Mycobacterium kansasii

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Mycobacterium kansasii
Scientific classification
Kingdom: Bacteria Phylum: Actinobacteria Order: Actinomycetales Suborder: Corynebacterineae Family: Mycobacteriaceae Genus: Mycobacterium Species: M. kansasii
Binomial name
Mycobacterium kansasii Hauduroy 1955, ATCC 12478

Mycobacterium kansasii

Contents 1 Description 2 Pathogenesis 3 Type Strain 4 References

[edit] Description

Gram-positive, nonmotile, moderately long to long and acid-fast rods.

Colony characteristics

• Smooth to rough colonies after 7 or more days of incubation.
• Colonies grown in dark are nonpigmented, when grown in light or when young colonies are exposed briefly to light, colonies become brilliant yellow (photochromogenic).
• If grown in a lighted incubator, most strains form dark red crystals of β-carotene on the surface and inside of colony.

Physiology

• Growth on Middlebrook 7H10 agar at 37°C within 7 days or more.
• Resistant to pyrazinamide.
• Susceptible to ethambutol.

Differential characteristics

• Closely related to the non-pathogenic, also slowly growing, nonpigmented, M. gastri.
• Both species share an identical 16S rDNA but differentiation is possible by differences in the ITS and hsp65 sequences
• A commercial hybridisation assay (AccuProbe) to identify M. kansasii exists.

[edit] Pathogenesis

• Chronic human pulmonary disease resembling tuberculosis (involvement of the upper lobe).
• Extrapulmonary infections, (cervical lymphadenitis in children, cutaneous and soft tissues infections and musculoskeletal system involvement), are uncommon.
• Rarely causes disseminated disease except in patients with severely impaired cellular immunity (patients with organ transplants or AIDS).
• Normally considered not to be contagious from person to person.
• Natural sources of infections unclear. Tap water is believed to be the major reservoir associated with human disease.
• Biosafety level 2

[edit] Type Strain

• First and most frequently isolated from human pulmonary secretions and lesions.

Strain ATCC 12478 = CIP 104589 = DSM 44162 = JCM 6379 = NCTC 13024.

[edit] References

• Hauduroy,P. 1955. Derniers aspects du monde des mycobactéries. Masson et Cie, Paris, 1955.