Mycoplasma Flashcards
What are Mycoplasmas?
- Bacteria with no cell wall
- Shapes: rod, coccus, spirallum
- Pleomorphic: ring-shaped, pear-shaped, spiral-shaped, filamentous
- Gram stain poorly
- Special Stains:
- Giemsa
- Castaneda
- Dienes, and more
- Special Stains:
What are the General Characteristics of Mycoplasma?
- Tiny, obligate Parasite
- Able to pass through 0.22 and 0.45 micron commonly used filters for sterilization of liquid media
- Attach to the Epithelium
- Do NOT survive outside a host
What antibiotics are effective against Mycoplasmas?
-
Cell Wall inhibitors - Not effective
- Penicillins
-
Protein Synthesis Inhibitors - Effective
- Tetracyclines, tylocin
-
DNA synthesis inhibitors - Effective
- Fluoroquinolones, Baytril
What tissues do Mycoplasmas affect?
- Primary colonization site is epithelium
- Respiratory Tract
- Joints
- Mammary gland
- Urogenital tract
- Eyes
How are mycoplasma transmitted?
- Aerosol
- Direct Contact
What is the Pathogenicity of Mycoplasmas?
- Host Cell attachment
- Membrane associated products such as:
- hemolysins
- proteolytic enzymes
- Urease
- Endonucleases are virulence factor
- Primarily humoral immune response
- Antigenic variation is common
- Infection is associated with tress and other factors (virus, bacteria)
How is a Mycoplasma infection diagnosed?
-
Culture method (3-10 days)
- Need sterols, vitamins in the media
- Rapid sample collection and culturing
- Cell wall inhibitors used in the media
- Biochemical test have no value
- Histopathology
- Immunofluorescence
- Serology for antibody detection
- Molecular methods -PCR
What does Respiratory Disease Caused by Mycoplasma look like?
- Affects: Cattle, Small ruminants, Swine, Poultry, Laboratory Rodents and Humans
- Clinically silent and may become chronic
-
Upper respiratory track lesions
- Destruction of respiratory epithelium
- Secondary bacterial or viral infection
What Mycoplasma cause Respiratory Disease in Cattle / Sheep / Goats?
- M. bovis
- M. dispar
- M. diversum
- M. capricolum ssp. capricolum
- M. capricolum spp. capripneumoniae
What Symptoms are found in Respiratory Disease of Cattle / Sheep / Goats?
- Pneumonia
- Alveolitis
- Bronchiolitis
- Pleuropneumonia
What is the Treatment for Mycoplasma Respiratory Infections?
- Oxytetracycline
- Erythromycin
- Tylosin
How can Respiratory Mycoplasma infections be prevented?
- Strict Biosecurity protocol
- Avoid introducing infected calves to the herd
- Vaccines are not very effective
How does Respiratory Disease affect Swine?
- Caused by:
- M. hyopneumoniae
- M. hyorhinis
- M. hyosynoviae
- Dry cough
- Worldwide occurrence: 30-70% of hogs
- High economic losses
- Controlled by tiamulin or tylosin therapy, or vaccine
How does Respiratory Disease affect Poultry?
- Caused by:
- M. gallisepticum
- M. synoviae
- M. meleagridis
- Uncomplicated - low mortality
- Complicated infections: ~30% mortality
- Sinusitis, Air Sacculitis
- Economic losses:
- Downgrading meat
- Loss of egg production
- Medication and mortality
- Economic losses:
- Control by having clean stock, monitoring and removing susceptible flocks
What is Bovine Mycoplasmal Mastitis?
- M. Bovis and M. californicum
- Bacteria shed in milk, urine, feces, and respiratory secretions
- Transmitted via milking
- Variable clinical signs:
- Acute, Chronic, Sub clinical
- Sudden drop in milk production, rapid involvement of multiple quarters, swelling
- Milk thickness decreases, yellowish, flaky, large clots leaving watery supernate
- Fibrosis: permanent loss of milk production
- Treatment:
- antibiotics are not very effective
- Animals may resolve without intervention