A LONGITUDINAL-STUDY OF TRANSMISSION OF TUBERCULOSIS IN A LARGE PRISON POPULATION

The purpose of this study was to determine the extent of transmission of tuberculosis in a large prison population over an 18-mo period. Res triction-fragment-length polymorphism (RFLP) analysis of isolates of M ycobacterium tuberculosis was performed, using the insertion sequence IS6110 and the plasmid pTBN12. Patients infected with strains having t he same fingerprint were grouped in clusters. Medical records were rev iewed and movement of inmates among prisons was examined for selected patients. Tuberculosis was diagnosed in 216 inmates (case rate = 2,283 per 100,000 per year). Isolates from 210 (97%) patients were fingerpr inted, 155 (74%) were grouped in 25 clusters, and 55 (26%) showed a un ique fingerprint. Recent infection was inferred in 62% of these patien ts. Eighty-four percent (161 of 192) of patients tested were human imm unodeficiency virus (HIV)-positive, of whom 121 were in clusters and 4 0 were not(p = 0.74). Patients in clusters were less adherent with tub erculosis treatment than those not in clusters (p < 0.05), and prison transmission of resistant strains was observed. It is crucial that inf ection control guidelines be fully implemented in the prison setting t o prevent tuberculosis transmission.