Jean Marie Pages

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..pneumoniae isolates that are non susceptible to cefoxitin (FOX) and susceptible to amoxicillin+clavulanic acid in our hospital. Assessing the role of efflux pumps in this beta-lactam phenotype was the aim of this study...

..The present study was designed to evaluate the antibacterial activities of the methanol extracts of eleven Cameroonian spices on a panel of twenty nine Gram negative bacteria including MDR strains...

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..This new family of molecules represents the first antibacterial class of compound specifically targeting active transport in the bacterial cell...

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..These results suggest that the Lys-16 residue plays an important role in the process of diffusion through the OmpF lumen...

..Inhibitory activity of this alkylaminoquinoline is observed on clinical isolates showing different resistance phenotypes...

..D113 appeared to play an essential role for colicin A activity, whereas colicin N activity was more dependent on D121 than on D113...

..The resistance strategies used by these isolates appear to be similar to that induced by stress in Escherichia coli cells...

..These effectors activate the expression of specific global regulators, marA, ramA, or target other genes located downstream in the regulation cascade...

..Microbiol. 41 (2001) 189]. This is the first genetic identification of impermeability-mediated resistance to beta-lactams in various clinical E. aerogenes strains...

..Both derivatives were more susceptible to antibiotics than the parental strain. Sequence analysis and complementation experiments revealed that the multidrug-resistant isolate is an acrR mutant...

..The overexpression of marA, involved in the genetic control of membrane permeability via porin and efflux pump expression, indicated the activation of the resistance genetic cascade in imipenem resistant variants...

..The involved resistance mechanisms exhibited by the successive isolates were associated with alterations of the outer membrane that caused a porin decrease and lipopolysaccharide modifications...

..aerogenes acrAB or tolC derivatives compared to that in the parental strain. Two independent efflux pumps, inhibited by phenylalanine arginine beta-naphthylamide, expel macrolides and telithromycin in E. aerogenes...

..lari strains tested were positive. A PCR assay was developed, using the omp50 gene as a species-specific target. We propose a combination of a hippurate test and an omp50 assay to perform identification of Campylobacter species...

..A molecule exhibiting a morpholine functional group and a propyl extension of the side chain was more active...

..Consequently, the early control of ompX and ompF induced by external stresses may represent a preliminary response to antibiotics, thus triggering the initial bacterial line of defense against antibiotherapy...

..CadF, an E. coli OmpA-like protein, facilitates the binding of C. jejuni to the extracellular matrix component, fibronectin...

..Quinazoline molecules exhibiting a nitro functional group are more active, and structure-activity relationship studies may be undertaken to identify the pharmacophoric group involved in the AcrB and MexB affinity sites...

..This interaction introduces several changes in the internal morphology of the channel which are responsible for the inhibition of antibiotic uptake using the porin route...

..AcrA-TolC overproduction in E. aerogenes isolates was noted. An analysis of four E. aerogenes isolates for which cefepime MICs were high revealed no modification in porin expression but a new specific mutation in the AmpC beta-lactamase...

..coli. The same regulation was also observed in wild-type C. lari strains and in a C. coli strain supplemented by the plasmid, suggesting that omp50 expression is controlled by a mechanism conserved among Campylobacter species...

..Molecular modeling suggests that the charges harbored by the beta-lactam molecules interact with the charged residues located inside the porin eyelet...

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..These results demonstrate that these essential oils can alter efflux pump activity and may be attractive candidates to develop new drugs for chemosensitising multidrug-resistant strains to clinically used antibiotics...

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..After ultracentrifugation, the pellet was treated with 5% Triton X-100, 5 mM EDTA to solubilize the outer membrane proteins. Approximately 5 mg of 95% pure TolC-6His trimers per liter of culture was purified by INAC...

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..Clinical reports have linked the MDR phenotype to altered membrane permeability including porin modification and efflux pump expression...

..Current progress for the clinical use of efflux-pump inhibitors and new strategies to combat the drug-efflux mechanisms will be discussed...

..Geraniol, a component of one fraction, significantly increased the efficacy of beta-lactams, quinolones, and chloramphenicol...

..All these aspects play a key role in both membrane permeability and efficiency of the antibiotic resistance process...

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..Different strategies could be proposed to bypass the bacterial membrane barrier, comprising influx and efflux mechanisms, in order to restore the activity of antibiotics against resistant bacteria...

..Another characteristic of the TolC and EefC channels was the systematic closure induced by acidic pH. These results are discussed in respect to the physiological functions and structural models of TolC and EefC...

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..Parabens are currently used as antibacterial preservatives in pharmaceutical, cosmetic and food products but there are no precise data concerning their activity on bacterial membranes...

..This study indicates that the alteration in porin expression, including the shift of porin expression and lack of porins, contribute to the E. aerogenes adaptive response to IPM treatment...

..Antibiotics known to easily induce overexpression of these efflux pumps should be used with discernment in the treatment of Burkholderia infections...

..The efflux mechanisms and the development of efflux pump inhibitors (EPIs) are discussed regarding these two pathogens...

..In addition, thanatin was able to improve the activity of structurally unrelated antibiotics (norfloxacin, chloramphenicol, tetracycline) on a multidrug- resistant E. aerogenes clinical isolate...

..The bacterial susceptibility to such a cytoplasmic target primarily depends on the capacity of the compound to reach and accumulate in the cytosol...

..4 A Da(-1)). The other form exhibits trigonal symmetry (space group R3) with hexagonal unit-cell parameters a = b = 94.2, c = 161.2 A, but diffracts X-rays poorly to about 4 A with significant anisotropy...