Inhibition of efflux pumps in meticillin-resistant and resistant strains by triterpenoids from

Cátia Ramalhete , Gabriella Spengler , Ana Martins , Marta Martins , Miguel Viveiros , Silva Mulhovo (1) , Maria-José U. Ferreira , Leonard Amaral

1 Departamento de Ciências Agro-Pecuárias

Six cucurbitane-type triterpenoids (-) isolated from the aerial parts of were evaluated for their ability to inhibit the activity of bacterial efflux pumps of meticillin-resistant (MRSA) COL, ATCC 29212, subsp. I serovar Typhimurium 5408 and Typhimurium 5408CIP strains. The latter strain overproduces the AcrB transporter of the AcrAB-TolC efflux pump six-fold compared with its parent. Compounds - were also tested for similar activity against AG100 wild-type strain and AG100TET8 that overproduces the AcrAB-TolC efflux pump. Evaluation of efflux activity was performed using a semi-automated method that measures accumulation of the universal efflux pump substrate ethidium bromide (EtBr). Some of the compounds significantly inhibited efflux of EtBr by MRSA COL and ATCC 29212. A correlation between activity and the topological polar surface area of the compounds was found for MRSA COL.

Mots clés: Efflux pumps inhibitors; EPI; Ethidium bromide; Resistance; Triterpenoids; Cucurbitacins; Momordica balsamina

Cátia Ramalhete, Gabriella Spengler, Ana Martins, Marta Martins, Miguel Viveiros, et al.. Inhibition of efflux pumps in meticillin-resistant and resistant strains by triterpenoids from. International Journal of Antimicrobial Agents, 2010, 37 (1), pp.70. ⟨10.1016/j.ijantimicag.2010.09.011⟩. ⟨hal-00651646⟩