Bacteria of Mice Flashcards

1
Q

______ is a gram-negative spirochete that causes persistent infection in rats and mice?

A

Leptospira ballum

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2
Q

Why is leptospirosis challenging to diagnose in lab rodents

A
  • it’s rare
  • kidney culture can lead to false negatives, esp. in undiluted samples
  • infected neonates don’t seroconvert but are persistently infected
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3
Q

What virus causes persistent infection in mouse pups without seroconversion

A

LCMV

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4
Q

What kind of tissue does Pasteurella pneumotropica like to colonize

A

mucus cells (respiratory, enteric, and genital tracts of clinical normal mice)

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5
Q

T/F Salmonella is zoonotic

A

true

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6
Q

Why is treating Salmonella typhimurium with antibiotics not the best idea?

A

Gut bacteria are a natural barrier and the bacteria likes to hang out in macrophages. Treating with abx will wipe the good gut bacteria and give salmonella the room it needs to get in there.

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7
Q

What should you do with subclinical carriers of Salmonella typhimurium

A

cull and start over

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8
Q

Gross Findings of salmonella typhimurium

A
  • multifocal necrotizing splenitis and hepatitis
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9
Q

histopath findings of Salmonella typhimurium

A

necrotic foci in affected tissues, often accompanied by colonies of bacteria, edema, and erythema in Mesenteric LNs

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10
Q

Which age of mice are most susceptible to Salmonellosis

A

weanlings

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11
Q

what is the ideal tissue for diagnosis of Salmonellosis?

Ideal diagnostic?

A
  • oral swabs or fecal culture
  • culture on blood agar plates
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12
Q

What predisposes mice to Pseudomonas infection?

A
  • irradiation, immunosuppression, concurrent disease (esp. MCMV)
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13
Q

Which mice strains are susceptible to pseudomonas aeruginosa

A
  • C3H
  • Swiss-Webster
  • MyD88-/-
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14
Q

Where would streptococci typically colonize mice normally?

A
  • Intestines, skin, genital tract, upper respiratory tract
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15
Q

What predisposes mice to streptococci infection?

A
  • irradiation, skin wounds, experimental infection, contaminated biologicals, immunosuppression, immunodeficiency
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16
Q

Hematogenous spread can occur with streptococcal infections and lead to abcesses and infect which major organs?

A
  • heart (endocarditis)
  • spleen (splenomegaly)
  • LNs (lymphadenopathy, cervical lymphadenitis)
  • Skin (UD)
  • heart and kidney infections
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17
Q

What are differentials in a nude mouse with furunculosis?

A
  • staphylcoccus
  • Streptococcus
  • Corynebacterium bovis
  • Pasteurella pneumontropica
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18
Q

What is the process that leads to the hallmark chronic suppurative inflammation of staphyloccal infections?

What is the name of the material?

A

botryomycosis

  • Splendore-Hoeppli (brightly eosinophliic, amorphous-fibrillar)
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19
Q

How do we treat staphyloccal infections?

A
  • Monitor
  • open and drain abscesses +/- abx
  • euthanize if colony is at risk
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20
Q

T/F Trichophyton mentagrophytes does not fluoresce under UV light

A

True

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21
Q

How do you diagnose Trichophyton mentagrophytes?

A

DTM culture or Sabouraud agar

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22
Q

What stain should you use to ID Trichophyton mentagrophytes?

A

Silver stain or Schiff’s

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23
Q

What is the name of the disease associated with Citrobacter rodentium infection in Mice?

A

Transmissible Murine Colonic Hyperplasia

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24
Q

Gross lesion of Citrobacter rodentium infection

A

Severe thickening of the descending colon (may extend to the transverse colon)

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25
Q

Histopath lesions of Citrobacter rodentium infection

A

Marked hyperplasia of the crypt epithelium with retention of cells on the surface and leukocytic infiltration in the lamina propria

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26
Q

What specific anatomic sites are affected by Citrobacter rodentium?

A
  • the mucosal surface of the descending colon
  • brush border of the enterocytes -> dissolution of brush border, actin filament rearrangement, pedestal formation from the plasma membrane
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27
Q

Clinical signs expected with Citrobacter rodentium infection?

A
  • ruffled fur, slowed growth
  • Soft feces, diarrhea, rectal prolapse
  • moderate mortality in older suckling or recently weaned mice
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28
Q

Research implications of Citrobacter rodentium infection

A
  • hyperplastic lesions predispose to cancer
  • immune dysfunction
  • mortality, particular in immunocompromised mice
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29
Q

Which strains are the most susceptible strains to Citrobacter?

