Non-tuberculous cutaneous mycobacterioses

Abstract

Non-tuberculous mycobacteriosis, previously known as atypical, anonymous, opportunistic, or unclassified mycobacteriosis, refers to pathogenic mycobacterioses other than those caused by Mycobacterium tuberculosis and Mycobacterium leprae. These mycobacteria are known for their environmental distribution, mainly in water and soil. The incidence of non-tuberculous mycobacteriosis has been increasing in all countries and skin infections are being increasingly studied, mainly with the increase in immunosuppressive conditions and the development of new medications that affect immunological function. In the present article, a detailed narrative review of the literature is carried out to study the main non-tuberculous mycobacteriosis that cause diseases of the skin and appendages. The article also aims to present a historical context, followed by epidemiological, microbiological, and clinical characteristics of these diseases. Practical considerations about the diagnosis and treatment of non-tuberculous mycobacteriosis are detailed.

Keywords: Culture media; Diagnosis; Molecular biology; Mycobacterium infections, nontuberculous.

Figure 1

Non-tuberculous cutaneous mycobacteriosis caused by Mycobacterium chelonae in a child diagnosed by culture in Löwenstein-Jensen medium (identification by partial genetic sequencing of the rpoB gene). Treatment with monotherapy using clarithromycin resulted in complete cure.

Figure 2

Adverse reaction to Bacillus Calmette-Guérin (BCG) vaccination. (A), Three months after the vaccination, showing regional axillary adenomegaly. (B), Four months after the vaccination with increased lymph node enlargement. (C), Five months after the vaccination with abscess formation. (D), Six months after the vaccination, with suppurative lesion.

Figure 3

Non-specific granulomatous reaction caused by Mycobacterium fortuitum in an immunocompetent patient (Hematoxylin & eosin, ×40). Diagnosis was performed by amplification and partial genetic sequencing of the rpoB gene. Detection of mycobacteria can be hindered by the extensive granulomatous reaction.

Figure 4

Cutaneous mycobacteriosis caused by Mycobacterium haemophilum in an immunosuppressed patient caused by the use of infliximab for 15 years. Intense infiltration, predominantly constituted of histiocytes, can be seen at the dermo-hypodermic junction, permeated by lymphocytes and neutrophils, but without forming halos, nodules, suppurative foci. Staining: Hematoxylin & eosin; diagnosis carried out by amplification and partial genetic sequencing of the folP1 gene. (A), Panniculitis, ×4; (B), Poorly organized granuloma, ×20; (C), Detail of lymphohistiocytic infiltrate, ×40; (D), Panniculitis with nodular outline, ×10.

Figure 5

Non-tuberculous cutaneous mycobacteriosis. Polymerase chain reaction was positive for Mycobacterium sp. and negative for Mycobacterium tuberculosis specific primers. The genetic sequencing was inconclusive. The condition showed complete cure after treatment using a regimen for pulmonary tuberculosis associated with clarithromycin.

Figure 6

Cutaneous mycobacteriosis by Mycobacterium fortuitum, similar to lupus vulgaris. Diagnosis was performed by amplification and partial genetic sequencing of the rpoB gene.