GBS_Flashcards

Question 1

What is Group B Streptococcus (GBS)?

Answer 1

GBS is the most common cause of early-onset severe infection in the neonatal period.

Question 2

How prevalent is GBS in mothers?

Answer 2

Around 20-40% of mothers have GBS present in their bowel flora and may be thought of as ‘carriers’ of GBS.

Question 3

When may infants be exposed to maternal GBS?

Answer 3

Infants may be exposed to maternal GBS during labour and subsequently develop potentially serious infections.

Question 4

What are the risk factors for GBS infection?

Answer 4

Prematurity, prolonged rupture of the membranes, previous sibling GBS infection, maternal pyrexia (e.g. secondary to chorioamnionitis).

Question 5

What did the Royal College of Obstetricians and Gynaecologists (RCOG) publish regarding GBS?

Answer 5

RCOG published guidelines on GBS in 2017.

Question 6

Should universal screening for GBS be offered to all women?

Answer 6

No, universal screening for GBS should not be offered to all women.

Question 7

Is a maternal request an indication for GBS screening?

Answer 7

No, a maternal request is not an indication for screening.

Question 8

What should women who’ve had GBS detected in a previous pregnancy be informed about?

Answer 8

They should be informed that their risk of maternal GBS carriage in this pregnancy is 50%.

Question 9

What should be offered to women who’ve had GBS detected in a previous pregnancy?

Answer 9

They should be offered intrapartum antibiotic prophylaxis (IAP) OR testing in late pregnancy and then antibiotics if still positive.

Question 10

When should swabs for GBS be offered if necessary?

Answer 10

Swabs should be offered at 35-37 weeks or 3-5 weeks prior to the anticipated delivery date.

Question 11

Who should be offered IAP?

Answer 11

IAP should be offered to women with a previous baby with early- or late-onset GBS disease, in preterm labour regardless of GBS status, and women with pyrexia during labour (>38ºC).

Question 12

What is the antibiotic of choice for GBS prophylaxis?

Answer 12

Benzylpenicillin is the antibiotic of choice for GBS prophylaxis.

Question 13

summarise

Answer 13

Group B Streptococcus

Group B Streptococcus (GBS) is the most common cause of early-onset severe infection in the neonatal period. It is thought around 20-40% of mothers have GBS present in their bowel flora and may therefore be thought of as ‘carriers’ of GBS. Infants may be exposed to maternal GBS during labour and subsequently develop potentially serious infections.

Risk factors for Group B Streptococcus (GBS) infection:
prematurity
prolonged rupture of the membranes
previous sibling GBS infection
maternal pyrexia e.g. secondary to chorioamnionitis

Management

The Royal College of Obstetricians and Gynaecologists (RCOG) published guidelines on GBS in 2017.

The main points are as follows:
universal screening for GBS should not be offered to all women
the guidelines also state a maternal request is not an indication for screening
women who’ve had GBS detected in a previous pregnancy should be informed that their risk of maternal GBS carriage in this pregnancy is 50%. They should be offered intrapartum antibiotic prophylaxis (IAP) OR testing in late pregnancy and then antibiotics if still positive
if women are to have swabs for GBS this should be offered at 35-37 weeks or 3-5 weeks prior to the anticipated delivery date
IAP should be offered to women with a previous baby with early- or late-onset GBS disease
IAP should be offered to women in preterm labour regardless of their GBS status
women with a pyrexia during labour (>38ºC) should also be given IAP
benzylpenicillin is the antibiotic of choice for GBS prophylaxis

Question 14

A 28-year-old woman who is 34 weeks pregnant is diagnosed with a urinary tract infection after routine dipstick testing. Laboratory analysis shows group B streptococcus to be the cause and this is treated with a short course of oral antibiotics. How should this woman be managed with respect to delivering her baby in a few weeks time?

Neonatal antibiotics within 1 hour of birth
Caesarean section at 38 weeks
No additional measures needed
Intrapartum antibiotics
Vaginal swabs in early labour with treatment based on this result

Answer 14

Group B streptococcus (GBS) bacteriuria is associated with an increased risk of chorioamnionitis and neonatal sepsis. The Royal College of Obstetricians and Gynaecologists states that women with GBS bacteriuria should therefore be offered intrapartum antibiotics in addition to appropriate treatment at the time of diagnosis. For non-penicillin-allergic patients intrapartum antibiotics will consist of intravenous benzylpenicillin given as soon as possible after the start of labour, then at 4-hourly intervals until delivery.

Postnatal antibiotic treatment is not indicated unless there are signs of neonatal infection. Caesarean section is not indicated.

[RCOG Green-top Guideline No. 36]

Question 15

On routine antenatal swabs, a mother is found to be colonised with Group B Streptococcus. However, she did not receive adequate intrapartum antibiotic prophylaxis and she delivers a healthy baby girl by vaginal delivery. Her baby does not require any resuscitation and remains well in the post natal ward. The mother is eager for discharge home. What is the most appropriate course of action with regards to her child?

