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Class Actinobacteria
Genus Actinomyces, Micrococcus, Arthrobacter, Corynebacterium, Mycobacterium, Nocardia, Propionibacterium, and Streptomyces
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Genus Actinomyces
- Class Actinobacteria
- Straight or slightly curved rods.
- Filaments with varying degrees of branching may predominate in certain species.
- No aerial filaments.
- Perferentially anaerobic.
- Make up part of the microbial flora of the oral cavity and female genital tract.
- May be pathogenic to humans and animals.
- Disease caused by Actinomyces is called actinomycosis.
- Is a chronic granulomatous disease characterized by abscess formation.
- Periodontal desease
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Genus Micrococcus
- Class Actinobacteria
- Aerobic
- Catalase positive cocci that occur mainly in pairs, tetrads or irregular clusters
- Usually nonmotile
- Most produce carotenoid pigments.
- Primary natural habitats is mammalian skin.
- Nonpathogenic.
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Genus Arthrobacter
- Class Actinobacteria
- Aerobic
- Catalase positive
- Isolated most commonly from soil, saprophytic
- Characterized by an unusual rod coccus cycle.
- Cells in the logs phase are irregularly sharped rods.
- Whereas cells in the statinonary phase are distinctly coccoid.
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Genus Corynebacterium
- Straight to slightly curved rods that exhibits swelling.
- Clubs shapes or other deviations from a uniform rod shape.
- Generally facultatively anaerobic.
- Snapping division.
- Palisade arrangement and nonmotile.
- Not encapsulated.
- Older cells following staining with dyes such as methylene blue appear beaded of granulated.
- This is due to the presence of metachromatic granules.
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Genus Mycobacterium
- Class
- Aerobic
- Nonmotile
- Slow growing
- Rod acid fast bacteria.
- Lipid (wax) content of cells and cell wall high.
- Includes parasites, saprophytes and obligate parasites.
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Genus Nocardia
- Class Actinobacteria
- All found in the soil.
- Capable of metabolizing paraffin.
- Some are pathogenic for humans and animals.
- Nocardiosis usually occur in patients with cancer, chronic pulmonary disease, or immunosuppressed patients including transplant patients that receive immunosuppressive drugs.
- Site of infection is the lungs and is characterized by nodular abscesses.
- May become metastatic and involve CNS and kidneys causing abscess formation in the brain and kidneys.
- Fatality rates are high in undiagnosed disseminated disease.
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