Susceptibility ofLegionella spp. to imipenem and 27 other beta-lactam antibiotics

Abstract

With 28 beta-lactam antibiotics the susceptibilities of 60 strains ofLegionella spp. (49Legionella pneumophila and 11 ATCC type strains of otherLegionella species) were determined. Agar dilution testing was used on buffered charcoal-yeast extract agar to which 0.1% α-ketoglutarate was added. The most active of the penicillins tested were ampicillin (MIC=0.06–8mg/l) and temocilin (MIC=0.125–16 mg/l); the most active cephalosporins were ceftazidime (MIC=0.03–0.5 mg/l), HR 810 (MIC=0.06−1 mg/l) and cefoxitin (MIC=0.125 – 2 mg/l). Of all the drugs tested imipenem had the most pronounced activity (MIC=.0075 – 0.06 mg/l).