  • most resistant to mortality?
A
  • infant and immunodeficient mice most susceptible to disease
  • susceptible strains: C3H; AKR; FVB
  • Strains resistant to mortality: DBA, NIH Swiss, and C57BL/6 mice
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30
Q

Diagnosis of Citrobacter

Transmission of Citrobacter

Prevention/control of citrobacter

A
  • Dx: Isolation of bacteria in GI or feces in conjunction w/ lesions
  • Tx: Fecal-oral route
  • Prev/control:
    – Addition of antimicrobials to water
    – Disinfection/disposal of contaminated food, water, and bedding
    – Sentinel monitoring
    – Microbarrier caging to prevent transmission
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31
Q

Which bacteria are associated with Clostridial Enteropathy in mice?

A
  • Clostridioides difficile (Toxin A (TcdA) and Toxin B(TcdB))
  • Clostridium perfringens (Nontype A, type A, Type B, and Type D)
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32
Q

Which C. perfringens type most often produces enterotoxin

A

Type A

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33
Q

Gross pathological findings of Clostridial enteropathy

A
  • small and large intestines gas and fluid-distended
  • Mucosa is reddened, may have petechiae, ulcers, or fibrinous pseudomembranes
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34
Q

CS of Clostridial enteropathy

A
  • Hunched posture, ruffled hair coat
  • Enlarged or painful abdomen
  • Diarrhea
  • Sudden Death (C. perfringens nontype A, type B, and Type D)
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35
Q

Histopath findings of Clostridial enteropathy

A
  • mucosal ulcers, hemorrhage, and inflammation w/ pseudomembranes and large #s of bacteria (mucosal necrosis is more common in C. perfringens)
  • Generalized lymphoid apoptosis
  • Recover phase: diffuse mucosal hyperplasia
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36
Q

Transmission of clostridium/clostrioides

A
  • normal inhabitants of mouse intestine
  • spread via fecal oral route (spores shed in feces)
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37
Q

Infections and disease of clostridium/clostridioides is often _______

A

secondary to intestinal dysbiosis

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38
Q

Diagnosis of clostridium/clostridioides

A

Detection of toxins in GI and feces via PCR or cytotoxicity assays

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39
Q

Prevention and control of clostridium/clostridioides

A
  • Decontamination
  • Prevent sudden diet changes and unnecessary antibiotic use
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40
Q

T/F E. coli is a normal inhabitant of the mouse intestine

A

true

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41
Q

Which mice are susceptible to disease (colibacillosis)

A
  • nonpathogenic to immunocompetent mice
  • immunodeficient mice may be susceptible
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42
Q

Clinical signs of colibacillosis

A
  • lethargy, diarrhea, and fecal staining in SCID mice from non-lactose-fermenting e. coli
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43
Q

Gross lesions of colibacilosis

A
  • segmental thickening of colon or cecum with reddened mucosa
  • blood-tinged feces
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44
Q

histopath lesions of colibacillosis

A
  • mucosal hyperplasia with inflammation and / or erosions
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45
Q

Diagonsis of E. coli

Prevention / control of E. coli

Research implications of E. coli

A

Dx: combination of lesions and non-lactose-fermenting E. coli isolation on growth plate (culture)

Prev/control:
- remove affected animals
- disinfect cage and equipment

Research implications: clinical illness in immunodeficient mice

46
Q

Histological features of Chlamyida spp.

A
  • obligate intracellular organism
  • elementary and reticulate bodies within cytoplasm of infected cells
47
Q

Which chlamydial species is used as a model of human chlamydial disease?

A
  • Chlamydia muridarum (“Nigg agent”) is the model for chlamydia trachomatis infections in humans
48
Q

Which other Chlamydia spp. can cause disease in mice

A
  • Chlamydia trachomatis
  • Chlamydophila psittaci
49
Q

Diagnosis of Chlaymid

A
  • PCR
  • Cell culture or inoculation of embryonated chicken eggs
  • Giemsa or Macchiavello stains
50
Q

Clinical signs associated with chlamydial/chlamydophila infection in mice

A
  • natural infection typically subclinical
  • route of infection affects clinical signs
    — conjunctivitis
    — infection of the urogenital tract results in hydrosalpinx, cervical and vaginal inflammation, and/or urethritis
51
Q

What does Chlamydia muridarum (Mouse Pneumonitis (MoPn) agent) infect?

What are the clinical signs in mice?

