Background: The aim of this study was to characterize perinatal Escherichia coli disease, and to analyze its possible correlation with the employment of prophylaxis for group B streptococcal (GBS)disease.

Methods: Between 1994 and 2000, 24 neonates born in our hospital were diagnosed of early-onset E. coli disease: 12 born to mothers who received prenatal care in our center and 12 born to mothers who were referred from other hospitals shortly before labor. Three further neonates born in other centers were also referred with the same diagnosis.

Results: The annual rate did not change significantly (RR:1.065; confidence interval [CI] 95% -0.873-1.301; p = 0.533):from 0.6 per 1,000 live births in 1994 to 1.7 per 1,000 in 1997 and 0.5 in 2000. Among mothers, 92% presented obstetric risk factors including 68% with prematurity (mean 32.9 gestation weeks, median 32), 64% with prolonged rupture of membranes (mean 184 hours,median 44), and 56% with intrapartum fever. Twelve percent of mothers received intrapartum ampicillin as prophylaxis against GBS and 80% received antibiotics: prophylaxis for rupture of membranes in 6 cases, treatment of urinary tract infection in 6 cases and treatment of probable chorioamnionitis in 8 cases. Ampicillin-resistant E. coli was isolated in 81% of neonates. No significant correlation was found between ampicillin resistance and prematurity(p = 0.57), rupture of membranes (p = 0.63), intrapartum fever(p = 0.24) or death (p = 0.53).

Conclusions: Our results suggest that perinatal E. coli disease is not related with the employment of prophylaxis against GBS disease. Instead, it seems to be related with prematurity, prolonged gestation in premature rupture of membranes and exposure to antibiotics.