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19 Cards in this Set
- Front
- Back
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Mycoplasma cell wall |
NO CELL WALL No peptidoglycan |
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Mycoplasma size |
- With Rickettsiae, smallest bacteria - Also flexible, can pass through very small filter pores |
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General Properties of Mycoplasma |
- Widely distributed in humans, mammals, fish, birds, reptiles, plants - Both haemotrophic (grow on RBCs) and nonhaemotrophic forms (can be grown on lifeless media, but complex nutritional rqmts) - Mycoplasma and Ureaplasma are the two genera of veterinary importance. Both require sterols for growth - in the cell wall, but can't make it. |
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Properties of Nonhaemotrophic Mycoplasma |
- Facultative anaerobes - Strict pathogens of the mucous membranes - Some are commensal - Associated with respiratory and urogenital tract infections, arthritis, mastitis, septicemia. - Resistant to antibiotics targeting peptidoglycan synthesis (beta lactams), as they have no cells wall |
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Nonhaemotrophic Mycoplasma Environment |
- Survive short periods in environment (substantial periods in cool, humid environments) - Susceptible to desiccation, heat, detergents - Require close association to animal host cells to get necessary nutrients - Major reservoir = host they infect - Most species are host-specific |
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Nonhaemotrophic Mycoplasma Transmission |
- Direct contact with oral, nasal, ocular, or genital secretions (bites!) - Mechanical transmission w/ bovine mastitis - Vertical transmission in poultry - Contaminated milk - Often introduced into a group via a healthy carrier being introduced |
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Nonhaemotrophic Mycoplasma Pathogenesis |
- Intimate contact with host cell for growth and nutrient assimilation. Adhesins! - Attachment to respiratory tract --> ciliary destruction or stasis - Build up of cytotoxins locally --> host cell membrane destruction - Lipoproteins induce cytokine response - Leads to chronic inflammatory response - Evade immune response by antigenic variation, bind and impair phagocytosis by neutrophils and macrophages, have antiphagocytic capsule |
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Avian Mycoplasmas |
- Egg transmitted & laterally by direct/indirect contact
- M. gallisepticum - chickens & turkeys - M. synoviae - chickens & turkeys - M. meleagridis - turkeys - M. iowae - turkeys |
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Mycoplasma gallisepticum |
- Nonhaemotrophic mycoplasma of chickens and turkeys - Chronic respiratory disease (severe sinusitis in turkeys, too) - Most important mycoplasma of poultry, economically - mortality, carcass condemnation, reduced egg production |
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Mycoplasma synoviae |
- Nonhaemotrophic mycoplasma of chickens and turkeys - Infectious synovitis --> lameness and swelling of the joints - Retarded growth and egg production |
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Mycoplasma meleagridis Mycoplasma iowae |
- Nonhaemotrophic mycoplasma of turkeys - Respiratory disease (air sacculitis) and bone deformities in young turkeys - Reduced hatchability |
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Control of Mycoplasmas in Poultry Industry |
- M. gallisepticum and M. synoviae controlled by periodic serologic monitoring and depopulation (works in broiler industry b/c of all-in all-out set-up). Doesn't work well in layer industry - Vaccines - Antibiotics (macrolides, tetracyclines), but don't clear infection well - just reduce effects |
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Mycoplasma mycoides subsp mycoides |
- Nonhaemotrophic mycoplasma of bovines - Causes Contagious Bovine Pleuropneumonia - Clinical signs: respiratory distress, coughing, nasal discharge, reluctance to move - First vet school founded b/c of this disease in Lyon (as well as Rinderpest) |
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Mycoplasma bovis |
- Nonhaemotrophic mycoplasma of bovines - Mastitis, bronchopneumonia, systemic infections, arthritis, abortion, meningitis - Predisposing factor for shipping fever (respiratory disease) - 1-8% of all dairy herds in US have >= 1 cow with mycoplasma mastitis |
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Control of Bovine Mycoplasmas |
- Respiratory disease: vaccines, but effectiveness is limited because of antigenic variation. Best to control stress and practice good management - Mastitis: Identify and eliminate infected animals from herd. Quarantine new members and test before admitting to herd. Cull positive animals. |
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Mycoplasmas of swine |
- M. hyosynoviae - young pigs, polyarthritis - M. hyorhinis - polyserositis & arthritis - M. hyopneumoniae - porcine enzootic pneumonia. Chronic cough and retarded growth in young pigs. When combined w/ other bacteria: porcine respiratory disease complex. - Vaccines give incomplete protection. Depopulate positive animals. |
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Mycoplasmas of Dogs and Cats |
- M. cynos - respiratory disease - M. canis - urogenital disease and infertility - M. felis - conjunctivitis in young cats NO VACCINES. Macrolide and tetracycline antibiotic therapy recommended. |
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Haemotrophic mycoplasmas |
- Wall-less bacteria that attach and grow on RBCs. Arthopod vectors involved. Infection usually not apparent until some event (splenectomy, immune suppression) - M. ovis - high mortality in lambs - M. suis - icteroanemia in swine - M. wenyonii - subclinical - M. haemofelis - infectious anemia in cats - M. haemocanis - infectious anemia in dogs - M. haemomuris - anemia in mice |
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Treatment of Haemotrophic mycoplasmas |
- Correction of the hemolytic anemia - Tetracyclines - If treatment is successful, remain chronic carriers |