A
  • Infects bronchiolar epithelium and type 1 pneumocytes
  • infects macrophages and can spread to other organs
  • CS:
    – hunched posture, ruffled fur, labored breathing
    – may die in 24h or persist as chronic infections with cyanosis and progressive emaciation
52
Q

Clinical signs in Proteus mirabilis infection

A
  • progressive weight loss
  • diarrhea
  • death over course of several weeks
53
Q

Gross findings of Proteus mirabilis infection

A
  • splenomegaly, multifocal hepatic necrosis, abscesses in organs
  • pulmonary edema
  • pyelonephritis with renal abscesses (presumed ascending infection)
54
Q

T/F Proteus is ubiquitous unless specifically excluded by the vendor, and is typically non-pathogenic, but may be opportunistically pathogenic in immunodeficient mice

A

True

55
Q

T/F Klebsiella spp. are not opportunistically pathogenic

A

False, they are opportunistically pathogenic

56
Q

What do you need to diagnose a Klebsiella infection

A
  • combination of lesions with culture of predominantly/purely Klebsiella
57
Q

Gross lesions of Klebsiella oxytoca

A
  • abscesses in many organs and other features of gram-negative septicemia
  • suppurative endometritis and inflammation of the female repro tract with abscesses (has been described in C57BL/6 mice
58
Q

Klebsiella pneumoniae is only pathogenic if _____

A

experimentally inoculated into respiratory or urinary tracts

59
Q

What gram-negative curved or spiral shaped bacteria wide-spread in both conventional and barrier colonies

A

Helicobacter

60
Q

Where is Helicobacter usually isolated form?

What other tissue can it infect?

A
  • GI tract, feces
  • Liver
61
Q

Diagnosis of Helicobacter

A
  • PCR of feces/tissues
  • molecular speciation
  • culture
  • clinical signs
  • Histo w/ sliver stains
62
Q

What Helicobacter spp. may be normal flora in rodents

A

H. rodentium

63
Q

Which Helicobacter spp. is most present in mice?

A

H. hepaticus

64
Q

Which Helicobacter spp. is also found in rats?

A

H. bilis

65
Q

Which Helicobacter spp. is a human pathogen also found in mice

A

H. pallorum

66
Q

Common clinical signs associated with helicobacter

A
  • asymptomatic
  • diarrhea
  • rectal prolapse
67
Q

Helicobacter causes increased susceptibility of what pathology in A/JCr mice

A
  • hepatomas and hepatocellular carcinomas
68
Q

What other pathology may you see w/ Helicobacter spp. in any mice?

A
  • Proliferative typhlitis, colitis
  • Lower bowel carcinoma
  • Bacterial translocation to liver: angiocentric, non-suppurative hepatitis, hepatic necrosis
69
Q

Impact of Helicobacter spp. on research

A
  • Proinflammatory
  • research involving GI tracts/IBD impaired
  • Immunodeficient colonies
  • General confounding factor??
70
Q

Control/prevention of Helicobacter spp.

A
  • Triple therapy: amoxicillin, metronidazole, pepto-bismol
  • Eradication may not be practical in large numbers
71
Q

Which bacteria should be rare in research animals, but is a historic model for leprosy?

A
  • Mycobacterium lepraemurium
72
Q

What other Mycobacterium causes clinical disease in mice?

A

Mycobacterium avium-intracellulare

73
Q

What pathogen is related to mouse mycobacterium and the causative agent for Johne’s disease in cows?

A
  • Mycobacterium avium subspecies paratuberculosis
74
Q

How do Mycobacterium spp. stain?

A
  • gram Positive
  • Acid-fast
  • Intracellular
  • Rods
75
Q

What pathology do Mycobacterium cause?

In what tissues?

A
  • granulomatous disease
  • lungs, liver, spleen, lymph nodes
76
Q

What is the causative agent of rat bite fever?

A
  • Streptobacillus moniliformis
77
Q

T/F Streptobacillus moniliformis is not zoonotic

A

False - it is zoonotic

78
Q

Transmission of Streptobacillus moniliformis

A
  • persistently infected rats
  • Aerosol, fomites, bite wounds
79
Q

Clinical signs of Streptobacillus moniliformis

A
  • Acute: high mortality, dull/damp hair coat, KCS
  • Variable: anemia, diarrhea, hemoglobinuria, cyanosis, emaciation
  • Chronic: arthritis, cutaneous ulceration, gangrenous amputation, hindlimb paralysis
  • Breeding: stillbirths, abortions
80
Q

What is the causative agent of proliferative enteropathy

A

Lawsonia intracellularis

81
Q

Which mice are naturally infected with Lawsonia intracellularis

A

wild mice (not been described in lab mice)

82
Q

Transmission of Lawsonia intracellularis

A

fecal-oral route

83
Q

Clinical signs of Lawsonia intracellularis

A

none

84
Q

Gross lesions of Lawsonia intracellularis

Histopath lesions of Lawsonia intracellularis

A

gross:
- hyperplastic ileitis, typhlitis and/or colitis
- may note hemorrhagic intestines

Histopath:
- intestinal epithelial hyperplasia

85
Q

Diagnoss of Lawsonia Intracelluaris

DDx of Lawsonia intracellularis

A
  • PCR, IHC, Warthin-Starry silver staining
  • C. rodentium
  • Enterohepatic helicobacter spp.
86
Q

