Acid-fast bacilli

species of bacterium

Mycobacterium is a genus of over 190 species of Gram-positive bacteria in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis (M. tuberculosis) and leprosy (M. leprae) in humans. The Greek prefix myco- means 'fungus', alluding to this genus's mold-like colony surfaces. Since this genus has cell walls with a waxy lipid-rich outer layer containing high concentrations of mycolic acid, acid-fast staining is used to emphasize their resistance to acids, compared to other cell types.

species of bacterium; form of leprosy

microbiological method for identification

thumb|Nocardia as found on a brain biopsy. Nocardia is a genus of weakly staining Gram-positive, catalase-positive, rod-shaped bacteria. It forms partially acid-fast beaded branching filaments (appearing similar to fungi, but being truly bacteria). It contains a total of 85 species. Some species are nonpathogenic, while others are responsible for nocardiosis. Nocardia species are found worldwide in soil rich in organic matter. In addition, they are oral microflora found in healthy human gingiva, as well as periodontal pockets. Most Nocardia infections are acquired by inhalation of the bacteria

species of bacterium

thumb|right|320px|Mycobacterium tuberculosis (stained red) in tissue (blue).

species of bacterium

species of bacterium

species of bacterium

nontuberculous bacteria in dust, water, soil; may infect lungs in immunocompromised people

species of bacterium

species of bacterium

histological technique

species of bacterium

species of bacterium