Runyon classification
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
The Runyon classification of nontuberculous mycobacteria based on the rate of growth, production of yellow pigment and whether this pigment was produced in the dark or only after exposure to light.[1] It was introduced by Ernest Runyon in 1959.[2] On these bases, the nontuberculous mycobacteria are divided into four Runyon groups. The first three groups (Runyon I, II, and III) are classified as slowly growing mycobacteria.
Runyon I: Photochromogens
Runyon I organisms are slow growing, and produce a yellow-orange pigment when exposed to light.
- Mycobacterium intermedium
- Mycobacterium simiae
- Mycobacterium szulgai (photochromogenic when grown at 24 degrees and scotochromogenic at 37 degrees)
Yellow and smooth
Yellow and rough
Runyon II: Scotochromogens
Runyon II organisms are slow-growing and produce a yellow-orange pigment regardless of whether they are grown in the dark or the light.
- Mycobacterium scrofulaceum
- Mycobacterium szulgai (photochromogenic when grown at 24 degrees and scotochromogenic at 37 degrees)
Yellow
- Mycobacterium conspicuum
- Mycobacterium botniense
- Mycobacterium farcinogenes
- Mycobacterium heckeshornense
- Mycobacterium interjectum
- Mycobacterium kubicae
- Mycobacterium lentiflavum
- Mycobacterium nebraskense
- Mycobacterium nebraskense
- Mycobacterium palustre
- Mycobacterium tusciae
Yellow-Orange
Rose-Pink
Runyon III: Nonchromogens
Runyon III organisms are slow-growing and never produce pigment, regardless of culture conditions.
Rough
- Mycobacterium africanum
- Mycobacterium bovis
- Mycobacterium caprae
- Mycobacterium lacus
- Mycobacterium lepraemurium
- Mycobacterium microti
- Mycobacterium pinnipedii
- Mycobacterium shottsii
- Mycobacterium tuberculosis
Smooth
- Mycobacterium branderi
- Mycobacterium heidelbergense
- Mycobacterium intracellulare
- Mycobacterium malmoense
Smooth to rough
Small and Transparent
- Mycobacterium avium avium
- Mycobacterium avium paratuberculosis
- Mycobacterium avium silvaticum
- Mycobacterium genavense
- Mycobacterium montefiorense
- Mycobacterium ulcerans
Runyon IV: Rapid Growers
Runyon IV organisms are rapid growing for mycobacteria (colonies in 5 days). They do not produce pigment. Some rapidly growing mycobacteria are considered “late-pigmenting”.[3]
- Mycobacterium abscessus
- Mycobacterium chelonae
- Mycobacterium fortuitum
- Mycobacterium peregrinum
- Mycobacterium thermoresistibile
References
- ↑ Rogall T, Wolters J, Flohr T, Böttger EC (October 1990). “Towards a phylogeny and definition of species at the molecular level within the genus Mycobacterium”. International journal of systematic bacteriology. 40 (4): 323–30. doi:10.1099/00207713-40-4-323. PMID 2275850.
- ↑ Runyon EH (January 1959). “Anonymous mycobacteria in pulmonary disease”. The Medical clinics of North America. 43 (1): 273–90. PMID 13612432.
- ↑ Brown-Elliott BA, Wallace RJ (October 2002). “Clinical and taxonomic status of pathogenic nonpigmented or late-pigmenting rapidly growing mycobacteria”. Clin. Microbiol. Rev. 15 (4): 716–46. doi:10.1128/cmr.15.4.716-746.2002. PMC 126856. PMID 12364376.
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