ID OLF STREP Flashcards
gram stain of strep
Gram positive cocci in pairs or chains
cultural characteristics of strep
pinpoint colonies
cultural characteristics in SBA group A - Streptococcus pyogenes
small, transparent and smooth;
beta-hemolytic; when grows in sheep’s blood agar
cultural characteristics in SBA group B - Streptococcus agalactiae
grayish white mucoid colonies;
beta-hemolytic (small zone)
catalase test result of strep
negative
Differentiates group A from other strep groups
Bacitracin Susceptibility Test (Taxo A)
Bacitracin Susceptibility Test (Taxo A) uses what sample
throat swab
a throat swab is used in Bacitracin Susceptibility Test (Taxo A) to inoculate in SBA containing ____ and ____
sulfamethoxazole and a bacitracin
disk
CAMP TEST stands for
● Christie, Atkinson, Munch, and Peterson
CAMP test is test for?
Group B - S. aglactiae
CAMP test is test for?
Group B - S. agalactiae
positive result of CAMP test
arrowhead hemolysis or bowtie appearance
Positive result for PYR hydrolysis Test
cherry red/pink
PYR hydrolysis test is test for
group A and group D
reagent for PYR hydrolysis test
p-dimethyl-aminocinnamaldehyde
the only specie of strep that is PYR positive
S pyogenes
PYR test determines the activity of an enzyme called
pyroglutamyl aminopeptidase
Hippurate test is for?
Group B
reagent indicator of hippurate test
ninhydrin
positive result for hippurate test
purple
salt intolerance test percentage of salt
six point five percent NaCl
The ______ test is a particularly important test used
to determine whether the gram positive cocci is a
staphylococci or a streptococci
catalase
enzyne detected in hippurate test
hippuricase
Hippurate hydrolysis test is used to detect the ability of
bacteria to hydrolyze substrate hippurate into ____ and ___by the action of the Hippuricase
enzyme present in the bacteria
glycine
and benzoic acid
principle behind camp test
Certain organisms including group B streptococci
produce a diffusible extracellular hemolytic heat stable
protein known as the camp factor that acts
synergistically with a beta lysin of staphylococcus aureus
to cause enhanced lysis of red blood cells.
principle behind hippurate test
Hippurate hydrolysis test is used to detect the ability of
bacteria to hydrolyze substrate hippurate into glycine
and benzoic acid by the action of the Hippuricase
enzyme present in the bacteria
test specifically for Group D strep
bile esculin test
enzyme involve in bile esculin test
esculinase
positive reaction in bile esculin test
blackening of medium
Principle behind bile esculin test
test for group D species of strep that are bile tolerant and can hydrolyzes esculin to esculetin through the use of enzyme esculinase
percentage of salt in salt tolerance test
6.5% Nacl
a further test for bile esculin test that determines if the group d specie is enterococci or non-enterococci
salt tolerance test (6.5% NaCl)
negative reaction in salt tolerance means
a clear/transparent broth means non-enterococci
reagent of Leucine aminopeptidase test
paradimethylaminocinnamaldehyde
positive reaction of Leucine aminopeptidase
red color
species positive in leucine aminopeptidase
viridans streptococci
this susceptibility test in
conjunction with bacitracin is used for the presumptive
identification of beta hemolytic streptococci on blood
agar
SXT or sulfamethoxazole Susceptibility Test
positive in SXT or sulfamethoxazole test
Resistant – Group A & B Strep
steps in gram stain strep
- Using a sterile loop, place a loopful of saline into a labelled slide
- Emulsify a colony from Plate into the saline
- Air dry and heat fix
- Stain with gram stain
- View under microscope
steps in catalase test strep
- Place 1 drop of hydrogen peroxide reagent in a glass slide
- Emulsify a colony from the plate using applicator stick
- Observe
(+) bubble formation
(-) no gas bubbles
steps in bacitracin dic test (taxo a)
- Make a bacterial suspension (pure inoculum) by placing 3-5 colonies from plate into sterile
distilled water. Match the turbidity with the MacFarland standard - Using lawn culture method, streak the pure inoculum into a blood agar plate
- After drying for 10 minutes, place the 0.04 units bacitracin disc into the blood agar plate
using sterile forceps - Incubate
(+) Zone of Inhibition (any size)
(-) No zone of inhibition
steps in camp test
- Inoculate beta-toxin producing S. aureus straight on the center of BAP
- Using bacteria from plate, inoculate a straight line at right angle to Staphylococcus streak.
Make sure the two streak lines do not touch. - Incubate at 35 C for 18 hours in a candle jar
- Observe
(+) Arrow head hemolysis at the junction of the colonies
steps in identifying colonial morphology of strep
- Using multiple interrupted streak, inoculate a BAP with bacteria from plate.
- Incubate for 18-24 hours
Take note of colony morphology: color, size, hemolytic pattern
steps in hippurate hydrolysis
- Inoculate bacteria on sodium Hippurate substrate to produce a milky suspension
- Incubate at 35 C for 2 hours
- Add 0.2 mL ninhydrin reagent and further incubate for 15 minutes
(+) Purple color
steps in bile esculin test
- Using multiple interrupted streak, inoculate a BEA plate with bacteria from plate.
- Incubate for 18-24 hours
(+) Growth and Blackening of agar
steps in salt tolerance test
- Inoculate loopful of bacteria to 6.5% NaCl broth
- Incubate at 35 C for 18 hours
(+) turbidity
