Actinomycetes
•Download as PPTX, PDF•
3 likes•3,175 views
Actinomycetes are a group of Gram-positive, filamentous bacteria that resemble fungi in some ways. They include the genera Actinomyces, Nocardia, and Streptomyces. Actinomycetes are commonly found in soil where they aid in decomposition. Many produce important antibiotics like streptomycin. While usually saprophytic, some Actinomycetes can cause disease in humans or animals through inhalation or direct inoculation, often taking advantage of breaks in mucous membranes to infect normally sterile tissues.
Recommended
More Related Content
What's hot
What's hot (20)
Similar to Actinomycetes
Similar to Actinomycetes (20)
More from Rinaldo John
More from Rinaldo John (20)
Recently uploaded
Recently uploaded (20)
Actinomycetes
- 2. General properties Gram positive branching filaments Slow growers Gram + ,filamentous bacteria. Resemble Corynebacteria, mycobacteria and fungi Include: Actinomyces – anaerobe, normal flora, grows in narrow range of temp Nocardia – aerobe, saprophyte – PARTIALLY ACID FAST, grows in wide range of temp Streptomyces- aerobe, saprophyte
- 3. Actinomycetes Classification Order – Actinomycetales Show fungus-like characteristics such as branching in tissues or in culture (look like mycelia). The cell wall and the internal structures are typical of bacteria rather than fungi. Some are aerobic and others are anaerobic. All are slow growing
- 4. ACTINOMYCETES ECOLOGY Predominantly soil bacteria Good at degrading recalcitrant compounds such as chitin & cellulose Often active at higher pH (contrast to fungi who may dominate at lower pH) Give soil the “earthy” smell
- 5. Genus - Actinomyces Strict anaerobe Gram positive Non-motile Non-proteolytic
- 6. ACTINOMYCES Anaerobic, filamentous, gram positive bacillus Exhibit true branching “Mykes” – Greek for “fungus” Thought by early microbiologist to be fungi because of: Morphology Disease they cause
- 7. ACTINOMYCOSIS Not highly virulent (Opportunist) Component of Oral Flora Periodontal pockets Dental plaque Tonsilar crypts Take advantage of injury to penetrate mucosal barriers suppurative A chronic and granulomatous disease of the cervico-facial, thoracic or abdominal areas Three-quarters of human cases are caused by Actinomyces israelii.
- 8. Morphology of Nocardia The Nocardia are branched, strictly aerobic, Gram-positive bacteria that are closely related to the rapidly growing mycobacteria. They are environmental saprophytes with a broad temperature range of 9
- 9. Nocardiosis Nocardiosis primarily presents as a pulmonary disease or brain abscess in the U.S. Subcutaneous infections, pulmonary infections, and brain abscesses N. asteroides; N. brasiliensis 10
- 10. • Over 500 distinct antibiotic substances have been shown to be produced by streptomycete. • produce many important antibiotics, including Streptomycin - originally from S. griseus. Antibiotics Actinomycete s
- 11. The genus Streptomyces includes- aerobic, Gram-positive, filamentous bacteria that produce well-developed vegetative hyphae with branches. They form a complex substrate mycelium that aids in scavenging organic compounds from their substrates.
- 12. Other antibiotics produced by Streptomyces spp: Antibiotic: affects: Spectinomycin M. tuberculosis, N. gonorrhea Neomycin Broad spectrum, topical Tetracyclines Broad spectrum, Chlamydias, Rickettsias etc. Nystatin Fungi, esp. Candida Erythromycin Gram + Bacteria and Legionella Chloramphenicol Broad spectrum, typhoid fever ACTINOMYCETES ANTIBIOTICS • Over 500 distinct antibiotic substances have been shown to be produced by streptomycete. • produce many important antibiotics, including Streptomycin - originally from S. griseus.
- 13. Ecology and isolation of Streptomyces: • Alkaline and neutral soils are more favorable •Streptomyces require a lower water potential for growth than many other soil bacteria. • Media often selective for Streptomyces contain the usual assortment of inorganic salts
- 14. Aerobic Actinomycetes: Natural Habitats Nocardia species and other aerobic Actinomycetes ubiquitous in soil and primarily responsible for decomposition of organic plant matter Rhodococcus species present in the intestinal bacterial flora of grazing herbivores especially horses Streptomyces species (>3,000) widely distributed in soil
- 15. Aerobic Actinomycetes: Modes of Infection Nocardia infection acquired by inhalation of or direct skin inoculation (traumatic) by environmental organisms Rhodococcus infection due primarily to inhalation of organisms by animal handlers (horses, pigs, cattle) Streptomyces are soil organisms that can infect traumatic wounds especially of the feet
- 16. Anaerobic Actinomyces: Natural Habitats Anaerobic Actinomyces species are normal inhabitants of the mucous membranes of humans and animals Anaerobic Actinomyces: Modes of Infection Actinomyces invades normally sterile tissue from endogenous mucous membrane sites of normal colonization
- 17. Environmental Importance of Actinomycetes Mineralization of organic matter in soil Antibiotic production Bulking and foaming in wastewater treatment plants https://goo.gl/yFJvxm
Editor's Notes
- There are more than a dozen suborders of actinomycetes; however, the heterogeneous nature of those organisms has been a source of taxonomic instability, and many await a more certain classification. Of the specific types of actinomycetes, Nocardia asteroides, an aerobic species, is the primary cause of nocardiosis, an infection of the lungs, brain, or skin in humans. Dermatophilus congolensis causes dermatophilosis, a severe dermatitis of cattle, sheep, horses, and occasionally humans. Several species of Streptomyces cause the disease actinomycosis in humans and cattle. Many of the actinomycetes are sources of antibiotics such as streptomycin.
