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a genus of bacteria, related to actinomycetes; it differs from true bacteria in a number of ways. The young vegetative cells are rodlike (0.5–0.8 × 2.2 microns); they are capable of branching and acquiring V or Y shapes. In old cultures spherical cells predominate. Mycobacteria, which do not form endospores, are nonmotile, gram-positive, and strictly aerobic. They reproduce mainly by dividing and budding. Mycobacteria contain carotenoids, and, as a result, their colonies are often pigmented (yellow, orange, or red). Owing to their cell composition (including lipides and wax), some myco-bacteria, in contrast to other bacteria, are acid-fast.

Mycobacteria are widely distributed in soils and are active in the mineralization of plant remains. Some species of Mycobacterium are nitrogen-fixing microorganisms; others are capable of metabolizing the carbohydrates of petroleum and natural gas and, when cultured, accumulate protein, which is used for fodder and other purposes. Some species of Mycobacterium are pathogenic to humans (for example, mycobacteria are the causative agents of tuberculosis and leprosy).


References in periodicals archive ?
Bloom, "Tuberculosis and other mycobacterial disease," in Textbook of Respiratory Medicine, J.
Griffith, "Pulmonary non-tuberculous mycobacterial infections," International Journal of Tuberculosis and Lung Disease, vol.
There is no doubt that BACTEC MGIT 960 provides a solution for the reliable and rapid diagnosis of tuberculosis, while the mycobacterial growth in liquid culture can go undetected by this automatic detection system [6].
Primary immunodeficiency leading to mycobacterial disease.
Thirty two cattle sample were identified based on mycobacterial culture, eleven positive samples, fourteen negative samples and seven doubtful samples.
As noted in the few other existing case reports, nontuberculous mycobacterial infection of the parotid gland is quite rare, especially in adults who are immunocompetent.
In the majority of cases this organism is considered to be nonpathogenic, and it is the most commonly isolated mycobacterial contaminant.
Published reports regarding the management of mycobacterial infections in the peritoneal dialysis patient population are scarce.
In cases where mycobacterial infection is suspected but the Ziehl-Neelsen stain is negative, it may be useful to perform a Fite stain, which differs in that tissue sections are deparaffinized using a mixture of mineral oil and xylene rather than xylene alone.
Pathologic examination of granulation tissue obtained from the ear canal revealed chronic inflammation with multinucleated giant cells, which suggested a mycobacterial infection (figure 1).