Characterization of mycobacterium isolates from pulmomary tuberculosis suspected cases visiting Tuberculosis Reference Laboratory at Ethiopian Health and Nutrition Research Institute, Addis Ababa Ethiopia：a cross sectional study

ABSTRACT

Objective:To characterize mycobacterium isolates from pulmomary tuberculosis suspected cases visitingNationalTuberculosisReferenceLaboratory atEthiopianHealth andNutritionResearch Institute, for diagnosis of pulmonary tuberculosis fromJanuary4 toFebruary22,2010 with total samples of263.Methods:Sputum specimens were collected and processed; the deposits were cultured.For culturingLowensteinJensen medium(LJ) andMycobacteriaGrowthIndicatorTube (BACTECMGIT960) were used.CapiliaNeo was used for detectingNTM isolates from isolates of BACTECMGIT960.InArmauerHansenResearchInstitute,AddisAbabaEthiopia,Deletion typing PCR method for species identification(from confirmedMycobacterium tuberculosis complex (MTBC) isolates byCapiliaNeo) was done.Results:Out of263 enrolled in the study,124 and117 of them were positive for mycobacterium growth byBACTECMGIT960 andLJ culture method, respectively.FromBACTECMGIT960 positive media of124 isolates,117 were randomly taken to performCapiliaTBNeo test.From these7(6%) of them were found to beNTM and110(94%) were MTBC.From these110MTBC isolates,81 of them were randomly taken and run by the deletion typingRD9PCR method of molecular technique.Out of these78(96.3%) were found to be species ofMycobacterium tuberculosis and3(3.7%) were found to be not in theMTBC.Regarding the types of methods of culture media,MycobacteriaGrowthIndicatorTube(BACTECMGIT960) method was found to have excellent agreement(with kappa value of0.78) with the routine method of LJ.Conclusions:Pulmonary tuberculosis suspected cases visiting theNationalTuberculosis ReferenceLaboratory atEHNRI that were confirmed to be pulmonary tuberculosis are caused by the species ofMycobacterium tuberculosis, hence treatment regimen including pyrazinamide can be applied to the patients as the first choice in the study area inAddisAbaba,Ethiopia.There is indication of the presence ofNTM in patients visiting the tuberculosis reference laboratory and this is important becauseNTM is known to cause pulmonary disease similar with sign and symptom of pulmonary tuberculosis but different in treatment.BACTECMGIT960 has excellent agreement withLJ media but it has high tendency of having high contamination rate unless a better decontamination method is designed.