Mycoplasma pneumoniae infection in a clinical setting.

Background: Mycoplasma pneumoniae infection predominantly affects the respiratory tract, although the other organs may also be involved. Previous studies compared the clinical features of patients with M. pneumonia pneumonia to other pathogens and these studies were predominantly adult case series rather than involving children. The objectives of the present study were to compare the clinical features, laboratory, and radiographic findings in children seropositive for M. pneumoniae infection with children tested for suspected M. pneumoniae infection who were seronegative.

Methods: Using a retrospective review of children who had complement fixation test (CFT) performed for suspected M. pneumoniae infection, children were classified as seropositive if the acute phase serum titer was >or=64, or paired samples taken 2-4 weeks apart showed a fourfold or greater rise in serum titer. In contrast, a patient with an antibody titer <64 or with paired sera showing less than a fourfold rise in titer was considered seronegative.

Results: One hundred and fifty-one children were included. Seventy-six children had serological evidence of M. pneumoniae infection and the remaining 75 were seronegative. Children with M. pneumoniae infection were more likely to have fever >6 days duration prior to admission, crackles on auscultation, radiographic consolidation and thrombocytosis at presentation. In addition, M. pneumoniae infection was associated with pneumonia whereas seronegative children were more likely to have upper respiratory tract infection or asthma.

Conclusions: Certain clinical parameters could assist in gauging the likelihood of M. pneumoniae infection in children, and thus direct whether antibiotic treatment is needed.