[Streptococcus agalactiae late onset infection associated with human milk: three cases report].

Group B β-hemolytic Streptococcus or Streptococcus agalactiae is a major cause of morbidity and mortality in neonates, especially in premature infants. Current prevention strategies have been effective in reducing the frequency of early onset neonatal sepsis caused by vertical transmission. The incidence of late onset sepsis due to this microorganism has not changed and the route of infection is less clear. In breastfed infants, transmission through breast milk is possible. We report three cases of late group B β-hemolytic streptococcal infection in breastfed preterm infants whose mothers had mastitis. In all cases, both the breast milk culture and the blood cultures of the neonates developed the same microorganism.