Tracing

Coagulase-negative staphylococci (CoNS) comprise about 50 species, some of which cause septicemia in preterm neonates. CoNS establish early on the skin and in the oral and gut microbiota, from where they may spread to the bloodstream. The colonization pattern preceding septicemia is not well-defined. Forty-two extremely preterm neonates (≤28 + 0 gestational weeks) were followed from birth to 2 months with regular sampling and culturing of the skin and oral and gut microbiota. Blood samples were drawn upon clinical suspicion of septicemia and cultured. CoNS species were identified using matrix-assisted laser-desorption ionization time of flight mass spectrometry (MALDI-TOF). Random amplified polymorphic DNA was used for strain typing, and strains were characterized regarding biofilm production and virulence gene carriage. CoNS blood isolates underwent whole genome sequencing. IMPORTANCE: Septicemia is a major cause of morbidity in preterm infants. Coagulase-negative staphylococci (CoNS) can colonize skin, oral cavity, and intestines and are a common cause of septicemia in this group. The relation between CoNS colonization pattern at the species and strain level and septicemia has scarcely been studied. We mapped colonization of the skin, oral cavity, and intestines by CoNS species in extremely preterm infants and speciated and strain-typed the skin, mucosal, and blood isolates. Two-thirds of the CoNS septicemia blood strains, including a majority of