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

Background 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.

Vaginal microecological imbalance and expression of serum inflammatory factors in pregnant women with group B streptococcus infection and pregnancy outcome

“…If the levels of inflammatory factors are elevated, the doctor may recommend further tests and treatment to protect the health of the mother and child. Studies have shown that inflammation during pregnancy is closely correlated with preterm birth, but the relationship between GBS infection and preterm birth has not been clear (16).…”

The Role of Breast Milk on Reducing the Risk of Neonatal Sepsis in Preterm and Low Birth Weight Infants: A Systematic Review and Meta-Analysis

“…Several studies revealed that late-onset sepsis in preterm infant was derived from contaminated breastmilk expression. 19,20 However, there is still limited evidence regarding the role of breast milk's effects on neonatal sepsis. Therefore, this systematic review and meta-analysis aimed to determine the role of breast milk on neonatal sepsis in preterm and low birth weight infants.…”