Virulence ofMycobacterium tuberculosis

An understanding of the virulence of Mycobacterium tuberculosis, the causative organism of tuberculosis, could assist the development of effective control measures against this widespread and tenaceous disease. Research is compromised by wide variations in virulence, and hence in the significance of determinants of virulence, in different host species. Determinants of virulence enhance survival within macrophages and, in the guinea pig, putative determinants include resistance to hydrogen peroxide, cell-wall sulpholipid content and the ‘Attenuation Indicator’ (AI) lipid. None of these correlate completely with virulence. More recently, the ability of tubercle bacilli to elicit inappropriate immune responses has emerged as an important aspect of the mechanism of virulence.