Bacteria Flashcards
L. intracellularis
Obligate intracellular, proliferative enteritis
Not encountered in research colonies
Mycoplasmosis
M. pulmonis, M. arthritidis, M. neurolyticum, M. collis, and M. muris
M. pulmonis
Gram negative
Murine respiratory mycoplasmosis
Suppurative rhinitis, otitis media, chronic pneumonia - CHATTERING, head tilt
Can be transmitted aerosol, venerally, transplacental (rats)
Rats are only significant resevoir for mice
Serology may not detect difference between M. pulmonis/M. arthritidis
Athymic mice not more susceptible (T-cell response exacerbates)
M. pulmonis - pathology
Colonizes apical surface of respiratory epithelium
Extracellular
B6 resistant, BALB/c, C3H, SJL, CBA, AKR, SWR, DBA/2 varying degrees of increased susceptibility
Inital lesions is suppurative rhinitis ->squamous metaplasia, syncytia sometimes
M. pulmonis rhinitis
Turbinate mucosa contains accumulations of plasma cells and lymphocytes, epithelial is decreased in thickeness and has lost most cilia, lumen contains neutrophilic exudate
M. pulmonis
Bronchiolitis and bronchiolectasis
Bronchioles are dilated, contain neutrophilic exudate and are surrounded by accumulations of plasma cells and lymphocytes. Mucosa is infiltrated with inflammatory cells
M. arthritidis
Antigentically related to M. pulmonis, nonpathogenic during natural infection
M. neurolyticum
Rolling disease
usually die within 4 hours
Experimental innculation with exotoxin
Astrocytic swelling
CAR bacillus induced bronchiolitis and pneumonia in mouse. Bronchiole is surrounded by lymphocytes, the lumen contains neutrophilic exudate, and the epithelium is hyperplastic. Adjacent alveoli contain neutrophils and macrophages
CAR bacillus induced rhinitis in a mouse
Epithelium is infiltrated by neutrophils and lymphocytes and the underlying tissue is hyperplastic. Basophilic CAR bacilli are visible among the cillia at the left
Hemotropic mycoplasmas
Mycoplasma hemomuris and Mycoplasma coccoides
Tropic for RBCs, anemia, hemolytic disease
Splenomegaly
Either acute febrile anemia or latent/subclinical infection that can be reactived by splenectomy/irradiation
Vector: Polyplax serrata (mouse louse)
Tranmissible Murine Colonic Hyperplasia
Descending colon is thickened and opaque
CAR Bacillus
Gram negative, non-spore forming
Produces clinical disease in rats
Transmitted through direct contact
Peribronchiole cuffing with lymphocytes and plasma cells
Warthin-Starry
tx: sulfamerazine
Colonic inflammation, edema, mild hyperplasia of the epithelium, and significant development of mucosa-associated lymphoid tissue (MALT) caused by C. rodentium
Multiple abscesses in a nude mouse caused by P. pneumotropica
Transmissible Murine Colonic Hyperplasia
C. rodentium, gram negative
Self-limiting to severe colitis
Retarded growth, ruffled fur, soft feces or diarrhea, rectal prolapse, and moderate mortality in older suckling or recently weaned
Contaminated mice, food, bedding
Model EPEC/EHEC
DBA, NIH/Swiss, C57BL resistent, C3H susceptible
Electron micrograph of H. hepaticus in hepatic bile canaliculi
H. bilis induce non suppurative hepatitis and hepatic necrosis. Inflammation originates in portal triads
TMCH - pathology
Attaches to mucosa of descending colon and displaces normal flora
Attaching and effacement lesions
Lasts 2-3 weeks in surviving animals
Can be cultured on MacConkey’s during early stages only
Psuedomoniasis
Pseudomonas aeruginosa, gram negative rod
Immunodeficient animals can be prone to septicemia
Equilibrium disturbances, conjunctivitis, serosanguinous nasal discharge, edema of the head, weight loss, skin infections, torticollis
Acidification/hyperchlorination of water
Antibiotic and quat resistant
P. pneumotropica
Gram negative
Usually subclinical, opportunistic pathogen
Suppurative lesions - preputial and orbital abscesses
Does not transmit from infected mice to contact/bedding sentinels
Tx: enrofloxacin
Helicobacter hepaticus
Chronic active hepatitis, hepatic tumors, IBD
Colonizes crypts of lower bowels
Helicobacters - mice
hepaticus, bilis (rats also), rodentium, ganmani, mastromyrinus, magdeburgensis, typhlonius
H. bilis
Isolated from livers and intestines of aged mice and experimentally induces IBD in SCID
H. muridarum
Colonizes ileum, cecum, and colon
Nonpathogenic
Helicobacter treatment
Amoxicillin, metro, and bismuth - H. hepaticus
Salmonellosis
S. enterica subsp. enteria serovar Typhimurium and serovar Enteritidis
Antimicrobial resistance genes, type III secretion systems, Vi antigen, LPS
PAMPs interact with TLRs/NOD-like receptors leading to inflammasome formation and release of pro-inflammatory cytokines
Acute infection severe in young mice - anorexia, weight loss, dull hair coat, lethargy, humped posture, conjunctivitis
Ingestion of contaminated products, subclinical carriers/shedders
ZOONOTIC
