Differential Abundances of Bdellovibrio and Rheinheimera in the Oral Microbiota of Neonates With and Without Clinical Sepsis

Abstract

Background: Neonatal sepsis is associated with high rates of morbidity and mortality, long hospital stays and high cost of care, thereby inflicting a burden on health care systems. Oral care with breast milk has been shown to modify the intestinal tract microbiota and immune system. Herein, we attempted to identify probiotics that may be beneficial to prevent or treat neonatal sepsis. Methods: This was a secondary analysis comparing the microbiota during oropharyngeal care in very-low-birth-weight infants with and without clinical sepsis. Oral samples were collected before oral feeding was initiated. The primary outcome was oral microbiota composition including diversity, relative abundance and linear discriminant analysis effect size. Results: Sixty-three neonates, including 39 and 24 with and without clinical sepsis, respectively, were enrolled. The medians gestational age and birth weight were 29 (27–30) weeks and 1010 (808–1263) g. Neonates with clinical sepsis had lower gestational age, birth weight (both P < 0.001) and lower rate of oral care with breast milk (P = 0.03), but higher doses and days of antibiotic exposure (both P < 0.001) compared to neonates without clinical sepsis. No differences in alpha and beta diversities were found between groups and Streptococcus agalactiae was the most common bacteria in both groups. Linear discriminant analysis effect size analysis revealed that neonates without clinical sepsis had significantly higher abundances of order Bdellovibrionales, family Bdellovibrionaceae, genus Bdellovibrio and genus Rheinheimera. Conclusions: Neonates without clinical sepsis had a significantly greater abundance of the Bdellovibrio and Rheinheimera genera.