Gram Pos, Catalase Neg, Aerobic Cocci

Question 1

Lower respiratory tract: normal flora?

Answer 1

No. Typically sterile

Question 2

Streptococci spp. are _____ ______

Answer 2

facultative anaerobes

Question 3

Streptococci spp cat? oxidase?

Answer 3

Catalase -

Oxidase -

Question 4

Which two may require increased CO2 for growth?

Answer 4

S. Pneumoniae and viridans strep

Question 5

Susceptibility testing is needed for:

Answer 5

Strep pneumoniae and viridans strep

*as a result of antibiotic resistance to PENICILLIN and CEPHALOSPORINS.

Question 6

Susceptibility testing is not needed for:

Answer 6

Strep pyogenes, Strep agalactiae, Groups C, F, and G

• Penicillin is drug of choice*
  
  • If allergic, erythromycin is drug of choice but requires susceptibility testing as resistance has been discovered.*

Question 7

Which organisms are considered normal flora?

Answer 7

Strep agalactiae (female genitourinary tract, lower GI)
Lancefield groups C,F, and G (skin, nasopharynx, GI, GU)
Strep pneumoniae (nasopharynx)
Viridans strep (oral cavity, GI, female genital)
Enterococcus (E.faecalis and E. faecium- GI and female GU)

Question 8

Which organism is not normal flora?

Answer 8

Strep pyogenes

Question 9

What hemolysis is displayed by Viridans strep?

Answer 9

Alpha hemolysis (green color)

Question 10

What hemolysis is displayed by Enterococcus spp?

Answer 10

Gamma hemolysis

Question 11

Which of the Lancefield groups are clinically significant?

Answer 11

Groups A,B,C,D,F, and G

Group A contains group A antigen…..

Question 12

Who is in group A and hemolysis

Answer 12

Strep pyogenes-beta hemolysis

Question 13

Who is in group B and hemolysis

Answer 13

Strep agalactiae- beta hemolysis

Question 14

Who is in group C and hemolysis

Answer 14

S. equisimilis- most common group C in humans
S. zooepidemicus- animal diseases. Humans can get through unpasteurized milk and cheeses
Beta hemolysis

Question 15

Who is in group D and hemolysis

Answer 15

S. bovis
S. equinus
alpha or gamma hemolysis

Question 16

What is the hemolysis of Strep pneumoniae?

Answer 16

Alpha

Question 17

Which strep species is the common cause of dental carries?

Answer 17

Strep mutans

Question 18

Which strep group is susceptible to Bacitracin?

Answer 18

Group A (S. pyogenes) 
*Not recommended anymore due to groups C and G also being susceptible.*

Question 19

Which organism is susceptible to optochin?

Answer 19

S. pneumoniae

Question 20

What does the bile solubility test detect? Which organism is it diagnostic for? How are positive positive tests indicated by?

Answer 20

It detects amidaae enzyme. Diagnostic for S. pneumoniae. Positive tests are indicated by cell lysis.

Question 21

Which organisms are PYR +

Answer 21

Group A (S. pyogenes) and Enterococcus spp

Question 22

Explain the concept of the PYR test

Answer 22

Substrate L-pyrrolidonyl-b-napthlyamide is hydrolyzed by the enzyme pyrrolidonyl arylamidase (PYR) to create beta -napthylamide which changes color when PYR reagent added forming a pink/ red color.

Question 23

What organisms are ID by the hippurate hydrolysis? How does it work?

Answer 23

Group B Strep, Gardnerella vaginalis, Campylobacter jejuni, and Listeria monocytogenes
Hydrolyzes sodium hippurate due to presence of enzyme hoppuricase forming a purple color.

Question 24

What organism is differentiated from other strep spp. using the CAMP test?

Answer 24

S. agalactiae

Question 25

Which organisms are positive when incubated in bile esculin agar?

