A comparative study on the pretreatment methods for the cultivation of Mycobacterium tuberculosis on LJ medium. Part II.

The sputa of 231 cases, who were admitted to Ojha Institute of Chest Diseases, Karachi were studied in order to compare the efficiency and reliability of three pretreatment methods viz. Standard method, Marks' method (1959), and Becker's method (1961). Out of the 231 specimens, 132 were film positive while 99 were film negative. 141 cases were found positive after cultivation on LJ medium. The number of cases found to be positive with Standard method, Marks' method and Becker's method were 91, 84, 105 respectively. Contaminations encountered with Standard method were 43, with Marks' method 41, and with Becker's method 20. 97 negatives were observed with Standard method and 106 each with Marks' and Beckers' methods. The merits and demerits of the three methods are discussed.