Which of the following is a slow grower:

Ans. (a) M. Kansasii M. kansasii is a slow growing atypical mycobacteria belonging to photochromogens. Other options M. fouitum and M. Chelonai belong to Group IV of atypical mycobacteria (rapid growers ) and their colony usually appear within seven days. Mycobacterium abscess is a rapidly growing mycobacterium that is a common water contaminant. It can cause chronic lung disease, post-traumatic wound infections, and disseminated cutaneous diseases, mostly in patients with suppressed immune systems. Note: M. abscessus and M. chelonae can be distinguished from M. fouitum by their failure to reduce nitrate and to take up iron. Tolerance to 5% NaCI in Lowenstein-Jensen media, and non-utilisation of citrate as a sole carbon source are characteristics that distinguish M. abscessus from M. chelonae.