Streptococcaceae and Similar Organisms

Question 1

Group A (S. pyogenes) transmission

Answer 1

respiratory secretions

Question 2

Group A Strep disease assocation

Answer 2

• pharyngitis
• scarlet fever
• otitis media
• necrotizing fasciitis
• impetigo
• cellulitis

Question 3

Group A strep sequelae

Answer 3

• rheumatic fever
• post-streptococcal glomerulonephritis

Question 4

Group A strep biochemical traits
bacitracin
PYR

Answer 4

• bacitracin susceptible
• PYR pos

Question 5

• Group A strep colony morphology

Answer 5

• pinpoint
• translucent
• large zone of beta hemolysis

Question 6

List Group A strep virulence factors

Answer 6

• M protein
• streptococcal pyrogenic exotoxin aka erythrogenic toxin
• streptokinase
• hyaluronic acid capsule
• Streptolysin O and S
• hyaluronidase

Question 7

M protein

Answer 7

inhibits phagocytosis
Ab to M protein are protective

Question 8

erythrogenic toxin

Answer 8

• causes rash seen in scarlet fever
• superantigen that interacts with macrophages and T helper cells -> TSS

Question 9

streptokinase

Answer 9

dissolves clots (fibrinolysis)

Question 10

hyaluronic acid capsule

Answer 10

inhibits phagocytosis

Question 11

streptolysins O and S

Answer 11

lyse erythrocytes, platelets, and neutrophils

Question 12

hyaluronidase

Answer 12

• hydrolyzes hyaluronic acid to aid infection spread
• strains that make hyaluronic capsule do not make hyaluronidase

Question 13

S. dysgalactiae subsp. equisimilis Lancefield Group

Answer 13

Lancefield Group C or G antigens

Question 14

S. dysgalactiae subsp. equisimilis disease association

Answer 14

• similar to S. pyogenes
• pharyngitis, necrotizing fasciitis, STSS, endocarditis, glomerulonephritis. acute rheumatic fever

Question 15

Group B strep (S. agalactiae) normal environment

Answer 15

normal flora of GIT

Question 16

Group B strep clinical significance

Answer 16

• important cause of infections in OB/GYN patients
• 25% of females carry it as normal vaginal flora

Question 17

Group B strep disease association

Answer 17

• neonate sepsis/meningitis
• postpartum fever
• osteomyelitis
• wound infections
• endocarditis
• pneumonia
• pyelonephritis

Question 18

Group B strep colony morphology

Answer 18

• medium size flat/creamy
• small zone beta hemolysis

Question 19

Group D streptococcus normal environment

Answer 19

normal fecal and oral flora

Question 20

Group D strep disease association

Answer 20

• wound infections
• UTIs
• abdominal abscesses
• colon cancer if in blood cultures

Question 21

Group D strep colony morphology

Answer 21

• gray to wite
• translucent
• round/convex
• alpha or non hemolytic

Question 22

Viridans strep normal environment

Answer 22

• oral cavity
• resp tract
• GIT mucosa

Question 23

Viridans strep disease assocation

Answer 23

• major cause of endocarditis in pt with damaged heart valves
• wound infections
• brain abscesses
• may enter blood after dental procedures

Question 24

List Viridans strep

Answer 24

• S. mutans
• S. salivarius
• S. sanguis
• S. bovis
• S. mitis

Question 25

Strep pneumo normal environment

Answer 25

upper resp tract

Question 26

S. pneumo disease association

Answer 26

- lobar pneumonia - otitis media - meningitis - community acquired pneumonia

Question 27

S. pneumo gram stain/morphology

Answer 27

GPC diplococci lancet or bullet shaped

Question 28

S. pneumo colony morphology

Answer 28

- mucoid - umbilicated depressed centers - kinda tan (my two cents)

Question 29

Enterococcus most commonly encountered spp

Answer 29

E. faecalis E. faecium

Question 30

Enterococcus biochemical traits **bile esculin** **6.5% NaCl** **PYR** **Lancefield group** **hemolysis**

Answer 30

- bile esculin pos - pos growth in 6.5% NaCl - PYR pos - Lancefield group D - alpha beta or most commonly nonhemolytic

Question 31

Gemella disease association

Answer 31

- endocarditis - meningitis - brain abscesses - lung abscesses - osteomyelitis

Question 32

Gemella biochemical traits **PYR** **leucine aminopeptidase LAP** **bile esculin** **catalase**

Answer 32

- PYR pos - LAP pos - bile esculin neg - catalase neg

Question 33

Leuconostoc disease association

Answer 33

- osteomyelitis - ventriculitis - postsurgical endophthalmitis - neonate bacteremia

Question 34

Leuconostoc spp biochemical traits **vancoymycin** **PYR** **LAP** **catalase**

Answer 34

- vancomycin resistant - PYR neg - LAP neg - catalase neg

Question 35

Abiotrophia and Granulicatella formerly referred to as _____ because they require _____

Answer 35

- nutritionally variant streptococci - vitamin B6 for growth

Question 36

List Abiotrophia and Granulicatella spp

Answer 36

- A. defectiva - G. adiacens - G. elegans

Question 37

Abiotrophia and Granulicatella normal environment

Answer 37

oral cavity

Question 38

Abiotrophia and Granulicatella disease association

Answer 38

- endocarditis - ophthalmic infections - CNS infections