Natural Sesquiterpene Lactones Enhance Oxacillin and Gentamicin Effectiveness Against Pathogenic BacteriaWithout Antibacterial Effects on Beneficial Lactobacilli

ELENA CARTAGENA; MARIANA ALVA; SUSANA MONTANARO; BARDON, ALICIA DEL VALLE

PHYTOTHERAPY RESEARCH

JOHN WILEY & SONS LTD

Lugar: Londres; Año: 2015 vol. 29 p. 695 - 700

0951-418X

This is a report on the synergistic interactions (SIs) between melampolide-type sesquiterpene lactones 1?8 fromAcanthospermum hispidum DC., and oxacillin or gentamicin, against four pathogenic strains of Staphylococcusaureus and Enterococcus faecalis; two of them were multi-resistant strains obtained from chronic infectiousprocesses. Our results showed that all associations of 1?8 with antibiotics (ATBs) are more effective than pureATBs to control pathogenic strains of S. aureus and E. faecalis. The most relevant SIs were observed whenthemajor lactone of A. hispidum, acanthospermal B [5], was combinedwith gentamicin (protein synthesis inhibitor)against an ex vivo culture of methicillin-resistant S. aureus SAR 1, displaying a significant MIC reduction in 5(312.5 to 78.1 μg/mL), and gentamicin (120 μg/mL to 3 μg/mL). Compound 4 improved the antibiotic potencyof oxacillin (cell wall synthesis inhibitor) against ampicillin-resistant E. faecalis (60 μg/mL to 1.5 μg/mL). It isimportant to remark that three beneficial lactobacilli were resistant to 1?8 and their mixtures with gentamicinor oxacillin in effective concentrations against pathogenic bacteria. Synergism between ATBs and phytochemicalsis a therapeutically helpful concept to improve ATB efficacy and prevent resistance. The present results showthat selective SIs occur between melampolides and gentamicin or oxacillin, and open a new field of research.