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Veterinary Bacteriology & Mycology > Mycoplasma > Flashcards

Mycoplasma Flashcards

1
Q

What is another nickname for Mycoplasma?

A

pleuropneumonia-like organism = PPLO

(smallest bacteria)

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2
Q

What shape does Mycoplasma take? How is it able to do this?

A

pleomorphic - lack a cell wall (rather, has a cell membrane)

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3
Q

What are the 3 functions of the electron-dense core terminal organelle/disc present in Mycoplasma?

A
  1. adherence/attachment onto host cell surface receptors
  2. gliding motility
  3. cell division
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4
Q

What makes Mycoplasma β-lactam, polymixin/colistin, sulfa/trimethoprim, and rifampin resistant?

A

β-lactam —> no cell wall
polymixin/colistin —> no LPS
sulfa/trimethoprim —> no folic acid synthesis
rifampin —> DNA polymerase is prone to mutation

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5
Q

What 4 cell structures does Mycoplasma lack? 3 toxins? 2 enzymes?

A

CELL STRUCTURES: cell wall, flagella, fimbriae, LPS

TOXINS: toxins, cytolysins, invasins

ENZYMES: catalase, superoxide dismutase

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6
Q

What makes Mycoplasma have reduced capacities for ATP synthesis?

A
  • does not undergo the TCA cycle
  • no quinones
  • no cytochromes
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7
Q

What 6 unique structures coat the cellular membrane of Mycoplasma? What are each responsible for?

A
  1. glycolipids - antigen mimicry (autoimmunity)
  2. lipoglycans - antigen mimicry (autoimmunity)
  3. lipoprotein - switch ON/OFF regularly to change coat
  4. capsular polysaccharide - block phagocytosis
  5. host-derived cholesterol - adhesion, invasion
  6. adhesins - attachment to diverse host epithelial cells
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8
Q

What 7 substances do Mycoplasma secrete?

A
  1. hydrogen peroxide - kill host cells by oxidizing their lipids, proteins, DNA, and RNA
  2. superoxide - kill host cells by oxidizing their lipids, proteins, DNA, and RNA
  3. nucleases - degrade host nucleic acids
  4. immunoglobin protease - degrade antibodies
  5. antioxidant enzymes - detoxify free radicals
  6. sialidase - degrade mucus to reach epithelium
  7. hyaluronidase - degrade hyaluronate
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9
Q

How do Mycoplasma grow on media? What 7 substances are required in media for its growth?

A
  • highly fastidious and slow grower (1-2 weeks, chronic disease)

MYCOPLASMA AGAR
1. beef heart infusion
2. peptone
3. 5% yeast autolysate
4. nucleic acid precursors
5. penicillin - block Gram-positive bacterial growth
6. thallium acetate - block Gram-negative bacterial growth
7. 20% equine/human serum - provides cholesterol, amino acids, and fatty acids for cell membrane synthesis

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10
Q

What morphology does Mycoplasma undertake on media? How does it compare in different species?

A

fried egg colony with unique gliding motility

CATTLE —> M. mycoides subsp. mycoides —> small colony
GOAT —> M. mycoides subsp. mycoides —> large colony

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11
Q

What 8 antioxidant enzymes are produced by Mycoplasma? What is their function?

A
  1. methionine sulfoxide reductase
  2. organic hydroperoxide reductase
  3. osmotically inducible protein C
  4. superoxide dismutase
  5. catalase
  6. thioredoxin reductase
  7. thiol reductase
  8. peroxiredoxin

ensures bacterial survival in the presence of free radicals

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12
Q

What virulence factors are responsible for antigenic variability? Antigen mimicry?

A
  • lipoprotein
  • glycolipids
  • lipoglycans
    (autoimmunity, escapes detection by the immune system)
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13
Q

What does it mean when Mycoplasma “caps?”

A

incorporated host antigens into itself, allowing escape from the immune system

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14
Q

How is Mycoplasma able to survive in host cells? What can this lead to?

A

manipulate host genome

disease —> cancer?

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15
Q

How does Mycoplasma cause disease?

