[Diagnosis on Mycoplasma pneumoniae infections by DNA-probe assay in comparison with serological tests]

To evaluate the usefulness of DNA diagnosis as a diagnostic approach to Mycoplasma pneumoniae infections, we compared the DNA-probe assay with serological tests in 32 patients who were clinically suspected of having Mycoplasma pneumonia. The DNA-probe assay was carried out using the Gen-probe kit. Serological tests included complement fixation and passive hemagglutination tests. At first visit 10 patients were positive for the DNA-probe assay, while only 2 of them were positive for serological tests. The other 3 patients became positive for serological tests during the clinical course. In accordance with clinical improvement, these patients became negative for the DNA-probe assay. Three patients were negative for DNA-probe assay while they were positive for the serological tests. However, these patients had already received antibiotics; therefore, their conditions were considered to have been improved at the time of the study. The other 19 patients were negative for both the DNA-probe assay and serological tests. These patients might have suffered from respiratory tract infections of pathogenic organisms other than M. pneumoniae or the number of M. pneumoniae might have been too small to be detected by the DNA-probe assay. The results of the present work demonstrate that the DNA-probe assay was valuable in the diagnosis of mycoplasmal infections at the early stage, which indicates that DNA diagnosis provides useful information to determine the most appropriate therapeutic regimen.