Neonatal case of late-onset sepsis involving group B Streptococcus type Ib.

Group B Streptococcus (GBS) is an important pathogen that causes neonatal sepsis and meningitis, which have high mortality and morbidity. Most cases of infection are early onset, with late onset infections being less common. Moreover, many cases of infection are caused by type III GBS, while type Ib GBS infections are rare. We report a case of late-onset infection by type Ib GBS. A female neonate weighing 574 g was delivered at 27 weeks' gestation. An endotracheal tube was inserted shortly after birth because of respiratory distress syndrome, and ampicillin was administered by the age of 3 days. At the age of 54 days after cardiopulmonary adaptation had been achieved, the patient presented with tachycardia following refractory apnea and bradycardia, and her skin became pale. She was suspected of having sepsis, and intensive treatment, including intubation and administration of catecholamines, was started. Despite these measures, the patient died after 5 hours after the onset of sepsis. Type Ib GBS infection may be more frequent in Japanese infants because of the low concentration of IgG antibodies against type Ib in pregnant Japanese women.