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Ciprofloxacin: in vitro, experimental, and clinical evaluation
H Thadepalli1, M B Bansal, B Rao
1Department of Medicine, Charles R. Drew Postgraduate Medical School, Los Angeles, California 90059.
Abstract:
Ciprofloxacin at a concentration of 2 micrograms/mL inhibited the growth of approximately 90% of 584 strains of aerobic bacteria isolated from cultures of blood drawn from septicemic patients. An increase in the inoculum size did not result in an increased MIC, but serial passages through media containing ciprofloxacin at sub-MIC levels increased the MIC for Escherichia coli, Klebsiella pneumoniae, and Proteus vulgaris. In experimental subcutaneous abscesses in the mouse model, ciprofloxacin was more active than cefotaxime against a mixed infection induced with E. coli and Bacteroides fragilis. Against mixed E. coli and Staphylococcus aureus infection, no significant differences were noted between the two drugs. In a double-blind, prospective, randomized clinical study, perorally administered ciprofloxacin was compared with intravenously administered cefotaxime in the treatment of skin and soft-tissue infections severe enough to require hospitalization. In 70 patients treated, the therapeutic efficacy of peroral ciprofloxacin was comparable to that of intravenous cefotaxime, with two differences: S. aureus infections responded less favorably to oral ciprofloxacin (62%) than to intravenous cefotaxime (90%), and aerobic gram-negative bacillary infections responded more favorably to ciprofloxacin (92%) than to cefotaxime (64%).
Insights
Ciprofloxacin effectively inhibited aerobic bacteria from septicemic patients. In clinical trials, oral ciprofloxacin showed comparable efficacy to intravenous cefotaxime for skin infections, with better outcomes for gram-negative infections but poorer for Staphylococcus aureus.
Area of Science:
- Microbiology
- Pharmacology
- Clinical Medicine
Background:
- Ciprofloxacin is a fluoroquinolone antibiotic with broad-spectrum activity.
- Bacterial resistance and treatment efficacy are key concerns in managing septicemia and skin infections.
Purpose of the Study:
- To evaluate the in vitro activity of ciprofloxacin against aerobic bacteria from septicemic patients.
- To assess the in vivo efficacy of ciprofloxacin in a mouse abscess model.
- To compare the therapeutic efficacy of oral ciprofloxacin with intravenous cefotaxime in treating severe skin and soft-tissue infections.
Main Methods:
- In vitro susceptibility testing of ciprofloxacin against 584 bacterial strains.
- Mouse subcutaneous abscess model to compare ciprofloxacin and cefotaxime.
- Double-blind, prospective, randomized clinical trial in hospitalized patients with skin infections.
Main Results:
- Ciprofloxacin (2 µg/mL) inhibited ~90% of aerobic bacteria from septicemic patients.
- Serial passage increased minimum inhibitory concentration (MIC) for E. coli, K. pneumoniae, and P. vulgaris.
- In vivo, ciprofloxacin was more active than cefotaxime against E. coli/B. fragilis; comparable against E. coli/S. aureus.
- Clinical study: Oral ciprofloxacin efficacy comparable to IV cefotaxime; 92% vs 64% for gram-negative, 62% vs 90% for S. aureus.
Conclusions:
- Ciprofloxacin demonstrates significant in vitro activity against key pathogens in septicemia.
- Ciprofloxacin shows promise in treating mixed bacterial infections and certain skin infections.
- Treatment outcomes vary by pathogen, with superior efficacy against aerobic gram-negative bacteria but less favorable results for S. aureus infections.