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Mycobacterial Infections

»	What is the classification system of mycobacteria?
»	What are the staining characteristics of mycobacteria?
»	How many species of Mycobacterium cause infection in human beings?
»	Name three mycobacteria in the tuberculosis complex responsible for tuberculosis.
»	What is tuberculosis?
»	What is the difference between a primary and secondary infection?
»	Explain the route of infection in cutaneous tuberculosis.
»	Who is at risk of acquiring tuberculosis?
»	Describe the histopathologic hallmark of tuberculosis.
»	How can one acquire primary cutaneous tuberculosis?
»	Describe the clinical manifestation of primary-inoculation cutaneous tuberculosis.
»	What are the different types of cutaneous tuberculosis?
»	What laboratory tests are used to diagnose Mycobacterium tuberculosis?
»	Is lupus vulgaris related to lupus erythematosus or lupus pernio?
»	Describe the clinical manifestations of lupus vulgaris.
»	Where and when does lupus vulgaris develop?
»	What is scrofuloderma?
»	Name the vaccination against tuberculosis. What type of vaccination is it?
»	What drugs are used in the treatment of tuberculosis?
»	What are the major side effects of antituberculous agents?
»	What factors have led to multidrug-resistant tuberculosis?
»	Are there any special treatment considerations for cutaneous tuberculosis?
»	What is the mechanism of action of TNF-a in tuberculosis?
»	Describe the pathogenesis of the atypical mycobacteria.
»	Describe the pathogenesis of the atypical mycobacteria.
»	What is a “swimming pool granuloma”?
»	What is a Buruli ulcer?
»	Describe the clinical manifestations of Mycobacterium avium-intracellulare complex (MAC) in both non-AIDS and AIDS patients.
»	Which atypical mycobacteria are associated with mesotherapy?
»	Which atypical mycobacteria are associated with tattoos?
»	Which atypical mycobacteria have been associated with soft tissue fillers?
»	How are infections with rapidly growing mycobacteria managed?
»	What are some of the key features of Mycobacterium kansasii?

What is the classification system of mycobacteria?

A, M. scrofulaceum. The slow-growing colonies that are forming yellowish-orange pigment without light (scotochromogen). B, M. chelonei. Rapid-growing colonies (within 7 days) without evidence of pigment production (rapid grower). (Courtesy of the Fitzsimons Army Medical Center teaching files.)

Fig. 30.1 A, M. scrofulaceum. The slow-growing colonies that are forming yellowish-orange pigment without light (scotochromogen). B, M. chelonei. Rapid-growing colonies (within 7 days) without evidence of pigment production (rapid grower). (Courtesy of the Fitzsimons Army Medical Center teaching files.)

Extensive taxonomic work has been done to classify the more than 60 species of organisms belonging to the genus Mycobacterium. In the 1950s, Runyon classified the atypical mycobacteria based on their rate of growth, ability to form pigment, and colony characteristics (Fig. 30-1). The Runyon classification may also include distinctions among obligate human pathogens requiring direct person-to-person transmission, facultative human pathogens found in the environment that are rarely responsible for direct person-to-person spread, and nonpathogens (Table 30-1).

Table 30-1. Classification of Pathogenic Mycobacteria
	CLASSIFICATION	OBLIGATE HUMAN PATHOGEN	FACULTATIVE HUMAN PATHOGEN
	Slow Growers
	M. tuberculosis complex
	M. tuberculosis	×
	M. bovis	×
	M. africanum	×
	M. mycoti	×
	Photochromogens (Runyon Group 1) Form Yellow-Orange or Rust Pigment with Light
	M. kansasii		×
	M. marinum		×
	M. simiae complex (M. simiae, M. triplex, M. genavense, M. heidelbergense, and M. lentiflavum)		×
	Others include M. intermedium, and M. asiaticum		×
	Scotochromogens (Runyon Group 2) Form Light Yellow to Orange Pigment with and without Light
	M. scrofulaceum		×
	M. szulgai		×
	Others include M. injectum, M. lentiflavum, M. gordonae		×
	Nonchromogens (Runyon Group 3) Unable to Form Pigment
	M. avium-intracellulare complex (M. avium, M. intracellulare, and other unidentified species)		×
	M. haemophilum		×
	M. xenopi		×
	M. ulcerans		×
	Others include M. celatum, M. genavense, M. gastri, and M. malmoense		×
	Rapid Growers (Runyon Group 4) Growth within 7 Days
	M. fortuitum		×
	M. abscessus		×
	M. chelonei ssp. chelonei, abscessus, unnamed subspecies		×
	Others include M. phlei, M. smegmatis, M. fredericksbergense		×
	Noncultivable Unable to Cultivate in Media
	M. leprae	×

	Data from Bhambri S, Bhambri A, Del Rosso JQ: Atypical mycobacterial cutaneous infections, Dermatol Clin 27(1):63–73, 2009.