USE OF SPECIES-SPECIFIC OLIGONUCLEOTIDE PROBES TO DETECT MYCOPLASMA-GALLISEPTICUM, MYCOPLASMA-SYNOVIAE, AND M-IOWAE PCR AMPLIFICATION PRODUCTS

Three digoxigenin-labeled oligonucleotide probes, complementary to the variable region of the 16S ribosomal RNA (rRNA) gene of Mycoplasma ga llisepticum, M. synoviae, and M. iowae were designed. The oligonucleot ides were used in a dot blot hybridization assay. The target DNA is a 780-bp fragment of the 16S rRNA gene of avian mycoplasmas amplified by a single set of primers (multispecies polymerase chain reaction [PCR] ). The oligonucleotide probes were specific for their corresponding PC R products at hybridization conditions of 56 C and 50% formamide. The detection limit of the dot blot hybridization assay was approximately 70, 50, and 30 colony-forming units for M. gallisepticum, M. synoviae, and M. iowae, respectively, per 4 mu l of PCR. In general, the oligon ucleotide probe dot blotting assay was a more sensitive and effective method of detecting PCR products than detection by gel electrophoresis .