首页>
外文期刊>Antimicrobial Agents and Chemotherapy
>Differential roles of rnd efflux pumps in antimicrobial drug resistance of sessile and planktonic burkholderia cenocepacia cells
【24h】
Differential roles of rnd efflux pumps in antimicrobial drug resistance of sessile and planktonic burkholderia cenocepacia cells
Burkholderia cenocepacia is notorious for causing respiratory tract infections in people with cystic fibrosis. Infections with this organism are particularly difficult to treat due to its high level of intrinsic resistance to most antibiotics. Multidrug resistance in B. cenocepacia can be ascribed to different mechanisms, including the activity of efflux pumps and biofilm formation. In the present study, the effects of deletion of the 16 operons encoding resistance-nodulation-cell division (RND)-type efflux pumps in B. cenocepacia strain J2315 were investigated by determining the MICs of various antibiotics and by investigating the antibiofilm effect of these antibiotics. Finally, the expression levels of selected RND genes in treated and untreated cultures were investigated using reverse transcriptase quantitative PCR (RT-qPCR). Our data indicate that the RND-3 and RND-4 efflux pumps are important for resistance to various antimicrobial drugs (including tobramycin and ciprofloxacin) in planktonic B. cenocepacia J2315 populations, while the RND-3, RND-8, and RND-9 efflux systems protect biofilm-grown cells against tobramycin. The RND-8 and RND-9 efflux pumps are not involved in ciprofloxacin resistance. Results from the RT-qPCR experiments on the wild-type strain B. cenocepacia J2315 suggest that there is little regulation at the level of mRNA expression for these efflux pumps under the conditions tested. This work was supported by the Italian Cystic Fibrosis Research Foundation (FFC project 10/2012 G.R., adopted by Associazione Trentina FC onlus in ricordo di Zaira Tutino, Gruppo di Sostegno FFC di Palermo-in ricordo di Elisa Pepe; Delegazione FFC di Imola), by the Fund for Scientific Research-Flanders (FWO-Vlaanderen), and by the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office. We thank Lisa Slachmuylders and Sanne Kiekens for excellent technical assistance.
展开▼
