Association of Mycoplasma pneumoniae infection with primary atypical pneumonia.

A controlled epidemiologic experiment was conducted at the Great Lakes Naval Training Center to measure the relationship of Mycoplasma pneumoniae infection and the syndrome of primary atypical pneumonia. Recruits admitted with pneumonia were matched with suitable control subjects with nonrespiratory illness. Using a two-plate cultural system with both aerobic and anaerobic incubation, respiratory secretions yielded M. pneumoniae in 11 patients. Mycoplasma salivarium and M. pharyngis were equally prevalent in both the pneumonia group and the control group. With the addition of seroconversion of complement-fixing antibodies as a criterion of infection, M. pneumoniae was implicated in 20 per cent of patients with pneumonia. Cold agglutinin reactivity was significantly related to this infection. The association of M. pneumoniae with atypical pneumonia was significant.