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Evaluation of a new cephalosporin antibiotic, cephapirin
Abstract:
Cephapirin sodium, a parenterally administered derivative of cephalosporanic acid, was tested in vitro against 150 stock cultures of Enterobacteriaceae and 30 stock cultures each of Pseudomonas aeruginosa and Staphylococcus aureus. Both broth- and agar-dilution techniques were employed with two sizes of inocula of organisms. At a concentration of 7.5 mug or less/ml, cephapirin inhibited and killed 100% of strains of Escherichia coli and Proteus mirabilis and more than 80% of Klebsiella species when tested against an inoculum of 10(5) bacterial cells/ml. However, even at 100 mug/ml, only a few isolates of other Enterobacteriaceae and Pseudomonas were inhibited. A 100-fold increase in the inoculum resulted in decreased susceptibility of organisms. All penicillin-susceptible as well as penicillin-resistant S. aureus isolates were inhibited and killed by 5 mug or less of cephapirin/ml when tested with an inoculum of either 10(4) or 10(6) organisms/ml. The drug also was studied in various doses in the treatment of 77 patients with diverse infections. Cephapirin was effective in the treatment of 27 of 32 patients with pulmonary infection, as well as in 6 of 7 patients with staphylococcal or streptococcal soft tissue infection. Of 25 patients with urinary-tract infections, 19 developed a negative culture during therapy. A single 4-g intramuscular dose of cephapirin was effective in only 2 of 11 patients with gonococcal urethritis or endocervicitis. Two patients with gonococcal urethritis treated with multiple injections were cured. The drug was well tolerated except for pain at the site of injection in 14 patients and phlebitis in 4 patients. No abnormalities in renal or hepatic function could be attributed to cephapirin. In addition, no abnormalities were found in the renal tubules of rabbits challenged with 500 mg of cephapirin/kg. If further studies document that cephapirin is well tolerated by the parenteral route, it may have advantages over cephalothin or cephaloridine.
Insights
Cephapirin sodium shows potent in vitro activity against E. coli, P. mirabilis, and S. aureus. Clinical trials indicate efficacy in pulmonary and soft tissue infections, with mixed results for urinary tract and gonococcal infections.
Area of Science:
- Microbiology
- Pharmacology
- Clinical Medicine
Background:
- Cephapirin sodium is a parenterally administered cephalosporanic acid derivative.
- Understanding its antimicrobial spectrum and clinical efficacy is crucial for therapeutic applications.
Purpose of the Study:
- To evaluate the in vitro antimicrobial activity of cephapirin sodium against various bacteria.
- To assess the clinical efficacy and safety of cephapirin sodium in treating diverse human infections.
Main Methods:
- In vitro susceptibility testing using broth- and agar-dilution techniques against Enterobacteriaceae, Pseudomonas aeruginosa, and Staphylococcus aureus.
- Clinical trials involving patients with pulmonary, soft tissue, urinary tract, and gonococcal infections.
Main Results:
- Cephapirin sodium demonstrated high efficacy against Escherichia coli, Proteus mirabilis, and Staphylococcus aureus in vitro.
- Clinical studies showed effectiveness in pulmonary and soft tissue infections, with varying success in urinary tract and gonococcal infections.
- The drug was generally well-tolerated, with localized pain and phlebitis as primary adverse events. No significant renal or hepatic toxicity was observed.
Conclusions:
- Cephapirin sodium exhibits significant in vitro antibacterial activity, particularly against Gram-positive cocci and certain Gram-negative bacilli.
- Clinical utility is demonstrated in specific infection types, though further investigation may be needed for others.
- Parenteral administration of cephapirin sodium appears safe, with potential advantages over other cephalosporins.