Detection of Mycobacterium leprae by the polymerase chain reaction in nasal swabs of leprosy patients and their contacts.

Nose swabs from 4 paucibacillary (PB) and 8 multibacillary (MB) leprosy patients and their contacts were tested for the presence of Mycobacterium leprae by two polymerase chain reactions (PCR); 30% of the samples contained inhibitors for the PCR, 1 of 52 (1.9%) swabs and 13 of 164 (7.9%) swabs were positive for M. leprae among contacts of PB and MB patients, respectively. Since this difference is not significant, and some positives were found among contacts of MB patients treated and cured of their infection, it is concluded that the observed infections are community acquired.