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Published on: July 9, 2012

Comparative activity of ampicillin and seven cephalosporins against group D streptococci

J M Hamilton-Miller

    Journal of Clinical Pathology
    |October 1, 1974
    PubMed

    Insights

    Ampicillin demonstrates superior activity against group D streptococci compared to newer cephalosporins. It remains the preferred beta-lactam antibiotic for treating enterococcal infections.

    Area of Science:

    • Microbiology
    • Infectious Diseases
    • Pharmacology

    Background:

    • Group D streptococci, including enterococci, are significant human pathogens.
    • Antibiotic resistance in streptococci necessitates ongoing evaluation of antimicrobial agents.
    • Beta-lactam antibiotics are commonly used for streptococcal infections.

    Purpose of the Study:

    • To determine the in vitro activity of ampicillin and seven cephalosporins against clinical isolates of group D streptococci.
    • To compare the efficacy of ampicillin with newer cephalosporin agents against these bacteria.
    • To identify potential candidates for further investigation, possibly for synergistic therapy.

    Main Methods:

    • Minimum inhibitory concentrations (MICs) were determined for ampicillin and seven cephalosporins.
    • Testing was performed on 93 recent clinical isolates of group D streptococci.
    • Data analysis focused on modal MIC values to assess antimicrobial activity.

    Main Results:

    • Ampicillin exhibited the highest activity with a modal MIC of 1.6 µg/ml.
    • Cephaloridine, cephacetrile, and cefazolin showed modal MICs of 25 µg/ml.
    • Other cephalosporins (cephalothin, cephradine, cephalexin, cefoxitin) displayed significantly higher modal MICs, ranging from 50 to 800 µg/ml.

    Conclusions:

    • Ampicillin is the most potent beta-lactam antibiotic against group D streptococci among those tested.
    • Newer cephalosporins do not offer improved in vitro activity compared to existing agents against enterococci.
    • Certain cephalosporins warrant further study for potential synergistic effects with aminoglycosides in treating infections.

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