A significant proportion of the world’s population is infected with Mycobacterium tuberculoszs , with estimates in 1992 of 8 million new mfections and 3 million deaths from tuberculosis (TB) per annum (1 ). There are several other causes for concern. There IS a close assoclatlon between the human inmunodeficiency virus (HIV) and tuberculosis; for example, in some African countries recent studies found that up to 70% of tuberculosis patients are comfected with HIV and 40% of AIDS patients had tuberculosis (for a summary, see ref. 2 ). Not only is HIV increasing the overall numbers of tuberculous patients, but it complicates the clinical picture of infection leading to more extrapulmonary disease at a diverse range of body sites (2 ,3 ). Another cause for concern is the emergence of M. tuberculosis strains that are resistant to the frontline antituberculosls drugs. Multidrug resistant (MDR) strains of tuberculosis, those resistant to two or more frontline drugs (usually defined as those strains resistant to isomazld and rifamplcm), have already caused outbreaks at several dlfferent sites including well-documented outbreaks in New York, which included transmission within the State prison system (4 ).