The prevention of early-
ont neonatal group B streptococcus infection: New Zealand Connsus
Guidelines 2014
Brian Darlow, Norma Campbell, Nicola Austin, Adrienne Chin, Celia Grigg, Craig Skidmore, Lesley Voss, Tony Walls, Michelle Wi, Anja Werno
ABSTRACT
AIMS: Group B streptococcal (GBS) dia is the leading cau of early-ont neonatal psis in New Zealand. Dia follows vertical transmission of GBS from the mother, which can largely be prevented by intravenous intrapartum antibiotics. A 2004 New Zealand guideline recommended using clinical risk factors to identify mothers who would qualify for intrapartum antibiotics. An expert multidisciplinary group met to reconsider the guidelines in the light of a two year survey of the incidence of early ont GBS neonatal psis. METHODS: Reprentatives from the New Zealand College of Midwives, the Fetus and Newborn Committee of the Paediatric Society of New Zealand, the Royal New Zealand College of General Practitioners, the New Zealand Committee of the Royal Australi
an and New Zealand College of Obstetricians and Gynaecologists, the New Zealand sub-Committee of the Australasian Society of Infectious Dias, and the Canterbury Home Birth Association met to review the literature and the most recent New Zealand data.
RESUL TS: The multi di sci pli nary group noted that the esti mated i nci dence of early-ont GBS psi s had halved over a 10-year period to be 0.26 per 1,000 live births in 2009–11 and that there were misd opportunities for preventing GBS infection. Connsus was reached that adoption of a national guideline on prevention and management of early ont GBS neonatal psis by all practitioners and District Health Boards would have the greatest potential to further reduce the incidence.
CONCLUSION: A risk-bad GBS prevention strategy continues to be recommended as being the most clinically and cost effective for the New Zealand context. Universal routine antenatal GBS screening is not recommended.
E arly-ont neonatal group B strepto-
coccus (EOGBS) infection is acquired
by the baby by vertical transmission from the birth canal around the time of birth and is an important and largely pre-ventable public health problem.
Two strategies for identifying women at incread risk of giving birth to an affected baby have been ud; one bad on uni-versal antenatal screening and the other on clinical risk factors. In both strategies, mothers identified as at risk are offered appropriate intravenous antibiotics from when labour is established. This intrapar-tum antibiotic prophylaxis (IAP) has been shown to be effective in preventing vertical transmission of GBS.1
In 2004, an expert multidisciplinary group reviewed the evidence on IAP and the results of a national two year surveillance study of EOGBS in New Zealand (1998–9).2 The group agreed a t of guidelines appropriate for New Zealand, which recommended a risk factor-bad prevention strategy.3
A repeat, national, two-year study of EOGBS infection was completed in 2011 through the New Zealand Paediatric Surveil-lance Unit.4 This showed that the incidence
of EOGBS had halved in the 10 years since the first survey, when it was 0.5 per 1,000 live births,2 and was estimated as 0.26 per 1,000 (95% CI 0.18–0.37) live births.4 The study also found there weget up是什么意思
re misd opportu-nities for preventing GBS infection.4
In late 2012, the multidisciplinary group was reconvened to review the current literature and the New Zealand data. The group comprid reprentatives from the New Zealand College of Midwives, the Fetus and Newborn Committee of the Paediatric Society of New Zealand, the Royal New Zealand College of General Practitioners, the New Zealand Committee of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists, the New Zealand sub-Committee of the Austral-asian Society of Infectious Dias, and the Canterbury Home Birth Association. The group considered that the adoption
of a national guideline by all practitioners and District Health Boards (DHBs) would have the potential to improve prevention of EOGBS infection.
The group noted that the most recent recommendation from North America1 was for universal screening, whilst that from the UK5 was for a risk-bad approach. Neither will prevent all cas of EOGBS and factors such as the practicalities and cost-effec-tiveness need to be considered. Screening has to be carried out at the right time (35–37 weeks) with the correct technique (vaginal and anorectal swab), reach the laboratory where lective media and enrichment broth are required, and the results need
to be available and acted upon. A recent study6 has shown that 10% of women with negative screening were actually positive for GBS when in labour, whilst 50% of women with a positive screen result were negative for GBS when in labour. The screening approach is more expensive and expos more women to antibiotics than the risk-bad approach. Lastly, it is likely that the approach to GBS prevention will need to be reviewed again and potentially signifi-cantly altered as rapid diagnostic testing
in labour and maternal immunisation are developed and become cost-effective.4
The following guidelines on the prevention and management of EOGBS infection reprent the connsus statement from this group. Recommendations 1. A risk-bad EOGBS prevention
报考二级建造师的条件
strategy continues to be recom-
mended, as it is the most clinically
图度
and cost effective for the New
Zealand context. Universal routine
antenatal GBS screening is not
recommended.
