5.8 Miscellaneous Gram-Negative Aerobic Rods Flashcards
how does Brucella spp. stain
gram negative and acid-fast
what type of bacteria are brucella spp.
facultative anaerobes, capnophilic, nutritionally fastidious
what is the term for bacteria that require CO2 to grow and name an example
capnophilic; brucella spp.
are brucella spp. intracellular or extracellular pathogens
neither; facultative intracellular
what part of the body does Brucella spp. target
reproductive organs
what bacteria causes undulant fever in humans
brucella
what 4 brucella spp. have zoonotic potential
B. abortus
B. melitensus
B. suis
B. canis
what are the sources of Brucella infection
infected animals (primarily cattle, sheep, goats and caribou) and infected animal products (birth fluid, fetus, placenta, milk)
what is the main ROUTE of Brucella transmission
mainly ingestion; also through breaks in the skin or in airborne infection of labs or abbatoirs
who does Brucella mainly infect
veterinarians, consumers of raw milk, producers, butchers, lab workers
what is the incubation period of Brucella
2-4 weeks (can be up to 2+ months)
what Brucella spp. are reportable in Canada? how does this differ from the list with zoonotic potential?
B. abortus, B. melitensis, B. suis (all of these also have zoonotic potential, B. canis is missing)
what species does brucella abortus infect
cattle (obligate pathogen)
what is the Brucella abortus status in Canada
eradicated everywhere except for in Wood Buffalo national park
describe the spores, capsule and motility of B. abortus
has none of them (non motile, non-capsulated, non-spore forming)
how does Brucella abortus survive in the environment
for months but does not grow very well
how do cattle get B. abortus
ingestion, nasal and oral mucosae, includes inhalation and wounds
what cells does B. abortus infect
invades any epithelial cells or M cells in the intestine; then survives inside phagocytes and non-phagocytic cells
how does B. abortus cause placentitis
inside macrophages it travels to the placenta, where it uses erythritol to multiply massively in the placenta
in what organs does B. abortus cause infection (2)
reticulo-endothelial system and placenta
what diseases does B. abortus cause
- contagious abortion in cows
- epididymitis and orchitis
- placentitis
what is the pattern of abortion that B. abortus causes in
- cows
- calves < 6 months
- calves > 6 months
cows: abort once or twice after which they don’t abort again but shed the organism at parturition
calves < 6 months clear
calves > 6 months persist for list and “breakdown” at each calving
when were Canadian cattle herds declared free of B. abortus and due to what efforts
federal test-and-slaughter program using 2 tests (rapid buffered plate test followed and positives were followed by serum agglutination and complement fixation); declared free in 1995
how does Canada maintain a Brucella-free status in Canada
Bovine Surveillance System run by the CFIA -> random sampling at slaughter, targeted surveillance, import/export and AI testing
what happens if a positive serological test is detected in Canada
the herd will be investigated and further tested -> quarantine, further testing, destruction of animals
producers may get compensation
how many biovars does B. suis have and what one do we care about (in what animals)
4; we care about biovar 4 in wild caribou and reindeer
T/F slaughter serological screening includes both B. abortus and B. suis
T
what disease does B. suis cause
chronic inflammation of reproductive tract, stillbirth, neonatal mortality, sterility (temporary)
how do we diagnose B. suis
rose-bengal plate agglutination -> culture and PCR
where is B. canis prevalent in Canada
puppy mills and in imported dogs
where is B. canis very common
countries with free-ranging dogs (ex. Mexico)
what does B. canis cause
chronic, persistent reticuloendothelial infection, bacteremia, vertebral osteomylitis, late-term abortion, epididymitis, orchitis
how do you treat B. canis
long-term treatment with tetracycline (aminoglycosides may be effective)
where is B. ovis present
almost all sheep-raising countries
what does B. ovis cause
epididymitis, abortions, lamb mortality, placentitis, genital lesions in rams
what are the 2 ways to detect B. ovis and which is preferred for routine diagnosis
- direct isolation from semen, vaginal discharge or milk of ewes
- indirect diagnosis based on serological tests
Indirect diagnosis (serological testing) is preferred for routine diagnosis)
burns that are inflamed and infected with a sweet smell and green tinge should make you immediately suspect
Pseudomonas aeruginosa
what is unique about that way that P. aeruginosa is cultured
green colonies!
P. aeruginosa is aerobic/anaerobic
strict aerobe
where is P. aeruginosa ubiquitious and what does this mean in terms of infection
in water and soil ; opportunistic (immunocompromised or burn patients)
what host cells kill P. aeruginosa and what does this mean in terms of infection
neutrophils; occurs in neutropenic, immunocompromised patients
what makes treating P. aeruginosa difficult
resistant to many antibiotics (P in ESKAPE)
are there vaccines for P. aeruginosa
only in mink
what bacteria is one of the main causes of otitis EXTERNA in dogs? how does it appear?
P. aeruginosa; purulent
name a disease caused by P. aeruginosa in the following species:
- dogs
- horses
- sheep
dogs: otitis externa
horses: corneal ulcers
sheep: fleece rot
what disease does Moraxella bovis cause and why is it a problem
infectious bovine keratoconjunctivitis (pink-eye): conjunctivitis -> keratitis -> corneal ulceration -> blindness
the animals do not eat well, creating welfare and production issues
how is Moraxella bovis transmitted
by flies or direct contact from carrier cows
what is one of the main virulence factors for M. bovis
RTX haemolysin; other lytic enzymes; abundant pili for adhesion (also creates antigenic variation)
how do we control and treat infectious bovine keratoconjunctivitis caused by Moraxella bovis
fly control, early diagnosis; antibiotics, NO VACCINE
bartonella spp. are easy or difficult to culture
difficult
what type of secretion system do Bartonella spp. use
Type IV secretion system (vs Salmonella which uses a Type III secretion system)
is Bartonella intracellular or extracellular and in what cells (if intracellular)
intracellular in RBC and vascular endothelium
what does Bartonella cause
persistent, usually subclinical bacteremia
how is Bartonella transmitted
fleas and ticks
what disease does Bartonella henselae cause
cat scratch fever (bacteremia)
how is B. henselae spread between cats
fleas
what disease does B. henselae cause in cats and in people
cats: usually subclinical bacteremia
humans: cat scratch fever
how do we diagnose Bartonella henselae
PCR
what is the treatment for cat scratch fever (2 different considerations to keep in mind…)
how do we prevent cats from B. henselae?
healthy individuals: not treated as poor response to antibiotic treatment
immunocompromised individuals: aggressive antibiotic treatment
hygiene and flea control
what is the A in ESKAPE
Acinetobacter baumannii
what is the importance of acinetobacter baumannii
emerged more recently as an important nosocomial pathogen and is appearing in veterinary hospitals
your clients ask you about cases of septicemia and meningitis in humans following bites from their dogs… they are very concerned about their risk.. what do you tell them (first of all, what is the agent, second of all, what is the risk)
the agent is called Capnocytophaga canimorsus and it is part of the normal flora of dogs; is usually not a problem in healthy adults; predisposing factors include alcoholism, splenectomy, cancer treatment…. long term antibiotic treatment with PenG is usually successful following the infection
