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Penicillin sensitive nutritionally variant streptococcal endocarditis: relapse after penicillin therapy
The American Journal of the Medical Sciences
|July 1, 1983
Summary
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.