[Comparison of MB-Check, BACTEC, and egg-based media for recovery of mycobacteria].

The rate of recovery and time to the detection of mycobacteria from clinical specimens were measured for biphasic and radiometric liquid-based culture systems and egg-based media (3% Ogawa and Ogawa K). From the 245 sputum specimens processed, a total of 86 (35.1%) mycobacterial isolates were detected. Of these, 81 (94.2%) and 80 (93.0%) isolates were detected with the MB-Check and BACTEC systems, respectively, and 65 (75.6%) isolates were detected with the 3% Ogawa egg method. The difference in the percentages of positive cultures between the two systems based on liquid media and the 3% Ogawa egg method was significant (P < 0.01). This difference was even greater among smear-negative specimens. The detection time was shorter with the liquid-based systems. The mean times to the detection of the Mycobacterium tuberculosis complex were 19.1 days with the MB-Check system, 13.4 days with the BACTEC system, and 21.7 days with the 3% Ogawa egg method. These results indicate that both the MB-Check and the BACTEC systems, based on liquid media, are efficient for the recovery of mycobacteria.

Comparison of MB-Check, BACTEC, and egg-based media for recovery of mycobacteria.

The rate of recovery and time to the detection of mycobacteria from clinical specimens were measured for biphasic (MB-Check; Nippon Roche Co., Ltd., Tokyo, Japan) and radiometric (BACTEC; Nippon Becton Dickinson Co., Ltd., Tokyo, Japan) liquid-based culture systems and egg-based media (3% Ogawa and Ogawa K). From the 245 sputum specimens processed, a total of 86 (35.1%) mycobacterial isolates were detected. Of these, 81 (94.2%) and 80 (93.0%) isolates were detected with the MB-Check and BACTEC systems, respectively, and 65 (75.6%) isolates were detected with the 3% Ogawa egg method. The difference in the percentages of positive cultures between the two systems based on liquid media and the 3% Ogawa egg method was significant (P less than 0.01). This difference was even greater among smear-negative specimens. The detection time was shorter with the liquid-based systems. The mean times to the detection of the Mycobacterium tuberculosis complex were 19.1 days with the MB-Check system, 13.4 days with the BACTEC system, and 21.7 days with the 3% Ogawa egg method. These results indicate that both the MB-Check and the BACTEC systems, based on liquid media, are efficient for the recovery of mycobacteria.

[Serological diagnosis of pulmonary aspergillosis by ELISA].

Pulmonary aspergillosis usually develops on the basis of systemic immunosuppression and/or local impairments of respiratory system. Diagnosis of pulmonary aspergillosis has many difficulties. Chest X-ray findings of most cases are complicated with pre-existing changes due to the underlying diseases, and the detection rate of the pathogenic fungi from clinical specimens is unsatisfactorily low. Therefore, immunological or serological diagnosis is urgently required and precipitation-in-gel method has been widely applied. In this report, we compared clinical usefulness of the determination of anti-aspergillus antibodies by ELISA with that of precipitation-in-gel method. ELISA was carried out according to the method previously reported by us (Yamamoto S. et al.: Kekkaku 62: 549, 1987). About two-thirds of 45 healthy adults (control) did not show any detectable IgG anti-aspergillus antibody and mean of IgG anti-aspergillus antibody titer of the control group was 28.97. Patients, who had shown positive culture of fungus or was clinically diagnosed or strongly suspected as pulmonary aspergillosis, showed significantly high anti-aspergillus IgG antibody titer in comparison with the control group. Further, patients who were positive in precipitation-in-gel tests showed significantly higher IgG antibody titers than those who were negative in that test. IgG antibody titer determined by ELISA corresponded with clinical diagnosis much more exactly than the results of precipitation-in-gel test. Further, the results obtained by ELISA were objective and quantitative in comparison with the latter test. We concluded that ELISA was much superior to precipitation-in-gel test and that ELISA IgG antibody titers 2500 or more were confirmative and those between 570 and 2500 were strongly suggestive for the diagnosis of aspergillosis. IgM anti-aspergillus antibody titers were not different among healthy control group and patient groups, and could not be used for the diagnosis.