Group B Streptococcal Infection In Pregnancy

Question 1

What is group B streptococcus?

Answer 1

A commensal bacterium found in the vagina or rectum

Question 2

In what % of pregnant women is group B streptococcus found?

Answer 2

25%

Question 3

What is true in most cases of group B streptococcus?

Answer 3

Colonisation has no symptoms or consequence

Question 4

What can sometimes happen with group B streptococcus infection in pregnancy?

Answer 4

It can cause infection in the neonate, called GBS disease of the newborn

Question 5

What is the incidence rate of early onset GBS?

Answer 5

0.05%

Question 6

What is the mortality rate in babies that develop GBS?

Answer 6

5%

Question 7

What kind of bacteria are streptococci?

Answer 7

Gram positive cocci

Question 8

How do streptococci typically grow?

Answer 8

In chains

Question 9

What can streptococci be classified into?

Answer 9

Alpha, beta, and gamma haemolytic groups

Question 10

What can beta haemolytic streptococci be further divided into?

Answer 10

A-H (but not including E)

Question 11

What is the pathogen in group B streptococcus?

Answer 11

Streptococcus agalactiae

Question 12

Other than GBS disease of the newborn, what can streptococcus agalactiae cause?

Answer 12

Chorioamnioitis or endometritis in the mother

Question 13

What are the risk factors for colonisation with group B strep?

Answer 13

Poorly understood

Question 14

What are the risk factors for GBS infection in the newborn?

Answer 14

• GBS infection in previous baby
• Prematurity <37 weeks
• Rupture of membranes >24 hours before delivery
• Pyrexia during labour
• Positive test for GBS in mother
• Mother diagnosed with UTI found to be GBS in pregnancy

Question 15

Does maternal vaginal or rectal colonisation with GBS cause symptoms?

Answer 15

No

Question 16

How can GBS infection in the mother manifest?

Answer 16

• UTI
• Chorioamnioitis
• Endometritis

Question 17

How does a UTI caused by GBS present?

Answer 17

• Frequency
• Urgency
• Dysuria

Question 18

When does chorioamnioitis caused by GBS occur?

Answer 18

Intrapartum

Question 19

How does chorioamnioitis caused by GBS present?

Answer 19

• Fever
• Lower abdominal/uterine tenderness
• Foul discharge
• Maternal and/or fetal tachycardia

Question 20

When does endometritis caused by GBS occur?

Answer 20

Postpartum

Question 21

How does endometritis caused by GBS present?

Answer 21

• Fever
• Lower abdominal pain
• Intermenstural bleeding
• Foul discharge

Question 22

How is the presence of group B streptococcus detected?

Answer 22

Swabs

Question 23

How are the swabs for group B streptococcus taken?

Answer 23

A single swab is used for the vagina, and then the rectum

Question 24

What are the ways of detecting GBS on swabs?

Answer 24

• Culturing on ‘enriched culture medium’

- PCR

Question 25

When might GBS be detected on urine cultures?

Answer 25

If the woman is symptomatic for a UTI

Question 26

When does screening for GBS occur, if performed?

Answer 26

Between 35-37 weeks

Question 27

How does screening for GBS differ across the country?

Answer 27

In the UK, different hospital trusts have different policies for testing for GBS in pregnancy

Question 28

What does RCOG recommend regarding GBS screening?

Answer 28

Women are not screened routinely, but only women identified as being high risk for GBS are tested

Question 29

What is classified as high risk for GBS?

Answer 29

- Symptoms of UTI or chorioamnioitis during pregnancy - STI symptoms pre-pregnancy - Previous GBS infected baby

Question 30

Why is screening not recommended to be performed routinely?

Answer 30

- Most GBS infections occur in the pre-term population, and they would be missed by screening as they would likely have delivered before the screening date - Not all women who screen positive for GBS are positive at delivery, and these women would receive inappropriate treatment

Question 31

What treatment is used for GBS?

Answer 31

High dose IV penicillin, usually benzylpenicillin, throughout labour

Question 32

What antibiotic is used for treatment throughout labour of GBS in penicillin allergic patients?

Answer 32

Cefurozime or clindamycin

Question 33

When is antibiotic treatment during labour for GBS indicated?

Answer 33

- GBS positive swabs - UTI caused by GBS during this pregnancy - Previous baby with GBS infection - Pyrexia during labour - Labour onset <37 weeks - Rupture of membranes >18 hours

Question 34

What will be done if there is rupture of membranes in woman >37 weeks gestation who is known to be GBS positive?

Answer 34

She will be induced immediately

Question 35

Why would a GBS positive woman >37 weeks gestation with rupture of membranes be induced immediately?

Answer 35

To reduce the amount of time the fetus is exposed

Question 36

Which women can choose whether or not to have antibiotics for GBS in labour?

Answer 36

Women who have been GBS positive in previous pregnancy, but baby was unaffected

Question 37

What typically happens with women who have been GBS positive in previous pregnancy, but the baby was not affected?

Answer 37

They are tested during weeks 35-37 to see if they are carrying GBS in the current pregnancy

Question 38

What is the purpose of testing women who have been GBS positive in a previous pregnancy but the baby was not affected at 35-37 weeks?

Answer 38

To help stratify the risk to the neonate

Question 39

Are antibiotics indicated in planned C-sections for GBS positive women?

Answer 39

No

Question 40

Why are antibiotics not indicated for GBS positive women when they are having planned C-sections?

Answer 40

As it is the rupture of membranes that exposes the baby to GBS