1.
Alpha-hemolytic organism: S. pneumoniae
2.
Beta-hemolytic organism: S. pyogenes
3.
Characteristics of Streptococci: Fastidious, gram + cocci in pairs and chains, catalase -, falcultative anaerobes,
4.
Example of a Bacitracin sensitive organism: Streptococcus pyogenes
5.
Example of a gamma hemolytic organism: Enterococcus faecalis
6.
Example of a SXT sensitive organism: Group C Strep
7.
Example of an Optochin resistant organism: Streptococcus viridans
8.
Example of an Optochin sensitive organism: Streptococcus pneumonieae
9.
Example of an organism that can grow in 6.5% NaCl: Enterococcus faecalis
10.
Example of bile-esculin positive organism: Enterococcus faecalis
11.
Example of hippurate positive organism: Streptococcus agalactiae
12.
How are Streps classified?: Based on antigens found in their cell walls (Lancefield)
13.
How does serology for streptococci work?: It identifies Lancefield's groups (A,B,C,D,F, and G). Antigens in cell wall are liberated using nitrous acid extraction + rabbit antibodies.
14.
How quickly does the QuickVue test work?: In 5 minutes
15.
In the snyder test, how many hours will it take to produce a result that shows that there is high degree of susceptibility to caries? Moderate, low, and minimal?: High= 24 hrs
Moderate= 48 hrs
Low= 72 hrs
Minimal= no change after 72 hrs
16.
Purpose of BHI medium?: Grow Strep on it to test hemolysis because sometimes organisms can give false positive results in the catalase test if grown on SBA.
17.
True/False: Alpha hemolytic Streps are the predominant natural flora?: True
18.
What denotes a positive result in the bile esculin test?: Dark brown to black color in medium.
19.
What denotes a positive result in the hippurate hydrolysis test?: Purple color change
20.
What denotes a positive result in the NaCl broth test?: Turbidity or color change in the medium
21.
What denotes a positive result in the PYR test?: A bright pink to cherry red color
22.
What denotes a positive result in the QuickVue test? The control?: A pink line is positive for GAS. Blue lien is the control.
23.
What denotes a positive result in the Snyder test?: The media turns from green to yellow indicating a lowering of pH due to the growth and plaque formation of specific organisms in the mouth.
24.
What does BHI stand for?: Blood heart infusion
25.
What does hydrolysis of the substrate yield that combines with the reagent in the PYR test to form a positive result?: beta-naphthylamide
26.
What does the bile esculin test detect?: Ferrous citrate
27.
What does the hippurate hydrolysis test detect?: Glycine (hippurate by-product) causes blue/purple color change
28.
What is bacitracin used to identify (group and species)? What growth medium is used?: Group A beta-hemolytic Streptococci. S. pyogenes. Blood agar plate.
29.
What is optochin used to identify (type and species)? What medium is used?: Used for differentiation of alpha-hemolytic Streptococci. S. pneumoniae. Sheep blood agar.
30.
What is the indicator in the hippurate hydrolysis test?: Nihydrin
31.
What is the indicator in the Snyder test?: Bromcresol green
32.
What is the purpose of the bile esculin test? What medium is used?: To differentiate group D Streptococci and Enterococci. Slant.
33.
What is the purpose of the hippurate hydrolysis test?: To test for the ability of Streptococcus agalactieae to hydrolyze hippurate
34.
What is the purpose of the NaCl broth?: To differentiate gram + cocci that will grow in 6.5% NaCl concentration from those that are inhibited by this salt concentration.
35.
What is the purpose of the PYR test?: It differentiates gram + cocci that hydrolyze the PYR substrate
36.
What is the purpose of the Snyder test?: It helps predict susceptibility to dental caries based on acid production by using Snyder medium.
37.
What is the QuickVue Test?: A rapid test used to identify GAS or S. pyogenes; a lateral-flow immunoassay containing a highly specific antibody to Group A strep antigen.
38.
What is the reagent in the PYR test?: PYR reagent
39.
What organisms are PYR positive (2)?: 1. S. pyogenes
2. Enterococcus
40.
What organisms are sensitive to trimthoprim/sulfametoxazol?: Group A and B Streptococci
41.
What reagents are used in the QuickVue test and what are their purposes?: Reagents A and B extract the antigen and solubilize the cell wall of the bacteria.
42.
What shows that an organisms is susceptible to bacitracin?: Any zone of inhibition
43.
When doing a gram stain of respiratory samples what is acceptable and not acceptable?: Acceptable: WBC's > epithelial cells
Unacceptable: WBC's < epithelial cells
44.
Which bacteria are grouped according to their hemolytic patterns?: Streptococci
45.
Which group of Streptococci is the most significant cause of pharyngitis?: GAS
46.
Which groups of Streptococci are beta hemolytic?: Group A (GAS), F, and G
47.
Which organisms grow and produce acid as a result of their metabolism that can be detected in the snyder test?: Streptococcus mutans, S. sobrinus, and Lactobacillus spp.
48.
Which streps hemolytic group require CO2 for growth?: Alpha hemolytic
49.
Which Streptococci (species) are alpha hemolytic?: S. pneumoniae and S. viridans
