Mycobacterium kansasii

File:Mycobacterium kansasii growing on Lowenstein–Jensen medium.jpg

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Mycobacterium kansasii is a species of bacteria in the genus Mycobacterium. It is a slow-growing, non-tuberculous mycobacterium (NTM) that can cause pulmonary disease resembling tuberculosis.

Characteristics

Mycobacterium kansasii is a Gram-positive bacterium that is acid-fast and rod-shaped. It is known for its slow growth rate, typically taking 2-3 weeks to form colonies on solid media. The colonies are usually smooth and pigmented, appearing yellow when exposed to light, a characteristic known as photochromogenicity.

Pathogenesis

Mycobacterium kansasii primarily affects the lungs, causing a chronic pulmonary disease that mimics tuberculosis. Symptoms include chronic cough, hemoptysis, fever, night sweats, and weight loss. It can also cause extrapulmonary infections, although these are less common.

Diagnosis

Diagnosis of Mycobacterium kansasii infection involves microbiological culture and molecular techniques such as polymerase chain reaction (PCR). Chest radiography and computed tomography (CT) scans are used to assess the extent of pulmonary involvement.

Treatment

The treatment of Mycobacterium kansasii infection typically involves a combination of antibiotics over an extended period. The standard regimen includes rifampin, isoniazid, and ethambutol for a duration of 12-18 months. Drug susceptibility testing is recommended to tailor the treatment to the specific strain of Mycobacterium kansasii.

Epidemiology

Mycobacterium kansasii is found worldwide but is more prevalent in certain regions, including the United States, Europe, and South Africa. It is commonly isolated from water sources, including municipal water supplies, which are considered the primary reservoirs for human infection.

Prevention

Preventive measures for Mycobacterium kansasii infection include avoiding exposure to potential environmental sources, particularly for individuals with compromised immune systems. Proper maintenance and disinfection of water systems can also help reduce the risk of infection.

See also

• Mycobacterium avium complex
• Mycobacterium tuberculosis
• Non-tuberculous mycobacteria
• Pulmonary disease