Risk factors
The risk-bad approach recommends
that all women with one or more of the following factors be offered intravenous intrapartum antibiotic prophylaxis (IAP):
a. a previous GBS-infected baby
tler
b. GBS bacteriuria of any count during
the current pregnancy
c. preterm (<37 weeks) labour and
imminent birth
d. intrapartum fever > 380C
e. membrane rupture > 18 hours
2. Women who have had an incidental
finding of GBS on a vaginal swab
earlier in pregnancy need to have
this repeated between 35–37 weeks. If
this has not occurred, then this should
be considered a risk factor and she
breakfast是什么意思should be offered IAP.5
3. All maternity providers need be
updated about the current GBS
recommendations, to improve
practice and outcomes, and achieve
national equity.
4. All hospitals should have an acces-
sible and agreed protocol, bad on
the current recommendations and
which should be followed by all
practitioners.
5. GBS information needs to be
developed for pregnant women and
their whānau/family, using both
written and web-bad material.
Accurate and appropriate infor-
mation will help decision making.
Practical Applications
1. Antenatal management of group b streptococcus (GBS)
i. Incidental finding of GBS on vaginal swab
An incidental finding of vaginal and/or rectal GBS colonisation during pregnancy does not require treatment with antibiotics antenatally, as GBS cannot be eliminated from its rervoir in the large bowel. An incidental finding of GBS in pregnancy greater than 5 weeks before labour is unreliable1,7 and may result in unnecessary intervention in labour.idea pocket
If the woman has had a previous GBS-infected baby or GBS bacteriuria in the current pregnancy she should be offered intrapartum antibiotic prophylaxis (IAP).
In other cas, it is recommended the woman is re-swabbed at 35–37 weeks’ gestation if an incidental finding has occurred, using the following technique:
• Low vaginal and rectal swab (u same swab for both; clinician or patient collected)
• The request form must clearly state “GBS screen” and “u lective broth process”.
This result informs labour management. If this swab returns positive the woman should be offered IAP. If the swab returns with no evidence of GBS colonisation, IAP is not required.1 (However, if intrapartum fever occurs there should be an asssment for chorioamnionitis).
If the woman has had an incidental vaginal GBS positive swab early in the current pregnancy and has not been re-swabbed at 35–37 weeks, this should be considered a risk factor and she should be offered IAP.5 ii. G BS bacteriuria or GBS urine infection during pregnancy
GBS bacteruria of any count and at any stage in pregnancy is a risk-factor for early ont GBS infection. Most experts will only treat the bacteruria with appropriate antibiotics when the colony count is >105 colony forming units.ml.1,8
There is no need to take or repeat a GBS vaginal swab when GBS bacteriuria has been diag-nod—this is a sufficient risk-factor in itlf.
IAP is recommended even when GBS bacteriuria has been successfully treated. (The only excep-tion to this is if caesarean delivery is performed before the ont of labour in a woman with intact membranes).
2. Principles of GBS management in labour
All women with risk factors for early ont neonatal GBS infection (listed above) should be offered treatment, when labour commences, with IAP. Oral antibiotics are ineffective in this context. Women with clinical signs of chorioamnionitis require immediate treatment with intravenous
broad-spectrum antibiotic therapy, instead of the prophylaxis regimen.
IAP is intended to have a narrow spectrum, to reduce the risk of antibiotic resistance and unwanted side effects.
Penicillin allergy may be significant in this context. Penicillin allergy may occur in 0.7%–4% (usually
a maculopapular rash), but the risk of anaphylaxis is estimated to be in the range of 4/10,000 to
4/100,000.1 Documentation of details of any previous, immediate (within 24 hours), hypernsitivity reactions (eg, anaphylaxis, angioedema, laryngospasm, bronchospasm or urticaria) is an important part of antenatal asssment.
3. Timing of IAP for EOGBS in active labour
七年级上册英语人教版4. Pre-labour caesarean ction
Women with risk factors for GBS, other than tho with signs of infection, and who have intact membranes and require pre-labour elective or emergency caesarean ction do not require IAP for EOGBS infection.12 5. Pre-term labour
remedyAs preterm babies are at incread risk of GBS psis, IAP for GBS is recommended for all women who are in established progressive preterm labour, with or without ruptured membranes.
If preterm labour is established, continue IAP.
If preterm labour does not establish and membranes are intact, discontinue IAP.
If preterm labour is not established but there are prolonged premature ruptured membranes, conside
r appropriate antibiotics are recommended to prolong pregnancy (as per local DHB guidelines).13
6. Pre-labour rupture of membranes (ROM) at term—with no GBS risk factors
A comprehensive asssment of all women with pre-labour ROM at term, to check maternal and fetal wellbeing is recommended.
