Invasive Group B Streptococcal Infections in Neonates and Foetuses

Abstract

Background: Group B Streptococcus (GBS) remains a leading cause of neonatal infection. Objective: To evaluate the clinical impact of CDC-2002 prevention guidelines, to describe characteristics and outcomes of patients with neonatal GBS disease and to study foetal deaths secondary to GBS infection. Methods: Retrospective study of GBS perinatal infections recorded during two periods: 2000-2004 / 2005-2008. Infants younger than 6 months of age and foetuses with GBS positive cultures of blood, urine, cerebrospinal fluid or tissues were included. A total of 186 patients were eligible, 107 were excluded. Results: Overall, there were 79 infants. Median and range of ages were 1 day (1-6), 31 days (10-88) and 137 days (100-180), for early (EOD)-late (LOD)-and very late diseases, respectively. Between the first and second studied periods, we observed a significant decrease of EOD (15 vs. 3 cases) p<0.005; OR 0.15 (CI: 0.04-0.57), however, LOD increased (23 vs. 33 cases), p<0.004; OR 5.17 (CI: 1.68-15.91). We also observed a decrease in bacteraemia p<0.02; OR 0.33 (CI: 0.12- 0.86) while the rate of meningitis, urinary tract infection, pneumonia and osteomyelitis remained stable. Mortality rate was 6.3%; of survivors, 12.7% presented serious long term sequelae. Meningitis was more frequently diagnosed in premature than in term infants p<0.003; OR 4.46 (CI: 1.64- 12.10), and leucopenia was significantly found in these cases p<0.001; OR 20.36 (CI: 4.98-83.29). Urinary infection was seen in term newborns p<0.017; OR 0.08 (CI: 0.01-0.63). EOD was associated with multiparity p<0.001; OR 16.79 (CI: 4.24-66.44), whereas LOD with primiparity p<0.001; OR 0.13 (CI: 0.05-0.39). Median age of the 27 mothers who delivered infected foetuses was 30.5 years (17-42) and median gestational age was 22 weeks (17-38). Overall, 66.7% presented in the second study period. Median foetal weight of these foetuses was 401.9 gr (114-3645) and 59.3% were males. GBS was isolated from 76.2% of placentas and from body fluids or tissues biopsies for the remainder. Conclusions: The observed changes in clinical presentation of GBS perinatal infections between the two studied periods suggest an improvement of adherence to intrapartum prophylaxis guidelines. We have no explanation for the increase of LOD. We noted an increase in foetal death; this is a group for which intrapartum antibiotics would not be effective, but potentially preventable by vaccination. Appropriate prophylactic interventions should remain a high priority to reduce the rate of perinatal GBS diseases.