- Corynebacterium is a genus of Gram-positive, aerobe, rod-shaped bacteria. Mycobacterium is a genus of Actinobacteria, given its own family, the Mycobacteriaceae. The genus includes pathogens known to cause serious diseases in mammals, including tuberculosis and the classic Hansen's strain of leprosy. Actinomycetes are filamentous bacteria. Their morphology resembles that of the filamentous fungi; however, the filaments of actinomycetes consist of prokaryotic cells. Some actinomycetes resemble molds by forming externally carried asexual spores for reproduction. Filamentous, High G + C content, Gram-positive (63 – 78% GC) (larger genomic size) They are facultative anaerobes, but often fail to grow aerobically on primary culture. They grow best under anaerobic or micro-aerophilic conditions with the addition of 5-10% carbon dioxide
- Actinomyctes are branching Gram positive bacilli. They are facultative anaerobes, but often fail to grow aerobically on primary culture. They grow best under anaerobic or micro-aerophilic conditions with the addition of 5-10% carbon dioxide
- recalcitrant compounds – complex , difficult to manage compounds
- Proteolysis- the hydrolysis of proteins or peptides with formation of simpler and soluble products. Three-quarters of human cases are caused by Actinomyces israelii.
- Almost all species are commensals of the mouth and have a narrow temperature range of growth of around 35-37°C. They are responsible for the disease known as actinomycosis.
- A chronic suppurative and granulomatous disease of the cervico-facial, thoracic or abdominal areas A granuloma is a small area of inflammation in tissue. Granulomas are most often the result of an infection and most frequently occur in the lungs, but can occur in other parts of the body as well. They typically cause no signs or symptoms and are found incidentally on a chest X-ray done for some other reason.
- Purulent- discharge of pus
- Nocardia astroides
- In Latin America, it is more frequently seen as the cause of a subcutaneous infection, with or without draining abscesses. It can even present as a lesion in the chest wall that drains onto the surface of the body similar to actinomycosis. Brain abscesses are frequent secondary lesions.
- More than 50 antibiotics have been used in human and veterinary medicine, agriculture and industry
- Alkaline and neutral soils are more favorable for the development of Streptomyces than are acid soils.
- ubiquitous :present, appearing, or found everywhere.
- Actinomycetes are one of the most diverse groups of filamentous bacteria capable of surviving in a number of ecological niches due to their bioactive potential. Actinomycetes are well recognized for their metabolic versatility that is frequently accompanied by the production of primary and secondary metabolites of economic importance. They are a promising source of wide range of important enzymes, some of which are produced on an industrial scale, but many other remained to be harnessed. They have the ability to degrade a wide range of hydrocarbons, pesticides, and aliphatic and aromatic compounds. They perform microbial transformations of organic compounds, a field of great commercial value. Members of many genera of actinomycetes have potential for use in the bioconversion of underutilized agricultural and urban wastes into high-value chemical products. A large fraction of antibiotics in the market are obtained from actinomycetes. They produce enzyme inhibitors useful for cancer treatment and immunomodifiers that enhance immune response. Actinomycetes are also important in plant biotechnology as strains with antagonistic activity against plant pathogens are useful in biocontrol. Their metabolic potential offers a strong area for research. Accordingly, this special issue is dedicated to the role of actinomycetes in biotechnology and medicine. Contribution of research papers and review articles with focus on characterization and applications of novel biomolecules from actinomycetes will be considered after peer review. Preliminary data on screening for novel biomolecules will be acceptable if techniques used in screening are not reported previously and offer high throughput or rapidity over existing techniques. Potential topics include, but are not limited to: Biochemical characterization and/or applications of biomolecules from actinomycetes Enzymes Antibiotics Enzyme inhibitors Immunomodulators Actinomycetes and their products in plant and environment biotechnology Genetic improvement of actinomycetes