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strep
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Question | Answer |
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what are some general properties of streptococci? | gram positive cocci in chains, catalase negative, ferment sugars to lactic acid, causing low pH. they need enrichment with blood to support growth |
describe the classificaiton of streptococci | there are 20 serological groups based upon C carbohydrate (lancefied groups A-U) the preliminary grouping is based upon hemolysis of five percent sheep blood (alpha, beta, gamma hemolysis) |
which class of strep have bet ahemolysis? | S. pyogenes, S. agalactiae |
which class of strep have gamma hemolysis? | s. faecalis |
which class of strep have alpha hemolysis? | s. pneumoniae |
what are group A step? | strep pyogenes |
which is group B strep? | strep agalectiae? |
which is group D strep? | strep faecalis |
what lab test do u do with strep pyogenes? | bacitracin S |
what lab test do u do with strep agalectiae? | hippurate hydrolysis pos |
what lab test do u dowith s. faecalis? | bile esculin pos |
what lab test do u do with s. pneumoniae? | optochin S, bile solubility pos, quelling test pos. |
the structural virulence factors of this bacteria are capsule, fibrils (consist of M proteins) and lipoteichoic acid, peptidoglycan layer, T and R proteins | Group A strep (s. pyogenes) |
the soluble virulence factors for s. pyogenes consist of this | streptokinase, streptodornase, hyaluronidase, erythrogenic toxin, NADase, hemolysins |
what is the pathogenesis of group A strep? | encounter through infected individual or carrier, spread through tissues, and damage ellicits a strong inflammatory response. it causes chemotaxins for white blood cells. activates complement via alt. pathway |
what are some localized infections caused by S. pyogenes? | pharyngitis, scarlet fever, impetigo |
what are some invastive infections caused by s. pyogenes? | wounds, erysipelas, cellulitis, puerperal fever, endocarditis |
what are some postinfection diseases caused by S. pyogenes? | rheumatic fever, glolmerulonephritis |
lab diagnosis of pharyngitis consists of this | throat cultures and direct antigen test |
what are lab tests for invasive infections? | gram stain and culture, blood culture if bacteremia is present |
scarlet fever is cause by what bacteria? | group A strep |
what is scarlet fever treated with? | penicillin, long acting penicillin g, and oral penicillin for ten days to prevent rheumatic fever |
what type of strep infects neonates and also causes septicemia, meningitis, and pneumonia? | group B |
what type of strep causes UTI's, wounds, and sepsis? | group D strep |
what type of strep causes subacute endocarditis and dental carries? | vridans strep or alpha strep |
what type of strep causes pneumonia, otitis media, and sinusidis? | streptococcus pneumoniae |
impetigo is caused by what? | strep pyogenes. but may be mixed with staph aureus |
what is the defining characteristic of erysipelas? | sharp defined borders |
in this disease, there are ulcers formed into the dermis and is caused by strep pyogenes | ecthyma |
what bacteria causes necrotizing fasciitis? | strep pyogenes |
these are opportunistic pathogens that do not ferment glucose | gram negative nonfermenters |
what are some general characteristics of pseudomonas aeruginosa | motile with polar flagella, oxidase positive that are obligate aerobes, grow at 42 degrees C, colony produces a fruity odor |
what are some virulence factors for pseudomonas aeruginosa | pili, pollysaccharide capsule-slime layer, endotoxin (lipopolysaccharide), many extracellular enzymes, exotoxin A (inhibits protein synthesis), |
pseudomonas aeruginosa forms this during tissue necrosis | eschar |
list some diseases caused by pseudomonas aeruginosa | they afect immunocompromised or those with physical barriers: skin infections following burns, super infections following use of broad spectrum antibiotics, wounds, colonize respirators pneumonia, colonize respiratory tract patients, conjuctivitis, etc. |
where is a common place u can get pseudomonas from | hot tubs |
this is an oxidase negative (aerobic) nonfermentative nonmotile short gram negative rod | acinetobacter. it causes a variety of opportunistic and nosocomial infections similar to pseudomonas in temperate climates. has multiple drug resistance. |