Evaluation of PCR mediated DNA amplification in non-invasive biological specimens for subclinical detection of Mycobacterium leprae.

DNA from Mycobacterium leprae, present in non-invasive clinical samples from leprosy patients, such as nasal secretion and hair bulbs, was submitted to amplification by the polymerase chain reaction using a M. leprae-specific repetitive sequence as a target. After optimization of sample processing and of the PCR conditions, we were able to detect DNA from M. leprae in both types of clinical samples, even from paucibacillary leprosy patients. The use of hair bulbs and nasal secretion as clinical samples for screening of household contacts and for the evaluation of a risk population, or for the follow-up of patients under chemotherapy, and monitoring of bacterial load is discussed.