Infection and Drug Resistance (Sep 2022)
Late-Onset Sepsis in a Premature Infant Mediated by Breast Milk: Mother-to-Infant Transmission of Group B Streptococcus Detected by Whole-Genome Sequencing
Abstract
Aiyun Li,1,* Ming Fang,2,* Dongjie Hao,1 Qiaoai Wu,1 Yaqi Qian,1 Hao Xu,3,4 Bo Zhu1 1Department of Clinical Medicine, The Women’s Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People’s Republic of China; 2Institute of Infection Disease Control, Shandong Center for Disease Control and Prevention, Jinan, People’s Republic of China; 3State Key Laboratory for Diagnosis and Treatment of Infectious Disease, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People’s Republic of China; 4Department of Structure and Morphology, Jinan Microecological Biomedicine Shandong Laboratory, Jinan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Hao Xu; Bo Zhu, Email [email protected]; [email protected]: Late-onset group B Streptococcus (LOGBS) sepsis is a cause of infection and death in infants. Infected breast milk has been considered a source of neonatal GBS infection and invasive infection. However, mother-to-infant transmission of GBS detected by the high-resolution diagnostic method is rarely reported.Methods: This study describes a low-weight premature infant who developed late-onset GBS septicemia 21 days after birth. GBS strains isolated from the mother’s cervical secretion, the mother’s milk, and the baby’s blood were cultured to identify the source of GBS infection. We further confirmed the GBS isolates through matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS). Finally, we performed whole-genome sequencing (WGS) and phylogenetic analyses on the GBS strains recovered.Results: GBS isolates were cultured from the bloodstream of the premature infant and the mother’s milk, respectively. Subsequently, WGS and phylogenetic analyses on three GBS isolates demonstrated that the GBS strain from the infant’s bloodstream was 100% homologous to that from the mother’s breast milk, which had some different gene fragments from the GBS strain from the mother’s cervical secretion. It provided evidence that this infant’s late-onset GBS septicemia originated from his mother’s breast milk instead of the vertical mother-to-infant transmission.Conclusion: Through WGS and phylogenetic analysis of the GBS strains, we proved in this study that the late-onset GBS sepsis in a premature infant was derived from his mother’s breast milk. It indicated that WGS diagnosis is an effective tool for infection tracing. Furthermore, this report provides direction for preventing late-onset GBS infection.Keywords: group B Streptococcus, late-onset GBS sepsis, breast milk, whole-genome sequencing, phylogenetic analysis
