Simple combined agar-strip test for detection of enterococcal susceptibility to ampicillin, moderate- or high-level gentamicin resistance and potential additive activity of ampicillin plus gentamicin.
A simple combined agar-strip test (CAST), involving filter paper strips charged with 20 micrograms of ampicillin or 40 micrograms of gentamicin, accurately detected high-level gentamicin resistance among 43 of 146 isolates of Enterococcus faecalis and additive activity of ampicillin plus gentamicin against 101 of 103 (98%) isolates of E. faecalis with moderate-level gentamicin resistance (MLGR). All 15 MLGR Enterococcus faecium isolates were moderately to highly resistant to ampicillin; 5 isolates with moderate resistance to ampicillin (minimal inhibitory concentrations = 16 micrograms/ml) were additively inhibited by ampicillin plus gentamicin, whereas the highly ampicillin-resistant E. faecium isolates yielded an indifferent effect with the CAST procedure.
Traub
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WH
Institut für Medizinische Mikrobiologie, Universität des Saarlandes, Homburg/Saar, BRD.
Leonhard
B
B
D000667:Ampicillin / Q000494:pharmacology*; D000668:Ampicillin Resistance; D004352:Drug Resistance, Microbial; D004357:Drug Synergism; D013293:Enterococcus faecalis / Q000187:drug effects*; D016984:Enterococcus faecium / Q000187:drug effects*; D005839:Gentamicins / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D011934:Reagent Strips
D005839:Gentamicins; D011934:Reagent Strips; D000667:Ampicillin