Early-onset neonatal group B streptococcal infections in New Zealand 1998-1999.
OBJECTIVE
To determine in New Zealand infants the attack rates, risk factors, preventive policies, strain serotype and antibiotic susceptibilities of early-onset neonatal group B streptococcus (GBS) infection.


METHODS
A 2-year prospective active surveillance study was conducted in New Zealand's 19 neonatal units. Cases had to present within 48 h of delivery, be unwell, possess abnormal haematological indices and have GBS isolated from sterile sites.


RESULTS
Of the 112 402 infants born in New Zealand during 1998-1999, 56 had early-onset GBS infection, an attack rate of 0.5 per 1000 live births (95% confidence interval [CI] 0.38, 0.65). Seven had meningitis and there was one death (case fatality rate of 1.8%; upper 95% CI 9.5%). Univariate analysis identified young maternal age, parity, preterm labour, prolonged membrane rupture, maternal fever and assisted delivery as risk factors. Preventive policies for GBS were reported by 14 (74%) obstetric centres associated with neonatal units. Of the 56 cases, five (9%) were born to mothers receiving intrapartum antibiotics, 32 (57%) had mothers with risk factors but were not treated with antibiotics, and 19 (34%) were born to mothers without identifiable risk factors for GBS prevention. Serotypes Ia and III predominated, while two isolates were resistant to erythromycin and/or clindamycin.


CONCLUSIONS
Rates of early-onset GBS infection are similar to other countries following the introduction of prevention policies. Further reductions are possible with full implementation of these guidelines. Meanwhile, emergence of antibiotic resistance complicates the management of women with penicillin allergy. Vaccine development therefore remains a priority.
Grimwood
K
K
Department of Paediatrics and Child Health, Wellington School of Medicine and Health Sciences, Wellington, New Zealand. grimwood@wnmeds.ac.nz
Darlow
B A
BA
Gosling
I A
IA
Green
R
R
Lennon
D R
DR
Martin
D R
DR
Stone
P R
PR
D000328:Adult; D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D015331:Cohort Studies; D016001:Confidence Intervals; D003428:Cross Infection / Q000175:diagnosis / Q000453:epidemiology; D004352:Drug Resistance, Microbial; D005260:Female; D019538:Health Care Surveys; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008297:Male; D008423:Maternal Age; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D007752:Obstetric Labor, Premature; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D012720:Severity of Illness Index; D013290:Streptococcal Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000517:prevention & control; D013292:Streptococcus agalactiae / Q000187:drug effects / Q000302:isolation & purification*; D013997:Time Factors
D000900:Anti-Bacterial Agents