Comparison of the in vitro activity of new beta-lactams and aminoglycosides against clinical isolates of Pseudomonas aeruginosa.

In vitro susceptibility of 338 clinical isolates of Pseudomonas aeruginosa to twelve antipseudomonal antibiotics were determined. Correlation between antibiotic resistance and serotypes was also performed. It was shown that the newer beta-lactams cefsulodin, piperacillin, azlocillin and mezlocillin had high biological activity against carbenicillin-resistant strains of P. aeruginosa. The most active aminoglycosides against gentamicin-resistant strains of P. aeruginosa were amikacin and netilmicin. Carbenicillin-resistant strains were most frequently observed among serotypes 4, 11 and NT group, and gentamicin-resistant strains among serotypes 3, 11 and NT group.