EVALUATION OF RADIORESPIROMETRIC TECHNIQUE FOR DETECTION OF MYCOBACTERIUM TUBERCULOSIS STRAINS FROM PULMONARY TUBERCULOSIS PATIENTS

A simple and rapid radiorespirometric method, for early detection of tubercle bacilli from sputum samples has been developed. A biphasic liquid scintillation vial system is used for detection of 14CO2 produced by metabolism of acetate 1-2-l4C on glycerol free Lowenstein- Jensen Media (LJM). Total 207 sputum samples were tested by smear, visual growth method (VGM) and radiorespirometric method (RRM) for detection of Mycobacterium tuberculosis (M. tuberculosis) strains. Total 27.54 % sputum samples were scored positive by smear, 21.7% samples by VGM and 33.3 % samples by RRM. There is significant difference between three methods related to sensitivity, specificity, positive and negative predictive value for detection of M. tuberculosis strains. RRM was found to be most sensitive and specific method amongst three. The average detection time by RRM was 9.48 days, compared to 34.47 days by VGM. There is a correlation of number of bacilli in smear and rate of growth in RRM and VGM.