Mycoplasmal pneumonia in Chinese veterans

From 1967-1973, a total of 54 strains of Mycoplasma pneumoniae was isolated from patients suffering from different acute respiratory diseases, with an average positive isolation rate of 4.7%. Most mycoplasmas were isolated from patients aged 40-60, and with pneumonia of primary atypical pneumonias. The highest frequency of isolation was found in sputum collected 4-8 days after onset of illness. Colony formation on PPLO medium usually occurred 7-12 days after incubation. Serological tests were methods of choice for diagnosis of mycoplasmal pneumonia. In the 6 years period, 163 patients were diagnosed: 74 were positive only by metabolic inhibition test (MIT), 55 were positive only by cold agglutination test (CAT), and 34 gave positive by both tests. Of the above 2 tests, the CAT is nonspecific, but the MIT appears to be more sensitive and specific. Of the 94 sera positive by MIT, 42 (48.2%) were also positive by CAT; of those negative by MIT, 45 of 507 (8.8%) were positive by CAT. Of 45 sera with positive mycoplasma isolation, 37 (82.2%) were also positive by MIT, but only 22 (48.9%) showed the rises of CAT titers. Clinical features of mycoplasmal pneumonia were almost similar to those described by the other investigators. The chief symptoms were fever, coughs, chills, rales, malaise, sore throat headache and chest pain. The sedimentation rate of erythrocytes was accelerated. White count was normal in most cases. Both leucocytosis and leucopenia were found in 10% of the cases. Seasonal variation in incidence of mycoplasmal pneumonia was not obvious, however the lowest incidence occurred during summer. A roentgenogram of the chest was necessary for diagnosis of mycoplasmal pneumonia, and the lung infiltration was mainly located on right side (57.1%), segmentally, and limited to one lobe, especially the lower lobe.