The leprosy agents Mycobacterium lepromatosis and Mycobacterium leprae in Mexico

Authors

  • Xiang Y. Han MD, PhD,

    1. Clinical Microbiology Laboratory, University of Texas MD Anderson Cancer Center, Houston, TX, USA
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  • Kurt Clement Sizer MD,

    1. Clinical Microbiology Laboratory, University of Texas MD Anderson Cancer Center, Houston, TX, USA
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  • Jesús S. Velarde-Félix PhD,

    1. Department of Dermatology, Faculty of Medicine, Universidad Autónoma de Sinaloa (Autonomous University of Sinaloa), Culiacán, Sinaloa, Mexico
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  • Luis O. Frias-Castro MD,

    1. Department of Dermatology, Faculty of Medicine, Universidad Autónoma de Sinaloa (Autonomous University of Sinaloa), Culiacán, Sinaloa, Mexico
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  • Francisco Vargas-Ocampo MD, MSc

    1. Laboratorio de dermatopatologia, Instituto de Diagnóstico y Referencia Epidemiológicos (InDRE [Institute of Epidemiological Diagnosis and Reference]), Mexico City, Mexico
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  • Funding: This work was supported in part by a University Cancer Foundation grant from the University of Texas MD Anderson Cancer Center (MDACC) to XYH and a National Institutes of Health (NIH) grant (CA16672) to the MDACC histology core facility.

  • Conflicts of interest: None.

Xiang Y. Han, md, Phd
Department of Laboratory Medicine, Unit 84
University of Texas MD Anderson Cancer Center
1515 Holcombe Boulevard
Houston
Texas 77030
USA
E-mail: xhan@mdanderson.org

Abstract

Background  Mycobacterium leprae was the only known cause of leprosy until 2008, when a new species, named Mycobacterium lepromatosis, was found to cause diffuse lepromatous leprosy (DLL), a unique form of leprosy endemic in Mexico.

Methods  We sought to differentiate the leprosy agents among 120 Mexican patients with various clinical forms of leprosy and to compare their relative prevalences and disease features. Archived skin biopsy specimens from these patients were tested for both M. leprae and M. lepromatosis using polymerase chain reaction-based species-specific assays.

Results  Etiologic species were confirmed in 87 (72.5%) patients, of whom 55 were infected with M. lepromatosis, 18 with M. leprae, and 14 with both organisms. The endemic regions of each agent differed but overlapped. Patients with M. lepromatosis were younger and were distributed across more states; their clinical diagnoses included DLL (n = 13), lepromatous leprosy (LL) (n = 34), and eight other forms of leprosy. By contrast, the diagnoses of patients with M. leprae did not include DLL but did include LL (n = 15) and three other forms of leprosy. Thus, M. lepromatosis caused DLL specifically (P = 0.023). Patients with M. lepromatosis also showed more variable skin lesions; the extremities were the most common sites of biopsy in these patients. Finally, patients with dual infections manifested all clinical forms and accounted for 16.1% of all species-confirmed cases.

Conclusions  Mycobacterium lepromatosis is another cause of leprosy and is probably more prevalent than M. leprae in Mexico. It mainly causes LL and also specifically DLL. Dual infections caused by both species may occur in endemic areas.

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