A single step culture technique for tubercle bacilli

A single step method for the digestion and decontamination of sputum for culture of tubercle bacilli is described. This method employs a transport medium containing tri-sodium phosphate and penicillin. Sputum samples are collected directly into the medium and, after standing overnight, deposits are inoculated onto Löwenstein-Jensen medium. The method was found to be superior to several other commonly used techniques and it avoids the problems of lengthy, multi-step procedures with associated risks of contamination from the atmosphere, costly reagents, the killing of tubercle bacilli by over-exposure to decontaminating agents, the unpleasantness of manipulating unprocessed sputum and the need for sophisticated equipment and special technical skills. The method is therefore ideal for use under the prevailing laboratory conditions in the developing countries.