Final Flashcards
What is the primary cell target for rickettsia?
endothelial cells (non professional phagocytes)
What is the morphology of rickettsia?
very small pleomorphic coccobacilli
How is rickettsia spread in the host?
reitculoendothelial and vascular endothelial cells or erythrocytes
What is the diagnostic test of choice for rickettsia?
PCR
What age does anaplasma marginale cause the most disease?
animals older than 18 months
How is anaplasma marginale spread?
ticks and biting flies
How is anaplasma marginale diagnosed?
cytology - blood smear and special staining
What kind of cell is targeted by ehrlichia canis?
WBCs (different from rickettsia)
What are the CS of ehrlichia canis?
pancytopenia, epistaxis, hypergammaglobulinemia, lymphadenopathy, increased RBC sedimentation
What bacteria causes Potomac horse fever?
Neorickettsia risticii
What are the symptoms of potomac horse fever?
anorexia, fever, leukopenia, explosive diarrhea
usually in the summer months
How is neorickettsia risticii transmitted?
new info - ingestion of infected trematodes, also by biting arthropods
How is chlamydia transmitted?
direct contact
What are the two life cycle forms, infective and non infective, of chlamydia?
Elementary bodies - infective
reticulate or initial bodies - non infectious
What is the cell tropism of chlamydia?
epithelial cells of mucous membranes and phagocytes
What inclusion bodies does chlamydia produce?
membrane inclusion bodies (not free in cytoplasm like rickettsia)
What is the incubation period for young and older birds for chlamydia psittici?
older - a few days to several weeks
young - 3-7 days
What are the symptoms of psitticosis?
anorexia, diarrhea, mucopurulent discharge
What is the treatment for psittacosis?
chlorotetracycline (peniciillin NOT effective) (intracellular)
What are the symptoms of bartonella henselae?
regional lymphadenopathy, cutaneous inoculation lesion, fever, anorexia, resolves in 1 month
What bacteria is the cause of infectious bovine keratoconjuctivitis?
Moraxella bovis
What is the morphology of Moraxella bovis? What kind of colonies does it form?
gram negative diplobaccilli
forms pits on agar surface
How does Moraxella bovis become infectious?
opportunistic! (concurrent viral or mycoplasma infection), solar radiation
What are the two important virulence factors for moraxella bovis?
pilli
hemolysin - lyse RBCs and corneal cells
What is the treatment of choice for moraxella bovis?
oxytetracycline (intracellular)
Which burkholderia species is non motile and mammalian host adapted?
B. mallei
What species is burkholderia an obligate parasite?
equidae family
How does Pseudomonas and Burholderia encounter the host?
inhalation or wounds
What are the two pigments produced by Pseudomonas aeruginosa?
pyoverdin and pyocanin
What are the diseases caused by Pseudomonas aeruginosa in swine, cows, dogs, sheep, and chinchillas?
Swine - necrotic pneuomonias, enteritis, and rhinitis Cow - mastitis Dogs - otitis externa sheep - green wool or fleece rot chins - hemorrhagic pneumonia
What is the unifying feature of the CMN group? (coryne, myco, nocardia)
mycolic acids - long chain, alpha branched, beta-hydroxy fatty acids in cell wall
What is the cord factor and in what bacteria is it found?
cord factor - glycolipid composed of mycolic acid and an oligosaccharide
found in M. tuberculosis and M. bovis
How does cord factor act as a virulence factor?
grow in serpentine cords –> granulomatous reaction
What two stains can be used for mycobacterium?
acid fast and carbol-fuschsin stain
What two media can be used to culture mycobacterium?
middlebrooks and lowenstein-jensen (both have glycerol)
What is the morphology of mycobacterium?
small rods, non motile, strict aerobes
What can tissue be treated with to kill competing organisms to look for mycobacterium?
1:1000 bleach and 2% NaOH (myco are resistant to acid and alkali)
What happens with M. tuberculosis infects an immunodeficient host?
dissemination of tubercle bacilli (instead of nodules)
What is the term for cell density dependent communication system in bacteria that use N-acyl hemoserine lactones or small peptides to coordinate virulence?
quorum sensing (master regulator of virulence)
What starts biofilm formation in Pseudomonas?
rhamnolipids
What are the three advantages to Pseudomonas when in a biofilm?
antiphagocytic
protection from antimicrobials
mutate at higher frequency
What kind of disease does Burkholderia pseudomallei cause?
meliodosis - pain, skin infections, associated with suppurative or caseous lesions
Where is B. pseudomallei endemic to?
SE asia, other tropical countries, saprophytic, high humidity
What media can be used to help diagnose Burkholderia pseudomallei? What does it look like microscopically?
