Jean Claude Pechere

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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)
Invasion and intracellular survival of Campylobacter jejuni in HEp-2 cells were analyzed by transmission electron microscopy and by viable counts after killing of extracellular bacteria by gentamicin. During the first 30 min after challenge, no bacteria were seen in association with the host cell. After 1 h, campylobacters apparently attached to the cell(More)
Pseudomonas aeruginosa is an opportunistic pathogen, and this organism is a major cause of pulmonary damage and mortality in patients with cystic fibrosis (CF), diffuse panbronchiolitis (DPB) and other forms of bronchiectasis. A break-through in the treatment of DPB and associated chronic P. aeruginosa pulmonary infection was realized when a patient with(More)
To understand the role of Campylobacter jejuni surface proteins in the interaction of C. jejuni with cultured mammalian cell lines in vitro, we developed a ligand-binding assay. This procedure allowed us to antigenically identify C. jejuni outer membrane proteins (OMPs) that attach to intact host cell membranes. OMPs isolated from an invasive strain and a(More)
Salmonella typhimurium strain LT2 is able to invade HeLa cells in vitro. The effect of the motility and chemotaxis of the bacteria on cell invasion were examined by two methods: (1) conventional invasion assays where the HeLa cell monolayers were placed horizontally at the bottom of plastic wells and (2) vertical assays where the HeLa cell monolayer(More)
We report the development of an in vitro assay using HEp-2 cell monolayers in which cell association of five C. jejuni strains and E. coli K12 C600 were tested under different experimental conditions. Both total cell associated colony forming units (CFU) and the CFU protected from gentamicin killing (i.e. internalized bacteria) were determined. Pretreatment(More)
A murine experimental infection with a hemolysin-producing (Hly+) strain of Listeria monocytogenes and a non-hemolysin-producing (Hly-) mutant was used as an in vivo model to evaluate the role of hemolysin production in the immune response. No antilisterial antibodies were detectable following sublethal infection with Hly+ bacteria, but consistent(More)
The broad antibacterial activity of carbapenems includes Gram-negative rods resistant to third generation cephalosporins. To increase the understanding of this improved activity, the factors involved in the efficacy of imipenem and ceftriaxone against Enterobacter cloacae have been examined. Resistance to ceftriaxone is primarily the result of a selection(More)
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