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

Area of Science:

• Neonatal infections
• Bacterial pathogenesis
• Streptococcal diseases

Background:

• Group B Streptococcus (GBS) is a leading cause of neonatal morbidity and mortality, particularly in preterm infants.
• While early-onset GBS sepsis is reduced by current prevention strategies targeting vertical transmission, late-onset GBS sepsis incidence remains unchanged.
• The transmission route for late-onset GBS infection is not well-defined, especially in breastfed neonates.

Observation:

• Three cases of late-onset GBS infection in breastfed preterm infants are presented.
• All infants' mothers had mastitis, an inflammation of the breast tissue.
• Simultaneous GBS detection in maternal breast milk and infant blood cultures was observed in all cases.

Findings:

• Breast milk can be a source of GBS transmission to neonates.
• Maternal mastitis is associated with GBS transmission to breastfed infants.
• Identical GBS strains were cultured from breast milk and infant blood, confirming transmission.

Implications:

• Breastfeeding may pose a risk for GBS transmission in specific maternal conditions like mastitis.
• Further investigation into GBS transmission via breast milk is warranted.
• Clinical awareness and diagnostic approaches for late-onset GBS sepsis in breastfed infants should consider maternal mastitis.