[Comparative activity of azlocillin on Pseudomonas species excluding Pseudomonas aeruginosa].

The minimal inhibitory concentrations (MIC) of three acylureidopenicillins (azlocillin, mezlocillin, piperacillin) and three third generation cephalosporins (cefotaxime, cefoperazone, cefsulodin) against 249 randomized strains of Pseudomonas spp. representing 10 species other than Pseudomonas aeruginosa, were determined by the agar dilution method in Mueller-Hinton agar and compared by parametric statistical tests. Fresh clinical and environmental hospital isolates belonged to the following species: P. fluorescens (35), P. putida (37), P. stutzeri (17), P. mendocina (4), P. cepacia (37), P. pickettii (22), P. acidovorans (36), P. diminuta (5), P. paucimobilis (23), P. maltophilia (37). Azlocillin inhibited over 88% of Pseudomonas spp at 64 mg/l or less. This good antipseudomonal activity in vitro was comparable to those of piperacillin and cefotaxime with a minimal inhibitory concentrations 50 value of 8 mg/l. Against these Pseudomonas spp, the ranking order of activity was azlocillin = piperacillin = cefotaxime greater than cefoperazone greater than mezlocillin greater than cefsulodin. Like piperacillin or cefotaxime, azlocillin, was effective against ticarcillin--and aminoglycoside--resistant Pseudomonas spp. Against P. maltophilia and P. cepacia, the two Pseudomonas spp other than P. aeruginosa that are important pathogens in opportunistic infections and in their vast majority are resistant to amino glycosides, azlocillin was significantly active. Only in the case of P. maltophilia, cefoperazone had a lower minimal inhibitory concentrations 50 (8 mg/l vs. 32 mg/l).