Epidemiology of neonatal early-onset sepsis in a geographically diverse Australian health district 2006-2016

Aim To describe the epidemiology of EOS including blood culture utilisation, across a large and geographically diverse Australian health district. Background Sepsis in the first three days of life remains a leading cause of death and morbidity. In high-income countries, group B Streptococcus (GBS) and Escherichia coli (E. coli) have dominated as causes of EOS for five decades. Method An 11-year retrospective cohort study to determine the epidemiology of EOS. Incidence rates were calculated per 1000 live births. Logistic regression with linear temporal trend and covariates for potential effect modifiers were employed. Blood culture utilisation was determined by examining the rate of babies undergoing blood culture within 72 hours of birth. Results Among 93,584 live born babies, 65 had confirmed EOS (0.69/1000 live births); 22 term, 43 preterm. Across the 4 largest birth units, the proportion of babies having blood culture within 72 hours of birth varied from 1.9-5.1% for term and 21-35% for preterm babies. The annual change in the EOS rate was significant, OR 0.91 (95% CI, 0.84 to 0.99, p = 0.03). Group B Streptococcus was the most common cause of EOS in term neonates at 0.35/1000 live births (95% CI, 0.07-0.63) in 2006 and 0.1/1000 live births (95% CI, 0-0.2) in 2016. Escherichia coli was the most common cause in preterm babies at 3.4/1000 (95% CI, 0.11-6.76) in 2006 reducing significantly to 1.35/1000 live births (95% CI, -0.07-2.78) by 2016. Conclusions Escherichia coli and GBS were the most common causes of EOS in preterm and term babies respectively. Rates of all cause term and preterm EOS declined significantly as did preterm sepsis due to E. coli. While rate of sepsis due to early-onset GBS declined, this did not reach significance. Given the high proportion of preterm babies undergoing blood culture, it is unlikely that any EOS events were missed.