title: In vitro synergistic effect of Psidium guineense (Swartz) in combination with antimicrobial agents against methicillin-resistant Staphylococcus aureus strains.
abstract: The aim of this study was to evaluate the antimicrobial activity of aqueous extract of Psidium guineense Swartz (Araçá-do-campo) and five antimicrobials (ampicillin, amoxicillin/clavulanic acid, cefoxitin, ciprofloxacin, and meropenem) against twelve strains of Staphylococcus aureus with a resistant phenotype previously determined by the disk diffusion method. Four S. aureus strains showed resistance to all antimicrobial agents tested and were selected for the study of the interaction between aqueous extract of P. guineense and antimicrobial agents, by the checkerboard method. The criteria used to evaluate the synergistic activity were defined by the fractional inhibitory concentration index (FICI). All S. aureus strains were susceptible to P. guineense as determined by the microdilution method. The combination of the P. guineense extract with the antimicrobial agents resulted in an eight-fold reduction in the MIC of these agents, which showed a FICI ranging from 0.125 to 0.5, suggesting a synergistic interaction against methicillin-resistant Staphylococcus aureus (MRSA) strains. The combination of the aqueous extract of P. guineense with cefoxitin showed the lowest FICI values. This study demonstrated that the aqueous extract of P. guineense combined with beta lactamics antimicrobials, fluoroquinolones, and carbapenems, acts synergistically by inhibiting MRSA strains.
authors.affiliation: Laboratório de Fisiologia e Bioquímica de Microorganismos, Departamento de Antibióticos, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, 50670-901 Recife, PE, Brazil.
authors.forename: Tiago Gomes
authors.initials: TG
authors.lastname: Fernandes
authors.forename: Amanda Rafaela Carneiro
authors.initials: AR
authors.lastname: de Mesquita
authors.forename: Karina Perrelli
authors.initials: KP
authors.lastname: Randau
authors.forename: Adelisa Alves
authors.initials: AA
authors.lastname: Franchitti
authors.forename: Eulália Azevedo
authors.initials: EA
authors.lastname: Ximenes
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004357:Drug Synergism; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000494:pharmacology*; D031647:Psidium / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts