Cutaneous Mycobacterial Infections.

Humans encounter mycobacterial species due to their ubiquity in different environmental niches. In many individuals, pathogenic mycobacterial species may breach our first-line barrier defenses of the innate immune system and modulate the activation of phagocytes to cause disease of the respiratory tract or the skin and soft tissues, sometimes resulting in disseminated infection. Cutaneous mycobacterial infections may cause a wide range of clinical manifestations, which are divided into four main disease categories: (i) cutaneous manifestations of Mycobacterium tuberculosis infection, (ii) Buruli ulcer caused by Mycobacterium ulcerans and other related slowly growing mycobacteria, (iii) leprosy caused by Mycobacterium leprae and Mycobacterium lepromatosis, and (iv) cutaneous infections caused by rapidly growing mycobacteria. Clinically, cutaneous mycobacterial infections present with widely different clinical presentations, including cellulitis, nonhealing ulcers, subacute or chronic nodular lesions, abscesses, superficial lymphadenitis, verrucous lesions, and other types of findings. Mycobacterial infections of the skin and subcutaneous tissue are associated with important stigma, deformity, and disability. Geography-based environmental exposures influence the epidemiology of cutaneous mycobacterial infections. Cutaneous tuberculosis exhibits different clinical phenotypes acquired through different routes, including via extrinsic inoculation of the tuberculous bacilli and dissemination to the skin from other sites, or represents hypersensitivity reactions to M. tuberculosis infection. In many settings, leprosy remains an important cause of neurological impairment, deformity, limb loss, and stigma. Mycobacterium lepromatosis, a mycobacterial species related to M. leprae, is linked to diffuse lepromatous leprosy of Lucio and Latapí. Mycobacterium ulcerans produces a mycolactone toxin that leads to subcutaneous tissue destruction and immunosuppression, resulting in deep ulcerations that often produce substantial disfigurement and disability. Mycobacterium marinum, a close relative of M. ulcerans, is an important cause of cutaneous sporotrichoid nodular lymphangitic lesions. Among patients with advanced immunosuppression, Mycobacterium kansasii, the Mycobacterium avium-intracellulare complex, and Mycobacterium haemophilum may cause cutaneous or disseminated disease. Rapidly growing mycobacteria, including the Mycobacterium abscessus group, Mycobacterium chelonei, and Mycobacterium fortuitum, are increasingly recognized pathogens in cutaneous infections associated particularly with plastic surgery and cosmetic procedures. Skin biopsies of cutaneous lesions to identify acid-fast staining bacilli and cultures represent the cornerstone of diagnosis. Additionally, histopathological evaluation of skin biopsy specimens may be useful in identifying leprosy, Buruli ulcer, and cutaneous tuberculosis. Molecular assays are useful in some cases. The treatment for cutaneous mycobacterial infections depends on the specific pathogen and therefore requires a careful consideration of antimicrobial choices based on official treatment guidelines.

Zoonotic Leprosy in the Southeastern United States.

Nine-banded armadillos (Dasypus novemcinctus) are naturally infected with Mycobacterium leprae and have been implicated in zoonotic transmission of leprosy. Early studies found this disease mainly in Texas and Louisiana, but armadillos in the southeastern United States appeared to be free of infection. We screened 645 armadillos from 8 locations in the southeastern United States not known to harbor enzootic leprosy for M. leprae DNA and antibodies. We found M. leprae-infected armadillos at each location, and 106 (16.4%) animals had serologic/PCR evidence of infection. Using single-nucleotide polymorphism variable number tandem repeat genotyping/genome sequencing, we detected M. leprae genotype 3I-2-v1 among 35 armadillos. Seven armadillos harbored a newly identified genotype (3I-2-v15). In comparison, 52 human patients from the same region were infected with 31 M. leprae types. However, 42.3% (22/52) of patients were infected with 1 of the 2 M. leprae genotype strains associated with armadillos. The geographic range and complexity of zoonotic leprosy is expanding.

Indigenous Cases of Leprosy (Hansen's Disease) in Southern Mississippi.

Hansen's disease or leprosy is a chronic infection of the skin and peripheral nerves caused by Mycobacterium leprae. In the U.S., leprosy is mainly reported in immigrants, but indigenous leprosy cases have been also reported in this country, especially in semitropical southern states (i.e., Texas, Louisiana). The objective of this series of cases is to describe indigenous leprosy cases reported in southern Mississippi (MS) during the period 2012-2014. Information was collected from medical records at Hattiesburg Clinic and the MS Department of Health. Four cases were reported during the period of study (3 Caucasian males, 1 African-American woman). Non of visited endemic leprosy country. The age ranged from 60 to 83 years (median: 75.5 years). Of the four cases, three presented with a slowly progressive erythematous rash disseminated mainly on the thorax and abdomen, with a lesser degree on the extremities. The time between onset of rash until the diagnosis ranged from 5 to 16 months (median: 7 months). Only one case had direct contact with armadillos (blood exposure). Non of these patients had a history of immunosuppression. The most common symptoms were neuropathic pain (n=2), generalized pruritus (n=2) and loss of sensation in extremities (n=2). One case had severe peripheral neuropathy with muscle weakness, atrophy in left arm, and wasting on left hand. Skin biopsies showed diffuse granulomatous infiltrate with foamy histiocytes along with acid fast bacilli by Fite stain. By Ridley-Jopling classification system, three cases were diagnosis as lepromatous leprosy, and one, borderline lepromatous. Treatment included clofazimine, dapsone and rifampin that was offered free of charge by the National Hansen's Diseases Program, Baton Rouge, L.A. One patient did not tolerate therapy. In conclusion, a slowly progressive disseminated erythematous skin rash on the trunk should raise suspicion for leprosy in the elderly population in south MS.