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Infectious Agents > Gram Positive Rods > Flashcards

Gram Positive Rods Flashcards

1
Q

What are 4 bacteria that are gram-pos rods?

A
  • erysiopelothrix
  • corynebacteria
  • rhodococcus
  • listeria
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2
Q

Erysiopelothrix rhusiopathiae (E. insidisa)

A

Non-motile, non-spore forming, non-acid fast, incomplete hemolysis

  • catalase neg
  • produce H2S on TSI
  • survives in soil
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3
Q

Erysiopelothrix is found in up to _____

A

50% of pigs

- major source is carrier animals = pigs carry in tonsils and lymphatics

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4
Q

Erysiopelothrix is resistant to

A

Chemicals, and to drying, pickling, salting, smoking

is a non-spore forming bacterium!

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5
Q

4 forms of disease caused by erysiopelothrix

A
  • acute septicemia
  • urticarial cutaneous lesions (diamond skin)
  • vegetative endocarditis
  • arthritis
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6
Q

Joint ill in lamb

A

Wound infections in sheep that lead to polyarthritis, caused by erysiopelothrix

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7
Q

Wound infections in dogs leads to

A

Rheumatoid arthritis and heart valve endocarditis

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8
Q

Erysiopelothrix is an _________ of butchers, fish handlers, and veterinarians

A

Occupational disease

- erypsipeloid and local wounds can lead to fatal septicemia or joint/heart valve infection

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9
Q

Development and severity of erysiopelothrix infection depends on ______

A

Virulence of strain and resistance of host

  • stress
  • age 3-18 months
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10
Q

What are 3 routes of exposure for erysiopelothrix?

A
  • oral
  • cutaneous
  • respiratory
  • could also inseminated hens with contaminated sperm*
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11
Q

________ occurs in acute septicemia

A

Vascular disturbances

- starts as hyaline thrombosis and progresses to fibrinous thrombosis by 4 days

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12
Q

Erysiopelothrix causes ______ accumulation in joints, heart valves, and arteries

A

Fibrin

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13
Q

What is the virulence factor for erysiopelothrix?

A

Neuraminidase (enzyme)

  • removes N-acetylneuraminic acid (sialic acid) from substrates (RBCs, mucin, fibrinogen, leukocytes, thrombocytes)
  • leads to anemia, leukopenia, and thrombocytopenia
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14
Q

Antineuraminidase antibodies are _____

A

Protective

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15
Q

Clinical signs of erysiopelothrix infection in swine

A
  • acute: fever, anorexia, depression, death in 2-3 days
  • stiff gait, urticarial cutaneous lesions, diamond skin lesions (non-specific), possible abortion
  • subacute: less severe than acute, with possible recovery
  • chronic: lameness, possibly a sequal to acute, subacute, or unrecognized infection
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16
Q

Diagnosis of erysiopelothrix

A
  • acute: blood smears from live animals, liver/spleen/heart blood from necropsy
  • chronic: affected skin, heart, joint fluid
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17
Q

Erysiopelothrix immunity

A
  • Humoral!!!
  • hyperimmune antiserum: short term, passive protection
  • bacterins: short duration
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18
Q

Erysiopelothrix vaccine

A

EVA (erysipelas vaccine avirulent)

  • live vaccine, same for swine and birds
  • injectable, aerosol, or oral
  • prevents septicemia, but not chronic form
  • cannot be given with antibiotics!!
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19
Q

Erysiopelothrix treatment

A

Penicillin is best drug

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20
Q

Rhodococcus equi

A

Chronic suppurative bronchopneumonia of foals

  • 2 weeks to 5 months, peaks at 4-6 weeks old
  • too young to develop a vaccine
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21
Q

R. equi characterization

A

Extensive lung abscessation and ulcerative enteritis and mesenteric lymphadenitis
- summer or enzootic pneumonia

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22
Q

Route of entry for R. equi

A

Inhalation of pathogentic R. equi in dust

- is also carried in the GIT of gregarious birds

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23
Q

Environmental requirements of R. equi

A
  • is an aerobe that accumulates in feces in soil

- ammonia accumulation in environment inhibits normal defense system of respiratory tract (allows for easy infection)

