Jean Claude Pechere

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We investigated the regulation of the MexEF-OprN multidrug efflux system of Pseudomonas aeruginosa, which is overexpressed in nfxC-type mutants and confers resistance to quinolones, chloramphenicol and trimethoprim. Sequencing of the DNA region upstream of the mexEF-oprN operon revealed the presence of an open reading frame (ORF) of 304 amino acids encoding(More)
Originally described in bacteria, drug transporters (or efflux pumps) are now recognized as major determinants in the modulation of the accumulation and efflux of antibacterials in virtually all cell types, from prokaroytes to superior eukary-otes. Transport proteins are in fact major cellular products. Based on sequence similarities with known transporters(More)
Quorum-sensing systems are critical regulators of the expression of virulence factors of various organisms, including Pseudomonas aeruginosa. Las and Rhl are two major quorum-sensing components, and they are regulated by their corresponding autoinducers, N-3-oxododecanoyl homoserine lactone (3-oxo-C(12)-HSL) and N-butyryl-L-homoserine lactone (C(4)-HSL).(More)
The ability of trovafloxacin and ciprofloxacin to select efflux mutants in vivo was studied in a model of acute Pseudomonas aeruginosa pneumonia in rats. Twelve hours after intratracheal inoculation of 10(6) CFU of P. aeruginosa strain PAO1 enmeshed in agar beads, two groups of 12 rats were treated by three intraperitoneal injections of each antibiotic(More)
We investigated the unusual susceptibility to meropenem observed for seven imipenem-resistant clinical isolates of Pseudomonas aeruginosa. These strains were genetically closely related, expressed OprD, as determined by Western blot analyses, and were resistant to imipenem (>5 microg/ml) but susceptible to meropenem (<1 microg/ml). The oprD genes from two(More)
Originally described in bacteria, drug transporters (or efflux pumps) are now recognized as major determinants in the modulation of the accumulation and efflux of antibacterials in virtually all cell types, from prokaroytes to superior eukary-otes. Transport proteins are in fact major cellular products. Based on sequence similarities with known transporters(More)
One group of newborn rats were given 50 mg/kg gentamicin for 20 days, 8 days after birth and were housed during the treatment in a regular incubator. They were compared to a similar group housed in regular cages and to two groups of unintoxicated newborn rats, one being exposed to the incubator noise and one being unexposed. Incubator noise was found to(More)
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