title: Antibacterial activity of the human host defence peptide LL-37 and selected synthetic cationic lipids against bacteria associated with oral and upper respiratory tract infections.
abstract: OBJECTIVE
  We aim to develop antibacterial peptide mimics resistant to protease degradation, with broad-spectrum activity at sites of infection.
  
  
  METHODS
  The bactericidal activities of LL-37, ceragenins CSA-13, CSA-90 and CSA-92 and the spermine-conjugated dexamethasone derivative D2S were evaluated using MIC and MBC measurements. Gingival fibroblast counting, interleukin-8 (IL-8) and lactate dehydrogenase (LDH) release from keratinocytes (HaCat) were used to determine effects on cell growth, pro-inflammatory response and toxicity.
  
  
  RESULTS
  All tested cationic lipids showed stronger bactericidal activity than LL-37. Incubation of Staphylococcus aureus with half the MIC of LL-37 led to the appearance of bacteria resistant to its bactericidal effects, but identical incubations with CSA-13 or D2S did not produce resistant bacteria. Cathelicidin LL-37 significantly increased the total number of gingival fibroblasts, but ceragenins and D2S did not alter gingival fibroblast growth. Cationic lipids showed no toxicity to HaCat cells at concentrations resulting in bacterial killing.
  
  
  CONCLUSIONS
  These data suggest that cationic lipids such as ceragenins warrant further testing as potential novel antibacterial agents.
authors.affiliation: Department of Diagnostic Microbiology, Medical University of Białystok, 15-230 Białystok,  Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Leszczynska
authors.forename: Dorota
authors.initials: D
authors.lastname: Namiot
authors.forename: Fitzroy J
authors.initials: FJ
authors.lastname: Byfield
authors.forename: Katrina
authors.initials: K
authors.lastname: Cruz
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Zendzian-Piotrowska
authors.forename: David E
authors.initials: DE
authors.lastname: Fein
authors.forename: Paul B
authors.initials: PB
authors.lastname: Savage
authors.forename: Scott
authors.initials: S
authors.lastname: Diamond
authors.forename: Christopher A
authors.initials: CA
authors.lastname: McCulloch
authors.forename: Paul A
authors.initials: PA
authors.lastname: Janmey
authors.forename: Robert
authors.initials: R
authors.lastname: Bucki
mesh_terms: D000293:Adolescent; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D009055:Mouth / Q000382:microbiology*; D012141:Respiratory Tract Infections / Q000382:microbiology*
chemical_list: D023181:Antimicrobial Cationic Peptides