Gram Pos: Corynebacterium, Rhodococcus, Nocardia Flashcards
Describe acid fast partial VS acid fast.
- Acid fast partial
-corynebacterium
-rhodoccus
-nocardia - Acid fast
-mycobacterium
Describe the key bacterial characteristics of corynebacterium.
-gram pos
-pleomorphic
-aerobes or facultative anaerobes
-short mycolic acids in cell wall *
-non spore forming
-pathogenic are non motile
-commensal on mucus membrane *
-species found in soil & environment
-host specific
-opportunistic pathogen causing pyogenic inf *
-tissue trauma precede est of pathogenic corynebacteria *
-lipid rich outer layer = survive in macrophages (facultative intracellular pathogen)
-chronic granulomatous diseases
Describe the virulence factors & pathogenesis of corynebacterium.
Describe the species of vet IMP.
Describe corynebacterium pseudo tuberculosis in sheep & goats.
-chronic pyogranulomatous inf of LN -> caseous necrosis *
-abscess & enlargement of superficial or internal LN *
-inf spread by pus from rupture abscess & nasal/oral secretion
-organism survive in environment for months
-internal abscess = weight loss (thin ewe syndrome *)
-caused by non nitrate reducing bio type C. Pseudotuberculosis *
-portal of entry thru abrasions
-incubation: 3mo
-curse of goat industry
Describe the pathogenesis of c. Psuedotuberculosis in sheep & goats.
-initial lesion begins as lymphadenitis w the formation of multiple microscopic abscesses in the cortex -> coalesce of microabcesses -> areas of caseation
-encapsulation of abscess by fibrous CT -> enlargement of LN
-goats: exudate less dry & not concentrically laminated or mineralized
Describe caseous lymphadenitis (c. Pseudotuberculosis) in sheep & goats diagnosis.
-economic loss: death, hide & wool loss
-diagnosis:
>CS = abscess, weight loss
>culture purulent material
>radiograph & ultrasonography to detect internal abscesses
>serology
—synergistic hemolysis inhibition (SHI) test: detect antibodies to phospholipase D exotoxin
—pos titer indicate past resolved infections, recent exposure, recent vaccination or active lesions *
(When in doubt - repeat titer in 2-4wk to see if titer rises)
—false neg = testing done too early in the infection (<2wk) or animals w chronic walled off abscess
—interpretation in young difficult bc maternal antibodies (<6MO)
[LOW OR NO TITER DOESNT RULE OUT INF] *
Describe caseous lymphadenitis (c. Pseudotuberculosis) in sheep & goats control.
-caseous lymphadenitis not a curable disease
>educate owner stressing the persistent, recurrent nature of disease *
-animals w genetic or emotional value are treated
>isolate animals in area that can be disinfected
>lance, drain, excise abscess
>iodine, bleach, chlorahex to disinfect
>systemic antibiotics & intralesional antibiotics
-infected animals culled ideally
-commercial vaccines species specific
>not rec for clean herds w no history of CL
-good biosecurity, hygiene, management practices (proper shearing)
Describe c. Pseudotuberculosis in horses.
‘Pigeon fever, dry land distemper’
-ulcerative lymphangitis
-infectious, inflam condition of the cutaneous lymphatic system of lower limbs & chronic abscess in the pectoral & ventral region
-caused by nitrate reducing bio type C. Pseudotuberculosis *
-swelling of chest or abdomen, fever, loss of appetite, lameness, deep SQ external abscess
-most common & economically imp infectious disease in Cali & Texas w inc prevalence in other western/midwest states of US
Describe the key characteristics of ulcerative lymphangitis in horses.
-common in dry areas
-seasonal incidence = more prevalent in autumn & early winter *
-stable flies, horn flies, house flies: role in dissemination of organism *
-bacteria enter thru skin abrasion
-treatment: long term systemic antibiotic w topicals
-prevention: isolation of infected horses, fly control, sanitation
Describe c. Renale group.
‘Contagious bovine pyelonephritis’
-inflam of urinary bladder (cystitis) -> ascend to ureters to cause inf of kidneys (pyelonephritis)
-reservoir: vulva & vag of clinically normal carrier cows (commensal)
-contributing factors: stress of birth, peak lactation, high protein diet, trauma to bladder & urethra
-CS: fever, loss of appetite, painful urination, ammoniac odor of urine, acute ab pain (kicking), decrease rumen contraction & milk prod
Describe c. Kutscheri.
‘Murine Pseudotuberculosis’
-lung: suppurative pneumonia
-kidney, liver, heart = nodular lesion
-joint: arthritic lesion of pedal extremities
-LN: lymphoid hyperplasia of regional nodes
Describe the key bacterial characteristics of Rhodococcus.
-gram pos (cocci or rods)
-aerobic soil saprophyte
-non motile
-mucoid salmon pink colony
-weak acid fast (envelope rich in mycolic acid)
-opportunistic pathogen in young foals (<6MO) *
-facultative intracellular pathogen *
-survival in macrophages w granuloma formation *
-main respiratory pathogen of foals that cause suppurative bronchopneumonia
>caused by bacterial directed inappropriate th2 rather than th1 immune response
Describe virulence factors & pathogenesis of Rhodococcus.
-Virulence is maintained in horses (isolates from non-equine hosts usually lack virulence-associated
proteins) *
-sus of foals < 6mo bc impaired cellular immunity in the lungs *
Describe Rhodococcus equi in foals.
‘Suppurative bronchopneumonia’
-lung abscessation (1-4mo of age)
-inf in first 2wks of life
-sign of acute disease in 1mo old foals: fever, anorexia, diarrhea, cough, dyspnea
-slow progression: CS difficult to detect until pulmonary inf reaches critical mass -> decomp of foals
-polysynovitis, intestinal & mesenteric abscesses, ulcerative enterocolitis
Describe the key bacterial characteristics of Nocardia.
-gram pos
-pleomorphic
-aerobe
-facultative intracellular bacterium
-non motile, non spore forming
-acid fast partial
-ubiquitous in soil & water *
-non path for immunocompetent *
-opportunistic
-non contagious
-pyogranulomatous to suppurative disease of domestic animals, wildlife, people
-thoracic (pneumonia, pyothorax), cutaneous (abscesses), disseminated in dogs & mastitis in cattle