S. enteritidis
Reach Peyer’s patches w/i 12h after innoculation -> mesenteric lymph nodes
Persists in spleen, liver, lymphnodes, gall bladder
Chronic arthritis
Visceral hyperemia, pale livers, catarrhal enteritis, acute death
Spleen/liver - yellow/pale foci of necrosis
Granulomatous lesions - characteristic of chronic salmonellosis
Culture for salmonella
Selenite F broth plys cystine followed by streaking on brillant green agar
Feces, mesenteric lymph node
Streptobacillosis
Streptobacillus moniliformis, gram negative
Can exist as a nonpathogenic L-phase varient in vivo or can revert to virulent bacillus form
Acute phase - high mortality, subacute phase, chronic phase
Dull, damp hair coat and keratoconjunctivitis
Anemia, diarrhea, hemoglobinuria, cyanosis, emaciation, hindlimb paralysis, cutaneous ulceration, athritis, gangrenous amputation, urinary bladder distension, stillbirths, abortions
ZOONOTIC - Haverhill (rat bite) fever
S. moniliformis
Necrotic lesions in thoracic and abdominal viscera, septic thrombi, fibrin
Chronic - purulent polyarthritis
C. piliforme in liver
C. kutscheri
Pseudotuberculosis in mice and rats, often subclinical, inappetence, emaciation, rough hair coat, hunched posture, hyperpnea, nasal and ocular discharge, cutnaeous ulceration, arthritis
Gray-white nodules on liver, kidney, lung, cervical lymphadenopathy and arthritis
Coagulative/caseous necrosis with intense neutrophilic infiltration
“Chinese letters”
Staphylococcosis
Most common - S. aureus (highly pathogenic) and S. epidermidis (nonpathogenic)
Pathogenic Strep generally coagulase positive (except S. xylosus)
Suppurative conjunctivitis, orbital abscesses, preputial adenitis, pyoderma
B6, C3H, DBA, BALB/c mice most susceptible
Streptococcosis
Pathogenic streptococcal infeciton are caused by Beta-hemolytic in Lancefield’s group C
Group D - Enterococcus
Cutaneous infection, conjunctivitis, rough hair coat, hyperpnea, somnolescence, and emacitation
Colibacillosis
Hyperplastic typhlocolitis has been reported in SCID mice
Lethargy, fecal staining
Klebsiella pneumoniae
Gram-negative
Opportunistic pathogen
AAHC in humans, model with Clavamox
Utero-ovarian infections in aged B6C3F1
Tilivalline - cytotoxin
C. difficile
Antimicrobial-associated pseudomembranous colitis
Also in GPs, rabbits, Syrian hamsters, prarie dogs, ostriches, and horses
Cycloserine-cefoxitin-fructose agar for culture
Nonhemolytic, gray, umbonate profile with filamentous edges and ground glass appearance
Toxins A and B
Rapidly germinate and established infeciton
C. perfringens
Double zone of hemolysis, gray, smooth, round
Five types based on four major toxins - major is enterotoxin
Ingestion of spores
Type A - part of normal microbiota
Type D - report of mortality in 2-3 week old mice
Tx: chlortetracycline Hcl, Penicillin G
C. piliforme
Tyzzer’s, first described in Japanese Waltzing mice
Gram negative
Unexpected deaths, diarrhea, inactivity, high mortality
Stress
B6 more resistant, DBA/2 more susceptible (B cell function)
Cross-infection - mice, rats, hamsters
Spore can retain infectivity at room temp for at least 1 year
C. piliforme - pathology
Begins in GI -> liver, heart
Necrosis (above and MLNs)
Ileum, cecu, colon, may be red and dilated, watery, fetid contents
Liver, MLN, heart - gray-white foci
Necrosis of mucosal epithelium, liver - coag necrosis along portal vein
Silver stains, Giemsa, or PAS are required for visualization
Mycobacteriosis
M. avium-intracellulare and M. lepraemurium
Chronic granulomatous disease, Langhans giant cells, acid-fast bacteria
M. lepraemurium may cause alopecia, thickening of skin, SQ swellings, ulceration
Hallmark is perivascular granulomatosis with accumulation of large, foamy epitheloid macrophages (lepra cells) packed with acid-fast bacilli
Proteus mirabilis
Ubiquitous gram-neg, can remain latent in the resp and intestinal tracts of mice
Commonly found in lab mice
Ass. with ulcerative lesions in Gi of immunodeficient mice (lose weight, diarrhea, die, septicemia)
Pyelonephritis - abscessation and scarring
Splenomegaly and focal necrotizing hepatitis - immunodeficient
Leptospirosis
One of the most common zoonoses transmissible from rodents, but very rate in lab mice
L. interrogans serovar ballum (zoonotic)
Gram negative, establish infection in renal tubules
Subclinical
Chlamydia infection
C. trachomatis (intracellular) - produces glycogen-positive intracytoplasmic inclusions (elementary bodies)
Ocular and urogenital disease in humans
C. psitaci
Chlamydia muridarum
“Nigg agent” - C. muridarum - experimental model of human chlamydia
Also known as “mouse pneumonitis agent”
Severe, acute infection, ruffled fur, hunched posture, labored respiration due to interstitial pneumonitis and death
Cyanosis of ears and tail
Dx: impression smears stained with Giemsa/Macchiavello stains
