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what are some general characteristics of pseudomonas ?
- straight rods sometimes curved
- arrange in pars
- motile ( single, polar flagellum)
- capsule
- nonferment can used nitrate as electron acceptor
- biofilm formation
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what are some growth conditions ?
- 37 optimal growth but it grows between 4-42
- special media (p/F) > production of blue green colonies pyocicin Vs. Fluorescein
- colonies after 1, 2 days
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factors associated with pathogenesis of psudemonas :
- adhesins bind to basement membrane
- laminin exposed after damage of epithelium
- capsule> anti phagocytic, anti complement and anti antibiotic
- LPS> proinflamatory leading to septic shock
- TTSS> important for transport of effector into target cell
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what are exotoxins and secreted enzymes by psudemonas associated with its pathogenisis?
- pyocyanin ( blue colony)
- >secreted in large amounts
- > inhibits ciliary movement
- exotoxin A ( inhibits protein synthesis)
- > A.B toxin
- > structurally and functionally similar to diphterea ( targeting
- different receptors)
- Enzyme S+T
- > inhibit cytosleketon polymerization
- > inhibit wound healing via inhibition of cell division
- ( important for estabilating colonization in epithelium)
- Elastases
- > degrade elastin
- > induce tissue damage
- > degradation of complement
- phospholipid C
- > heat labile homolysin
- rhamnlipid
- > heat stable homolysin
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what is the hemolytic pattern of psudemonas ?
beta
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how is P.aeroginosa transmitted?
- ubiquitous in environment
- minimal nutritional
- persist on dry surface for month
- opportunistic
- mostly on CF patients
- cause of nosocomial
- 75% of all intensive care unit patients are colonized
- extracellular pathogen
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what are some clinical manifestation associated with p.aeroginosa in uncomprimized individuals?
- swimmers ear ( treatment with common antibiotic , in sever case aggrasive tantimicrobial treatment and surgical)> external otitis
- tub rash (folliculitis, self limiting)
- ** both infections above can be caused by exposure to contaminated water
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what are some clinical manifestation in case of opportunistic psudemonas causing tissue damage?
- Eye infection
- > inital truma to cornea via contaminated water
- > corneal ulcer development
- > prompt treatment necessary
- Primary skin infection
- > burn wounds
- > severe burns
- > leads to vascular damage and tissue necrossis
- > often cause bacteremia
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clinical manifestation of opportunistic psudemonas due to medical device?
- UTI
- > mostly in patients with catherets
- > patients who have gone through multiple round of antibiotic treatment
- for previous nosocomial causing psudemona
- Pneumoniea
- > in immunocomprimised patients with recent antibiotic treatment
-
what are some diagnostic tools for psudemonas?
- culture ( beta hemolytic/ (p.F) pigmentation/ grape odor)
- biochemical test > nitrate reduction
- Oxidase positive
-
what are some reasons causing drug resistance in psudemonas?
- degrease uptake
- b.lactamase production/ alteration of PBP
- altered target
-
what are treatments possible for psudemonal infections?
- treatment is difficult due to antibiotic resistance
- usually combination of two antibiotics with different targets
- broad spectrum of antibiotics should be avoided due to elimination of common microglora
-
what are some ways to prevent psudemonal infections?
- no vaccine
- it can't be totally eliminated
- increase effort to avoid contamination of medical devices
-
what are some resistance mechanism in 1b.lactamase , 2aminoglycoside , 3chloramphenicol and 4flouroqunilols?
- 1. btactamase hydrolysis, alteration of protein binding
- 2. enzyme hydrolysis by acetylation and phosphorelation altering ribosomal target
- 3. enzymatic hydrolysis
- 4. altered target ( DNA gyrease)
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