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[In vitro comparative effect of cefixime and 7 other beta-lactamines against Streptococcus pneumoniae]
1Laboratoire de Microbiologie, Hôpital Louis-Mourier, Université Paris VII, Colombes.
Abstract:
The comparative in vitro activities of cefixime, penicillin G, amoxicillin, cefotaxime, cefaclor, cefadroxyl, cefotiam and cefuroxime against 83 recent clinical isolates of S. pneumoniae were determined. In addition, the susceptibilities of 17 relatively or fully penicillin-resistant strains of S. pneumoniae were evaluated. Cefixime was more active than the first generation cephalosporins cefaclor and cefadroxyl against penicillin-susceptible strains. The MIC50 and MIC90 obtained by the agar dilution method were 0.25 and 0.5 mg/l respectively. The MICs obtained by a microdilution technique were one dilution lower. Cefixime exhibited little or no activity against relatively or fully penicillin-resistant strains.
Insights
Cefixime shows good in vitro activity against penicillin-susceptible Streptococcus pneumoniae but is less effective against penicillin-resistant strains. This study compared cefixime with other antibiotics against S. pneumoniae isolates.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Streptococcus pneumoniae is a leading cause of bacterial infections worldwide.
- Antibiotic resistance in S. pneumoniae, particularly penicillin resistance, is a growing public health concern.
- Evaluating the in vitro activity of newer antibiotics is crucial for guiding clinical treatment decisions.
Purpose of the Study:
- To compare the in vitro antibacterial activity of cefixime against clinical isolates of S. pneumoniae.
- To assess the efficacy of cefixime in relation to other beta-lactam antibiotics, including penicillin G and various cephalosporins.
- To evaluate the susceptibility of penicillin-resistant S. pneumoniae strains to cefixime.
Main Methods:
- Comparative in vitro analysis of cefixime and other antibiotics against 83 clinical isolates of S. pneumoniae.
- Agar dilution method and microdilution technique were employed to determine minimum inhibitory concentrations (MICs).
- Specific evaluation of 17 relatively or fully penicillin-resistant S. pneumoniae strains.
Main Results:
- Cefixime demonstrated superior in vitro activity compared to first-generation cephalosporins (cefaclor, cefadroxyl) against penicillin-susceptible S. pneumoniae strains.
- The MIC50 and MIC90 for cefixime against susceptible strains were 0.25 and 0.5 mg/l, respectively, using agar dilution.
- Cefixime showed limited or no activity against relatively or fully penicillin-resistant S. pneumoniae strains.
Conclusions:
- Cefixime is an effective antibiotic against penicillin-susceptible S. pneumoniae.
- The emergence of penicillin resistance in S. pneumoniae may limit the clinical utility of cefixime in certain patient populations.
- Further research is warranted to understand the resistance mechanisms and explore alternative treatment options for resistant strains.