Application of PCR for Mycoplasma pneumoniae detection in children with community-acquired pneumonia.

Between April 2002 and March 2003, to detect Mycoplasma pneumoniae by polymerase chain reaction (PCR), a primer set designed for the 16S rRNA gene was used to examine clinical samples from 369 children with community-acquired pneumonia. Samples were collected from 12 Japanese institutions participating in a study group concerning acute respiratory infectious diseases. The sensitivity of primers--2 CFU per reaction tube, using M. pneumoniae M129, a standard strain--was calculated to represent 1.1 x 10(3) M. pneumoniae organisms adherent to the tip of the swab used to collect clinical samples. Results for PCR were obtained within 2.6 h. Cases identified by PCR, cultures, and serologic tests were 68 (18.4%), 53 (14.4%), and 76 (20.6%) respectively. Among 57 PCR-positive patients tested serologically, 56 showed a significant elevation or rise in antibody titer. PCR positivity was high among patients prescribed beta-lactam antibiotics (86.7%) or no antibiotic (87.0%) before PCR analysis, but was low among patients receiving macrolides, new quinolones, or tetracyclines (37.5%). We concluded that the PCR constructed by us had a high probability for confirming a diagnosis of M. pneumoniae pneumonia and for guiding antibiotic choice for patients not yet treated.