Mycobacterium chelonae
Cultural characteristics
Biochemical characters
Phylum Actinobacteria, Class Actinobacteria, Order Actinomycetales, Suborder Corynebacterineae, Family Mycobacteriaceae, Genus
Mycobacterium chelonae (Bergey et al. 1923) Gupta et al. 2018, three subspecies:
Mycobacterium chelonae subsp. bovis Kim et al. 2017,
Mycobacterium chelonae subsp. chelonae corrig. (Bergey et al. 1923) Kubica et al. 1972,
Mycobacterium chelonae subsp. gwanakae Kim et al. 2018.

Synonym (incorrect name): "Mycobacterium chelonei
" Bergey et al. 1923, possible synonyms: “Mycobacterium borstelense”,
"Mycobacterium friedmannii", "Mycobacterium runyonii".
Subsp. bovis: acid-fast rods, frequently curved. Gram-staining positive. Non-motile. Nonspore forming.

Subsp. chelonae: strongly acid-fast, pleomorphic rods, ranging from long and narrow to short and thick (1-6 x 0.2-0.5 μm), with coccoid
forms (0.5 μm). In cultures older than 5-days non-acid-fast forms begin to develop. Mycelia not formed. No cord fomation.

Subsp. gwanakae: acid-fast cells; generally rod-shaped and frequently curved.
Subsp. bovis: colonies on Middlebrook 7H10 agar medium, after 5 days incubation  
are white and rough.

Subsp. chelonae: colonies may be smooth, moist, and shiny or rough. They are
usually nonchromogenic to creamy buff in color and are produced from dilute inocula
after incubation for 3-4 days on most media.Temperature range for growth is 22-40
ºC. Some strains may not grow (or may grow poorly) at temperatures of 37
ºC or
higher; does not grow at 42 or 45 ºC. No growth on media supplemented with5% (w/v)
NaCl.  No growth on Sauton agar containing 0.2% picric acid. Grows on MacConkey
agar without crystal violet.

Subsp. gwanakae: colonies on Middlebrook 7H10 agar medium, after 5-7 days
incubation are white and smooth. Grows well at 30 ºC, but not at 45 ºC.
Subsp. bovis: isolated from the lymph nodes of Korean native cattle (3 strains),
Hanwoo (
Bos taurus coreanae).

Subsp. chelonae: first has been isolated from tortois tubercle, later from sputum
(rarely), clinical samples and soil. Also isolated from three Knysna seahorses
Hippocampus capensis) in South Africa.
Resistant to tiophene-2-carboxylic acid hydrazide (1 µg/ml),  hydroxylamine  (500
µg/ml), ethambutol (5 µg/ml), rifampicin (25 µg/ml), streptomycin, and isoniazid.

Subsp. gwanakae: isolated from sputum in Korean patients.
Subsp. chelonae: may be involved in cervical adenitis, corneal infections, prosthetic valve endocarditis, and post-operative infections.
May produce granulomatous lesions and ulcers to aquatic animals.

Subsp. gwanakae: isolated from patients with pulmonary disease.
  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. Kim BJ, Kim BR, Jeong J, Lim JH, Park SH, Lee SH, Kim CK, Kook YH, Kim BJ. A description of Mycobacterium chelonae subsp.
    gwanakae subsp. nov., a rapidly growing mycobacterium with a smooth colony phenotype due to glycopeptidolipids. Int J Syst Evol
    Microbiol 2018; 68:3772-3780.
  4. Tsukamura M, Yano I, Imaeda T. Mycobacterium fortuitum subspecies acetamidolyticum, a new subspecies of Mycobacterium
    fortuitum. Microbiol Immunol 1986; 30:97-110.
  5. 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.
  6. Michio Tsukamura. A Review of the Methods of Identification and Differentiation of Mycobacteria. Reviews of Infectious Diseases,
    Vol. 3, No. 5, International Conference on Atypical Mycobacteria (Sep. - Oct., 1981), pp. 841-861.
  7. 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.
  8. 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.
  9. Gcebe, N., Michel, A.L. & Hlokwe, T.M. Non-tuberculous Mycobacterium species causing mycobacteriosis in farmed aquatic
    animals of South Africa. BMC Microbiol 18, 32 (2018).
Common characters using API ZYM (bioMerieux):
Positive results for esterase (C4), esterase lipase (C8), leucine arylamidase, acid phosphatase, beta galactosidase (weak results),
naphthol-AS-BI-phosphohydrolase, alpha- and beta-glucosidase, and valine arylamidase (weak results).
Negative results for trypsin, alpha-chymotrypsin, alpha-galactosidase, beta-glucuronidase, N-acetyl-beta-glucosaminidase and

Subsp. chelonae (classical identification characters):
Positive results for arylsulfatase (3  and 7 days), catalase inactivated at 68 ºC (most strains), semiquantitative catalase test,
beta-esterase, beta-galactosidase, nicotinamidase, pyrazinamidase and urea hydrolysis.
Can utilize citrate, succinate, glucose, acetate, pyruvate as sole carbon source in the presence of ammonia.
Negative results for niacin accumulation, nitrate reduction, and iron uptake.
No utilization of benzoate, malonate, mannitol, sorbitol, mio-inositol, ethanol, n-propanol, n-butanol, galactose, arabinose, and xylose.
Variable results for acid phosphatase, alpha-esterase, tellurite reduction, Tween 80 hydrolysis, fumarate, malate  and trehalose
(c) Costin Stoica
Culture media
Biochemical tests
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