Isolation of Mycoplasma pneumoniae from adults with respiratory infections

Abstract

Isolation of Mycoplasma organisms from sputum was attempted in 254 patients with various syndromes of respiratory disease. Isolates were obtained In 56% of the 197 patients with pneumonia, 50% of patients with chronic bronchial diseases who were not treated with tetracycline, and 33% of persons with acute upper respiratory infection. These differences are not statistically significant and indicate a nonpathogenic role for M.pharyngis and M. sallvarium which were the strains most frequently isolated. The highest frequency of isolation was from males 15 to 30 years of age. Isolation of M. pneumonlae requires 1 to 2 weeks: therefore, It is not useful for rapid diagnosis. Also, it underestimates the prevalence of infection, expeclally if patients have received tetracycline. Of the serologic tests, complement-fixation (CF) was the most specific. The growth inhibition test (TRI) was the most sensitive and was significantly related to a typical pneumonia. The 2 tests may measure different antibodies against M. pneumonlae. Serum cold agglutinins developed in many cases of pneumonia and were poorly discriminatory in etiologic diagnosis. M. pneumonlae infection occurred in a minimum of 9% and a maximum of 20% of civilian patients hospitalized for pneumonia during the season studied. Serologic evidence for Mycoplasma pneumonia was rare in lobar pneumonia. In nonlobar pneumonia, M. pneumonlae accounted etiologically for 13% to 50% of cases. The Incidence of M. pneumonlae infection was constant in different seasons but greatest relative to the occurrence of pneumonia in the fall and spring.