Micro-Oxidase+, G- Rods
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- Describe the general characteristics of the genus Pseudomonas?
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Oxidase +, G- straight rods, polar flagella, obligate aerobes easily grown anywhere with water (mops, hot tubs, H20 supply) & assoc. with plant material
-Often cause enteric disease - Which Psuedomonas species is more clinically important? Describe distinguishing features of this bug
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P. aeruginosa
Grape-like smell
Produces 2 water-soluble pigments: Pyocyanin (bluish green) & Fluorescin (greenish-yellow) - Infections caused by P. aeruginosa?
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Opportunistic pathogen - cause of death in immunosuppresed pts.
Resisant to multiple antibiotics.
Septicemia, endocarditis, UTIs, gastroenteritis, infections of lungs, ear, eye, musculosketal and burn wounds - Virulence factors of P. aeruginosa?
- Pili, polysaccharids capsule, Exotoxin A (similiar to diptheria toxin), Exoenzyme S (effector protin & collapses cytoskeleton), Cytotoxin(pore forming, kills PMNs), Extracellular proteases (cyto- & hemolysins, help spread infection), Phospholipase, Endotoxin
- Describe the general charcteristics of the genus Vibrio
- Oxidase +, G- curved rod, 1 flagellum, like pH 9, typically cause enteric symptoms
- What are the 2 clinically important species of Vibrio?
- V. Cholerae & V. parahaemolyticus (V. vulnificus & V. alginolyticus also cause some wound infections)
- How is V. cholerae classified?
- 139 serotypes (O1-O139). Epidemics of cholera by O1 and more receitnly by O139. O1 has 2 biotypes, each with 3 subtypes (Ogawa, Inaba, Hikojima).
- How is Cholera spread? What regions is it endemic?
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V. cholerae is motile, living in water or food, free in brackish water & in shellfish Very high infection dose - about 10^9.
Parts of Asia,sometimes Africa, India & Bangledesh.
Also in S. America & Mexico - Pathogenesis of V. Cholerae?
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Toxin of 1 A and 5 B subunits. B delivers A into cells to cause disruption of ions transport.
Cl & bicarb hypersecreted with water - up to 15-20 L of watery diarrhea with flecks of mucus/day leads to hypovolemic shock. - Describe V. parahaemolyticus
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Halophilic (salt loving, 8%), freeliving in costal waters/estuaries everywhere.
Gastroenteritis usually from eating infected, inproperly coods seafood. - Describe V. parahaemolyticus infection
- Often seen 5-92 hrs after eating infected sushi, explosive diarrhea (self-limiting, supportive tx only)
- Significance of V. vulnificus?
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Particularly virulent, causes rapidly progressing wound infections after exposure to contaminated seawater OR septicemia after eating raw oysters (usually in pts with liver disease).
Septicemia- 50% die if antibiotic tx delayed. - Describe characteristics of genus Campylobater
- (No "F" sound in name!) Oxidase +, G-, highly motile, slender curved rod. Microaerophilic & suppressed by other flora In food, water & animals
- Name 2 species of Campylobacter that are infectious. Results?
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C. jejuni - #1 cause of bacterial diarrhea - usually self-limiting w/in 7 days.
C. fetus - bacteremic infection in immunocompromised pts. - Describe genus Helicobacter
- G-, highly motile, Oxidase +, very curved rod, microaerophili & hard to grow in culture. Can grow at very low pH due to Urease (makes ammonia) Found in stomach mucosa, secretes exotoxin which induces inflammation