Cephamycins, a new family of beta-lactam antibiotics. 3. In vitro studies

Effects of rate of infusion and probenecid on serum levels, renal excretion, and tolerance of intravenous doses of cefoxitin in humans: comparison with cephalothin

Using a randomized crossover design, 1-g intravenous doses of cephalothin and cefoxitin, a cephalosporinase-resistant cephamycin, were infused into 12 normal adult males over periods of 120, 30, and 3 min, the last with and without prior intravenous infusions of probenecid (1 g). Mean peak serum concentrations of antibiotic activity after cephalothin infusions were 23, 56, 103, and 102 mug/ml, respectively, and after cefoxitin infusions they were 27, 74, 115, and 125 mug/ml, respectively. Probenecid treatment prolonged the terminal serum half-life of cephalothin-like activity from 0.52 to 1.0 h, and of cefoxitin from 0.68 to 1.4 h. In contrast to cephalothin, which was found to be metabolized about 25% to the less active desacetyl form, cefoxitin was metabolized less than 2% to the virtually inactive descarbamyl form, as judged from urinary recoveries. Neither antibiotic displayed detectable organ toxicity. Of 300 recent clinical isolates of gram-negative bacilli other than Pseudomonas spp., 83% were susceptible to cephalothin but 95% were susceptible to cefoxitin. Organisms resistant to cephalothin but susceptible to cefoxitin included strains of Escherichia coli, Proteus vulgaris, Klebsiella spp., Serratia marcescens, Enterobacter spp., and Bacteroides spp.

Cloning of a Streptomyces clavuligerus DNA fragment encoding the cephalosporin 7 alpha-hydroxylase and its expression in Streptomyces lividans

A 26-mer DNA probe was designed from N-terminal sequence data for the cephalosporin 7 alpha-hydroxylase (CH) of Streptomyces clavuligerus NRRL 3585 and used to screen a DNA library from this organism. The library was constructed in the lambda GEM-11 phage system. After plaque purification and reprobing, positive recombinant phages were chosen for further analysis. Characterization of the cloned DNA by restriction mapping and Southern hybridization showed that a 1.5-kb SalI fragment hybridized to the probe. Polymerase chain reaction assays using this fragment as a template and the probe as a primer indicated that the fragment carries the entire putative CH gene (cmcI). This was confirmed through the expression of CH enzymatic activity when the fragment was introduced into Streptomyces lividans. A putative beta-lactamase activity was detected in S. lividans.

An evaluation of cefoxitin in the prevention of postoperative infections following orthopedic surgical procedures

An open, nonrandomized study of 25 patients was conducted to evaluate the efficacy of cefoxitin in the prevention of postoperative infection following orthopedic surgical procedures. Cefoxitin was administered in a 2 g dose preoperatively and continued postoperatively at a dose of 2 g every six hours for 72 hours. The mean peak serum level achieved ten minutes after the preoperative dose was 153.7 mcg/ml. The mean bone level in samples taken during the procedure was 10.14 mcg/ml. All patients were monitored postoperatively and at intervals of six weeks, four months and six months for signs of early or late morbidity. No signs of major morbidity were observed in the study group.

Cefoxitin therapy in aerobic, anaerobic, and mixed aerobic-anaerobic infections

Cefoxitin, a new beta-lactamase-resistant cephamycin, was evaluated in 66 patients for clinical and bacteriological efficacy, serum levels, tolerance, and toxicity. Seventeen patients had soft tissue infections, 14 had pleuropulmonary infections, 14 had intraabdominal infections, 13 had pelvic infections, and 8 had urinary tract infections. Among the 66 patients, 62 were cured and 4 could not be evaluated. Twelve patients had hospital-acquired infections, 31 had underlying disease, and 45 required a surgical procedure. Isolates included 116 aerobic and 72 anaerobic bacteria. Cefoxitin was more active than cephalothin against facultative and obligate anaerobic gram-negative organisms isolated from these patients. Mean peak cefoxitin levels in sera were 52 micrograms/ml after a 2-g infusion and 30 micrograms/ml after a 1-g infusion. Phlebitis occurred in two patients, eosinophilia in one, rash in two, vasculitis in one, and transient rises in SGOT and SGPT in two. Cefoxitin appears to be a safe and effective drug for the treatment of many aerobic, anaerobic, and mixed aerobic-anaerobic infections.

