micobacterias

Mycobacteria are a genus of acid-fast, rod-shaped bacteria in the phylum Actinobacteria. They have a thick, lipid-rich cell wall containing mycolic acids, which gives acid-fast staining and resistance to desiccation and many antibiotics. Most species are slow-growing; some rapidly form colonies within seven days.

Most are environmental saprophytes found in soil and water; several species are human pathogens. The medically important groups include the Mycobacterium tuberculosis complex (tuberculosis) and the Mycobacterium leprae complex (leprosy). Non-tuberculous mycobacteria (NTM), such as M. avium complex, M. kansasii, and M. abscessus, cause pulmonary, lymphatic, cutaneous, and disseminated infections, especially in people with lung disease or weakened immunity.

Transmission varies: TB is mainly airborne; leprosy requires prolonged contact; NTMs are usually acquired from the environment and are not commonly transmitted person-to-person.

Diagnosis uses acid-fast staining, culture on Löwenstein-Jensen or Middlebrook media, and molecular methods (PCR, sequencing). Growth can be slow, delaying results, but molecular tests hasten identification and susceptibility testing.

Treatment depends on species. TB regimens use multiple drugs for at least six months; MDR-TB and XDR-TB require longer regimens. Leprosy is treated with multidrug therapy (dapsone, rifampicin, clofazimine) for months to years. NTMs require species-specific regimens guided by susceptibility data, often lengthy.

Public health notes: BCG vaccination is used in some settings; control focuses on early detection, airborne infection control, and antibiotic stewardship; NTMs are increasingly recognized as disease-causing in vulnerable populations. Note: in English the standard plural is mycobacteria; micobacterias is used in some languages.