Neonatal Sepsis and GBS Carriage Study

Globally 4 million neonates die each year, the most common cause of death is sepsis. Causes of neonatal sepsis in low and middle income countries are reported to differ from those in the developed world. Gram negative organisms are thought to be more common. Despite group B streptococcus (GBS) carriage rates being apparently similar to the developed world, GBS sepsis is rarely reported in developing countries: our hypothesis is that GBS is an under recognized neonatal pathogen in the developing world. There are many possible explanations why GBS infection may be under reported including wider, less discriminating use of antibiotics in the period just before the onset of labour and inadequate microbiological diagnostic services.

The proposed study, to be conducted at Maela Refugee Camp Thailand, has two components, both being prospective descriptive cohort studies which will be run concurrently:

• Contribution of GBS to early onset neonatal sepsis at Maela refugee camp
• GBS carriage, seroepidemiology and GBS antibody study. Infants with neonatal sepsis will be identified clinically. They will be assessed and, after informed consent is taken from their mother, they will have a full septic screen including a complete blood count, serum C-reactive protein, blood culture, lumbar puncture and a deep swab taken from their ear canal. If the ear swab is positive for GBS, and the blood culture is negative for other pathogens, a presumptive diagnosis of EO GBS sepsis will be made. The mother will have 5ml blood sample for GBS serotype-specific antibody testing and a vaginal rectal swab obtained (if this has not been performed already).

Women who consent to take part in the GBS carriage study will, during labour, have a low vaginal and rectal swab taken which will be processed using the CDC Group B streptococcus guideline. Additionally, a GBS-specific PCR of the swab will be used to identify culture-negative cases of GBS carriage. 5ml of venous blood will be taken from the mother and 5ml of blood taken, after delivery, from the placenta (from the umbilical vein) for GBS antibody studies.

This study will establish the burden of clinical early onset neonatal sepsis in our population. Additionally this study will establish the prevalence of maternal GBS carriage and assess the potential for intrapartum antibiotic prophylaxis for reducing the burden of neonatal sepsis in this setting. It will also define the serotypes and antibiotic susceptibility profile of carried and invasive GBS strains.

Part 1. The contribution of GBS to EO neonatal sepsis at Maela Refugee Camp study

• Infants, < 7 days of age, who are born to mothers who followed antenatal care at SMRU antenatal clinic, Maela Refugee Camp and have a clinical diagnosis of sepsis
• Written informed consent from the mother

Exclusion criteria

• Severe congenital abnormality identified prenatally or at birth
• Infants less than 28 weeks gestation Part 2. The GBS carriage, seroepidemiology and GBS antibody study

Inclusion criteria

• Mothers following antenatal care at SMRU antenatal clinic, Maela camp who are 28 - 30 weeks gestation
• Written informed consent from the mother

Exclusion criteria

• Mothers receiving antibiotics at the time of sampling