MICRO EXAM 2 CH15 Flashcards
Oxygen requirement for Streptococcus and entercoccus?
Facultative anaerobic
Gram stain result?
GPC in pairs and chains.
4 types of hemolytic patterns?
Alpha, beta and gamma
Motile or non-motile?
Non-motile
Colony morphology?
Small to medium, circular, off-white or grey.
Anatomical site for normal flora?
URT, GI and urogenital tract
Cell wall structure of Streptococcus and Enterococcus?
Thick layer of peptidoglycan, teichoic acid, carbohydrate layer (lancefield) and capsule.
What does alpha hemolytic bacteria release and converts to?
Biliverdin to bilirubin
Color and amount of lysing for alpha hemolysis?
Greenish and partial lyses
Color and amount of lysing for beta hemolysis?
Complete clearing
Color and amount of lysing of gamma hemolysis?
No hemolysis
What species are alpha hemolytic?
S. pneumoniae and some viridans strep
What species are beta hemolytic?
S. pyogenes and S. agalactiae
What 2 other factors does beta hemolysis release that alpha and gamma does not have?
Streptolysin O and Streptolysin S
What is streptolysin O?
Oxygen label and immunogenic.
Causes hemolysis on plates.
What is streptolysin S?
Oxygen stable and non-immunogenic
What part of the bacteria classifies its lancefield grouping?
Carbohydrate region of cell wall?
Only what bacteria that exhibit __ hemolysis has lancefield grouping?
Beta hemolytic Streptococcus spp.
What Strep Sp. does bacitracin susceptibility test detect for?
S. pyogenes (GAS)
What is the bacitracin susceptibility test also known as?
Taxo A disc
What Strep Sp. does Opotchin susceptibility test detect for?
S. pneumoniae
What is the Optochin susceptibility test also known as?
Taxo P disc
How much zone of inhibition is needed to be a positive result for Optochin susceptibility?
Greater than 14mm
How long and under what conditions do you incubate Bacitracin and Optochin susceptibility test?
24 hrs at 37ºC in CO2
What enzyme does bile solubility test detect for?
Amidase
What is the reagent for bile solubility test called?
Sodium desoxycholate
What is a positive bile solubility test?
Solubilized suspension or org on plate
Clear on tube media
What is a negative bile solubility test?
Colony remains intact on plate
Turbidity on tube media
How do you perform PYR test?
Place colony on disc
Drop reagent
Wait for result
Which Strep Sp. is pos for bile solubility test?
S. pneumoniae
What enzyme does PYR hydrolysis test detect for?
L-pyrrolidonyl arylamidase (peptidase(
What color is a pos result for PYR?
Pink
What color is a neg result for PYR?
No pink/same color as disc
What Strep Sp. does PYR test identify?
S. pyogenes or Enterococcus spp.
What enzyme does hippurate hydrolysis test detect for?
Hippucate hydrolysis (hippuricase)
Neg result of hippurate test?
No purple or clear tube
Pos result of hippurate test?
Purple color test tube
What Strep Sp. does hippurate test identify?
S. agalactiae (GBS)
What organism do you need to perform a CAMP test?
S. aureus
Pos CAMP test?
Arrowhead formation with hemolysis
How do you do a CAMP test?
Streak S. aureus along the middle of media
Perpendicularly streak unknown (but not
touching)
Neg CAMP test
No arrow head formation
What Strep. sp. does a pos CAMP test identify?
S. agalactiae (GBS)
What organism grows in bile esculin hydrolysis?
Enterococcus spp. and other group D strep
Bile esculin test performed on media plate or slanted tube?
Slanted tube
What does Enterococcus do to the media?
Hydrolyzes esculin and grows in bile.
Pos Bile esculin result?
Blackening of agar
Neg bile esculin result?
No blacking of agar
What ability does an organism need to be able to grow in NaCl broth?
Ability to grow in salt
What does this test differentiate?
Enterococcus from other Group s strep
Pos NaCl result?
Turbidity in broth
Neg NaCl result?
No growth (clear broth)
What type of hemolytic strep species cause agglutination on slide agglutination test?
Beta hemolytic spp.
What does slide agglutination detect and differentiate?
Lancefield grouping in Beta hemolytic spp.
6 Virulence factors of S. pyogenes?
Protein F and lipoteichoic acid
Hyaluronic acid capsule
M protein
Hemolysins
Streptococcal pyrogenic exotoxin
Enzymes
What does Protein F and lipoteichoic acid do?
Mediates attachment and adherence to epi cells.
What does hyaluronic acid capsule do?
Allows antigen to mask and prevent phagocytosis.
What does M protein do?
Allows resistance to phagocytosis and plays a role in adherance.
What are hemolysins?
Streptolysin O and S
What does streptococcal pyrogenic exotin do?
Cause a rash aka scarlet fever
What do enzymes do?
Hyaluronidase solubilized connective issue and streptokinase lysis fibrin clots.
Clinical pyodermal infections of S. pyogenes?
Impetigo
Erysipelas
Cellulitis
Wound infections
Scarlet fever
What test should you do if patient has scarlet fever?
ASO titer
Clinical invasive infections of S. pyogenes?
Streptococcal TSST
Necrotizing fascitis
Normal flora of S. agalactiae?
Urogenital flora in women
