A non-radioactive DNA probe for the detection of Mycoplasma pulmonis in murine mycoplasmosis

Differential detection of Mycoplasma pulmonis and Mycoplasma arthritidis with species-specific DNA probes

Mycoplasma pulmonis and Mycoplasma arthritidis are both significant causes of infection in colonies of rodents, which are common experimental animals for biomedical research. Since differential diagnosis has proven difficult due to similar homology between these two murine Mycoplasma species, the development of a reliable identification system is of importance. In this study DNA probes specific for M. pulmonis and M. arthritidis were generated after cross-hybridization between two reference strains and cloning of the specific DNA fragments into the pGEM-3 blue vector. Two clones, harboring plasmids pGEM-89 (specific for M. pulmonis) and pGEM-31 (specific for M. arthritidis) were selected based on their specificity upon colony hybridization and were used as species-specific probes. These probes could detect in dot blots 150 pg of M. pulmonis DNA or 300 pg of M. arthritidis DNA with no visible hybridization with up to 100 ng of heterologous DNA. When hybridized with dot blots of culture grown organisms, the pGEM-89 probe produced a positive signal with all 12 isolates of the M. pulmonis strains tested, but none of the four M. arthritidis, and vice versa for the pGEM-31 probe. We thus anticipate that these probes will be useful for routine detection and identification of mycoplasmal infections of rodents.

The polymerase chain reaction for Mycoplasma pulmonis

In vitro DNA amplification by polymerase chain reaction was examined to detect Mycoplasma pulmonis. A pair of synthetic oligonucleotide primers was constructed, and used to amplify a unique sequence of M. pulmonis DNA. Amplified products were detected by agarose gel electrophoresis and verified by blot hybridization with a synthetic oligonucleotide probe. This system detected cellular DNA of M. pulmonis but not M. arthritidis or M. neurolyticum, and thus appears to be useful for M. pulmonis diagnosis.