Mycoplasma Flashcards

1
Q

What are Mycoplasmas?

A
  • 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
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2
Q

What are the General Characteristics of Mycoplasma?

A
  • 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
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3
Q

What antibiotics are effective against Mycoplasmas?

A
  • Cell Wall inhibitors - Not effective
    • Penicillins
  • Protein Synthesis Inhibitors - Effective
    • Tetracyclines, tylocin
  • DNA synthesis inhibitors - Effective
    • Fluoroquinolones, Baytril
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4
Q

What tissues do Mycoplasmas affect?

A
  • Primary colonization site is epithelium
    • Respiratory Tract
    • Joints
    • Mammary gland
    • Urogenital tract
    • Eyes
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5
Q

How are mycoplasma transmitted?

A
  • Aerosol
  • Direct Contact
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6
Q

What is the Pathogenicity of Mycoplasmas?

A
  • 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)
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7
Q

How is a Mycoplasma infection diagnosed?

A
  • 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
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8
Q

What does Respiratory Disease Caused by Mycoplasma look like?

A
  • 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
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9
Q

What Mycoplasma cause Respiratory Disease in Cattle / Sheep / Goats?

A
  • M. bovis
  • M. dispar
  • M. diversum
  • M. capricolum ssp. capricolum
  • M. capricolum spp. capripneumoniae
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10
Q

What Symptoms are found in Respiratory Disease of Cattle / Sheep / Goats?

A
  • Pneumonia
  • Alveolitis
  • Bronchiolitis
  • Pleuropneumonia
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11
Q

What is the Treatment for Mycoplasma Respiratory Infections?

A
  • Oxytetracycline
  • Erythromycin
  • Tylosin
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12
Q

How can Respiratory Mycoplasma infections be prevented?

A
  • Strict Biosecurity protocol
  • Avoid introducing infected calves to the herd
  • Vaccines are not very effective
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13
Q

How does Respiratory Disease affect Swine?

A
  • 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
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14
Q

How does Respiratory Disease affect Poultry?

A
  • 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
  • Control by having clean stock, monitoring and removing susceptible flocks
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15
Q

What is Bovine Mycoplasmal Mastitis?

A
  • 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
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16
Q

How is Bovine Mycoplasmal Mastitis controlled?

A
  • Screen newly acquired cows
  • Isolate affected animals
  • Market severely affected cows
  • Return recovered cows to normal milking herd only after 2 negative cultures
  • Impose strict hygienic measures
  • Do not feed unpasteurized milk to calves
17
Q

What is Bovine Mycoplasmal Arthritis?

A
  • Secondary to mastitis
  • Primarily caused by M. bovis
  • Mortality rate is ~10%
  • Affected limbs are held stiff to minimize articular action and pain
18
Q

What is Poultry Mycoplasmal Arthritis?

A
  • Caused by M. synoviae
  • Lethargy, decreased growth, pale comb, breast blisters, lameness, and joint swelling
  • Progresses to chronic stage and may resolve in some cases
  • Severe infections in chickens, more than turkeys
19
Q

What is Swine Mycoplasmal Arthritis?

A
  • M. hyosynoviae and M. hyorhinis
  • Young pigs (6 weeks to 6 months)
  • Decreased weight gain and growth
  • Exacerbated by stress
  • Polyarthritis in young pigs
  • May induce respiratory disease
  • Tiamulin and Tylosin Therapy
20
Q

What is Bovine Genital Disease?

A
  • Four species are involved:
    • M. bovis
    • M. bovigenitalium
    • M. alkalescens
    • Ureaplasma diversum
  • Abortion and other genital infections
21
Q

What does M. conjunctivae cause?

A
  • Keratoconjunctivitis in sheep, goats, cattle, and birds
  • Eyes recover in 2-3 weeks
  • Control: Good hygienic practices
22
Q

How does Mycoplasma affect canines?

A
  • M. edwardi - Upper respiratory tract and genital tract infections
  • M. canis
  • M. maculosum
  • M. spumans from genital tracts
23
Q

How does Mycoplasma affect Felines?

A
  • M. felis causes conjunctivitis and pneumonia
  • M. feliminutum isolated from oral cavity- Significance
24
Q

How does Mycoplasma affect horses?

A
  • M. subdolum - respiratory and genital tracts
  • M. equigenitalium - reproductive tract
25
Q

Why is M. pneumoniae of public health significance?

A
  • Causes walking pneumonia in humans
  • Can also infect oral and genito-urinary tracts
  • AIDS and Chemotherapy patients most at risk