Induced resistance to the antimicrobial peptide lactoferricin B in Staphylococcus aureus.
This study was designed to investigate inducible intrinsic resistance against lactoferricin B in Staphylococcus aureus. Serial passage of seven S. aureus strains in medium with increasing concentrations of peptide resulted in an induced resistance at various levels in all strains. The induced resistance was unstable and decreased relatively rapidly during passages in peptide free medium but the minimum inhibitory concentration remained elevated after thirty passages. Cross-resistance to penicillin G and low-level cross-resistance to the antimicrobial peptides indolicidin and Ala(8,13,18)-magainin-II amide [corrected] was observed. No cross-resistance was observed to the human cathelicidin LL-37. In conclusion, this study shows that S. aureus has intrinsic resistance mechanisms against antimicrobial peptides that can be induced upon exposure, and that this may confer low-level cross-resistance to other antimicrobial peptides.
Samuelsen
Orjan
O
Department of Medical Microbiology, University Hospital of North Norway, P.O. Box 56, N-9038 Tromsø, Norway. orjan.samuelsen@unn.no
Haukland
Hanne H
HH
Jenssen
Håvard
H
Krämer
Manuela
M
Sandvik
Kjersti
K
Ulvatne
Hilde
H
Vorland
Lars H
LH
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D007781:Lactoferrin / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; C073143:indolicidin; C082171:lactoferricin B; D007781:Lactoferrin; D010400:Penicillin G