title: Eﬄux-mediated resistance to a benzothiadiazol derivative effective against Burkholderia cenocepacia.
abstract: Burkholderia cenocepacia is a major concern for people suffering from cystic fibrosis as it contributes to serious respiratory tract infections. The lack of drugs effective against this opportunistic pathogen, along with the high level of resistance to multiple antibiotics, render the treatment of these infections particularly difficult. Here a new compound, belonging to the 2,1,3-benzothiadiazol-5-yl family (10126109), with a bactericidal effect and a minimal inhibitory concentration (MIC) of 8 μg/ml against B. cenocepacia, is described. The compound is not cytotoxic and effective against B. cenocepacia clinical isolates and members of all the known B. cepacia complex species. Spontaneous mutants resistant to 10126109 were isolated and mutations in the MerR transcriptional regulator BCAM1948 were identified. In this way, a mechanism of resistance to this new molecule was described, which relies on the overexpression of the RND-9 eﬄux pump. Indeed, rnd-9 overexpression was confirmed by quantitative reverse transcription PCR, and RND-9 was identified in the membrane fractions of the mutant strains. Moreover, the increase in the MIC values of different drugs in the mutant strains, together with complementation experiments, suggested the involvement of RND-9 in the eﬄux of 10126109, thus indicating again the central role of eﬄux transporters in B. cenocepacia drug resistance.
authors: Laboratory of Molecular Microbiology, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani," Università degli Studi di Pavia Pavia, Italy.
authors: Viola C
authors: VC
authors: Scoffone
authors: Bakh Institute of Biochemistry, Russian Academy of Science Moscow, Russia.
authors: Olga
authors: O
authors: Ryabova
authors: Bakh Institute of Biochemistry, Russian Academy of Science Moscow, Russia.
authors: Vadim
authors: V
authors: Makarov
authors: Laboratory of Molecular Microbiology, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani," Università degli Studi di Pavia Pavia, Italy.
authors: Paolo
authors: P
authors: Iadarola
authors: Laboratory of Molecular Microbiology, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani," Università degli Studi di Pavia Pavia, Italy.
authors: Marco
authors: M
authors: Fumagalli
authors: Department of Biology, University of Florence Florence, Italy.
authors: Marco
authors: M
authors: Fondi
authors: Department of Biology, University of Florence Florence, Italy.
authors: Renato
authors: R
authors: Fani
authors: Laboratory of Molecular Microbiology, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani," Università degli Studi di Pavia Pavia, Italy.
authors: Edda
authors: E
authors: De Rossi
authors: Laboratory of Molecular Microbiology, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani," Università degli Studi di Pavia Pavia, Italy.
authors: Giovanna
authors: G
authors: Riccardi
authors: Laboratory of Molecular Microbiology, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani," Università degli Studi di Pavia Pavia, Italy.
authors: Silvia
authors: S
authors: Buroni
keywords: Burkholderia; Gram-negatives; cystic fibrosis; drug resistance; eﬄux pumps; new antimicrobials