Comparison of agar dilution, tube dilution, and broth microdilution susceptibility tests for determination of ramoplanin MICs.
Standard broth microdilution (with and without bovine serum albumin [BSA] supplementation), tube dilution, and agar dilution susceptibility tests were compared for determining ramoplanin MICs. With a data base of 246 clinical isolates of gram-positive bacteria from 33 U.S. sites, it was shown that (i) agar and tube dilution susceptibility tests gave essentially the same results (93.9% of the test results were within 1 doubling dilution of equivalence), (ii) broth microdilution susceptibility tests gave results up to 5 doubling dilutions higher than agar or tube assays, and (iii) this data skewing could be reversed by BSA supplementation (final concentration, 0.02%) of the broth microdilution test medium.
Kenny
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Marion Merrell Dow, Inc., Kansas City, Missouri 64134-0627.
Brackman
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D000362:Agar; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003470:Culture Media; D047630:Depsipeptides; D016983:Enterococcus / Q000187:drug effects; D005069:Evaluation Studies as Topic; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods* / Q000706:statistics & numerical data; D010456:Peptides, Cyclic; D012710:Serum Albumin, Bovine; D013210:Staphylococcus / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D003470:Culture Media; D047630:Depsipeptides; D010456:Peptides, Cyclic; C041438:ramoplanin; D012710:Serum Albumin, Bovine; D000362:Agar