Systematic Review of Hansen Disease Attributed to Mycobacterium lepromatosis

In 2008, bacilli from 2 Hansen disease (leprosy) cases were identified as a new species, Mycobacterium lepromatosis. We conducted a systematic review of studies investigating M. lepromatosis as a cause of HD. Twenty-one case reports described 27 patients with PCR-confirmed M. lepromatosis infection (6 dual M. leprae/M. lepromatosis): 10 case-patients in the United States (7 originally from Mexico), 6 in Mexico, 3 in the Dominican Republic, 2 each in Singapore and Myanmar, and 1 each in Indonesia, Paraguay, Cuba, and Canada. Twelve specimen surveys reported 1,098 PCR-positive findings from 1,428 specimens, including M. lepromatosis in 44.9% (133/296) from Mexico, 3.8% (5/133) in Colombia, 12.5% (10/80) in Brazil, and 0.9% (2/224) from the Asia-Pacific region. Biases toward investigating M. lepromatosis as an agent in cases of diffuse lepromatous leprosy or from Mesoamerica precluded conclusions about clinicopathologic manifestations and geographic distribution. Current multidrug treatments seem effective for this infection.