-Case Reports-

A Case of Bacteremia and Meningitis in a Neonate Infected with Group B Streptococcus via Breastfeeding Who Survived without Neurological Sequelae: A Case Report

Ryohei Fukunaga¹, Takeshi Asano¹, Ryosuke Matsui¹, Masanori Abe¹, Naruhiko Ishiwada² and Yoshio Shima³

¹Department of Pediatrics, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
²Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba, Japan
³Department of Neonates, Nippon Medical School Musashi Kosugi Hospital, Kanagawa, Japan

Invasive neonatal infection with Group B Streptococcus (GBS) is a disease of concern that can lead to neurological sequelae. Guidelines for preventing mother-to-child transmission have been introduced to reduce the incidence of early-onset infection, but guidelines for controlling the late-onset form are lacking. Recently, the trans-breastfeeding route of transmission has been highlighted as an example of late-onset infection, but no consensus on how to manage such infections has been reached. In this report, we describe a case of late-onset bacteremia/meningitis in a neonate suspected to have been infected with GBS via breastfeeding. A vaginal culture test of the mother at 35 weeks' gestation was negative for GBS. Since she had symptoms of mastitis, breast milk and nipple cultures were also tested and found to be positive for the strain of GBS identified in the neonate on genetic analysis. Diagnosis of trans-mammary GBS infection is challenging because breastfeeding-related events are difficult to identify. In our case, the diagnosis was based on the mother's history of mastitis, and the patient was treated without escalation to sequelae. When a neonate develops a fever, physicians should consider GBS infection and examine the mother's medical history to facilitate accurate diagnosis, especially if the history includes mastitis. A breast milk culture should be performed if the mother has mastitis, especially in cases of infection in preterm infants and in recurrent cases.

J Nippon Med Sch 2024; 91: 495-498

Keywords
Group B streptococcus, mastitis, neonatal meningitis

Correspondence to
Takeshi Asano, Department of Pediatrics, Nippon Medical School Chiba Hokusoh Hospital, 1715 Kamagari, Inzai, Chiba 270-1694, Japan
july1364@nms.ac.jp

Received, January 14, 2023
Accepted, May 1, 2023