title: Staphylococcus epidermidis isolated from newborn infants express pilus-like structures and are inhibited by the cathelicidin-derived antimicrobial peptide LL37.
abstract: Coagulase-negative staphylococci and its subtype Staphylococcus epidermidis are major indigenous Gram-positive inhabitants of the human skin. Colonization occurs in direct connection with birth and terrestrial adaptation. This study focuses on factors that may influence skin colonization of the newborn infant that relates to the immune status of both the bacteria and the host. Skin is an effective barrier against bacteria, and this function is partly mediated by the presence of antimicrobial peptides including human cathelicidin peptide LL37. Gram-positive bacteria have been described to have adhesive pili on their surface that mediates specific attachment to the host. Here, we identify, by negative staining transmission electron microscopy (EM), two different types of pilus-like structures commonly expressed on S. epidermidis isolated from newborn infants. We also show that the cathelicidin antimicrobial peptide LL37, constitutively expressed in the skin barrier of the newborn, significantly inhibited growth of S. epidermidis indicating its importance for the ecological stability of the skin microbiota. Further studies are required to elucidate molecular mechanisms of host-microbe interactions, both for the maintenance of a mutually beneficial homeostatic relationship and for the protection of self when it results in overt disease.
authors.affiliation: Department of Woman and Child Health, Karolinska Institutet, Stockholm 17176, Sweden.
authors.forename: Annika
authors.initials: A
authors.lastname: Nelson
authors.forename: Kjell
authors.initials: K
authors.lastname: Hultenby
authors.forename: Eva
authors.initials: E
authors.lastname: Hell
authors.forename: Hilde M
authors.initials: HM
authors.lastname: Riedel
authors.forename: Hjalmar
authors.initials: H
authors.lastname: Brismar
authors.forename: Jan-Ingmar
authors.initials: JI
authors.lastname: Flock
authors.forename: Joachim
authors.initials: J
authors.lastname: Lundahl
authors.forename: Christian G
authors.initials: CG
authors.lastname: Giske
authors.forename: Giovanna
authors.initials: G
authors.lastname: Marchini
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D023181:Antimicrobial Cationic Peptides / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms; D054804:Cathelicidins; D005260:Female; D010861:Fimbriae, Bacterial / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D011247:Pregnancy; D012867:Skin / Q000382:microbiology; D013207:Staphylococcal Skin Infections / Q000378:metabolism; D013212:Staphylococcus epidermidis / Q000166:cytology* / Q000378:metabolism* / Q000472:pathogenicity
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D001426:Bacterial Proteins; D054804:Cathelicidins