Mycobacterium haemophilum

Mycobacterium haemophilum is a species of bacteria belonging to the genus Mycobacterium. It is a slow-growing, nontuberculous mycobacterium that was first isolated in 1978. This pathogen is known to cause infections primarily in immunocompromised individuals, such as those with HIV/AIDS, cancer patients undergoing chemotherapy, and recipients of organ transplants. Mycobacterium haemophilum is notable for its requirement of hemin or ferric ammonium citrate for growth in culture, a characteristic that distinguishes it from most other mycobacteria.

Epidemiology

Mycobacterium haemophilum infections are relatively rare and have been reported in various parts of the world. The bacterium is thought to be environmentally acquired, but the specific natural reservoir remains unidentified. Infections have been associated with exposure to water sources, suggesting a possible aquatic or soil habitat for the organism.

Clinical Manifestations

Infections caused by Mycobacterium haemophilum can present in multiple forms, depending on the immune status of the host. In immunocompromised patients, it can cause skin and soft tissue infections, presenting as nodules, ulcers, or abscesses. It can also lead to pulmonary infections, lymphadenitis, and disseminated disease affecting multiple organs. In contrast, immunocompetent individuals may experience localized skin infections without systemic involvement.

Diagnosis

Diagnosing Mycobacterium haemophilum infections can be challenging due to its fastidious growth requirements. Culture of the organism requires media supplemented with hemin or ferric ammonium citrate at lower temperatures (30-32°C) than those used for other mycobacteria. Molecular methods, such as PCR, can be used to identify the DNA of Mycobacterium haemophilum directly from clinical specimens, offering a more rapid diagnosis.

Treatment

Treatment of Mycobacterium haemophilum infections typically involves a combination of antibiotics for an extended period, often including clarithromycin or azithromycin combined with rifampicin, ciprofloxacin, or other antimycobacterial agents. The choice of antibiotics and duration of treatment depend on the site and severity of the infection, as well as the patient's immune status.

Prevention

Preventive measures for Mycobacterium haemophilum infections are not well established due to the limited understanding of its transmission and environmental reservoirs. However, immunocompromised individuals should avoid exposure to potential sources of infection, such as unchlorinated water or soil.

See Also

• Mycobacterium
• Nontuberculous mycobacteria
• Immunocompromised host

References

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