Unit 3 - Pseudomonas, Burkholderia, Aeromonas, and Flavobacterium Flashcards
Which Pseudomonas species is the most important?
Pseudomonas aeruginosa
On gram stain, what does Pseudomonas aeruginosa look like?
gram negative slender rod with flagella and a capsule (frequently present)
What are suitable disinfectants for the genus Pseudomonas?
phenolics and beta-glutaraldehyde
What ‘group’ does Pseudomonas aeruginosa belong in?
the fluorescent group
What does green pus bacillus do?
it produces the pigment pyocyanin which is responsible for blue-green color
What do most pyocins produced by Pseudomonas aeruginosa do?
cause damage to other bacterial cells
What type of organism is Pseudomonas aeruginosa in regards to oxygen?
it is an obligate aerobe however it is able to use nitrate as a terminal electron acceptor so it can grow in anaerobic conditions
What other nutrient (other than nitrate) can Pseudomonas aeruginosa use to anaerobically as an energy source?
arginine
What media does Pseudomonas aeruginosa grow well on?
brilliant green and MacConkeys
Is Pseudomonas aeruginosa lactose positive or negative?
negative
Is Pseudomonas aeruginosa oxidase positive or negative?
positive
Pseudomonas aeruginosa ferments carbohydrates with acid production but this is overwhelmed by ________ produced by utilization of the protein in the media.
ammonia
What do colonies of Pseudomonas aeruginosa look like?
they are usually large and mucoid but can be flat and dry, the colonies are green in color and have a characteristic sharp zone of complete beta hemolysis
What is the natural habitat of Pseudomonas aeruginosa?
water, soil, skin, mucous membranes, and the intestinal tract
How is Pseudomonas aeruginosa transmitted?
it is a common skin contaminant or can be introduced to tissues through contaminated intravenous solutions, endotracheal tubes, surgical instruments, water in hot tubs and swimming pools, surgical scrubs, and other sources
Explain the pathogenesis of Pseudomonas aeruginosa.
it has comparratively low virulence and does not usually actively invade tissues - it is a classical opportunist and infection is associated with immunosuppression or some type of damage to the tissues
What toxins and virulence factors does Pseudomonsas aeruginosa have?
Phsopholipase C, Exotoxin A, Exoenzyme S, Elastase B and A, proteasesm extracellular slime, and pyocyanin
What does phospholipase C of Pseudomonas aeruginosa do?
it causes beta hemolysis, paralysis, death, dermonecrosis, and vascular permeability in mice
What is an initial function of phospholipase C of Pseudomonas aeruginosa that is unique to humans?
it can contribute to the virulence of the organism by breaking down pulmonary surfactant and causing tissue damage and necrosis
What is the function of Exotoxin A produced by Pseudomonas aeruginosa?
it inhibits protein synthesis by NAD-dependent, ADP-ribosylation of elongation factor 2
What is the structure of Exotoxin A produced by Pseudomonas aeruginosa?
it has a typical A-B structure with the exception that it is essentially composed of a single polypeptide chain with three domains
What is the role of the three domains of Exotoxin A produced by Pseudomonas aeruginosa?
the first domain is the binding unit, the middle one is responsible for facilitating the translocation of the third domain which is the carboxy terminal end or active domain into the cell
What is the target organ of Exotoxin A produced by Pseudomonas aeruginosa?
the liver
What is the role of Exoenzyme S produced by Pseudomonas aeruginosa?
it serves to enhavce the severity of infection and has been shown to damage a number of cell types in vitro
What type of infections are Elastase B and A produced by Pseudomonas aeruginosa associated with?
corneal infections and pulmonary infections
What is the function of Elastase B produced by Pseudomonas aeruginosa?
it degrades immunoglobulins G and A, complement, airway, lysozome, and coagulation factors. It also inhibits gamma interferon and NK cell activity
The production of proteases by Pseudomonas aeruginosa is greater in what tissues?
damaged ones
Extracellular slime produced by Pseudomonas aeruginosa is ________(its protective mechanism).
antiphagocytic
What is the function of extracellular slime produced by Pseudomonas aeruginosa?
it generates microcolonies in tissues (such as the lungs) and restricts access of immunoglobulins to the O-antigen polysaccharides
What diseases are associated with Pseudomonas aeruginosa?
urinary tract infections, otitis externa, post-surgical infections, sepsis in compromised hosts (burn wounds), nasal infections (dogs and cats), mastitis, reproductive tract infections, and hemorrhagic pneumonia (mink and chinchillas)