GBS

Question 1

What is GBS?

Answer 1

Streptococcus agalactiae

An encapsulated gram-positive coccus that colonizes the vaginal & GI tract

Question 2

Manifestations of GBS in the mother

Answer 2

Urinary tract infection
Chorioamnionitis
Endometritis
Bacteremia
Stillbirth

Question 3

What are the 2 types of newborn GBS infection?

Answer 3

Early-onset - usually within first 24 hrs of life, up to 6 days after birth
Late-onset - Usually at 3-4 weeks of age, can occur any time from 7 days - 3 months

Question 4

Symptoms of neonatal GBS

Answer 4

Early-onset:
Respiratory distress
Shock
Pneumonia
Meningitis (occasionally)

Late-onset:
Bacteremia (common)
Meningitis (common)
Poor feeding
Irritability
Extreme drowsiness
Listlessness
Localized infection: middle ear, sinuses, bones, joints, skin

Question 5

Prevalence of asymptomatic GBS anovaginal colonization in pregnant women

Answer 5

20%, can be transient or persistent

A substantial portion of women colonized in one pregnancy will not have colonization during a subsequent pregnancy

Question 6

Percentage of neonates born to mothers colonized with GBS that are colonized themselves

Answer 6

40-75%

Question 7

Risk factors for early-onset GBS disease

Answer 7

Prolonged ROM (>/= 18 hrs)
Preterm birth (but >80% GBS are term)
Termp >/= 38 deg C
Maternal GBS colonization btw 35-37w
Previous infant with invasive GBS disease
Maternal choio
Black or Hispanic
GBS bacteriuria during pregnancy

DM or GBS colonization in a previous pregnancy are not risk factors

Question 8

Neonatal mortality due to GBS disease

Answer 8

5%

25% if < 33w GA

Question 9

Is there a vaccine for GBS?

Answer 9

accination against GBS is potentially the most effective method of preventing the morbidity and mortality caused by infection. GBS vaccines have been investigated as a tool to reduce maternal colonization and prevent transmission to the neonate; however, a licensed vaccine is not yet available.

Question 10

What percentage of neonates with early-onset GBS sepsis are born to women without risk factors?

Answer 10

20%

Question 11

How effective is a screening-based strategy compared to a risk factor-based strategy for GBS?

Answer 11

> 50% more effective for early-onset GBS, but does not affect the incidence of late-onset GBS sepsis

Question 12

For whom is intrapartum GBS prophylaxis indicated?

Answer 12

Previous infant with invasive GBS disease
GBS bacteriuria during current pregnancy
+GBS screening culture during current pregnancy (unless C/S prior to ROM)
Unknown GBS status and:
/= 18 hrs
Intrapartum temp >38 deg C
Intrapartum NAAT GBS+

Question 13

For whom is intrapartum GBS prophylaxis NOT indicated?

Answer 13

Previous pregnancy with a positive GBS screening culture (unless indication present during current pregnancy)
C/S in absence of labor or ROM (regardless of culture status)
Negative vaginal & rectal GBS screening culture 35-37w, regardless of intrapartum risk factors

Question 14

What is the NPV of GBS cultures at 35-37w

Answer 14

95-98%, if prevalence 20%

Question 15

Recommended regimen for GBS prophylaxis

Answer 15

Penicillin G, 5 million units IV x 1, then 2.5-3 million units IV q 4 hrs until delivery

Question 16

Alternative GBS regimen

Answer 16

Amp 2 g IV x 1, then 1 g IV q 4 hrs until delivery

Question 17

GBS prophylaxis - PCN allergic, but not at high risk for anaphylaxis

Answer 17

Cefazolin 2 g IV x 1, then 1 g IV q 8 hrs until delivery

Question 18

GBS prophylaxis - PCN allergic, at high risk for anaphylaxis, susceptible to clinda & erythro

Answer 18

Clinda 900 mg IV q 8 hrs until delivery

Question 19

GBS prophylaxis - PCN allergic, but not at high risk for anaphylaxis - resistant to clinda or erythro or susceptibility unknown

Answer 19

Vancomycin 1 g IV q 12 hrs until delivery

Question 20

How is susceptibility testing for GBS performed?

Answer 20

Resistance to erythromycin is often, but not always, associated with clindamycin resistance. If a strain is resistant to erythromycin, but appears susceptible to clindamycin, it may still have inducible resistance to clindamycin. Treatment with erythromycin is not recommended.

Question 21

Have current prevention strategies decreased the incidence of late-onset GBS disease.

Answer 21

Nope.

Question 22

How long is a GBS screening culture valid for?

Answer 22

5 weeks