[Nephrotoxicity of cefsulodin: experimental studies in animals (author's transl)]

Experimental investigations in wistar rats indicate that cefsulodin, a new cephalosporin antibiotic with high activity against Pseudomonas aeruginosa, is more nephrotoxic than cephaloridine, the cephalosporin with the lowest renal tolerance up until new. Therefore, when cefsulodin is used clinically, renal function should be carefully controlled.

[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.

Effect of combination of cefsulodin and mecillinam

The effect of cefsulodin in combination with mecillinam was examined against a wide range of bacterial species. The antibacterial spectrum was widened by the combination of cefsulodin and mecillinam in the ratio of 5:1 and 10:1. In overall observations, in the in vitro test, a synergistic effect against clinical isolates was found on Klebsiella pneumoniae, Citrobacter freundii, Enterobacter cloacae, Serratia marcescens, proteus mirabilis and Proteus vulgaris, and an additive effect was found on Staphylococcus aureus, Escherichia coli, Proteus morganii, Proteus rettgeri, Proteus inconstans and Pseudomonas aeruginosa. In in vivo tests, a synergistic effect was observed on S. marcescens TN 66 and K. pneumoniae DT infections and an additive effect was observed on S. aureus 308 A-1, E. coli O-111 and T-7, C. freundii TN 518, E. cloacae TN 603, P. vulgaris GN 4712, P. morganii Tn 373 and P. aeruginosa U 31 infections.

[Clinical application of cefsulodin to Pseudomonas aeruginosa infections in the surgical field (author's transl)]

Cefsulodin (CFS), a new antipseudomonas cephalosporin, was clinically evaluated for treatment of the Pseudomonas aeruginosa infections in the surgical field to obtain the following results. 1. CFS was administered to total 11 cases of the surgical infections caused by P. aeruginosa, comprising of 5 cases with wound infections, 3 cases with infected burn and 1 case each with muscular abscess, decubitus and postoperative pneumonia in 0.5 approximately 1 g twice a day by intravenous bolus or drip infusion. Good clinical responses were obtained in 9 out of 11 cases (81.8%). 2. Bacteriological responses were observed in all cases. P. aeruginosa was eradicated in 9 cases and suppressed in 2 cases by CFS treatment. However, replacement of pathogens with the other organisms was observed in 6 out of 8 cases caused by P. aeruginosa only. 3. Neither objective and subjective side effects nor abnormalities of laboratory tests associated with CFS treatment were observed. 4. It can be, therefore, concluded that CFS is one of the useful drugs for treatment of the surgical infections caused by P. aeruginosa.

The influence of protein binding upon tissue fluid levels of six beta-lactam antibiotics

The effect of protein binding upon the penetration of six-beta-lactam (three penicillins and three cephalosporins) antibiotics into tissue fluid was studied in humans. A cantharides blister technique was used. It was found that there was a linear relationship between the percentage of protein binding and the penetration into the blister fluid of the antibiotic as measured by the area under the curve of the protein-free fraction. This finding is further evidence that protein binding may have important influence upon the likely efficacy of an antimicrobial agent.

Effect of inoculum size and beta-lactamase production on in vitro activity of new cephalosporins against Haemophilus species

Sixty-three strains of Haemophilus species, 38 of which were beta-lactamase producers (37 H. influenzae type b, 1 H. parainfluenzae) and 25 of which were beta-lactamase negative (20 H. influenzae, 5 H. parainfluenzae), were tested for susceptibility to cefoxitin, moxalactam (LY127935) (Lilly), cefsulodin (CGP 7174 E, Ciba), and cefoperazone (T 1551, Pfizer). Cefsulodin was relatively inactive at both low and high inocula. LY127935 and cefoperazone displayed inoculum-dependent bactericidal activity. Cefoxitin displayed little inoculum effect against beta-lactamase-producing strains: 8 and 16 microgram/ml killed at least 90% of those tested at 10(4) and 10(6) colony-forming units per ml, respectively.

In vitro antibacterial activity and susceptibility of cefsulodin, an antipseudomonal cephalosporin, to beta-lactamases

Cefsulodin sodium (SCE-129, CGP-7174/E), active in minimum inhibitory concentrations (MICs) of 0.5 to 64 microgram/ml, was about 16- to 32-fold more active than carbenicillin against Psuedomonas aeruginosa. It was also active against P. diminuta, P. maltophilia, P. paucimobilis, and P. pseudoalcaligenes (MICs of 1 to 32 microgram/ml) but not against other species of Pseudomonas or other gram-negative bacteria. Except with highly carbenicillin-resistant isolates, MICs of cefsulodin for P. aeruginosa were little affected by an increase in the inoculum. With a small inoculum, minimum bactericidal concentrations (MBCs) were the same as or twice the MIC, but increasing the inoculum had a greater effect on the MBC than on the MIC. Cefsulodin was not hydrolyzed by the beta-lactamase induced in P. aeruginosa by growth in the presence of benzylpenicillin and was a poor substrate for beta-lactamases from Enterobacter cloacae and Proteus morganii. However, it was hydrolyzed, albeit slowly, by the beta-lactamase produced by most of our highly carbenicillin-resistant isolates of P. aeruginosa and by TEM-type beta-lactamases.

