Group B Group B Streptococcal Streptococcal

Disease in Disease in NeonatesNeonatesMichael AddidleMichael Addidle

Clinical MicrobiologistClinical Microbiologist

Neonatal Group B Neonatal Group B InfectionInfection

Bi-modal distributionBi-modal distribution Early onsetEarly onset – First 7 days, mean 12 hrs – First 7 days, mean 12 hrs Late onset-Late onset- 7days to 3 months, mean 3 7days to 3 months, mean 3

weeks.weeks. Higher attack rates in premature babiesHigher attack rates in premature babies 50% of babies born to colonised mothers 50% of babies born to colonised mothers

acquire the organism. 1-2% of those will acquire the organism. 1-2% of those will become ill from it.become ill from it.

Early Onset Group B Strep Early Onset Group B Strep DiseaseDisease

Approx 1-2 per 1000 birthsApprox 1-2 per 1000 births Septicaemia 80%Septicaemia 80% Pneumonia 10%Pneumonia 10% Meningitis 10%Meningitis 10% Mortality 5-10%, inversely proportional to Mortality 5-10%, inversely proportional to

birthweight.birthweight. Irritability, lethargy, tachypnoea, grunting, Irritability, lethargy, tachypnoea, grunting,

hypoxia, temp. instability, hypotension and poor hypoxia, temp. instability, hypotension and poor perfusion.perfusion.

Fever is uncommon in first 24 hrs.Fever is uncommon in first 24 hrs. WCC may be low, normal or highWCC may be low, normal or high

Strategies to prevent Early Strategies to prevent Early Onset neonatal Group B Onset neonatal Group B Streptococcus InfectionStreptococcus Infection

Universal based screening Universal based screening strategystrategy. (US policy) Screen all pregnant . (US policy) Screen all pregnant women at 35-37 weeks gestation with a recto-vaginal women at 35-37 weeks gestation with a recto-vaginal swab, then giving all those positive for Group B swab, then giving all those positive for Group B Streps intra-partum antibiotics. Streps intra-partum antibiotics.

Risk factor based approach. Risk factor based approach. (UK (UK and NZ policy)and NZ policy) Previous infant with GBS diseasePrevious infant with GBS disease GBS bacteriuria during this pregnancyGBS bacteriuria during this pregnancy Pre-term labour <37 weeksPre-term labour <37 weeks Prolonged rupture of membranes (>18hrs)Prolonged rupture of membranes (>18hrs) Intra-partum fever >38CIntra-partum fever >38C

Funding and lack of evidence

Compliance

Intra-partum antibioticsIntra-partum antibiotics Note that antenatal antibiotics not shown to have benefit for Note that antenatal antibiotics not shown to have benefit for

vaginal colonisation with Group B streptococci.vaginal colonisation with Group B streptococci. 1.2g IV Benzyl penicillin initially and then 0.6g 4 hrly during 1.2g IV Benzyl penicillin initially and then 0.6g 4 hrly during

labour. labour. If penicillin allergic (and no history of anaphylaxis), cephazolin If penicillin allergic (and no history of anaphylaxis), cephazolin

2g initially then 1g 8hrly2g initially then 1g 8hrly If prior anaphylactic reaction to penicillin the either vancomycin If prior anaphylactic reaction to penicillin the either vancomycin

1g 12 hrly, or clindamycin 600mg 8hrly are indicated. (NZ 1g 12 hrly, or clindamycin 600mg 8hrly are indicated. (NZ guidelines recommend vancomycin but clindamycin is fine if Gp guidelines recommend vancomycin but clindamycin is fine if Gp B strep isolated and known to be susceptible.)B strep isolated and known to be susceptible.)

This will decrease incidence of invasive disease in newborn by This will decrease incidence of invasive disease in newborn by approx 90%, most effective if abx started more than 4 hrs approx 90%, most effective if abx started more than 4 hrs beforebefore delivery. delivery.

If maternal chorio-amnionitis (intra-partum fever with two of the If maternal chorio-amnionitis (intra-partum fever with two of the following signs: foetal tachycardia, uterine tenderness, offensive following signs: foetal tachycardia, uterine tenderness, offensive vaginal discharge or increased maternal WCC) then penicillin vaginal discharge or increased maternal WCC) then penicillin alone is insufficient. Broad spectrum abx required eg alone is insufficient. Broad spectrum abx required eg Amoxycillin clavulanateAmoxycillin clavulanate

Strategies to prevent Strategies to prevent neonatal Group B neonatal Group B

Streptococcus InfectionStreptococcus Infection

Incidence of Group B neonatal Incidence of Group B neonatal disease slightly lower in screening disease slightly lower in screening based approach (0.33 v 0.59 per 1000 based approach (0.33 v 0.59 per 1000 live births respectively)live births respectively)

No discernible effect on mortalityNo discernible effect on mortality UK (and NZ) believe that screening UK (and NZ) believe that screening

approach is not cost-effective. approach is not cost-effective.

Strategies to prevent neonatal Strategies to prevent neonatal Group B Streptococcus Group B Streptococcus

Infection in New ZealandInfection in New Zealand Grimwood K, Darlow BA, Gosling IA, et al. Early-Grimwood K, Darlow BA, Gosling IA, et al. Early-

onset neonatal group B streptococcal infections onset neonatal group B streptococcal infections in New Zealand, 1998-1999. J Paediatr Child in New Zealand, 1998-1999. J Paediatr Child Health. 2002;38:272–7. Health. 2002;38:272–7.

0.5 cases per 1000 live births.0.5 cases per 1000 live births. 60% of these cases had risk factors but had 60% of these cases had risk factors but had

not received intra-partum antibiotics.not received intra-partum antibiotics.

Journal of the New Zealand Medical Association, 20-August-Journal of the New Zealand Medical Association, 20-August-2004, Vol 117 No 1200 The prevention of early-onset 2004, Vol 117 No 1200 The prevention of early-onset neonatal group B streptococcus infection: technical report neonatal group B streptococcus infection: technical report from the New Zealand GBS Consensus Working Party. from the New Zealand GBS Consensus Working Party.

Downside of GBS Downside of GBS prevention strategiesprevention strategies

Risk of serious anaphylactic reaction Risk of serious anaphylactic reaction to penicillin is 1 in 10,000 and of a to penicillin is 1 in 10,000 and of a fatal reaction 1 in 100,000.fatal reaction 1 in 100,000.

Increased resistance to Group B Increased resistance to Group B streptococci. Anecdotal evidence for streptococci. Anecdotal evidence for lincosamides in particular.lincosamides in particular.

Theoretical possibility of increased Theoretical possibility of increased non-GBS infection eg E.coli has not non-GBS infection eg E.coli has not been backed up by the majority of been backed up by the majority of evidence however.evidence however.

SummarySummary Neonatal Group B streptococcal disease remains Neonatal Group B streptococcal disease remains

an important cause of morbidity and mortality.an important cause of morbidity and mortality. No strategy will prevent all early-onset neonatal No strategy will prevent all early-onset neonatal

GBS disease.GBS disease. Compliance is key to a risk factor based approach.Compliance is key to a risk factor based approach. Regular audit of above is recommended to ensure Regular audit of above is recommended to ensure

compliance. Audit of the 5 main risk factors is compliance. Audit of the 5 main risk factors is straightforward.straightforward.

Recognition of the signs of sepsis and early Recognition of the signs of sepsis and early treatment of affected babies is just as important.treatment of affected babies is just as important.

Questions?Questions?