Complex transmission dynamics of clonally related virulent Mycobacterium tuberculosis associated with barhopping by predominantly human immunodeficiency virus-positive gay men

Limited data suggest that measures to reduce tuberculosis transmission shou ld be based on locations rather than on personal contacts. Molecular epidem iologic methods (analysis of IS6110 patterns, spoligotypes, variable number s of tandem DNA repeats, and automated DNA sequence data) identified a coho rt of 48 persons who were infected with progeny of the same Mycobacterium t uberculosis strain. Epidemiologic investigation documented that a large pro portion of the patients were gay white human immunodeficiency virus-positiv e men, Most practiced barhopping, an activity that involved patronizing man y bars in the same neighborhood each night, Few subjects were directly link ed to more than 1 or 2 other persons by conventional investigation methods, which shows that the transmission dynamics were unusually complex compared with most previously described episodes of strain spread. The data support the concept that identification of locations where pathogen dissemination likely occurs may provide additional strategies for targeted tuberculosis c ontrol.