Phylum Actinobacteria, Class Actinobacteria, Order Actinomycetales, Suborder Corynebacterineae, Family Mycobacteriaceae, Genus
Mycobacterium, Mycobacterium riyadhense van Ingen et al. 2009.
Species description is based on a single isolate.
Colonies are rough and white after 28 days of incubation at 36 ºC on Middlebrook
7H10, Ogawa and Stonebrink media; growth is slower at 25 and 30 ºC and no growth
occurs at 42 ºC. No growth on MacConkey agar, p-nitrobenzoic acid, hydroxylamine
and oleic acid.
Isolated from maxillary sinus lavage fluid of 19-year-old male in Riyadh, Saudi Arabia.
Resistant to thiophene-2-carboxylic acid hydrazide (TCH), thiacetazone, amikacin (10 μg/ml) and p-aminosalicylate (1 μg/ml).
Intermediate to isoniazid (1 μg/ml). Susceptible to rifampicin (0.2 μg/ml), rifabutin (0.2 μg/ml), ethambutol (5 μg/ml), clarithromycin (2
μg/ml), ciprofloxacin (2 μg/ml), cycloserine (20 μg/ml), prothionamide (1 μg/ml), clofazimine (0.5 μg/ml) and streptomycin (5 μg/ml) and
hydroxylamine (1 μg/ml).
- Van Ingen J, Al-Hajoj SA, Boeree M, Al-Rabiah F, Enaimi M, de Zwaan R, Tortoli E, Dekhuijzen R, van Soolingen D. Mycobacterium
riyadhense sp. nov., a non-tuberculous species identified as Mycobacterium tuberculosis complex by a commercial line-probe
assay. Int J Syst Evol Microbiol 2009; 59:1049-1053.
Positive results for arylsulfatase (3 days), semiquantitative catalase test, nitrate reduction, Tween 80 hydrolysis, and urease.
Negative results for heat-stable catalase (68 ºC), niacin accumulation, beta-glucosidase, and tellurite reduction.
(c) Costin Stoica