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24
Q

_____ may follow pneumonia

A

Enteritis

  • via swallowing of infected sputum
  • ingestion leads to microscopic enteritis, no diarrhea
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25
R. equi is common in the feces of _____
Herbivores and swine | - is not usually in the normal flora
26
Pathogenesis of R. equi
- survives, multiplies, kills alverolar macrophages leading to caseous necrosis and lung destruction - pyogranulomatous response
27
R. equi is an _____
Facultative intracellular parasite
28
Virulence factors of R. equi
- capsular polysaccharides are antiphagocytic and resistant to complement - exoenzymes: cholesterol oxidase and phospholipase C - cell wall mycolic acid facilitates intracellular survival - plasmid encoded Vap A protein that interferes with phagolysosome formation
29
Host factors that facilitate R. equi infection
- clinical disease is related to immunocompetency of foals ---> foals that produce no detectable IFN-gamma are at risk of developing pneumonia - decline in colostral antibody
30
Diagnosis of R. equi
Collect specimens from: - nasal discharge - bronchial wash - feces - intestine - mesenteric lymph nodes - blood
31
Treatment of R. equi
Lipid soluble antibiotics that penetrate bacteria - erythromycin with rifampin*** - 80% survival rate if treated early with no lasting damage
32
Corynebacterium
Opportunistic urinary tract commensal of cattle
33
What are the 3 species of Corynebacterium?
- C. pilosum: mild, cystitis only - C. renale: chronic cystitis and ascending pyolonephritis - C. cystitidis: chronic pyelonephritis and most severe cystitis
34
Corynebacterium is most common in _____
Mature cows due to short urethra of females | - predisposed to by pregnancy and parturition
35
Corynebacterium is spread by ______
Bull and urine
36
Virulence factors of corynebacterium
- pili: adherence to host cells - urease: produces toxic ammonia and inactivates complement - renalin (exoprotein): lyses host cell membrane
37
Diagnosis of corynebacterium
Urine | - stain and culture
38
Treatment of corynebacterium
- large doses of penicillin | - remissions are common (reculture)
39
C. (ovis) pseudotuberculosis
Facultative intracellular pathogen - sheep/goats: caseous lymphadenitis - horses: ulcerative lymphangitis and folliculitis - other hosts: chronic lymphadenitis and abscesses
40
C. pseudotuberulosis usually follows ____
Wound infections in adults | - shearing, docking, castration, earbiting, headbutting
41
Canadian horsepox
C. psudotuberculosis infection in horses that presents as folliculitis with mildly pururitic skin lesions - progresses from nodules to alopecia and crusts with underlying pus
42
Pigeon's fever
C. pseudotuberculosis in horses with slowly enlarging, localized and nonpainful abscesses
43
Virulence factors of C. pseudotuberculosis
- phospholipase D: increase vascular permeability, facilitate dissemination, inhibition of chemotaxis - cell wall lipid and mycolic acid: facilitate intracellular survival
44
Treatment of C. pseudotuberculosis
Penicillin (works on skin lesions only) and trimethoprim/sulfonamide
45
Is there a vaccine for C. pseudotuberculosis?
Crude vaccine: austrailan whole cell bacterins (is being evaluated in US sheep)
46
C. diptheria
Human pathogen, carried in throat - exotoxin and temperate phage - subunit toxin inhibits protein synthesis
47
C. bovis
Commensal of bovine udder (20% of quarters) | - mild neutrophil response may protect against pathogens
48
C. suis
Cystitis and ascending pyelonephritis in sows - anaerobe carried in prepuce and preputial diverticulum of 60-80% of boars - transmitted during mating
49
C. ulcerans
Mastitis in cows - mild to severe pharyngitis in people - causes caseous lymphadenitis in sheep/goats
50
C. haemolyticum
Pharyngitis and skin infection in people
51
C. kutscheri (murium)
Carried by normal experimental mice and rats | - caseous tuberculosis-like focal lesions in lungs and other organs
52
Listeria
Slender, nonsporing, gram-pos rod, palisades in young cultures - motile at room temp, but not at 37 C - best grown on blood agar
53
What are the pathogenic forms of listeria?
- L. monocytogenes | - L. ivanovii
54
L. monocytogenes
Resistant to freezing and high salt concentrations - may survive pasteurization - grows within 4-44 C or 39 to 111 F, and pH of 5-9
55
Environmental requirements of L. monocytogenes
Saprophyte in nature, soil, water, feces, sewage | - latent, healthy carriers shed it in feces and milk during stress
56
What are the 2 natural reservoirs on L. monocytogenes?
Soil and mammalian GIT
57
Transmission of L. monocytogenes
Animal to animal via fecal-oral route
58
Listeriosis
Primarily a winter/spring disease of feedlot or housed ruminants - less acidic pH of silage enhances growth - outbreaks occur after feeding spoiled silage - remove silage to stop the spread
59
Disease of L. monocytogenes
- meningoencephalitis is most common form of listeriosis in ruminants - septicemia is common in monogastrics (inclu. young ruminants) - abortion/stillbirth are common in septicemia
60
L. monocytogenes pathogenesis
Facultative intracellular pathogen - entry thru alimentary tract (Peyer's patch) - interaction between Internalin A and E-cadherin, Internalin B and Met mediates internalization - multiplies in epithelial cells and phagocytes
61
____ and ____ mediates internalization into host cells
InlA and InlB
62
Escape from phagosome by ____ and _____
Listeriolysin O (LLO) and phospholipases (PLCs)
63
ActA
Actin polymerization into filamentous actin
64
Encephalitis or meningoencephalitis affects
Sheep, cattle, goats, and pigs
65
______ of all domestic animals is susceptible
Uterus
66
Cell mediated immunity from listeria
Infected animals develop both DTH and acquired CMI at same time - mediated by T cells and activated macrophages
67
Diagnosis of listeria
- sample of lumbosacral CSF - specimen from brain or aborted fetus - confirmed only by isolation and identification of L. monocytogenes (cold enrichment for up to 12 weeks)
68
Why is serology not used for listeria diagnosis?
Many healthy animals have high Listeria titers
69
Treatment of listeria
Tetracylines or penicillin/ampicillin with aminoglycoside - antibiotics have no use against the neurologic form - remove silage - only have experimental bacterins and attenuated vaccines

Infectious Agents (44 decks)

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