The efficacy and tolerance of cefoxitin in the treatment of paediatric infections

Eleven paediatric patients ranging in age from 7 weeks to 7 years were treated with intravenous cefoxitin for a variety of moderate or severe infections. All identifiable pathogens were sensitive to cefoxitin and the clinical outcome for every patient was regarded as a cure. Cefoxitin was well tolerated by all patients, the institution of therapy being associated in many cases with a rapid improvement in clinical condition.

Cephamycin C treatment of induced swine salmonellosis

Weanling pigs in groups of 12 were infected orally with Salmonella choleraesuis and were treated intramuscularly with doses of cephamycin C ranging from 12.5 to 337.5 mg twice daily for 10 days beginning 1 day postinoculation. Pigs in two other infected groups either received 300 mg of tetracycline orally on a similar schedule or served as nonmedicated controls. Optimal responses to cephamycin C were achieved at a twice daily dose of 112.5 mg. With this regimen, the febrile response was significantly reduced on day 2 and eliminated by day 5 postinfection, and the shedding of Salmonella spp. in feces was eliminated by day 5 postinfection; essentially, no lesions were found in the gastrointestinal tract at necropsy (day 26 postinfection). There was no mortality among recipients of the 112.5-mg dose; diarrhea was present on only 2% of the observation days. In contrast, 83% of the infected, nonmedicated pigs and 25% of the tetracycline-medicated pigs died, and diarrhea was present in these groups on 63 and 54% of the observation days, respectively. The striking benefits of cephamycin C treatment was achieved without adverse reactions. The weight gain and feed efficiency of the infected pigs treated with the 112.5-mg dose of cephamycin C and the noninfected, nonmedicated control pigs were equivalent.

Cephamycin C treatment of induced enterotoxigenic colibacillosis (scours) in calves and piglets

Cephamycin C is a beta-lactam antibiotic that has broad gram-negative activity and is resistant to degradation by beta-lactamases and safe for use in animals. In colostrum-fed calves infected with Escherichia coli strain B44, cephamycin C administered by gavage at 31.3 to 1,000 mg per calf (0.75 to 24 mg/kg) twice a day for 6 days starting at 20 h post-inoculation eliminated the diarrhea and reduced the mortality from 90% in infected, nonmedicated calves to 14% in infected, medicated calves (P < 0.01). Comparable results were obtained with a shorter treatment regimen (30 mg of cephamycin C per calf [0.71 mg/kg] twice a day for 3 days). In colostrum-fed piglets infected with E. coli strain P155 and housed in cages, cephamycin C administered prophylactically by gavage at 12.5 mg per piglet (10.4 mg/kg) twice a day for 4 days completely prevented both diarrhea and mortality, whereas nonmedicated piglets had 100% diarrhea and all died. When eight doses of cephamycin C were given therapeutically starting at 6 h post-inoculation, mortality was reduced from 79 to 23% (P < 0.02), and diarrhea was eliminated in the surviving medicated piglets by 4 days post-inoculation. In infected suckling piglets, cephamycin C administered therapeutically by gavage at 12.5 mg per piglet twice a day for 3 days starting at 6 h post-inoculation, diarrhea and mortality were reduced (P < 0.05): infected, nonmedicated piglets had 87% diarrhea and 75% mortality, whereas infected, medicated piglets had 25% diarrhea and 31% mortality. All surviving medicated piglets had solid feces by 2 days post-inoculation. Thus, cephamycin C was highly effective in restoring the calves and piglets to good health by eliminating diarrhea and reducing mortality.

