[Cefsulodin, a new antibiotic of the group of cephalosporins: its action on Pseudomonas aeruginosa (author's transl)].

Cefsulodin is a new second generation cephalosporin with a narrow antibacterial spectrum. Its main use is in the treatment of Pseudomonas aeruginosa infections. It is resistant to the action of the beta-lactamases of gram negative bacilli, especially to that of the cephalosporinases. We have studied 170 strains of P. aeruginosa and 10 of other species of Pseudomonas, determining the MIC by the serial dilution test in solid medium and the sensitivity by the agar diffusion test. With 8 microgram/ml, a concentration which is accepted as a limit of sensitivity from the therapeutic point of view, 90% of the P. aeruginosa strains studied are inhibited; the MIC50 is obtained with 2 microgram/ml. Within the strains considered sensitive (MIC less than 8 microgram/ml) there is a marked dispersion of the zone diameters corresponding to each of the values of MIC. This behavior limits the value of the regression line. We have also studied the MIC of carbenicillin for nearly all the strains and we have also studied the MIC of carbenicillin for nearly all the strains and we have found that 86.58% are sensitive to both preparations, 4.96% are sensitive to cefsulodin and resistant to carbenicillin, 4.02% resistant to cefsulodin and sensitive to carbenicillin and 4.69% are resistant to both preparations. From the clinical point of view the number of strains sensitive (or resistant) is similar with both substances but cefsulodin is in absolute values from 8 to 128 times more day active than carbenicillin. Cefsulodin is administered by a parenteral route and is eliminated by the urine in active form. The recommended therapeutic dose for the treatment of systemic infections is 2 g daily IV. This dose may be increased if it is considered advisable. There is good local tolerance (IM and IV), it is only slightly toxic, hardly alters the intestinal flora and may be used at all ages, in patients with immunological alterations and in patients with an altered renal function.