Mycobacterium tuberculosis, also known as Koch's bacillus, is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, M. tuberculosis has an unusual, waxy coating on its cell surface primarily due to the presence of mycolic acid. This coating makes the cells impervious to Gram staining, and as a result, M. tuberculosis can appear weakly Gram-positive. Acid-fast stains such as Ziehl–Neelsen, or fluorescent stains such as auramine are used instead to identify M. tuberculosis with a microscope. The physiology of M. tuberculosis is highly aerobic and requires high levels of oxygen. Primarily a pathogen of the mammalian respiratory system, it infects the lungs. The most frequently used diagnostic methods for tuberculosis are the tuberculin skin test, acid-fast stain, culture, and polymerase chain reaction.
Mycobacterium is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis and leprosy in humans. The Greek prefix myco- means 'fungus', alluding to this genus' mold-like colony surfaces. Since this genus has cell walls with Gram-positive and Gram-negative features, acid-fast staining is used to emphasize their resistance to acids, compared to other cell types.
A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious organisms including bacteria and fungi, as well as other materials such as foreign objects, keratin, and suture fragments.
Mycobacterium leprae, is one of the two species of bacteria that cause Hansen’s disease (leprosy), a chronic but curable infectious disease that damages the peripheral nerves and targets the skin, eyes, nose, and muscles.
Cutibacterium acnes is the relatively slow-growing, typically aerotolerant anaerobic, gram-positive bacterium (rod) linked to the skin condition of acne; it can also cause chronic blepharitis and endophthalmitis, the latter particularly following intraocular surgery. Its genome has been sequenced and a study has shown several genes can generate enzymes for degrading skin and proteins that may be immunogenic.
Nontuberculous mycobacteria (NTM), also known as environmental mycobacteria, atypical mycobacteria and mycobacteria other than tuberculosis (MOTT), are mycobacteria which do not cause tuberculosis or leprosy. NTM do cause pulmonary diseases that resemble tuberculosis. Mycobacteriosis is any of these illnesses, usually meant to exclude tuberculosis. They occur in many animals, including humans and are commonly found in soil and water.
Buruli ulcer is an infectious disease characterized by the development of painless open wounds. The disease is limited to certain areas of the world, most cases occurring in Sub-Saharan Africa and Australia. The first sign of infection is a small painless nodule or area of swelling, typically on the arms or legs. The nodule grows larger over days to weeks, eventually forming an open ulcer. Deep ulcers can cause scarring of muscles and tendons, resulting in permanent disability.
Mycobacterium marinum is a slow growing mycobacterium (SGM) belonging to the genus Mycobacterium and the phylum Actinobacteria. The strain marinum was first identified by Aronson in 1926 and it is observed as a pathogenic mycobacterium. For example, tuberculosis like infections in fish (mycobacteriosis) and skin lesions in humans.
Mycobacteroides abscessus is a species of rapidly growing, multidrug-resistant, nontuberculous mycobacteria that is a common soil and water contaminant. Although M. abscessus most commonly causes chronic lung infection and skin and soft tissue infection (SSTI), it can also cause infection in almost all human organs, mostly in patients with suppressed immune systems. Amongst NTM species responsible for disease, infection caused by M. abscessus complex are more difficult to treat due to antimicrobial drug resistance.
Mycobacterium boenickei is a member of the Mycobacterium fortuitum third biovariant complex. They are rapidly growing ubiquitous environmental organisms that normally inhabit soil, dust and water. These organisms frequently are human pathogens that cause a wide spectrum of clinically significant disease. It is important for practitioners to be aware of these organisms as possible etiological agents, as they are resistant to most first-line anti-tuberculous agents.
Mycobacterium brisbanense is a member of the Mycobacterium fortuitum third biovariant complex. They are rapidly growing ubiquitous environmental organisms that normally inhabit soil, dust and water. These organisms frequently are human pathogens that cause a wide spectrum of clinically significant disease. It is important for practitioners to be aware of these organisms as possible etiological agents, as they are resistant to most first-line anti-tuberculous agents.
Mycobacteroides chelonae is a species of bacteria from the phylum Actinomycetota belonging to the genus Mycobacteroides. Mycobacteroides chelonae is a rapidly growing mycobacterium that is found all throughout the environment, including sewage and tap water. It can occasionally cause opportunistic infections of humans.
Mycobacterium cosmeticum is a rapidly growing mycobacterium that was first isolated from cosmetic patients and sites performing cosmetic procedures.
Mycobacterium elephantis, a bacterium of the family Mycobacteriaceae, was discovered and isolated from a deceased elephant near India and may be linked to respiratory dysfunction. Organisms in the genus Mycobacterium are known to be aerobic and non-motile. Organisms within Mycobacterium belong to either the rapid growing group or the slow growing group. M. elephantis is classified as a rapid grower and relates most closely to Mycobacterium confluentis and Mycobacterium phlei.
Mycobacterium gastri is a species of the phylum Actinomycetota, belonging to the genus Mycobacterium.
Mycobacterium hassiacum is a rapid-growing thermophilic mycobacterium that was isolated in human urine in 1997 by researchers at the German University of Regensburg. It's a species of the phylum Actinomycetota, belonging to the genus Mycobacterium.
Mycobacterium avium complex is a group of mycobacteria comprising Mycobacterium intracellulare and Mycobacterium avium that are commonly grouped because they infect humans together; this group, in turn, is part of the group of nontuberculous mycobacteria. These bacteria cause Mycobacterium avium-intracellulare infections or Mycobacterium avium complex infections in humans. These bacteria are common and are found in fresh and salt water, in household dust and in soil. MAC bacteria usually cause infection in those who are immunocompromised or those with severe lung disease.
Mycobacterium kansasii is a bacterium in the Mycobacterium genus. It is an environmental bacteria that causes opportunistic infections in humans, and is the one of the leading mycobacterial causes of human disease after tuberculosis and leprosy.
Mycobacterium triplex is a species of Mycobacterium.
Mycolicibacter terrae is a slow-growing species of mycobacteria. It is an ungrouped member of the third Runyon. It is known to cause serious skin infections, which are "relatively resistant to antibiotic therapy".
