Pseudomonas & Burkholderia Flashcards
What species of Pseudomonas and Burkholderia are of most importance? What respiration do they all undergo?
P. aeruginosa, P. fluorescens = opportunistic
B. mallei, B. pseudomallei = pathogen, bioterrorism
aerobic!
What is Pseudomonas aeruginosa?
Gram-negative, aerobic rod with polar flagella for motility and attachment
What is commonly associated with Pseudomonas aeruginosa wounds and cultures?
fruity, grape-like smell caused by aminoacetophenone
Pseudomonas are able to produce pigments. Which one is characteristic to P. aeruginosa?
pyocyanin
(others are pyoverdine, pyorubin, and pyomelanin)
Where is Pseudomonas aeruginosa typically found? What is its host range like?
in the environment
- water
- soil/plants
- hospitals, especially moist and plastic
- home
humans/animals –> broad, most common in immunocompromised (opportunistic)
What 5 factors of Pseudomonas aeruginosa contribute to its multidrug resistance?
- impermeability
- multidrug efflux pumps
- aminoglycoside-modifying enzymes
- β-lactamases
- biofilm (alginate) - slime, viscous gel
What 5 toxins are produced by Pseudomonas aeruginosa? How does it attach to its targets?
- exotoxin A - blocks endocytosis and protein synthesis
- phospholipase C - hemolysin breaks cell membrane
- pyocyanin - ROS
- pyoverdine - siderophore
- degradive enzymes
pili, flagella, LPS endotoxin
What is the point of Pseudomonas aeruginosa producing alginate and using T3SS?
ALGINATE - mucoid EPS used for biofilm formation, which blocks antibiotics
T3SS - translocates exoenzyme S into host cells to cause apoptosis and blocks immune response
What are common symptoms of skin and ear infections caused by Pseudomonas aeruginosa?
SKIN - fleece rot in sheep, pyoderma in dogs
EAR - otitis externa in dogs and cats, otitis media/interna in chinchillas
What are common symptoms of eye and respiratory infections caused by Pseudomonas aeruginosa?
EYE - ulcerative keratitis in dogs, cats, and horses
RESP - pneumonia in dogs, cats, and chinchillas
What are common symptoms of blood infections caused by Pseudomonas aeruginosa? What are 2 other common types of infection?
BLOOD - bacteremia and septicemia in chinchillas
- mastitis in sheep and cattle
- necrotic stomatitis in snakes
What specimen can be collected for Pseudomonas aeruginosa isolation? How does it grow on nutrient agar, MacConkey agar, and blood agar?
pus, respiratory aspirates, milk samples, ear swabs
NUTRIENT: fruity grape-like odor, produces pyocyanin
MACCONKEY: non-lactose fermenter (white/colorless)
BLOOD: β-hemolytic
How does Pseudomonas aeruginosa respond to oxidase and catalase tests?
oxidase +
catalase +
How is Pseudomonas aeruginosa treated/controlled?
- antibiotic therapy is difficult —> MDR
- vaccines for farmed mink and chinchillas
What is Pseudomonas fluorescens? What are 2 unique properties it contains?
Gram-negatice, motile, aerobic rod
- unable to ferment glucose
- produces a fluorescent pigment (pyoverdine) under UV light
Where is Pseudomonas fluorescens commonly found? What symptoms does it cause?
soil and water
skin ulcers and septicemia in freshwater fish and reptiles
What is Burkholderia mallei? Where is it most commonly found?
Gram-negative, non-motile, aerobic coccobacillus
facultative intracellular pathogen - cannot live outside of their host
What is Burkholderia mallei the causative agent of? Why must it be handled very carefully?
Glanders in horses, donkeys, and mules
it is a category B bioterrorism agent
What 5 virulence factors does Burkholderia mallei contain?
- capsule
- LPS
- multiple secretion systems
- quorum sensing mechanism
- adhesion proteins and fimbriae
What is Glanders? How is it transmitted from horses to humans?
contagious, sporadic, endemic, zoonotic disease common in horses and caused by Burkholderia mallei characterized by the formation of nodules and ulcers on the skin and in the respiratory tract
contact, ingestion, inhalation
What is the difference betwen acute and chronic forms of Glanders?
ACUTE: fever, septicemia, pneumonia
CHRONIC: more common, develops in several months
What are the 3 forms of Glanders based on presentation?
- PULOMARY: tubercle like lesions (nodules)
- CUTANEOUS (farcy): nodules, ulcers, yellowish pus
- NASAL: ulcerative nodules, nasal discharge (mucopurulent, bloody)
Glanders, pulmonary form:
nodules in lung —> black, miliated
Glanders, cutaneous form (farcy):
Glanders, nasal form:
In what media does Burkholderia mallei grow the best? What is it unable to grow in?
enriched blood agar containing 1% glycerol
MacConkey (unlike Pseudomonas)
What is the only test approved for Glanders diagnosis?
serological tests detecting antibodies in the blood
- complement fixation test
What test was created to diagnose Glanders in the field?
Mallein test —> glycoprotein from B. mallei culture used as an antigen and applied to the skin of lower eyelid or neck
- no longer really recommended due to animal welfare
How is Burkholderia mallei specimens processed? How can infection be treated and controlled?
must be processed within biohazard cabinet
- effective cleaning and disinfection with a contact time of 6 hours (formalin, iodophor, sodium hydrochloride, 70% ethanol)
- antibiotic therapy in endemic areas
- euthanasia in US
- no vaccine
What is Burkholderia pseudomallei? How does it characteristically stain? Where is it naturally found?
Gram-negative, aerobic, motile bacillus
bipolar stain, giving it a safety pin appearance
- facultative intracellular pathogen
- soil and water where it can lay dormant for years
What is Burkholderia pseudomallei the causative agent of?What does this cause?
melioidosis via contact in the environment, aka Whitmore’s disease or pseudoglanders (category B bioterrorism agent)
abscess formation in multiple organs
What 7 virulence factors do Burkholderia pseudomalleia contain?
- capsule
- LPS
- multiple secretion systems
- quorum sensing
- type IV pili
- exotoxins
- protease
How does Burkholderia pseudomallei typically present clinically? In sheep, goats, pigs, horses, dogs/cats, cows, and humans?
- local skin ulcers
- chronic abscess formation
- granuloma formation
- chronic pneumonia
- acute septicemia
SHEEP: lung abscesses, pneumnia
GOATS: mastitis
PIGS: asymptomatic lesions on the spleen
HORSE: pseudoglanders
DOG/CAT: abscess formation on multiple organs
COWS: pneumonia, CNS disease
HUMANS: pneumonia, subclinical abscessed
On what 2 media can Burkholderia pseudomallei grow?
- blood agar - greyish-white, non-hemolytic with musty odor
- MacConkey agar
How is it recommended to treat Burkholderia pseudomallei infection? What are 2 common interventions?
antibiotic therapy —> be careful with resistance and relapse
- surgical drainage of large abscesses
- enucleation in the case of eye infection
Pseudomonas and Burkholderia summary:
