[Detection of Mycoplasma pneumoniae by using polymerase chain reaction and nonradioactive DNA probes]

Mycoplasma pneumoniae is the causative agent of primary atypical pneumoniae, and two distinct groups (I and II) have been established. Serological tests are relatively insensitive and the diagnosis by culture is time-consuming. This study was therefore undertaken to detect and to identify M. pneumoniae on culture media and in throat swab specimens by using polymerase chain reaction (PCR) and hybridization probes conjugated to alkaline phosphatase (Alp). Primer pairs were selected for amplification of DNA fragments in the C to D, F, G and I to J regions of the M. pneumoniae cytadhesin P1 genes. Amplified DNA fragments were visualized by staining with ethidium bromide after 2% agarose gel electrophoresis and by Southern hybridization with Alp-labeled probes. No amplification of the P1 genes was seen with any of five related Mycoplasma species, the others from M. pneumoniae. In all of 30 clinical isolates on PPLO medium, M. pneumoniae was detected with the F and G primer pairs, giving 100% of sensitivity. Of 69 throat swab specimens, 25 were positive with the F primer pairs, and 23 positive with the Gen Probe test. From these results, we conclude that the PCR with F or G primer pairs can be adapted as a practical method for the rapid diagnosis of M. pneumoniae infections.