Streptococcus and Enterococcus

Question 1

What are the culture characteristics of Streptococcus pneumoniae?

Answer 1

GPC, dipplicocci, lancet-shaped

Catalase negative

alpha hemolytic

Optochin sensitive

bile soluble

No Lancefield antigen

Question 2

What diseases are associated with Streptococcus pneumoniae?

Answer 2

1. Community acquired pneumonia
2. Meningitis
3. Sinus infection
4. Otitis media
5. Blood stream infection
6. Endocarditis
7. May be associated with joint infections if disseminated

Question 3

Can Streptococcus pneumoniae be identified by MALDI?

Answer 3

• Not reliable identified by MALDI-TOF ( Cannot be distinguished from other members of the Streptococcus mitis/oralis group)

*Optochin test (24h) or Bile solubility (<1hr) can be performed

** Rapid test- Lateral flow assay with CSF or urine. moderate sensitivity, high specificity

Question 4

What is Group A Strep (GAS)?

Answer 4

Streptococcus pyogenes

Question 5

Characteristics of GAS?

Answer 5

beta hemolytic
catalase negative
GPC

Question 6

What diseases are associated with GAS?

Answer 6

1. Pharyngitis (rapid test) and followed by culture (MOST COMMMON)
2. Necrotizing fasciitis (life-threatning and skin must be surgically removed)
3. Recovered from brain biopsies

Question 7

What are complications of GAS pharyngitis?

Answer 7

1. Rheumatic fever- inflammation in heart, blood vessels, and joints
2. glomerulonephritis-inflammation to the filtering part of the kidneys (glomerulus)
3. abscesses
4. bloodstream infection
5. otitis media
6. Streptococcal toxic shock syndrome

Question 8

What is Group B Strep?

Answer 8

Streptococcus agalactiae

Question 9

Characteristics of GBS?

Answer 9

Lancefield Antigen B

Beta hemolysis

GPC

Question 10

Diseases associated with GBS?

Answer 10

1. Meningitis (neonates)
2. Bacteremia
3. Endocarditis
4. Pneumonia
5. Skin and soft tissue infections

Question 11

How are pregnant women screened for GBS?

Answer 11

1. Vaginal/rectal swab recommended at 36-37 weeks of pregnancy
2. Carrot broth (orange if positive). If negative broth, then must streak of GBS specific agar
3. Positive women are administered IV abx when labor starts

Question 12

What other diseases are associated with Streptococcus angionosus?

Answer 12

1. Pharyngitis
2. BSI and endocarditis
3. Pneumonia
4. Intra abdominal infections

Question 13

Which Streptococcus sp is most associated with head, neck and oral abscesses?

Answer 13

Streptococcus angionosus

Question 14

Where is Streptococcus angionosus found?

Answer 14

respiratory, GI, and reproductive tract!

normally does not cause disease.

Question 15

Who smells like butterscotch?

Answer 15

Streptococcus angionosus

Question 16

Which Streptoccocus sp is associated with colon cancer and endocarditis?

Answer 16

Streptococcus bovis!

Also associated with infective endocarditis!

Question 17

Who is part of Group D Streptococcus?

Answer 17

Non-enterococci: S. bovis

Enterococci: E. faecium and E. faecalis

Question 18

Diseases associated with E. faecalis?

Answer 18

1. BSI and endocarditis (prosthetic heart valves and males)
2. UTIs (catheters)
3. Peritoneal infections

nosocomial

Question 19

What is E. faecium/faecalis intrinsically resistant to?

Answer 19

1. Cephalosporins (may appear susceptible in vitro but is not in vivo!)
2. Clindamycin (used for gram positives only)
3. Aminoglycosides
4. Bactrim

Question 20

Which Serine-type d-Ala-d-Ala carboxypeptidase mediates Amp resistance in E. faecium?

Answer 20

1) Overproduction of PBP5
2) Mutations in PBP5

Beta lactamases can be inhibited by sulbactam

Question 21

How is vancomycin resistance mediated in VRE?

Answer 21

vanA and vanB = plasmid based!
VanC - chromosomal

an alanine in the cell wall is changed into a lactate residue so Vancomycin cannot bind.

Vancomycin usually bind D-ala-D-ala on peptidoglycan

Question 22

Which Enterococci are intrinsically resistant to Vancomycin and why?

Answer 22

They have vanC on chromosome

Enterococcus gallinerum and
Enterococcus casseliflavus/flavencens

Question 23

Diseases associated with Streptococcus mutans?

Answer 23

causes dental cavities

may also cause infective endocarditis

Question 24

Who causes subacute infective endocarditis in patient with prosthetic devices? (occurs over months)

Answer 24

S. epidermis and Viridians group Strep

Question 25

Name the subspecies of S. angionosus

Answer 25

S. constellatus
S. intermedius
S. anginosus

CIA

Question 26

Name the subspecies of S. bovis

BIG

Answer 26

S. bovis
S. infantarius
S. gallolyticus

BIG

Question 27

Name the subspecies of the pyogenic group

Answer 27

S. pyogenes
S. agalactiae

Question 28

Name the subspecies of the mitis/oralis group

Answer 28

S. mitis
S. oralis
S. pneumoniae

Question 29

Name the subspecies of the mutans group

Answer 29

S. mutans
S. sobrinus

Question 30

Name the subspecies of the salivarius group

Answer 30

S. salivarius
S. vestibularis

Question 31

Who are the viridians group streptococci and where are they found?

Answer 31

S. mutans group
S. salivarius group
S. anginosus group
S. mitis group
S. sanguinis group
S. bovis group

VGS are commensals of the oral mucosa, GI and genitourinary tracts.

Question 32

Name the Streptococci

Answer 32

S. pyogenes

S. agalactiae

S. angionosus

S. bovis

S. mutans

Question 33

Name the Enterococci

Answer 33

E. faecium

E. faecalis

E. gallinarum

E. cassiflavus/flavescens

Question 34

What are the NVS and name some members and associated diseases

Answer 34

Nutritionally variant Streptococci

Abiotrophia defectiva

Granulicatella adiencens

Infective endocarditis and bacteremia

Need pyridoxine (vitamin B6) or L-cysteine to grow