|Title:||Management of Infants at Risk of Early Onset Group B Streptococcal Disease (GBS)|
|Document ID:||Operational Circular OP 1867/04|
|Date of issue:||Thursday, 28 October 2004|
|Description:||This Operational Circular is to provide guidance for obstetricians, midwives, neonatologists, general practitioners and other relevant health care workers on the management of infants exposed to early onset neonatal group B streptococcal disease. This is an addendum to and should be read in conjunction with Operational Circular OP 1866/04 ďPrevention of Early Onset Group B Streptococcal Disease (GBS) in Neonates and Identification of Mothers who are Group B Streptococcal Carriers.Ē|
|Framework:||Public Health Policy Framework|
|Period of effect:||from 28 October 2004|
|Authorised by:||Dr Shirley Bowen, Director, Communicable Disease Control Directorate, 16-Oct-2004|
|Print version:||View print version|
|To be read in conjunction with:||
Management of Infants at Risk of Early Onset Group B Streptococcal Disease (GBS)
This Operational Circular is designed to advise Department of Health staff on Departmental policies and procedures.
This is an addendum to and should be read in conjunction with Operational Circular OP 1866/04 "Prevention of Early Onset Group B Streptococcal Disease (GBS) in Neonates and Identification of Mothers who are Group B Streptococcal Carriers".
To provide guidance for obstetricians, midwives, neonatologists, general practitioners and other relevant heath care workers on the management of infants exposed to early onset neonatal group B streptococcal disease.
Early onset Group B streptococcal (GBS) disease is the leading cause of infectious mortality and morbidity in the newborn.1-3 Neonatal early onset disease is vertically transmitted from the maternal genital tract at the time of delivery. The vertical transmission GBS colonisation rate from a GBS colonised mother is approximately 40% - 70%, with 1% - 2% of colonised neonates developing invasive disease.4 Invasive GBS usually presents with respiratory symptoms rapidly developing to septicaemia and shock with or without meningitis. Untreated the condition is usually fatal.
Recent epidemiological evidence supports routine screening of women at 35 - 37 weeks gestation to detect colonisation and the administration of intrapartum antibiotics to prevent neonatal GBS.5-7 A culture-based or risk-based screening approach has been recommended and recently adopted in Western Australia.
RISKS FOR NEONATES FOLLOWING MATERNAL INTRAPARTUM ANTIBIOTIC THERAPY
The management of the neonate either exposed to a colonised genital tract or delivered in the presence of risk factors for GBS disease has been controversial. In the past an empiric balance has been sought between the routine use of antibiotic prophylaxis in the neonate with inherent over-treatment and induced morbidities and a wait and see approach whereby an opportunity to manage early invasive disease may be lost. Data arising from centres using either risk-based or culture-based obstetric determinants of intrapartum antibiotic prophylaxis now provides more evidential basis for neonatal management.
ALGORITHMS FOR MANAGEMENT
Where symptomatic chorioamnionitis exists the infant is at a significantly increased risk from a variety of pathogens. All such infants should be screened for infection and antibiotic prophylaxis should be given.
†Previous infant with GBS disease
As there is currently insufficient evidence to clearly evaluate the effectiveness of maternal prophylaxis, routine neonatal treatment is advocated.
‡Intrapartum antibiotic prophylaxis < 4 hours
Evidence supports the duration of prophylaxis being a better determinant of efficacy than number of doses. A lag time of 2 hours has proven benefit in one study, 4 hours is an empiric time allowing a margin of safety. However, intrapartum antibiotics do neither delay the onset of nor mask the presentation of GBS sepsis in the neonate.8-9
NEONATAL SYMPTOMS OF SEPSIS
The presentation of sepsis in the neonate can be subtle and should be specifically considered in the following circumstances:
Premature infants (< 35/40) have a greater infection risk and require a lower threshold for the use of antibiotics.
Fever is a particularly poor marker of infection in the neonate. Variations from normal generally reflect the environment. Raised temperature may be a manifestation of dehydration.10
SCREENING FOR INFECTION
Methods used to screen for infection vary depending on local areas of expertise. Most centres either do a blood count, looking particularly at an immature neutrophil count, or a biochemical marker such as C-reactive protein (CRP). Care should be exercised, as either marker may be normal in the first few hours of a septic episode.
Surface swabs can give an indication of colonisation but are not necessarily correlated with infection. Growth on a surface swab can be useful in determining appropriate antibiotic therapy. A gastric aspirate prior to feeding and ear swab correlates well with amniotic fluid culture. Other surface swabs, particularly umbilical, are unhelpful as these areas are rapidly contaminated following birth.
Blood cultures are mandatory prior to commencing antibiotic therapy. Cultures should be obtained from a superficial vein under meticulous aseptic technique. Cord blood cultures are not recommended as they have a high rate of bacterial contamination.
There is much argument and little evidence concerning the value of a lumbar puncture (LP) in the early neonatal sepsis screen. Purists advocate an LP as mandatory prior to commencing antibiotics. Others argue only for an LP in infants showing specific neurological symptoms or perform the test at a later stage to determine duration of therapy. A clear recommendation cannot be made and the decision is left to the individual clinician.11
CHOICE OF ANTIBIOTICS
Unless specific maternal cultures determine otherwise, empirical cover is recommended with penicillin and gentamicin. This provides good cover against the two most common pathogens, GBS and Escherichia coli. Prophylactic antibiotics should be ceased at 48 hours, once central cultures have been confirmed as sterile. The cultures and clinical picture should determine the nature and duration of subsequent antibiotics.
Intravenous administration is preferable both for antibiotic efficacy and infant comfort. However, it is recognised that the expertise to maintain IV access is not available in all centres and IM delivery may be required.
ANTIBIOTIC ADMINISTRATION TO NEONATES OF MOTHERS WITH ANTIBIOTIC ALLERGY
Penicillin G, other semisynthetic penicillins and cephalosporins are used frequently in the neonatal period for both therapy and prophylaxis. These antibiotics are exceedingly well tolerated in neonates. Acute anaphylaxis secondary to their use is rare, even when administered to neonates born of mothers with type I hypersensitivity reactions to penicillin and related agents. Further, there is no evidence that use of penicillin and related agents in the neonatal period predisposes to subsequent beta-lactam allergy.12 As neonatal administration of penicillin and related agents may be lifesaving, their use should not be delayed because of concerns of maternal antibiotic allergy.
Dr Shirley Bowen
BIBLIOGRAPHY / REFERENCES:
This circular last updated: Thursday, 28 October 2004 at 12:00am