Women with signs of infection or chorioamnionitis should have immediate treatment with intravenous broad spectrum antibiotics and appropriate intervention.
Women who are well, and the fetus is healthy, with pre labour ruptured membranes and no risk factors for GBS do not require IAP.
• Women who go into spontaneous labour and give birth before 18 hours has elapd since ROM do not require IAP.
• Women who go into spontaneous labour but do not give birth within 18 hours of rupturing their membranes have developed a risk factor for EOGBS infection and IAP is recommended.
• Women who do not go into spontaneous labour within 18 hours of rupturing their membranes have
developed a risk factor for EOGBS infection.5The offer of an induction of labour, and then for IAP once labour is established, is recommended.
• Women with signs of infection in association with pre-labour rupture of membranes at term require careful asssment and the immediate consideration of intravenous broad spectrum antibiotic therapy. If vaginal birth is appropriate it is recommended that they are offered an
induction of labour as soon as possible.
7. Pre-labour rupture of membranes at term—with GBS risk factors
Women with risk factors (e previous ction for the) for EOGBS infection, who are well and have pre-labour rupture of membranes (ROM) at term, are at higher risk of having a baby affected by EOGBS infection. It is recommended that they are offered an induction of labour as soon as practicable, with IAP at commencement of the induction.
8. Maternal fever and suspected chorioamnionitis
Maternal fever is a special risk category which requires consideration of broad spectrum antibiotic therapy and additional monitoring, including fetal monitoring. Ruptured membranes are not neces-sa
ry for the diagnosis of chorioamnionitis. Women with a fever or signs of chorioamnionitis require immediate treatment and intervention.
Clinical signs of chrioamnionitis include maternal fever (≥38oC) with ≥2 of the following:
• abdominal tenderness
• fetal tachycardia
• maternal tachycardia
• vaginal discharge
• offensive liquor
Where there are clinical signs of infection, appropriate specimens including blood cultures are required before commencing empirical broad spectrum antibiotic treatment.
Recommended antibiotic regimes for
intrapartum antibiotic prophylaxis (IAP) 1. Maternal GBS risk factors with no clinical signs of infection—
standard IAP# Intravenous benzyl penicillin.
Initial do 1.2g and then 0.6g, 4 hourly until birth.
(If iv benzyl penicillin is unavailable, amoxycillin is an acceptable alternative. 2g initially and then 1g, 4 hourly until birth)
自考英语二Allergy to penicillin—YES (Low risk of anaphylaxis—Women who do not have history of anaphylaxis, angioedema, respiratory distress or urticaria after penicillin or a cephalosporin)
cephazolin 2g iv initially, then 1g 8 hourly until birth
Allergy to penicillin—YES (High risk of anaphylaxis—Women who do have a history of anaphylaxis, an-gioedema, respiratory distress or urticaria after penicillin or a cephalosporin)
vancomycin 1g iv and repeat 12 hourly until birth
序数词口诀(Erythromycin and clindamycin not recommended becau of increasing resistance patterns)
#When the risk factor is established labour <37 weeks, some DHB’s will u more broad spectrum antibiotics including coverage for GBS
2. Maternal GBS risk factors with clinical signs of chorioamnionitis
(e above)
Broad spectrum antibiotic treatment for chorioamnionitis, including coverage for GBS, as per local DHB guidelines.
Newborn babies guidelines
• All newborn babies should be obrved as outlined in the Ministry of Health Guideline Obrvation of mother and baby in the immediate postnatal period: connsus statements guiding practice.14
• Newborns of mothers who have risk factors, regardless of whether the mother has received intrapar-tum antibiotic prophylaxis (IAP), also require clo obrvation for signs of psis, particularly during the first 24 hours. Women and their families need to understand this so they also know what signs to look for in their baby.
• Signs of psis in the newborn may be non-specific and include respiratory distress, apnoea, tem-perature instability, tachycardia, lethargy, poor feeding, shock or “unwell”.
• If the baby is showing signs of psis immediate evaluation is required (at least a full blood count and blood cultures) and they should receive empiric therapy for at least 48 hours while culture results are awaited. The antibiotics are usually a penicillin and an aminoglycoside as this combination is active against common neonatal pathogens, including GBS and E. coli.
• When feasible a lumbar puncture should be performed on all ptic newborn babies and especially when blood cultures are positive or when, becau of clinical instability or other evidence of psis, therapy is continued beyond 48 hours since up to one-third of neonates with meningitis will have sterile blood cultures.15
• Maternal chorioamnionitis is associated with an incread risk of invasive dia, even if intra-partum antibiotics have been given. Some authorities recommend that all babies of women with chorioamnionitis should receive immediate evaluation and empiric antibiotic therapy. However, as the risk of an asymptomatic baby having psis is still very low no additional recommendation has been made.16