A
  • infection elicits inflammation (IL-1, 2,6) which can lead to MAKePSR syndrome, autoimmunity, and immune invasion
  • further immune evasion results in chronic inflammation
  • chronic inflammation can inhibit p53, a tumor suppresor protein, in host cells
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16
Q

What are the 2 lifestyles of Mycoplasma?

A
  1. INTRACELLULAR: alters host cell morphology and genetic architect to cause chronic diseases including colon, gastric, lung, prostate, and renal cancers
  2. EXTRACELLULAR: resides outside host cells very intimately to membrane surface
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17
Q

What are the 5 transmission routes of Mycoplasma?

A
  1. airborne** (as far as 9.2 km, like Chlamydia and Coxiella)
  2. contact
  3. sexual intercourse (humans)
  4. ingestion
  5. vertically by transovarial (birds)
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18
Q

What is a common way of contact being a transmission route of Mycoplasma? What does this cause?

A

sharing the same milking machines in dairy farms

Mycoplasma mastitis

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19
Q

What are 2 major sources of Mycoplasma infection?

A
  1. introduction of an infected animal into an uninfected population
  2. dispersed by wind/air
20
Q

What is the host range of Mycoplasma? What body systems are most commonly affected?

A

all vertebrates and fleas

mucosal tracts —> MAKePSR
(respiratory tract, urogenital tract, conjunctiva, alimentary canal, mammary glands, joints)

21
Q

What reproductive diseases does Mycoplasma cause?

A
  • abortion
  • vulvovaginitis
  • infertility
  • endometritis
  • dystocia
22
Q

What are the 3 major species of Mycoplasma causing disease in cattle?

A
  1. M. mycoides subsp. mycoides small colony variant
  2. M. bovis
  3. M. agalactia
23
Q

What does Mycoplasma bovis and Mycoplasma mycoides subsp. mycoides small colony variant cause in cows? What are 5 major symptoms on a physical exam that point towards this?

A

contagious bovine pleuropnemonia (CBPP) - trade ban by OIE

  1. extended head/neck forward
  2. open mouth
  3. legs far apart with elbows pointed out
  4. coughing
  5. ocular and nasal discharge
24
Q

What are 3 pathologies caused by contagious bovine pleuropneumonia (CBPP) seem postmortem?

A
  1. collection of pleural fluid in thorax
  2. thickening of the interlobular septa of lung, giving it a marbled appearance (meaty, fibrin)
  3. lung adherence to chest wall (lungs unable to collapse and refill —> hypoxia)
25
Q

What are 6 common diseases caused by Mycoplasma bovis?

A
  1. mastitis
  2. pneumonia (calf)
  3. polyarthritis (calf)
  4. metritis
  5. abortion
  6. sterility
26
Q

What species of Mycoplasma cause contagious caprine pleuropneumonia (CCPP)?

A

M. capricolum subsp. capripneumoniae
- trade ban!

27
Q

What are the 4 major species of Mycoplasma causing disease in sheep/goats?

A
  1. M. capricolum subsp. capricolum - mastitis, arthritis
  2. M. mycoides subsp. capri - pneumonia, mastitia, arthritis, septicemia
  3. M. agalactiae - infectious agalactia
  4. M. ovipneumoniae - pneumonia (lambs)
28
Q

What is the most common clinical sign of Mycoplasma agalactiae in sheep/goats?

A

mammary gland atrophy
- conjunctivitis
- arthritis

29
Q

What are 2 postmortem findings in M. capricolum, M. mycoides, and M. ovipneumoniae infection? 5 clinical symptoms?

A
  1. granular lung appearance
  2. marbled and hepatization of lung

high fever, anorexia, productive cough, wide stance, extended neck

30
Q

What is the most common Mycoplasma species causing infection in swine? What does it cause? 2 postmortem findings?

A

M. hyopneumoniae —> enzootic pneumonia

  1. lung hepatization - lung discoloration and consolidation
  2. lung lobe collapse (deflated)
31
Q

What are the 3 most common Mycoplasma species causing disease in poultry? What do they cause?

