Group B Streptococcal Infection In Pregnancy Flashcards Preview

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Flashcards in Group B Streptococcal Infection In Pregnancy Deck (40)
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1
Q

What is group B streptococcus?

A

A commensal bacterium found in the vagina or rectum

2
Q

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

A

25%

3
Q

What is true in most cases of group B streptococcus?

A

Colonisation has no symptoms or consequence

4
Q

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

A

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

5
Q

What is the incidence rate of early onset GBS?

A

0.05%

6
Q

What is the mortality rate in babies that develop GBS?

A

5%

7
Q

What kind of bacteria are streptococci?

A

Gram positive cocci

8
Q

How do streptococci typically grow?

A

In chains

9
Q

What can streptococci be classified into?

A

Alpha, beta, and gamma haemolytic groups

10
Q

What can beta haemolytic streptococci be further divided into?

A

A-H (but not including E)

11
Q

What is the pathogen in group B streptococcus?

A

Streptococcus agalactiae

12
Q

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

A

Chorioamnioitis or endometritis in the mother

13
Q

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

A

Poorly understood

14
Q

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

A
  • 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
15
Q

Does maternal vaginal or rectal colonisation with GBS cause symptoms?

A

No

16
Q

How can GBS infection in the mother manifest?

A
  • UTI
  • Chorioamnioitis
  • Endometritis
17
Q

How does a UTI caused by GBS present?

A
  • Frequency
  • Urgency
  • Dysuria
18
Q

When does chorioamnioitis caused by GBS occur?

A

Intrapartum

19
Q

How does chorioamnioitis caused by GBS present?

A
  • Fever
  • Lower abdominal/uterine tenderness
  • Foul discharge
  • Maternal and/or fetal tachycardia
20
Q

When does endometritis caused by GBS occur?

A

Postpartum

21
Q

How does endometritis caused by GBS present?

A
  • Fever
  • Lower abdominal pain
  • Intermenstural bleeding
  • Foul discharge
22
Q

How is the presence of group B streptococcus detected?

A

Swabs

23
Q

How are the swabs for group B streptococcus taken?

A

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

24
Q

What are the ways of detecting GBS on swabs?

A
  • Culturing on ‘enriched culture medium’

- PCR

25
Q

When might GBS be detected on urine cultures?

A

If the woman is symptomatic for a UTI

26
Q

When does screening for GBS occur, if performed?

A

Between 35-37 weeks

27
Q

How does screening for GBS differ across the country?

A

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

28
Q

What does RCOG recommend regarding GBS screening?

A

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

29
Q

What is classified as high risk for GBS?

A
  • Symptoms of UTI or chorioamnioitis during pregnancy
  • STI symptoms pre-pregnancy
  • Previous GBS infected baby
30
Q

Why is screening not recommended to be performed routinely?

A
  • 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
31
Q

What treatment is used for GBS?

A

High dose IV penicillin, usually benzylpenicillin, throughout labour

32
Q

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

A

Cefurozime or clindamycin

33
Q

When is antibiotic treatment during labour for GBS indicated?

A
  • 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
34
Q

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

A

She will be induced immediately

35
Q

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

A

To reduce the amount of time the fetus is exposed

36
Q

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

A

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

37
Q

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

A

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

38
Q

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?

A

To help stratify the risk to the neonate

39
Q

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

A

No

40
Q

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

A

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

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