Mycobacterium flavescens
Cultural characteristics
Biochemical characters
Phylum Actinobacteria, Class Actinobacteria, Order Actinomycetales, Suborder Corynebacterineae, Family Mycobacteriaceae, Genus
Mycobacterium flavescens Bojalil et al. 1962.
Acid-fast rods. Cords are not produced.
Colonies on Lowenstein-Jensen medium after 7-14 days incubation at 25-37 ºC,
usually are soft, yellow-orange, butyrous and  may adhere to the medium. The
temperature range for growth is 25-42 ºC. No growth at 45 ºC. May grow on media
supplemented with 5% (w/v) NaCl. No growth on MacConkey agar.
Isolated from drug-treated tuberculous guinea pig; other isolations as apparent normal flora of humans.
Susceptible to hydroxylamine (250 μg/ml), streptomycin (4.0 μg/ml), isoniazid ((0.25 μg/ml), and ethambutol (1.0 μg/ml). Resistant to
tiophene-2-carboxylic acid hydrazide (1 µg/ml) and rifampicin.
It is not considered a pathogen.
  1. John G. Magee and Alan C. Ward 2012. Family III. Mycobacteriaceae Chester 1897, 63AL in Bergey’s Manual of Systematic
    Bacteriology, Volume Five The Actinobacteria, Part A, Michael Goodfellow & al. (editors), 312-375.
  2. Loredana Gabriela Popa, Mircea Ioan Popa 2009. Identificarea bacililor acido-rezistenti in: Tratat de microbiologie clinica, Dumitru
    Buiuc, Marian Negut, ed. a III-a, Editura Medicala, 881-890, ISBN (13) 978-973-39-0593-6.
  3. Bojalil LF, Cerbon J, Trujillo A. Adansonian classification of mycobacteria. J Gen Microbiol 1962; 28:333-346.
  4. Kubica GP, Baess I, Gordon RE, Jenkins PA, Kwapinski JB, McDurmont C, Pattyn SR, Saito H, Silcox V, Stanford JL, et al. A co-
    operative numerical analysis of rapidly growing mycobacteria. J Gen Microbiol 1972; 73:55-70.
  5. Schroder KH, Naumann L, Kroppenstedt RM, Reischl U. Mycobacterium hassiacum sp. nov., a new rapidly growing thermophilic
    mycobacterium. Int J Syst Bacteriol 1997; 47:86-91.
  6. H. Saito, R. E. Gordon, I. Juhlin, W. Käppler, J. B. G. Kwapinski, C. McDurmont, S. R. Pattyn, E. H. Runyon, J. L. Stanford, I. Tarnok, H.
    Tasaka, M. Tsukamura And J. Weiszfeiler 1977. Cooperative Numerical Analysis of Rapidly Growing Mycobacteria. The Second
    Report. International Journal of Systematic Bacteriology, Apr.1977, p. 75-85.
  7. Tsukamura M, Mizuno S, Tsukamura S. Numerical analysis of rapidly growing, scotochromogenic mycobacteria, including
    Mycobacterium obuense sp. nov., nom. rev., Mycobacterium rhodesiae sp. nov., nom. rev., Mycobacterium aichiense sp. nov., nom.
    rev., Mycobacterium chubuense sp. nov., nom. rev., and Mycobacterium tokaiense sp. nov., nom. rev. Int. J. Syst. Bacteriol. 1981; 31:
  8. Levy-Frebault V, Rafidinarivo E, Prome JC, Grandry J, Boisvert H, David HL. Mycobacterium fallax sp. nov. Int. J. Syst. Bacteriol. 1983;
  9. Stanford JL, Gunthorpe WJ. A study of some fast-growing scotochromogenic mycobacteria including species descriptions of
    Mycobacterium gilvum (new species) and Mycobacterium duvalii (new species). Br J Exp Pathol 1971; 52:627-637.
  10. Kirschner P, Teske A, Schroder KH, Kroppenstedt RM, Wolters J, Bottger EC. Mycobacterium confluentis sp. nov. Int J Syst Bacteriol
    1992; 42:257-262.
Positive results for catalase (inactivated at 68°C), semi-quantitative catalase test, nitrate reduction, nicotinamidase (most strains),
pyrazinamidase, and Tween 80 hydrolysis. Acid is produced from D-mannitol, D-sorbitol and trehalose.
Can utilize citrate (negative in Saito's and Tsukamura's papers), pyruvate, propionate, succinate, malate, and  fumarate as sole
carbon source in the presence of ammonia.

Negative results for niacin production, beta-galactosidase, and iron uptake.
No utilization of benzoate.

Variable results for acid phosphatase, arylsulphatase (3 and 10 days), alpha-esterase, tellurite reduction and urease.
(c) Costin Stoica
Culture media
Biochemical tests
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