ABSTRACT
The fermentation-inhibition (FI) test for Mycoplasma pneumoniae was improved by using a combination of guinea pig complement and gamma globulin-depleted horse serum in place of unheated whole horse serum employed in the conventional assay system. As the test antigen for the new FI assay system, M. pneumoniae filtrated through a 3.0 microns membrane filter was used. Owing to the strong augmenting effect of guinea pig complement, the FI activity of rabbit immune serum was increased 32-fold in the new system compared with the conventional system. Furthermore, IgM antibody, which is barely detectable by the conventional system, could easily be titrated by the new system. With this sensitive method, rapid rise of FI titer was clearly demonstrable in most children with acute M. pneumoniae infections, and a prevalence of FI or growth-inhibitory antibody among healthy adults in Japan (82%) was revealed.
Subject(s)
Antibodies, Bacterial/analysis , Mycoplasma pneumoniae/immunology , Pneumonia, Mycoplasma/diagnosis , Adolescent , Adult , Animals , Antigens, Bacterial/immunology , Child , Child, Preschool , Complement System Proteins , Enzyme-Linked Immunosorbent Assay , Fermentation , Humans , Immunoglobulin M/immunology , Rabbits , Sensitivity and Specificity , Serologic Tests/methodsABSTRACT
Improvement of the fermentation-inhibition (FI) test for Mycoplasma pneumoniae was attempted. The sensitivity of detecting the FI antibody to M. pneumoniae in the homologous immune rabbit serum was notably elevated, when such FI medium containing gamma globulin-free horse serum and guinea-pig complement in substitution for unheated horse serum was used. The M. pneumoniae suspension was filtered to remove aggregates of the organisms and used as the antigen for this new FI test. In detection of the serum antibody of patients with M. pneumoniae infections, the new FI test showed much higher sensitivity than conventional FI test and strongly correlated (r = 0.84) with high density particle agglutination test known to detect both IgG and IgM antibodies.
Subject(s)
Antibodies, Bacterial/analysis , Complement System Proteins , Mycoplasma pneumoniae/immunology , Pneumonia, Mycoplasma/diagnosis , Animals , Fermentation , Guinea Pigs , Humans , Pneumonia, Mycoplasma/immunology , Serologic Tests/methodsABSTRACT
Throat swab culture was compared with indirect hemagglutination (IHA) antibody detection for diagnosis of Mycoplasma pneumoniae infection. These two methods were tried on the patients several times for a long term after onset of the disease. For five years from 1982 to 1986 in Kanagawa prefecture, a total of 566 patients were tested and 141 (25%) were diagnosed as M. pneumoniae infection by either of the two test methods. Both culture and antibody detection were performed on 110 patients out of 141, revealing that 96 patients (87%) were positive by culture and 89 (81%) were positive by antibody detection. Most of the patients with M. pneumoniae infection showed positive culture within a week after onset of the disease, and half of the patients treated with antibiotics such as macrolides or tetracyclines showed positive for two or three months after the onset. Positive rate of IHA antibody detection in the patients with M. pneumoniae infection was 43% within a week after onset of the disease and reached the maximum (92%) in 15 to 21 days after the onset. The rate did not decrease to less than 70% three months after the onset. Geometric mean titer of the antibody reached the maximum at the same time as the antibody positive rate. Both antibody positive rate and geometric mean titer declined significantly four months after the onset. In general, IHA antibody of infants with M. pneumoniae infection increased satisfactorily day by day after onset of the disease. Nine percent of the patient with M. pneumoniae infection developed otitis media with effusion, and M. pneumoniae was isolated from two of six patient effusions.
