Comparison of in vitro bacteriostatic effect of five betalactamins against Pseudomonas aeruginosa
Lesage, D.; Delisle-Mizon, F.; Denis, C.; Vergez, P.; Daguet, G.L.
Pathologie-Biologie 30(6): 440-443
1982
ISSN/ISBN: 0369-8114 PMID: 6213917 Document Number: 195061
In vitro activity of two penicillins (ticarcillin and azlocillin) and three cephalosporins (cefoperazone, cefsulodin and ceftazidime) was compared against one hundred clinical isolates of Pseudomonas aeruginosa originated in two different Paris hospitals. Twenty strains were resistant to carbenicillin at a concentration of 128 mg/l. Minimal inhibitory concentrations (MICs) were determined by a twofold agar dilution method. The required ceftazidime concentration to inhibit 90 p. cent of the carbenicillin-susceptible isolates was 1,9 mg/l. To achieve the same inhibition, 3,9 mg of cefsulodin, 12 mg of cefoperazone, 14 mg of azlocillin or 38 mg of ticarcillin per liter were needed. Against the 209 carbenicillin-resistant isolates, ceftazidime remained active at concentrations lower than 2 mg/l in 90 p. cent of the cases. To obtain such an inhibition with the other antibiotics higher concentrations were needed.