Evaluation of PCR primers to detectmycobacterium tuberculosiscomplex in feces

About 10, 000 new tuberculosis cases are reported annually in Sri Lanka and only about 40% of the cases receive bacteriological confirmation. Therefore, diagnosis often depends on unreliable clinical scoring systems and radiology. The objective of this study was to evaluate PCR primers to establish a sensitive assay to detect M. tuberculosis complex specific DNA in feces. Fecal samples were obtained from 25 patients (adults and children) diagnosed with pulmonary tuberculosis clinically and by sputum microscopy. All the patients included in the study have been followed-up for six months and fully recovered upon anti-tuberculosis treatments. Healthy adults were used as negative controls. The fecal PCR assay was conducted using total fecal DNA extracted with Qiagen Mini Stool Kit following manufacturer9s protocol. The PCR primers targeted IS 6110 (Ozkara, H.A. et. al. IJTLD 1998; 6:451-455), IS986 (Kolk, A.H.J. et. al. JCM 1992: 2567-2575) and HupB (in-house primers) genes. The below table provides a comparison between the smear test results and different PCR assays. The preliminary data suggests that IS-6110 based fecal PCR assay can be used to rapidly diagnose pulmonary tuberculosis with a good sensitivity.