Membrane-permeabilizing peptide acts synergistically with MccJ25 against salmonella typhimurium

MARÍA FERNANDA POMARES; RICARDO N. FARÍAS; MÓNICA A. DELGADO; PAULA A. VINCENT

Carlos Paz, Córdoba

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología molecular; 2008

The microcin J25 (MccJ25) is an antimicrobial peptide that inhibits the RNA polymerase activity and the membrane respiratory chain. MccJ25 is active on some Salmonella serovars, while Salmonella typhimurium is completely resistant because the inability of its FhuA protein to mediate penetration of the antibiotic. In the present study we test the adjuvant effect of the membrane-permeabilizing peptide (MPP) KFFKFFKFFK when it is administrated together with MccJ25. We demonstrated that under above condition Salmonella typhimurium 14028s became sensitive to the MccJ25 antibiotic. The in vivo transcription and oxygen consumption assays showed that the mix MccJ25-MPP was active on both antibiotic targets in Salmonella typhimurium. We also study the antimicrobial activity of MccJ25–MPP against Salmonella typhimurium inside of macrophage. We determined that the bacterial replication ability was hardly inhibited by the presences of MccJ25-MPP compared with untreated control. Additionally, the bacterial invasion ability was not affected by the treatment. Our results demonstrated that MPP perturbs the membrane to allow the MccJ25 penetration in an FhuA-independent way. According with our findings, the mix MccJ25-MPP would be considerate as a therapeutic agent against pathogenic Salmonella strains.