Evidence for transmission of Escherichia coli from mother to child in late-onset neonatal infection.

Genetic characterization of non-K1 Escherichia coli strains isolated from a mother and her neonate allowed us to provide evidence of the maternal origin of a late-onset neonatal infection. The use of ante- and peripartum antimicrobial prophylaxis with amoxicillin may have promoted the vertical transmission of this amoxicillin-resistant E. coli from mother to newborn. It allowed us to clarify the natural history of the disease.