A membrane-permeabilizing peptide sensitizes microcin J25-resistant strains

MARÍA FERNANDA POMARES,; MÓNICA A. DELGADO,; NATALIA S. CORBALÁN,; RICARDO N. FARIAS; PAULA A. VINCEN

APPLIED AND ENVIRONMENTAL MICROBIOLOGY

AMER SOC MICROBIOLOGY

Lugar: USA; Año: 2010 vol. 72 p. 6837 - 6842

0099-2240

ABSTRACT Microcin J25 (MccJ25) is a plasmid-encoded, 21-amino-acid, antibacterial peptide produced by Escherichia coli. MccJ25 inhibits the RNA polymerase and the membrane respiratory chain. The MccJ25 uptake into E. coli sensitive strains is mediated by the outer membrane receptor FhuA and the inner membrane proteins TonB, ExbB, ExbD and SbmA. This peptide is active on some E. coli, Salmonella and Shigella species strains while other gram negative bacteria such as clinical isolates of Enterobacter cloacae, Citrobacter freundii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Moraxella catarrhalis and Salmonella typhimurium, are completely resistant. In the present work, we demonstrated that the membrane-permeabilizing peptide (KFF)3K made some resistant strains, sensitive to MccJ25, among them, S. typhimurium where the antibiotic inhibits in vitro cell growth and bacterial replication within macrophages. The results demonstrate that the membrane permeabilization induced by (KFF)3K allows the MccJ25 penetration in a FhuA and SbmA-independent manner and suggest that the combination of both peptides could be taken into account as a therapeutic agent against pathogenic Salmonella strains.