Actinomycetes are a group of bacteria that are both saprophytic and pathogenic. They are found in soil, water, and air, and are best known for their biochemical production of antibiotics. Actinomycetes are Gram-positive, non-spore-forming bacteria, and they typically form branching filaments.
Examples of actinomycetes include species in the genera Streptomyces, Nocardia, Actinomyces, and Mycobacterium. Streptomyces is the best known and most studied of these genera, and it is responsible for producing many clinically important antibiotics, such as streptomycin, tetracycline, and erythromycin. Nocardia species are known for their ability to cause infections in humans, including pneumonia, brain abscess, and mycetoma. Actinomyces species are known for causing a localized infection in the mouth called actinomycosis. Mycobacterium species are known for causing tuberculosis and leprosy.
In addition to their medical importance, actinomycetes are also important in biotechnology. They are used in industrial production of antibiotics, enzymes, and other compounds. They are also used to degrade environmental pollutants, such as oil and pesticides.