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Biomedical subjects

S S Weaver

Publications and source records attributed to S S Weaver.

9 recordsLinked to original sources

Activity of beta-lactamase inhibitors in combination with new beta-lactam antibiotics against resistant gram-negative organisms.

Thirty-eight isolates of gram-negative bacilli resistant to four new beta-lactam antibiotics, aztreonam, moxalactam, ceftazidime, and cefoperazone, were tested in the presence of two beta-lactam inhibitors, clavulanic acid and sulbactam. Microorganisms tested included 22 isolates of Pseudomonas species, 5 of Klebsiella species, and 11 of Enterobacter species. A 2- to 10-fold decrease in minimum inhibitory concentration was noted when antibiotics and beta-lactamase inhibitors were combined compared to antibiotics alone. Four strains of Pseudomonas aeruginosa showed increased resistance to the combination of antibiotics and beta-lactamase inhibitors.

Anti-Bacterial Agents

Comparative in vitro study of temocillin (BRL 17421), a new penicillin.

The activity of temocillin (BRL 17421), a new penicillin, was tested in vitro against 653 isolates of gram-negative bacilli and gram-positive cocci. The drug was compared with other beta-lactam antibiotics and tobramycin. It inhibited the majority of gram-negative bacilli tested except for Pseudomonas aeruginosa and Acinetobacter calcoaceticus, which were highly resistant. It was active against more than 50% of the multiresistant strains tested. Temocillin was more active than mezlocillin against most gram-negative bacilli and more active than moxalactam, ceftriaxone, and ceftazidime against Enterobacter spp. In general, it was slightly less active than the other drugs tested and had no activity against the gram-positive cocci. There was no significant change in drug activity when pH and medium were varied, and the effect of serum binding was minimal. There was no significant inoculum effect when the size of the inoculum was increased from 10(4) to 10(6) organisms per ml.

Bacteria

Clinical pharmacology of moxalactam in patients with malignant disease.

Pharmacological studies of moxalactam were conducted with 37 cancer patients. Intramuscular administration of 500 mg of moxalactam to 10 patients produced a mean peak serum concentration of 12.4 micrograms/ml. The serum terminal-phase half-life was 3.9 h. Intravenous administration of 500 mg of moxalactam over 5 min to the same 10 patients produced a mean serum concentration of 42.0 micrograms/ml at 15 min, which decreased to 3.3 micrograms/ml at 6 h. A dose of 1 g of moxalactam was given in an identical manner to the same 10 patients. The mean serum concentration was 69.7 micrograms/ml at 15 min and 7.4 micrograms/ml at 6 h. The mean proportions of a drug recovered in the urine by 12 h after administration were 59% after the intramuscular dose and 61 and 55% after the single intravenous doses. Multiple-dose intravenous studies were also conducted. The serum terminal-phase half-life varied from 2.0 to 3.2 h. Continuous infusion studies were performed by up to 9 days by using a loading dose of 1 g over 0.5 h, followed by 2 g every 6 h. Serum concentrations were maintained at about 30.0 micrograms/ml during the study period.

Adult

Ceforanide kinetics.

Pharmacologic studies of the semisynthetic cephalosporin ceforanide were conducted in 29 cancer patients. Intravenous doses of 500 mg over 30 min every 6 hr to 10 patients induced mean peak serum concentrations between 44.7 and 51.5 micrograms/ml, while in 10 patients receiving 1 gm over 30 min every 12 hr mean peak serum concentrations varied from 73.4 to 91.8 micrograms/ml. Twelve hours after 1 gm of drug, mean serum concentrations varied between 5.6 and 6.5 micrograms/ml. After a 500-mg loading dose, continuous infusion of 500 mg every 4 hr, 10 patients maintained serum concentrations above 34.2 micrograms/ml for 7 or 8 days. Most of the drug was excreted in the urine in the initial 6 hr after administration and mean urinary concentration of 1,315 micrograms/ml were obtained during this time. Serum half-life ranged between 2.2 and 2.9 hr on all schedules and therefore wa longer than that of other cephalosporins. No serious toxicity was noted. The relatively broad spectrum of activity in addition to the long half-life suggests clinical utility for this drug.

Adolescent

CI-867, a new semisynthetic penicillin: in vitro studies.

CI-867, a new semisynthetic penicillin, has exhibited broad-spectrum activity in vitro against gram-positive cocci, except penicillin G-resistant Staphylococcus aureus, and against gram-negative bacilli. It was especially active against Pseudomonas aeruginosa and as active as mezlocillin and piperacillin against Klebsiella pneumoniae. CI-867 was bactericidal against most organisms. Its activity was greatly reduced when the inoculum was increased from 10(5) to 10(7) organisms per ml.

Bacteria

BL-S786 (ceforanide), a new parenteral cephalosporin: in vitro studies.

BL-S786 (ceforanide) is a new cephalosporin which showed broad-spectrum activity in vitro against 453 clinical isolates. At a concentration of 3.12 mug/ml, it inhibited greater than 75% of isolates of Escherichia coli, Klebsiella spp., Proteus mirabilis, Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae. Essentially no activity was observed against isolates of Serratia marcescens, and only minimal activity was observed against Enterobacter spp. Its activity was directly related to the size of the inoculum. The minimal bactericidal concentrations were similar to the minimal inhibitory concentrations for isolates of all organisms except S. aureus and S. pyogenes. The minimal bactericidal concentrations were considerably higher than the minimal inhibitory concentrations for these organisms.

Bacteria

Thienamycin: new beta-lactam antibiotic with potent broad-spectrum activity.

Thienamycin, a new beta-lactam antibiotic, exhibited potent, broad-spectrum activity in vitro against gram-negative bacilli and gram-positive cocci, including many isolates resistant to currently available antibiotics. All isolates were inhibited at concentrations less than or equal to 25 mug/ml, with the exception of 12% of isolates of Enterobacter spp. and 3% of isolates of Serratia marcescens. Its activity decreased with an increase in inoculum concentration of from 10(5) to 10(7) cells per ml.

Amoxicillin