Lysis if enterobacteria by cefoxitin, cefuroxime, and cephalothin

Cefoxitin, cefuroxime, and cephalothin were added to dense populations of beta-lactamase-producing enterobacteria, and the subsequent turbidity changes were monitored continuously. Viable counts and antibiotic assays were made at intervals after the addition of antibiotic, and the morphological appearances of the organisms were observed. Cephalothin caused lysis of most of the organisms tested, but even at high concentrations, after a few hours the antibiotic was destroyed and the organisms recommenced logarithmic growth. Cefoxitin produced lysis of all the strains of Escherichia coli and Klebsiella species tested, with supression of regrowth. With cephalothin and cefoxitin the viable counts after the addition of antibiotic correlated with the turbidity measurements. Cefuroxime infrequently caused lysis that suppressed multiplication, and the organisms became long and filamentous while the turbidity readings increased; the viable counts did not correlate with the turbidity measurements. Cefuroxime and cefoxitin were not destroyed by the beta-lactamases of any of the strains of enterobacteria that were studied.

Cephamycins: a review, prospects and some original observations

The cephamycins are a group with great potential. The first member of the group intended for therapeutic use offers the following advantages over existing cephalosporins: 1. Stability to various beta-lactamases; in an environment increasingly threatened by R-factors, this property may be of increasing value as time passes. 2. Possible lack of cross-allergenicity with other beta-lactam antibiotics. 3. Activity against anaerobic strains. Cefoxitin is only the first semi-synthetic derivative; presumably there are other compounds awaiting assessment which have even more favourable properties.

Interaction of penicillin with the bacterial cell: penicillin-binding proteins and penicillin-sensitive enzymes

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Cefoxitin, a semisynthetic cephamycin antibiotic: susceptibility studies

Cefoxitin, 3-carbamoyloxymethyl-7-alpha-methoxy-7-[2-(2-thienyl)acetamido]-3-cephem-4- carboxylic acid, is a new semisynthetic cephamycin with broad antibacterial activity. It is highly active against gram-negative microorganisms including indole-positive Proteus and Serratia strains, which are ordinarily reistant to the cephalosporins. Cefoxitin is also highly active against many strains of Escherichia coli and Proteus mirabilis which are resistant to the cephalosporins. Furthermore, E. coli and Klebsiella strains which are susceptible to the cephalosporins are generally more susceptible to the cephamycin analog. The susceptibility of the gram-positive bacteria falls well within the effective range of the antibiotic for gram-negative organisms, but cefoxitin is less active than cephalothin or cephaloridine. As is the case with the cephalosporins, strains of Pseudomonas and group D streptococci are resistant to cefoxitin. Changes in pH, inoculum density, and growth medium have no significant effect on the activity of the antibiotic.

Cephamycins, a new family of beta-lactam antibiotics: antibacterial activity and resistance to beta-lactamase degradation

The susceptibility to some cephalosporin antibiotics and to cephamycin C, a member of a new family of beta-lactam antibiotics, was evaluated for 466 cultures representing 11 different genera or species of gram-negative clinical isolates. The susceptibility of 39 gram-negative cultures known to produce beta-lactamase was also determined. The beta-lactamase activity of a representative group of the clinical isolates and the 39 enzyme producers was studied with the cephalosporins (cephalothin and cephaloridine) and cephamycin C as substrates and was related to the in vitro disc susceptibility to these same antibiotics. The significant resistance to beta-lactamase displayed by the cephamycins is reflected in the kinetics of enzyme activity (K(m) and V(max)) that are reported for the cephalosporins and the cephamycins. Resistance to beta-lactamase is probably one of the reasons that many cephalosporin-resistant cultures are susceptible to cephamycin C.

Cephamycins, a new family of beta-lactam antibiotics. IV. In vivo studies

Cephamycin A was found to be more active in vivo than cephamycin B. In comparison with cephamycin C, cephamycin A was more active against gram-positive organisms but less active against gram-negative organisms. Given subcutaneously, cephamycin C had good in vivo gram-negative activity, comparing favorably with cephalothin and cephaloridine against cephalosporin-susceptible organisms. In general, against the gram-negative organisms, it was more active than cephalothin or cephalosporin C and about as active as cephaloridine. In addition, cephamycin C protected mice against beta-lactamase-producing Proteus cultures, including clinically isolated strains. The compound is remarkably nontoxic. Cephamycin C was detected in the serum and recovered from the urine of treated mice to about the same extent as cephaloridine. Like cephaloridine and cephalosporin C, cephamycin C must be excreted mainly by glomerular filtration, because the use of probenecid did not enhance the therapeutic effectiveness nor concentrations of these agents in the sera of treated mice.