Effect of EPI on chloramphenicol susceptibility of <i>E. aerogenes</i> strains.

<p>I, R ^a: Intermediate, Resistant.</p><p>EP ^b: Efflux Pump susceptible when PAßN induces a decrease of at least 3 dilutions.</p

PFGE of <i>Xba</i>I-digested genomic DNA preparations from various clinical <i>Enterobacter aerogenes</i> isolates.

<p>1995 isolates: 6582, 106701, 313, 139, 120, 31, 70, 17, 49, 130, 109, 183, 52. 2003 isolates: 101979, 121653, 109688, 181243, 138074, 121435, 109709, 121652, 128500, 116621. ATCC13048 and EA27, used as reference strains. Molecular weight markers are indicated: a, 48.5 kb; b, 97 kb; c, 145.5 kb; d, 194 kb; e, 242.5 kb; f, 291 kb; g, 340 kb; h, 388 kb; i, 437 kb; j, 485 kb; h, 534 kb.</p

Susceptibilities of the <i>E. aerogenes</i> isolates (1995) to different antibiotics (MIC µg/mL)^a.

a<p>The values are the means of three independent assays.</p><p>Antimicrobial agent abbreviations: IMI, Imipenem; CEF, Cefepime; TET, Tetracycline; CHL, Chloramphenicol; NAL, Nalidixic acid; NFL, Norfloxacin; OFL, Ofloxacin; SPA, Sparfloxacin.</p

Susceptibilities of the <i>E. aerogenes</i> isolates (2003) to different antibiotics (MIC µg/mL)^a.

a<p>The values are the means of three independent assays.</p><p>Antimicrobial agent abbreviations: IMI, Imipenem; CEF, Cefepime; TET, Tetracycline; CHL, Chloramphenicol; NAL, Nalidixic acid; NFL, Norfloxacin; OFL, Ofloxacin; SPA, Sparfloxacin.</p

Antimicrobial susceptibilities and chloramphenicol accumulation in <i>E. aerogenes</i> strains.

a<p>Ratio of chloramphenicol accumulated at 600 s with and without CCCP.</p>b<p><i>E. aerogenes</i> control strains used: ATCC 15038 reference strain that expresses a normal level of the AcrAB efflux system; EAEP294 (<i>acrA⁻</i> deleted mutant)and EAEP289 that exhibits overexpression of the AcrAB efflux system.</p>c<p>N.D: not determined.</p><p>Antimicrobial agent abbreviations: IMI, Imipenem; CEF, Cefepime; TET, Tetracycline; CHL, Chloramphenicol; NAL, Nalidixic Acid; NFL, Norfloxacin; OFL, Ofloxacin; SPA, Sparfloxacin; CIP, Ciprofloxacin. Values in parentheses were determined in the presence of efflux pump inhibitor PAßN at 26.3 µg/ml.</p

Percentages of <i>Enterobacter aerogenes</i> resistant strains.

<p>Antimicrobial agent abbreviations: IMI, Imipenem; CEF, Cefepime; TET, Tetracycline; CHL, Chloramphenicol; NAL, Nalidixic Acid; NFL, Norfloxacin; OFL, Ofloxacin; SPA, Sparfloxacin.</p

Analyses of the detergent-insoluble membrane proteins of chloramphenicol-resistant variants.

<p>SDS-PAGE analysis was performed on ATCC700388 and PHLSE082, two wild-type strains of <i>B. thailandensis</i>, and on 64CM16 and 132CM128, their respectively chloramphenicol resistant derivative strains. Proteins were stained with Coomassie blue. The variants presented different additional bands at around 51 kDa (band A), 48 kDa (band B), 43 kDa (bands C and band E) and at 95 kDa (band D). Molecular weight standards are indicated in kilodaltons.</p

Membrane permeation assays.

<p>The effect on the PAO1 strain of compound <b>3</b> (black-filled and black-hatched bars) and PMBN (grey-filled and grey-hatched bars) were compared at concentrations ranging from 15.6 μM to 125 μM, as indicated. The relative effect corresponds either to efflux inhibition (filled-bars) or to outer-membrane permeation (hatched-bars). Error bars represent standard deviations of 2 independent experiments. * indicates statistically significant (p ≤ 0.05) differences of relative effect (efflux inhibition/outer membrane permeation) for compound <b>3</b> treatment compared to the respective PMBN treatment. Brackets indicate statistically comparable permeation effects.</p

WST1 cytotoxicity test of the compounds.

<p>WST1 cytotoxicity test of the compounds.</p

Structure of polyamino-isoprenic derivatives 1–4 identified in this study.

<p>LogD have been determined by using chemical simulation software Marvin Sketch 5.11.3.</p