Prev/control of Lawsonia intracellularis infection

Research impact of Lawsonia intracellularis

A
  • don’t house mice with more susceptible spp. (hamsters, rabbits)
  • none reported
87
Q

Transmission of Filobacterium rodentium

A
  • vertical transmission (dam to pup)
  • Direct contact and fomite transfer less efficient
88
Q

Other name for filobacterium rodentium

A

CAR bacillus

89
Q

Clinical signs of Filobacterium rodentium

A

oculonasal discharge, increased respiratory effort, hunched posture, anorexia w/ weight loss

90
Q

is filobacterium rodentium a primary or opportunistic disease-causing pathogen

A

opportunistic

91
Q

Gross lesions of Filobacterium rodentium

A
  • lungs lesions typically mild, with no apparent or discernable lesions with experimental infections
  • If severe enough, severe pneumonia and bronchiolitis are possible
92
Q

Histopath of Filobacterium rodentium

A
  • marked peribronchiolar cuffing with plasma cells and lymphocytes
93
Q

Diagnosis of Filobacterium rodentium

DDx of Filobacterium rodentium

A

Diagnosis:
- Serology (ELISA)
- PCR and histology for definitive diagnosis
- Silver stains (Warthin-Starry) can be used for active infections

DDx:
- Respiratory mycoplasmosis
- Bordetella
- Sendai Virus
- PVM

94
Q

Why is environmental disinfection for Filobacterium effective

A

its non-spore forming, and therefore more susceptible

95
Q

Tx of Filobacterium rodentium

Reseach impact of Filobacterium rodentium

A
  • Sulfamerazine in drinking water
  • Culling or embryo rederivation is recommended

may confound studies, esp. in immunocompromised mice

96
Q

What are the two Corynebacterium pathogens of interest in mice

A
  • Corynebacterium kutscheri
  • Corynebacterium bovis
97
Q

C. kutscheri is the causative agent of ______, while C. bovis is more associated with ____

A
  • pseudotuberculosis
  • hyperkeratosis
98
Q

What stimulates an active C. kutscheri infections

A

immunosuppression or environmental stress

99
Q

What is the morbidity/mortality of C. kutscheri

A
  • high mortality with acute disease
  • low mortality with chronic disease
100
Q

Clinical signs of C. kutscheri

A
  • inappetence, emaciation, rough hair coat, hunching, hyperpnea, oculonasal discharge, cutaneous ulceration, arthritis
101
Q

Clinical signs of C. bovis

A
  • hyperkeratotic dermatitis (scaly skin and alopecia)
  • KCS reported in aged C57BL/6 mice
102
Q

Gross lesions of C. kutscheri

A
  • hematogenous spread
  • gray-white nodules on liver, kidney, lung, etc.
  • Cervical lymphadenopathy
  • Mucopurulent arthritis
103
Q

Histopath lesions of C. kuscheri

A
  • Coagulative/caseous necrosis
  • Colonies of Gram(+) bacteria w/ acute angle alignment
104
Q

Gross lesions of C. bovis

Histopath lesions of C. bovis

A
  • gross: hyperkeratotic dermatitis (scaly skin and alopecia)
  • Histopath: prominent acanthosis and moderate hyperkeratosis accompanied by mild, nonsuppurative inflammation
105
Q

Transmission of C. Bovis and C. kutscheri

A
  • Fecal-oral
  • Direct contact
  • Aerosol
106
Q

Diagnosis of C. kutscheri

DDx of C. kutscheri

A

Diagnosis:
- Culture
- Gram stain

DDx:
- mycobacterium avium

107
Q

Diagnosis of C. bovis

DDx of C. bovis

A

Diagnosis
- PCR
- Skin culture
– hold for 7 days - slow-growing

DDX:
- Staphylococcus xylosus
- Low humidity in glabrous mice

108
Q

Why should you cull colonies infected with C. bovis or C. kutscheri

A

treatment is not curativeRes

109
Q

What is the causative agent of Tyzzer’s disease

A

Clostridium pilforme

110
Q

CS of Clostridium piliforme

Resistant strains

Transmission

Gross lesions

stain to ID

A

CS:
- diarrhea and acute death

resistant strains
- C57BL/6 > DBA/2

Natural infection transmitted by ingestion of orgs.

Gross lesions:
- necrosis of liver, mesenteric LNS, and heart (less so) (white foci)
- ileum, cecum, colon may be red and dilated with watery, fetid contents

Stains: Silver stains, Giemsa, periodic acid-Schiff stains usually required

111
Q

Pneumocystis murina
- CS
-Gross lesions

A

CS
- subclinical in immunocompetent mice
- severe in immunodeficient mice: pneumonia, dyspnea, hunched posture, wasting, scaly skin

gross lesions
- rubbery lungs that fail to inflate