Intravenous antibiotics for 24 hours
Check C-Reactive protein levels and take blood cultures
Discharge if no suspicion of infection
Perform routine 6 hour post natal check and discharge with community midwife follow up.
Regular observations for 24 hours

Answer 15

Regular observations for 24 hours

Maternal colonisation with group B streptococcus is a minor risk factor for early onset sepsis in the newborn. Newborns with only one minor risk factor for early onset sepsis should remain in hospital for at least 24 hours with regular observations. Two or more minor risk factor or one red flag warrant empirical antibiotic therapy with Benzylpenicillin and Gentamicin and a full septic screen. Red flags include the following:
Suspected or confirmed infection in another baby in the case of a multiple pregnancy
Parenteral antibiotic treatment given to the woman for confirmed or suspected invasive bacterial infection (such as septicaemia) at any time during labour, or in the 24-hour periods before and after the birth [This does not refer to intrapartum antibiotic prophylaxis]
Respiratory distress starting more than 4 hours after birth
Seizures
Need for mechanical ventilation in a term baby
Signs of shock

Question 16

A 28-year-old pregnant woman is in the labour ward and ready to deliver her second child. Her pregnancy has been uncomplicated so far. However, her first child had to stay in neonatal intensive care shortly after birth due to an infection but is now healthy. Recent vaginal swabs show the presence of Streptococcus agalactiae. She is otherwise well and has no other medical conditions.

What is the most appropriate step in management?

IV benzylpenicillin to the neonate
Intrapartum IV benzathine benzylpenicillin
Intrapartum IV benzylpenicillin
Intrapartum oral benzylpenicillin
No treatment as this strain does not cause neonatal sepsis

Answer 16

Intrapartum IV benzylpenicillin

Benzylpenicillin is the antibiotic of choice for GBS prophylaxis

Intrapartum IV benzylpenicillin is correct. Streptococcus agalactiae is the same as group B streptococcus (GBS) and it is important to be able to recognise this, as it may come up in exams. The Royal College of Obstetricians and Gynaecologists’ guidelines state that mothers who have had a previous pregnancy complicated by neonatal sepsis should be given benzylpenicillin antibiotic prophylaxis. This is given to the mother intravenously during delivery.

IV benzylpenicillin to the neonate is incorrect. The antibiotic prophylaxis should be given to the mother during birth, not to the neonate after birth unless the neonate shows signs and symptoms of sepsis.

Intrapartum IV benzathine benzylpenicillin is incorrect. This antibiotic does not play a role in the prophylaxis of GBS and is used in the management of syphilis.

No treatment as this strain does not cause neonatal sepsis is incorrect.Streptococcus agalactiae is the same as group B streptococcus (GBS) and can cause neonatal sepsis.

Intrapartum oral benzylpenicillin is incorrect. The guidelines state to give IV intrapartum antibiotics. This would not be effective.

Question 17

You are reviewing a female patient who is currently 28 weeks pregnant with her second child. Her first child, who is now 2 years old had neonatal sepsis caused by Group B Streptococcus (GBS).

Given this history, the patient is asking what will happen to her and/or the baby to prevent this from happening again in this pregnancy.

What treatment will the patient and/or baby require?

• Maternal intravenous (IV) antibiotics during labour
• Maternal IV antibiotics if the mother is pyrexial in labour
• Monitor the baby for signs of sepsis following birth for 72 hours
• Newborn IV antibiotics at birth
• Maternal IV antibiotics in labour and newborn infant IV antibiotics

Answer 17

Maternal intravenous (IV) antibiotics during labour

Maternal intravenous antibiotic prophylaxis should be offered to women with a previous baby with early- or late-onset GBS disease
Important for meLess important
Bacterial sepsis is a major problem in the newborn unit. The incidence of sepsis is higher in preterm infants, especially the very low birthweight infant (<1500g).

The most common cause is Group B Streptococcus (GBS). GBS is a commensal of the female genital tract. In the mother, it may be associated with urinary tract infection during pregnancy, septic abortion, and postpartum endometritis.

In the neonate, it can cause early or late infection (although there is overlap).

Maternal intravenous antibiotics in labour are recommended for all women who have had a previous baby with early or late-onset GBS disease. Therefore, option 1 is the only correct answer. Newborn antibiotics are recommended if there are signs of sepsis when the infant is born.

Question 18

A 32-year-old multiparous woman presents at 36 weeks gestation in established labour. She has recently emigrated from a low-income country. No history of prenatal care or screening tests is established. The patient has an uneventful vaginal delivery of a 3.2kg female. Soon after birth, the baby develops fever, tachycardia and respiratory distress. What is the most likely cause?

Herpes simplex infection
Hepatitis B transmission
Group B septicaemia
Toxoplasmosis infection
Vertical transmission of HIV

Answer 18

Group B septicaemia

Group B streptococcus infection is the most frequent cause of severe early-onset (< 7 days) infection in newborn infants.

Question 19

A 19-year-old woman who is 9 weeks into her first pregnancy is seen in the early pregnancy assessment unit with vaginal bleeding. Her ultrasound scan confirms a viable intrauterine pregnancy. However, the high vaginal swab has isolated group B streptococcus (GBS). How should she be managed?

Treat immediately with oral benzylpenicillin only
Treat immediately with oral erythromycin & intrapartum intravenous benzylpenicillin
No treatment required now, no intrapartum antibiotics
Intrapartum intravenous benzylpenicillin only
Intrapartum oral benzylpenicillin only

Answer 19

Intrapartum intravenous benzylpenicillin only

GBS is a vaginal commensal isolated in many women. It is known to be the most frequent cause of severe early-onset infection in the newborn and can cause significant morbidity and mortality.

If it is isolated during the antenatal period, it does not require treatment immediately, as it will not reduce the likelihood of colonisation at delivery.

However, intrapartum intravenous benzylpenicillin is required to reduce neonatal transmission. An alternative would be clindamycin. This applies to GBS isolated in vaginal swabs and urine. (GBS urinary tract infection in pregnancy requires appropriate antibiotics at the time also).

There is no screening programme in the UK for GBS, vaginal swabs should be taken only when clinically indicted. Women who have had a previous baby infected with GBS are also offered intrapartum intravenous benzylpenicillin in future pregnancies.

(Source - RCOG guidelines, GBS in pregnancy).