Mycoplasma pneumoniae in Primary Atypical Pneumonia

A cultural and serologic study of primary atypical pneumonia (PAP) was done prospectively in 239 randomly chosen recruit admissions to the US Naval Hospital, Great Lakes, III. Cold-agglutinin reactive sera were found in 172 patients, while evidence of Mycoplasma pneumoniae (Eaton agent) infection was detected in 41. M pneumoniae -associated PAP was consistently found among cold-agglutinin-positive patients. However, the number of cold-agglutinin reactors greatly exceeded that of recognizable M pneumoniae infections in this series. The isolation of wild strains of M pneumoniae from 25 patients on artificial agar medium was statistically related to the presence of complement-fixing antibodies to the FH strain (American Type Culture Collection, Mycoplasma pneumoniae No. 15531) of this microorganism.