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.