Late-onset invasive group B streptococcal infection with serotype VIII in a neonate having congenital biliary atresia

A female newborn was admitted to our department 15 days after birth for insufficient sucking and jaundice. The patient's blood and urine cultures were both positive for group B streptococcal (GBS) infection. A maternal vaginal sample at 35 weeks' gestation was negative for GBS in culture-based microbiologic screening. The patient recovered shortly after receiving systemic antibiotic therapy. On the basis of clinical evidence of white stool and progressive jaundice, we suspected that the newborn had complications related to congenital biliary atresia (CBA); surgery was performed. Isolates from the mother's vaginal sample obtained when the patient was 25 days old, along with neonatal blood, revealed identical patterns (serotype VIII and sequence type 1) of GBS capsular and multilocus sequence typing, suggestive of maternal transmission. Molecular epidemiologic examination may be useful to clarify the transmission route and etiology; culture-based microbiologic screening appears to have limitations for detecting the route of transmission.