Recent nosocomial transmission and genotypes of multidrug-resistant Mycobacterium tuberculosis.

MDR cases were more likely to be found in clusters than drug-susceptible cases (74.0% vs. 33.6%). Recent nosocomial transmission of MDR-TB is an important risk factor for the spread of multiresistance, and is associated with the Beijing genotype. Special attention should be paid to infection control measures in hospitals and ambulatory treatment should be enforced.