title: Human β-defensin 3 inhibits antibiotic-resistant Staphylococcus biofilm formation.
abstract: BACKGROUND
  Implantation-associated infections have increased significantly with the recent widespread use of medical implants. Treatments for these infections are not always successful because these infections are sometimes caused by multiantibiotic-resistant organisms. It is therefore particularly urgent to provide doctors with more effective antimicrobial agents against these antibiotic-resistant organisms. Human β-defensin 3 (hBD-3) has been shown to have strong broad-spectrum antibacterial activity. However, its effect on methicillin-resistant Staphylococcus epidermidis (MRSE) and methicillin-resistant Staphylococcus aureus (MRSA) in medical implant biofilm formation has not been reported.
  
  
  METHODS
  In this study, we evaluated the effects of hBD-3 on S epidermidis ATCC 35984 (methicillin-resistant strain), MRSE287, and MRSA (ATCC43300) by evaluating bacterial adhesion, biofilm formation, and maturation. In addition, we used the spread plate method, confocal laser scanning microscopy, scanning electron microscopy, and real-time polymerase chain reaction to evaluate the effect of hBD-3.
  
  
  RESULTS
  After evaluating biofilm adhesion and formation, we found that the number of each strain on the titanium surface was decreased in those groups exposed to 1MIC (minimum inhibitory concentration) of hBD-3 and was significantly lower than the number of colonies of the control. In the initial maturation of the biofilm, the numbers of each strain on the titanium surface from the 2MIC to 6MIC groups were significantly lower than the control. When the concentrations were further increased, hBD-3 was significantly effective against drug-resistant bacteria from the biofilms.
  
  
  CONCLUSIONS
  HBD-3 has the potential to eliminate the biofilm formation of Staphylococcus, especially antibiotic-resistant strains, effectively.
authors.affiliation: Department of Orthopaedic Surgery, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhu
authors.forename: Honglue
authors.initials: H
authors.lastname: Tan
authors.forename: Tao
authors.initials: T
authors.lastname: Cheng
authors.forename: Hao
authors.initials: H
authors.lastname: Shen
authors.forename: Junjie
authors.initials: J
authors.lastname: Shao
authors.forename: Yongyuan
authors.initials: Y
authors.lastname: Guo
authors.forename: Sifeng
authors.initials: S
authors.lastname: Shi
authors.forename: Xianlong
authors.initials: X
authors.lastname: Zhang
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects*; D002448:Cell Adhesion; D015870:Gene Expression; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D009876:Operon; D046915:Penicillin-Binding Proteins; D010641:Phenotype; D013212:Staphylococcus epidermidis / Q000187:drug effects*; D014025:Titanium; D023083:beta-Defensins / Q000494:pharmacology*
chemical_list: D001426:Bacterial Proteins; C422950:DEFB103A protein, human; C487495:MecA protein, Staphylococcus epidermidis; D046915:Penicillin-Binding Proteins; D023083:beta-Defensins; C487789:mecA protein, Staphylococcus aureus; D014025:Titanium