Answer 25

``` Group D (S. bovis and Enterococci) *Pos= blackening of the media* ```

Question 26

How does the bile esculin agar work?

Answer 26

If pos, organism has the ability to grow in bile and hydrolyze esculin to esculetin which reacts with Fe in the medium forming dark precipitate.

Question 27

What is the salt tolerance test used for?

Answer 27

To differentiate Enterococci (pos) from Group D Strep (neg). | *Broth starts purple. Positive turns yellow or turbid.*

Question 28

How do slide agglutination kits work?

Answer 28

Latex beads are coated with group specific anti-serum, which clump when mixed with a small amount of colony from the specific Strep spp.

Question 29

What organism has colonies that are gray-white and surrounded by large zones of beta hemolysis?

Answer 29

Strep pyogenes

Question 30

Which organism is a common pathogen in throat swabs?

Answer 30

Strep pyogenes | *Throat swabs: inoculate to SBAP with SXT (trimethoprim-sulfamethoxazole) which inhibits growth of normal flora.

Question 31

What are the virulence factors of Strep pyogenes?

Answer 31

Streptolysin O- causes lysis of erythrocytes, leukocytes, and platelets. Oxygen liable. Will see clearing in the subsurface adjacent to the stab marks. Antigenic Streptolysin S- causes lysis of erythrocytes, leukocytes, and platelets. Oxygen stable. Produces hemolysis on BAP. Non-antigenic. M protein- Induce antibody formation Streptococcal pyrogenic exotoxins (SPE's)- Induce fever and inflammation with release of many immune mediators which can induce shock and organ failure.

Question 32

What are some diseases from Strep pyogenes?

Answer 32

Necrotizing Fasciitis (flesh eating bacteria)- affects deep subcutaneous tissues; death of muscle, skin, and fat. Streptococcal Toxic Shock Syndrome induced by SPE's- Patients are bacterimic and have necrotizing fasciitis. Acute exudative pharyngitis (strep throat)- *complication in children is glomerulonephritis.*

Question 33

Which organism is the leading cause of morbidity and mortality in neonates in the US?

Answer 33

Strep agalactiae | Exposed during birthing process once membranes rupture.

Question 34

What are pregnant women screened for? What samples are used?

Answer 34

Group B strep. If pos, they'll receive intravenous antibiotics during labor. Vaginal and rectal swabs (need both)

Question 35

Which organism is alpha hemolytic, small gray colonies with central depression that develops with age (doughnut)?

Answer 35

Strep pneumoniae

Question 36

Which organism is the leading cause of bacterial pneumonia and meningitis?

Answer 36

Strep pneumoniae

Question 37

Who is most at risk from Strep pneumoniae?

Answer 37

Children under 2 and adults over 65

Question 38

What is the vaccine for Strep pneumoniae for children called?

Answer 38

PCV 13

Question 39

What is the vaccine for Strep pneumoniae for the elderly or adults with asthma or who smoke called?

Answer 39

PPSV23

Question 40

True/ false? Viridans strep are bile esculin pos.

Answer 40

False. They're neg which differentiates from Enterococcus and Group D Strep.

Question 41

Viridans strep possess non group ____

Answer 41

Antigens

Question 42

Enterococcus spp. are resistant to:

Answer 42

Cephalosporins and aminoglycosides | *Becoming increasingly resistant to Vancomycin (VRE's)*

Question 43

Most infections of Enterococcus are:

Answer 43

Hospital aquired UTI's (nosocomial)

Question 44

What is the treatment for Enterococcus spp?

Answer 44

Combination of vancomycin and an aminoglycoside.

Question 45

What does the pyruvate broth differentiate?

Answer 45

E. faecalis (pos) and E. faecium (neg)

Question 46

Which organism is the only Catalase neg cocci that are vancomycin resistant, PYR and Leucine aminopeptidase test (LAP) neg that produce CO2 from glucose?

Answer 46

Leuconostoc spp.

Question 47

What is the natural habitat of Leuconostoc spp?

Answer 47

Plants, veggies, and dairy products. Rarely a pathogen (immunocompromised) 1st considered a contaminant

Question 48

What are all spp of Leuconostoc resistant to?

Answer 48

Vancomycin