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Penicillin sensitive nutritionally variant streptococcal endocarditis: relapse after penicillin therapy

J F Levine, B A Hanna, A A Pollock

    The American Journal of the Medical Sciences
    |July 1, 1983
    PubMed

    Insights

    Nutritionally-variant streptococci (NVS) endocarditis may require combination antibiotic therapy. Penicillin alone may not suffice, even if the bacteria appear susceptible in vitro, suggesting a need for penicillin-aminoglycoside treatment.

    Area of Science:

    • Infectious Diseases
    • Cardiology
    • Microbiology

    Background:

    • Nutritionally-variant streptococci (NVS) are a cause of bacterial endocarditis.
    • NVS are often inhibited, not killed, by standard penicillin concentrations.
    • Effective treatment strategies for NVS endocarditis require further investigation.

    Observation:

    • A patient presented with endocarditis caused by an NVS strain.
    • This specific NVS strain was killed in vitro by a low penicillin concentration (0.09 µg/ml).
    • Despite four weeks of intravenous penicillin therapy, the patient experienced a relapse.

    Findings:

    • The relapsed infection was successfully treated with a combination of penicillin and gentamicin.
    • In vitro studies confirmed a synergistic effect between penicillin and gentamicin against the NVS strain.
    • This suggests that penicillin susceptibility in vitro does not guarantee cure for NVS endocarditis.

    Implications:

    • Combination therapy with penicillin and an aminoglycoside may be essential for treating all NVS endocarditis cases.
    • Current in vitro susceptibility testing may not fully predict treatment outcomes for NVS endocarditis.
    • This finding could alter clinical guidelines for managing NVS endocarditis.

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