Week 5

Question 1

S. agalactiae or Gr B strep, G stain, hemolysis, PYR, Bacitracin, CAMP, hippurate, GBS, Latex agg kit

Answer 1

Gram stain:everything G pos cocci
Hemolysis: smoky beta w/ translucent colonies
PYR: neg
Bacitracin: resistant
CAMP test: pos
Hippurate hydrolysis: pos
GBS screen: haze= pos
Latex agglutination kit: pos

Question 2

GBS screen

Answer 2

vag/ rectal swab for newborns- lims broth O/N pos= haze, carrot broth 6hrs pos = orange

Question 3

Hippurate hydrolysis

Answer 3

good strong purple

Question 4

CAMP test:

Answer 4

enhanced zone of hemolysis in arrow.

Question 5

S pneumoniae:

Answer 5

Gram stain- Gram pos diplococcus
Colony morph- penny edge
Hemolytic- alpha - met hemoglobin
SBA- pinpoint alpha
MAC- NG
CNA- small pinpoint
Optochin P disk- susceptible

Question 6

Viridans:

Answer 6

hemolysis- alpha
Optochin P disk- resistant
bile esculin- neg

Question 7

Staphs are catalase?

Answer 7

Positive

Question 8

Streps are catalase?

Answer 8

Negative

Question 9

Diseases of strep pneumoniae 3

Answer 9

-Pneumonia
-eye and ear infections- #2 S. pneumoniae #1 Haemophilus influenza
-meningitis and septicemia #1 Neisseria meningitidis #2 S. pneumoniae

Question 10

Strep pneumoniae virulence factors

Answer 10

Capsules
Mucoid on SBA
Pneumolysins- binds to cholesterol= lysis
Secretory IgA protease- destroys IgA
Phosphoryl choline- engulfs cells to cross into blood

Question 11

Bile solubility test

Answer 11

triggers autolytic enzymes

Question 12

Optichin test:

Answer 12

P disk- ethylhydrocupreine hydrocloride

Question 13

Enterococcus

Answer 13

-hemolytic reactions- all- mostly gamma hemolytic
-Colony morph translucent to light grey
-Cell morph: G pos cocci, elongated ovals
-bile esculin hydrolysis BEA plate- grows in presence of bile black = pos
-6.5% NaCl- pos = yellow
-PYR- pos
-latex agglutination- pos

Question 14

Gr D streps

Answer 14

-hemolytic reactions- all- mostly gamma hemolytic
-Colony morph translucent to light grey
-Cell morph: G pos cocci, elongated ovals
-bile esculin hydrolysis BEA plate- grows in presence of bile black = pos
-6.5% NaCl- neg= purple
-PYR- neg
-Latex agglutination- pos

Question 15

Nosocomial infection

Answer 15

opportunistic organisms that infects a patient 3 days in a hospital

Question 16

Viridans are opportunistic pathogens?

Answer 16

yes

Question 17

Urine cultures: ml?

Answer 17

1ml- common add 3 zeros
10ml- used for sterile sites add 2 zeros

Question 18

Explain how the PYR test works, and when it is used

Answer 18

Pyrrolidonase peptidase- reagent cinnamaldehyde= red color= pos
Pyrolidonyl-beta napthyl-amide, l-pyrrolidone and beta napthylamide

Question 19

Enterococccus vs Group D- bile esculin, NaCl, PYR

Answer 19

Enterococcus is pos for all 3. Group D is only pos for bile esculin

Question 20

Name an alternative plating media used to screen for Enterococcus resistant strains.

Answer 20

VRE- vancomycin

Question 21

Group D vs Enterococcus for penicillin

Answer 21

Group D is susceptible, enterococcus is resistant