Differential activity of innate defense antimicrobial peptides against Nocardia species.
BACKGROUND
Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs) in innate defense against Nocardia, the activity of human alpha-defensins human neutrophil peptides (HNPs) 1-3, human beta-defensin (hBD)-3 and cathelicidin LL-37 as well as bovine beta-defensins lingual and tracheal antimicrobial peptides (LAP, TAP) and bovine neutrophil-derived indolicidin against four important Nocardia species was investigated.


RESULTS
Whereas N. farcinica ATCC 3318 and N. nova ATCC 33726 were found to be susceptible to all investigated human and bovine AMPs, N. asteroides ATCC 19247 was killed exclusively by neutrophil-derived human alpha-defensins HNP 1-3 and bovine indolicidin. N. brasiliensis ATCC 19296 was found to exhibit complete resistance to investigated human AMPs and to be susceptible only to bovine indolicidin.


CONCLUSIONS
Selected AMPs are capable to contribute to the first line of defense against Nocardia, yet, susceptibility appears to vary across different Nocardia species. Obtained results of neutrophil-derived AMPs to possess the broadest antinocardial spectrum are remarkable, since nocardiosis is characterized by a neutrophil-rich infiltrate in vivo.
Rieg
Siegbert
S
Center for Infectious Diseases & Travel Medicine, University Medical Center, Hugstetter Strasse 55, 79106 Freiburg, Germany. siegbert.rieg@uniklinik-freiburg.de
Meier
Benjamin
B
Fähnrich
Eva
E
Huth
Anja
A
Wagner
Dirk
D
Kern
Winfried V
WV
Kalbacher
Hubert
H
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000276:immunology / Q000494:pharmacology*; D054804:Cathelicidins / Q000276:immunology / Q000494:pharmacology*; D002417:Cattle; D015169:Colony Count, Microbial; D006801:Humans; D007113:Immunity, Innate; D008826:Microbial Sensitivity Tests; D009615:Nocardia / Q000187:drug effects* / Q000276:immunology; D009617:Nocardia Infections / Q000276:immunology* / Q000382:microbiology; D015242:Ofloxacin / Q000276:immunology / Q000494:pharmacology; D023084:alpha-Defensins / Q000276:immunology / Q000494:pharmacology*; D023083:beta-Defensins / Q000276:immunology / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins; D023084:alpha-Defensins; D023083:beta-Defensins; C073143:indolicidin; D015242:Ofloxacin