Detection of M. tuberculosis in clinical samples of diversified nature by IS6110 based PCR.

ABSTRACT

Performance of the polymerase chain reaction technique based on IS6110 sequence was evaluated in clinical samples obtained from pulmonary and extrapulmonary cases of tuberculosis. One hundred and seventy two samples were processed for detection of M. tuberculosis by ZN stained smear examination, LJ medium culture, BACTEC radiometric culture and PCR tests amplifying 123bp region of IS6110 sequence. A significant difference was seen in the sensitivities of different tests, the figures being 83% for PCR test, 35.2% for smear examination, 47.16% for LJ culture and 53.45% for BACTEC culture (p < 0.05). However, no significant difference was found as far as specificity was concerned. PCR test sensitivity in. pulmonary and extrapulmonary clinical samples were 90.14% and 77.27% respectively and found to be significantly higher (p < 0.05) when compared with those of other tests. The mean detection time for M. tuberculosis was 24.03 days by LJ medium culture, 12.89 days by BACTEC culture and less than one day by PCR test. PCR based on IS6100 sequence is highly sensitive method for the early diagnosis of pulmonary and extrapulmonary tuberculosis.