Ashdowns media = unique colony form (purple, wrinkled) and odor
bipolar, safety pin shaped
What can B. pseudomallei do different with its TT3S than pseudomonas?
form multinucleated giant cells
What causes Glanders disease in animals and humans?
Burkholderia mallei
What does B. mallei cause in horses?
(glanders)ulcerating nodules in URT, lungs and skin –> fatal
What are the CS of acute glanders dz?
septicemia with high fever, followed by thick discharge and resp distress –> death
What are CS of the chronic nasal form of glanders?
nodules in nasal cavity, star shaped scars
What are the CS of the pulmonary form of chronic glanders?
tubercle like nodules with calcified centers, consolidation, upper respiratory tract infection
What is the name for the cutanous form of chronic glanders. What are CS?
Farcy = purulent lymphadenitis, nodules along course of lymph and extremities
What is the test for glanders?
Mallein test - injected into eyelid, eyelid will swell in 1-2 days
or PCR
What is cord factor composed of?
basically 2 glucose and 2 mycolic acids
How is M. bovis transmitted?
airoborne, humans can get thru milk, congenital, sexual
What causes Johnes dz?
M. avium subspecies paratuberculosis (MAP)
How can pigs become infected with Mycobacterium avium?
wild and domestic birds
How is Mycobacteria avium complex diagnosed?
acid fast staining or reference lab
What does Johnes dz cause in ruminants?
chronic enteritis and severe diarrhea in cattle
How is MAP (paratuberculosis) diagnosed?
PCR of 16S rRNA
What intracellular bacteria causes fever, headache, rash, and loss of appetite?
R. rickettsii
What is the cell tropism for Anaplasma marginale?
RBCs
What symptoms are caused by Anaplasma marginale?
severe anemia, depression, inappetance, fever, dehydration
How is chlamydia different from rickettsia when it enters endothelial cells?
chlamydia is not free in the cytoplasm
What are the early CS of IBK?
excessive tear production, dislike of sun, closed eyelids
What are the later CS of IBK?
cloudy eye, ulcer, painful, weight loss
When you find one cow with moraxella bovis, what is your next step?
see if more than one animal is affected (usually is)
What is the correlation between Moraxella bovis and clinical disease in calves and dams?
Calves - positive correlation
cows - no correlation
What is the culture requirement for pigment production for P. aeruginosa?
grow at 42 degrees C
What characteristics make P. aeruginosa preliminarily identifiable on mueller hinton agar?
green hue appearance and grape like odor
What are the three disposing factors to Pseudomonas aeruginosa infection?
- parasitic or fungal infections of the skin
- prolonged exposure to antimicrobials
- poor sanitation
What are the bacteria in the CMN group?
corynebacteria, mycobacteria, and nocardia
What drugs are effective against Pseudomonas aeruginosa?
necessary to run sensitivity tests!
What are the CS of burkholderia pseudomallei?
vary widely, most are subclinical
What are the two important preventative measures for B. pseudomallei? What is the treatment?
raise animals off soil, clean drinking water, minimize environmental contamination
tx - initial intensive therapy
What is the pathogenesis of nodules in M. tuberculosis in healthy animals/humans?
inhaled via aerosols –> alveolar macrophages –> macrophage activated by Th1 cytokines –> granuloma
What is the result of M. tuberculosis in immunodeficient hosts?
“Miliary tuberculosis” - unrestricted growth within macrophages –> dissemination of tubercle bacilli
What bacteria causes the ileum and colon to become corrugated and thickened and causes malabsorption of nutrients?
Johnes disease (M. avium ssp paratuberculosis)
What makes corynebacterium different than other bacteria in the CMN group?
not acid fast (despite mycolic acids)
What are two characteristic cellular components of corynebacterium?
metachromatic granules and “palisades” (picket fence) or chinese letters
What does it mean when you isolate corynebacterium from a clinical sample?
not necessarily cause of disease, is a commensal
What bacteria causes caseous lymphadenitis?
Corynebacterium pseudotuberculosis
What are the three species of corynebacterium renale group?
renale, pilosoum, cystitidis
What does the cell morphology of rhodococcus depend on?
pleiomorphic, 24 hours vs. 48 hours
What disease does C. renale cause?
posthitis (pizzle rot), also pyelonephritis, urethritis, and cystitis in cattle, sheep, horses
What makes Rhodococcus like the CMN group?
has mycolic acids
What can rhodococcus cells stain with if from fresh culture?
acid fast positive
What age are foals affected by rhodococcus equi?
4 - 12 weeks, coincides with decline in colostral Ab
What are the CS of rhodococcus equi?
slowly progressive, fever, increased respiratory rate, harsh lung sounds