A COMPARISON OF A COMMERCIAL PCR-BASED TEST TO CULTURE METHODS FOR DETECTION OF MYCOPLASMA-GALLISEPTICUM AND MYCOPLASMA-SYNOVIAE IN CONCURRENTLY INFECTED CHICKENS

The suitability of commercial PCR-based test kits for the detection of either Mycoplasma gallisepticum (MG) or M. synoviae (MS) was compared to detection by culture. The MG and MS kit detected six and five homo logous strains respectively in broth cultures and there were no reacti ons with thirteen heterologous species including M. imitans, a species phylogenetically closely related to MG. Tracheal and lung/air-sac swa bs were collected from twenty 17-week-old commercial pullets which wer e seropositive for MS and were compared for detection of MS by kit and by culture. The results were in agreement for 13 positive and 22 nega tive swabs, while the remaining five swabs were either PCR-positive on ly (two) or culture-positive only (three). Tracheal swabs taken from s eventy-six 31-week-old layers from a MS seropositive commercial hock w hich had been experimentally infected with MG were used to compare the MG DNA probe kit and culture. Of 76 swabs 39 were MG positive and 12 were negative by both methods. MG was detected by PCR test only in 23 other specimens, while only two swabs were negative by PCR but positiv e by culture. The difference between the detection methods was signifi cant (McNemar test, P < 0.001). Concurrent MS infection was detected b y the PCR-based kit in 45 of these hens.