%0 Journal Article
%T Assessment of three Resistance-Nodulation-Cell Division drug efflux transporters of Burkholderia cenocepacia in intrinsic antibiotic resistance
%A Silvia Buroni
%A Maria R Pasca
%A Ronald S Flannagan
%A Silvia Bazzini
%A Anna Milano
%A Iris Bertani
%A Vittorio Venturi
%A Miguel A Valvano
%A Giovanna Riccardi
%J BMC Microbiology
%D 2009
%I BioMed Central
%R 10.1186/1471-2180-9-200
%X To investigate the contribution of efflux pumps to intrinsic drug resistance of B. cenocepacia J2315, we deleted 3 operons encoding the putative RND transporters RND-1, RND-3, and RND-4 containing the genes BCAS0591-BCAS0593, BCAL1674-BCAL1676, and BCAL2822-BCAL2820. Each deletion included the genes encoding the RND transporter itself and those encoding predicted periplasmic proteins and outer membrane pores. In addition, the deletion of rnd-3 also included BCAL1672, encoding a putative TetR regulator. The B. cenocepacia rnd-3 and rnd-4 mutants demonstrated increased sensitivity to inhibitory compounds, suggesting an involvement of these proteins in drug resistance. Moreover, the rnd-3 and rnd-4 mutants demonstrated reduced accumulation of N-acyl homoserine lactones in the growth medium. In contrast, deletion of the rnd-1 operon had no detectable phenotypes under the conditions assayed.Two of the three inactivated RND efflux pumps in B. cenocepacia J2315 contribute to the high level of intrinsic resistance of this strain to some antibiotics and other inhibitory compounds. Furthermore, these efflux systems also mediate accumulation in the growth medium of quorum sensing molecules that have been shown to contribute to infection. A systematic study of RND efflux systems in B. cenocepacia is required to provide a full picture of intrinsic antibiotic resistance in this opportunistic bacterium.Burkholderia cenocepacia is a member of the Burkholderia cepacia complex (Bcc), a group of phenotypically similar Gram-negative bacteria [1] that are opportunistic pathogens and sometimes cause serious life-threatening infections in cystic fibrosis (CF) patients [2,3]. Infection in CF patients may result in asymptomatic carriage, but often leads to a rapid decline of the lung function and in some cases to the "cepacia syndrome", characterized by necrotizing pneumonia and sepsis [4].B. cenocepacia and other members of the Bcc demonstrate high-levels of intrinsic resistance to most cl
%U http://www.biomedcentral.com/1471-2180/9/200