Tuberc Respir Dis.  1976 Jun;23(2):85-91. 10.4046/trd.1976.23.2.85.

A Study on the Efficiency of Various Culture Methods in the Isolation of Tubercle Bacilli

• KMID: 2528961
• DOI: http://doi.org/10.4046/trd.1976.23.2.85

Abstract

Although it is technically superior to direct microscopy, expansion of culture examination as a diagnostic and/ or monitoring service depends largely on its practicability in various phases of a national tuberculosis (TB) programme. Greater emphasis on cultural examination will mean simplification of technical procedures and usage of less expensive materials. ln this regard several culture methods have been compared on the basis of positive-case yield, technical procedure, and expense. Specimens for this study were collected from 3,682 radiographic suspects found during the 3rd national prevalence survey which was conducted in 1975. Both the laryngeal swab and spot sputum collection methods were utilized. Examination of this group by both direct microscopy and by the oxalic acid (OA) culture method yielded 198, or 5.4%, bacteriologically positive cases. Of these, 93, or 2. 5%, and 115, or 3. 1%, were discovered by direct microscopy from laryngeal swabs and spot sputa, respectively, while 134 cases, representing 3.6%, and 138, or 3.8%, positive cases were discovered subsequently via culture examination. The figures, of course, indicate reason to favor spot sputum collection over the laryngeal swab within the peripheral laboratory where facilities are unsuited for culture examination. ln addition to these, findings comparing the results of the culture examination utilizing three relatively simple culture methods, the OA method, the Ogawa method, and the KIT (Korean lnstitute of Tuberculosis) method, also tabulated. Although statistically insignificant, they showed definitively that the OA method, which has been recommended by World Health Organization, produced fewer positive-case results, (130, or 5.0%), than those discoveries of either the Ogawa, which produced 140, or 5.4%, or the KIT method, whicb presented 145 cases or 5.6%. Examination of the 729 spot sputa following the OA method, the simple Ogawa and the KIT methods further substantiated, through demonstration, the superiority of either the simple Ogawa or the KIT methods over any other, not only in positive-case yield capabilities but in cost analysis as well. The results showed that the OA method produced 91 or 12. 5% cases could be found overall, while 105 cases or. 14.4% and 107 cases or 14.7% became available employing the Ogawa and the KIT methods, respectively. Furthermore, when the concentrated specimens were inoculated on L-J, Ogawa, and KIT media, 105(14.4%), 106(14.5%), and 120(16.5%) positive cases were found, respectively. Direct inoculation of spot sputum specimens with penicillin into the peritoneal cavity of mice produced a marked decrease in positives, 38, or 7.6%, then the findings given þy the direct microscopic or cuIture examination methods, which was 118 cases, representing 23.6%.