Group B Strep

Question 1

How does EOGBS present?

Answer 1

Respiratory symptoms and pneumonia

Question 2

How does late onset GBS present?

Answer 2

Meningitis and septicaemia

Question 3

What is the maternal colonisation rate of GBS?

Answer 3

10-30%

Question 4

Approximately ______% babies born to colonised mothers will become colonised with GBS

Answer 4

40-50%

Question 5

Preterm infants are ____ more likely to get EOGBS and ____ more likely to die from it than term infants

Answer 5

4x

10x

Question 6

What is the management for a mum who carried GBS in her previous pregnancy?

Answer 6

50% chance of carrying it again

Either

• IAP
• Swab and IAP as indicated

Question 7

The risk of EOGBS is reduced by _____ with intrapartum antibiotics

Answer 7

80%

Question 8

What are the indication for GBS prophylaxis in labour

Clinical risk-factor based approach

Answer 8

• GBS positive swab 35-37/40, or earlier without repeat
• GBS bacteruria at any point in pregnancy
• Previous baby affected by EOGBS / LOGBS
• Premature labour
• Prolonged rupture of membranes
• Fever > 38
• Clinical dx Chorioamnionitis
• Other twin with current EOGBS

Question 9

When and how should the GBS swab be taken

Answer 9

3-5 weeks before anticipated delivery
Normally 35-37, but could be earlier

Vaginal, then ano-rectal
Selectively enriched media with note on path from requesting GBS

Question 10

If a woman has a Penicillin allergy, what extra request should be on the test form?

Answer 10

Sensitivity for

• Clindamycin (resistance 20%)
• Erythromcyin (resistance 30%)

Question 11

What is the sensitivity, specificity, and NPV of a GBS swab at 35-37/40

Answer 11

Sensitivity 91%
Specificity 89%

NPV 95-98%

Without enriched culture, false negative 50%

Question 12

What is the antibiotic of choice for IAP in GBS?

Answer 12

Benzylpenicillin

Ideally at least 4 hours prior to delivery

Question 13

What is the antibiotic of choice for IAP in GBS with

• penicillin allergy
• penicillin anaphylaxis

Answer 13

Allergy - Cefazolin IV

Anaphylaxis - Clindamycin / Erythromcyin. If resistant, Vancomycin

Question 14

In PPROM with GBS positive, when should IOL be offered?

Answer 14

34/40

IAP for all actually

Question 15

How should you counsel a women declining IAP with GBS positive result

Answer 15

Advise that the risk of the baby developing EOGBS is significantly higher than if they received IAP

Question 16

What are symptoms and signs of EOGBS

Answer 16

Abnormal behaviour: inconsolable crying
Floppy tone
Difficulty feeding / not tolerating feeds
Temp <36 or > 38
Rapid breathing
Change in colour

Question 17

What is the treatment for neonatal EOGBS

Answer 17

Penicillin and Gentamicin within the hour

Question 18

What type of neonatal GBS infection does IAP reduce?

Answer 18

Early onset

It does NOT reduce LOGBS

Question 19

What is the neonatal mortality rate % of EOBGS?

What is the rate for preterm infants?

Answer 19

Overall mortality 14%

Preterm infant mortality 20%

Question 20

What % of GBS carriers do not have any maternal risk factors?

Answer 20

25-30%

Question 21

What pathogens are responsible for chorioamnionitis?

Answer 21

GBS, anaerobic cocci, enteric Gram negative bacilli (often polymicrobial)

Question 22

Outline your management if a woman with positive GBS carrier status or clinical risk factors develops sepsis in labour

Answer 22

Investigations:

• Peripheral blood culture
• HVS
• Urine for M/C/S
• FBC, CRP

Antibiotics:
- Switch to broad spectrum antibiotics e.g. amoxicillin 2g IV Q6H + Metronidazole 500 mg IV Q12H + gentamicin 4-6mg/kg IV once daily