[Comparative bactericidal activity of cefsulodin and ceftazidime on Pseudomonas aeruginosa]

This research concerns the bacteriostatic and the bactericidal activity of two beta-lactams (cefsulodin and ceftazidime) on ten strains of Pseudomonas aeruginosa affected by carbenicillin. Additionally to classical approaches in the broth and agar technics, a method of culture on filter membrane is used. The results obtained after a 2 hours and 24 hours contact are reported. The resulting values of minimum inhibitory concentrations are comparable. As far as minimum bactericidal concentrations values are concerned, there is no significant difference between the two methods or between the two antibiotics. The analysis of the bactericidal effect of a 2 hours contact allows no inference relative to the comparative effect of the two antibiotics. Each strain of P. aeruginosa has its specific behaviour, and there seems to be no way to extrapolate from their minimum inhibitory concentrations the bactericidal effect of cefsulodin and ceftazidime.