Comparative in Vitro Activity of Five Cathelicidin-Derived Synthetic Peptides Against Leptospira, Borrelia and Treponema Pallidum

J Antimicrob Chemother. 2002 Dec;50(6):895-902. doi: 10.1093/jac/dkf220.


Objective: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of five different cathelicidin-derived synthetic peptides (SMAP-29, LL-37, PG-1, CRAMP and BMAP-28) for Leptospira interrogans, Borrelia spp. and Treponema pallidum subsp. pallidum were investigated in vitro.

Methods: The MIC of individual peptides was defined as the lowest concentration able to inhibit the motility of spirochaetes after 2 h of incubation, as detected by dark-field microscopy. The MBC of individual peptides was defined as the lowest concentration at which no spirochaetes were subcultured either in cathelicidin-free medium (leptospires and borreliae) or in hamsters (T. pallidum).

Results: The MIC values of peptides for leptospires were highly variable, depending on the compound and the strain used. Of the five cathelicidin-derived peptides, SMAP-29 from sheep and BMAP-28 from cattle were the most active against L. interrogans serovars, with MIC values varying between 3 and 51 mg/L, depending on the strains. The MICs of the remaining synthetic peptides ranged between 4.3 and 224 mg/L. The MIC values of synthetic peptides for T. pallidum ranged between 32.3 mg/L for PG-1 and 449.4 mg/L for LL-37. The MICs of all cathelicidin-derived peptides tested for Borrelia strains ranged between 307 and 449.4 mg/L. The activity of the peptides on the motility of spirochaetes was both dose- and time-dependent. The MBC values of the peptides were the same as the MIC values.

Conclusion: The results of this study demonstrate that the activity of cathelicidin-derived peptides against spirochaetes is fast and highly variable, depending on the species and the strain.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology*
  • Antimicrobial Cationic Peptides / pharmacology*
  • Blood Proteins / pharmacology
  • Borrelia / drug effects*
  • Borrelia / isolation & purification
  • Cathelicidins
  • Cattle
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • Cricetinae
  • Humans
  • Leptospira / drug effects*
  • Leptospira / isolation & purification
  • Male
  • Mesocricetus
  • Mice
  • Microbial Sensitivity Tests / statistics & numerical data
  • Proteins / pharmacology
  • Rabbits
  • Sheep
  • Swine
  • Treponema pallidum / drug effects*
  • Treponema pallidum / isolation & purification


  • Anti-Bacterial Agents
  • Antimicrobial Cationic Peptides
  • BMAP-28
  • Blood Proteins
  • Cathelicidins
  • Proteins
  • SMAP29 protein, Ovis aries
  • protegrin-1
  • CAP18 lipopolysaccharide-binding protein