Comparative in vitro activity of 1-oxa-beta-lactam (LY127935) and cefoperazone with other beta-lactam antibiotics against anaerobic bacteria

The in vitro activity of 1-oxa-beta-lactam (LY127935), cefoperazone (T-1551), cefuroxime, cefsulodin, cefaclor, cefotaxime, and cefoxitin on 85 anaerobic clinical isolates (30 Bacteroides, 30 Clostridium, 25 Peptococcaceae) was simultaneously determined by the agar dilution test in two different media, Brucella Agar (Difco Laboratories) and Wilkins-Chalgren agar. In Wilkins-Chalgren agar, 90% of Bacteroides were inhibited by (micrograms per milliliter): LY127935, 0.5; T-1551, 64; cefoxitin or cefuroxime, 8; cefsulodin or cefotaxime, 32; and cefaclor, 128. All Clostridia were inhibited in Wilkins-Chalgren by (micrograms per milliliter): LY127935, 4; T-1551, 2; cefoxitin, 6; cefuroxime, 0.12; cefsulodin, 0.5; cefaclor, 1; and cefotaxime, 8. All Peptococccaceae were inhibited by T-1551, cefsulodin or cefotaxime at 4 microgram/ml and by cefoxitin or cefuroxime at 1 to 2 microgram/ml. With cefaclor at 8 microgram/ml, 92% of strains were inhibited, and LY127935 at 16 microgram/ml only inhibited 64% of strains. LY127935 was the most active of the antibiotics tested against Bacteroides, showing good activity against Clostridia and poor activity on Peptococcaceae, whereas T-1551 was more active against Peptococccaceae and had similar activity against Clostridia and poor activity on Bacteroides. There are no significant differences between minimal inhibitory concentrations obtained in Brucella Agar and those obtained in Wilkins-Chalgren.

In vitro evaluation of new penicillins and cephalosporins upon P. aeruginosa and their interaction with mecillinam

The in vitro activity of the new semisynthetic ureidopenicillins azlocillin (AZ) and mezlocillin (MZ), and of the new cephalosporin cefsulodin (CEF) were determined against 50 carbenicillin-sensitive (CARs) and 50 carbenicillin-resistant (CARr) P. aeruginosa clinical isolates. In the CARs group the most active antibiotics are AZ and CEF with MICs between 0.5 and 8 microgram/ml. Ticarcillin (TIC) and MZ showed more activity than CAR with MICs from 2 to 32 mu/ml. In this group there is a predominance of pyocine-type groups 1 and 3. In the CARr group, AZ is the most active antibiotic at low concentrations. At 64 microgram/ml of CEF, 72% of strains are inhibited as compared to 70% with AZ, 62% with MZ and 50% with TIC. In this group there is predominance of non-typeable strains. Interaction with mecillinam (MEC) and these antibiotics was studied on three different culture media (MH, NIH and DST). There were few cases of synergism with MEC and TIC combinations, mostly on DST medium. No appreciable synergism was found with other combinations of antibiotics.

Synthesis of a selective agar medium for Yersinia enterocolitica

A new agar medium for isolation of Yersinia enterocolitica was formulated based on growth studies which defined an optimum basal, and the evaluation of selective chemical agents, dyes, and antibiotics. The final formulation, designated cefsulodin-irgasan-novobiocin(CIN) agar, provided quantitative recovery of 40 different strains of Y. enterocolitica in 24 h using incubation at 32 degrees C or with 48 h of incubation at 22 degrees C. The medium was highly selective, especially against Pseudomonas aeruginosa. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. Colony morphology coupled with a differential reaction resulting from mannitol fermentation permitted discrimination of Y. enterocolitica from most of those Gram-negative bacteria that were able to grow on the medium. Recovery and selective characteristics of CIN agar were stable during storage at room temperature for 9 days. CIN agar gave a higher recovery of Y. enterocolitica from feces both direct and with cold enrichment (0.4/1.5%) than Salmonella-Shigella (0.0/0.7%) and MacConkey (0.0/0.9%) agars while significantly reducing the level of background organisms.