A
  1. M. gallicepticum - chronic respiratory disease (CRD) in chicken, sinusitis and infectious air sacculitis in turkey
  2. M. synoviae - air sacculitis, arthritis, tendosynovitis
  3. M. meleagridis - air sacculitis, sinusitis, arthritis (turkey)
  • trade ban in USA
32
Q

How are the air sacs affected by Mycoplasma gallisepticum and M. synoviae infection?

A

thickened and cloudy
(+ thickened blood vessels)

33
Q

What are common clinical signs of Mycoplasma gallisepticum infection in turkeys? Chickens?

A

sinusitis with swollen infraorbital sinuses and a clear mucoid exudate + dried nasal exudate

conjunctivitis, periorbital swelling, and dried nasal exudate

34
Q

What are 2 common clinical signs in chickens affected by Mycoplasma synoviae?

A
  1. swollen footpad with granulation tissue and purulent discharge surrounding digital flexors
  2. swollen hock joint with viscous yellow exudate around the tendons
35
Q

What Mycoplasma species affects horses? What does it couse?

A

M. felis - pleuritis

36
Q

What 2 species of Mycoplasma affect pets? What do they cause?

A
  1. M. cynos - pneumonia
  2. M. felis - conjunctivitis, penumonia (cats)
37
Q

What 2 species of Mycoplasma cause severe hemolytic anemia in dogs and cats? How are they transmitted?

A
  • M. haemocanis
  • M. haemofelis
  • FLEAS

(used to be part of Haemobatonella)

38
Q

What 3 Mycoplasma species affect humans? What do they cause?

A
  1. M. pneumoniae - pneumonia, tracheobronchitis
  2. M. hominis - urogenital disease, vaginosis (STD); 21-53% of women carry asymptomatically
  3. M. genitalium - reproductive diseases of males and females (STD)
39
Q

What 3 species of Mycoplasma are causes of trade bans in poultry by the USDA? 2 that cause a trade ban in goats and cattle by the OIE?

A

M. gallisepticum, M. synoviae, M. meleagridis

M. capricolum subsp. capripneumoniae (CCPP)
M. mycoides subsp. mycoides (CBPP)

40
Q

What are the 6 major pathologies of the lung due to Mycoplasma infection?

A
  1. thickening
  2. extensive fibrin and fibrosis
  3. hepatization
  4. marbline
  5. granuloma with poor blood perfusion
  6. encapsulation (+/- necrosis)
41
Q

What pathologies are found in the thoracic cavity and joints due to Mycoplasma infection?

A

straw-colored fluid acumulation

swollen + exudate

42
Q

What 3 aspects of the iceberg concept relate to Mycoplasma infection?

A
  1. can be carried asymptomatically, but herds/flocks have a high rate of morbidity due to close confinement
  2. proportion of dead animals among infected (mortalities) ranges from 30-80%
  3. 25% of recovered animals become carriers
43
Q

What is the gold standard of isolating Mycoplasma? What is a major limitation? What else is commonly done?

A

culturing on agar with the typical fried egg appearance with gliding motility - detects only 30-50% using bulk milk or individual cow of subclinical infections (low sensitivity)

  • serology (surveillance and biosecurity): direct/indirect fluorescent staining, ELISA, slide agglutination test
  • PCR: nucleic acid based test (best considering limitations of culture)
44
Q

What are the 3 antimicrobials of choice for Mycoplasma infections? What are 3 common causes of poor responsiveness to treatment?

A
  1. Doxycycline
  2. Tetracycline
  3. Erythromycin

bacteria….
- is slow growing
- can sequester in granulomas
- can hide intracellularly
(culling implications of infected animals!)

45
Q

In what 4 ways is Mycoplasma infection commonly controlled/prevented?

A
  1. chemotherapy of infected herd/flock
  2. vaccination - live and killed vaccine decreased clinical signs and pathologies, can still be infected and be carriers
  3. biosecurity - ALL-IN-ALL-OUT PRACTICE, single age farms, segregation, traffic control, cleaning and disinfection
  4. test and cull positive animals
46
Q

What is the overall recommended way of controlling Mycoplasma disease? Why?

A

culling

neither antibiotics nor vaccines are effective for treatment

Veterinary Bacteriology & Mycology (47 decks)

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