Detection of Mycoplasma bovis and Mycoplasma agalactiae by oligonucleotide probes complementary to 16S rRNA.

The partial sequences of 16S rRNA from Mycoplasma bovis and M. agalactiae were determined by dideoxynucleotide sequencing using reverse transcriptase. Two oligonucleotides complementary to different evolutionary variable regions of 16S rRNA from these two species were synthesized. The oligonucleotides were end-labelled with 32P and used as probes in filter hybridization experiments with different bovine, caprine and ovine mycoplasmas as samples. One of the probes, complementary to a sequence of the V8-region of both M. bovis and M. agalactiae, did not cross-hybridize to any bovine, caprine or ovine mycoplasmas except M. bovigenitalium and M. californicum. This probe is thus not useful for analysis of bovine samples, but can be used for detection of M. agalactiae in samples from goats and sheep, since M. bovigenitalium and M. californicum have never been isolated from these hosts and M. bovis only occasionally. The other probe, complementary to a sequence of the V6-region of M. bovis, gave some cross-hybridization with M. agalactiae but not with bovine mycoplasmas. M. agalactiae has never been isolated from cattle and this probe is therefore useful for rapid screening of bovine samples for M. bovis.