European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology
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Eur. J. Clin. Microbiol. Infect. Dis. · Aug 1988
Case ReportsAortic endocarditis caused by gentamicin-resistant Enterococcus faecalis.
A case is reported of a patient who developed aortic endocarditis after protracted hospitalization during which time the patient received multiple courses of aminoglycoside and cephalosporin therapy. The infecting organism, an Enterococcus faecalis strain, was resistant to gentamicin and to the combination of ampicillin with gentamicin. Valve replacement was performed after four weeks of therapy with ampicillin, and enterococci were isolated from cardiac vegetations. Valve replacement may be necessary to achieve cure of endocarditis due to enterococci highly resistant to gentamicin.
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Eur. J. Clin. Microbiol. Infect. Dis. · Jun 1988
In vivo significance of the inoculum effect of antibiotics on Escherichia coli.
The minimum dosage of antibiotics which reduced mortality in rats intraperitoneally inoculated with an Escherichia coli isolate was determined. Low mortality rates (0-10%) were obtained when antibiotics with minimal or no inoculum effect (cefoxitin, cefmetazole and gentamicin) were administered to yield serum levels 3 to 20 times the MIC, while antibiotics with a pronounced inoculum effect (cefotaxime and aztreonam) had to be administered to yield serum levels 200 to 1,000 times the MIC determined with a standard (low) inoculum. Thus, it seems that the inoculum effect observed in vitro with some antibiotics for Escherichia coli may have clinical significance.