Comparative in vitro activity of five cathelicidin-derived synthetic peptides against Leptospira, Borrelia and Treponema pallidum

• Published in: Journal of antimicrobial chemotherapy 2002-12, Vol.50 (6), p.895-902
• Main Authors: Sambri, Vittorio, Marangoni, Antonella, Giacani, Lorenzo, Gennaro, Renato, Murgia, Rossella, Cevenini, Roberto, Cinco, Marina
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antimicrobial Cationic Peptides - pharmacology; Biological and medical sciences; Blood Proteins - pharmacology; Borrelia; Borrelia - drug effects; Borrelia - isolation & purification; cathelicidin-derived peptide; Cathelicidins; Cattle; Cell Survival - drug effects; Cell Survival - physiology; Cricetinae; Humans; Leptospira; Leptospira - drug effects; Leptospira - isolation & purification; Male; Medical sciences; Mesocricetus; Mice; Microbial Sensitivity Tests - statistics & numerical data; Pharmacology. Drug treatments; Proteins - pharmacology; Rabbits; Sheep; Swine; Treponema; Treponema pallidum - drug effects; Treponema pallidum - isolation & purification
• ISSN: 0305-7453; 1460-2091; 1460-2091
• 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.