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 te...

We examined the reliability and accuracy of a colorimetric assay using Alamar Blue reagent in the performance of susceptibility tests for Candida albicans. We compared the broth macrodilution method recommended by the National Committee for Clinical Laboratory Standards (NCCLS) with a macrodilution method modified with the Alamar reagent and a microdilution method modified with the Alamar reage...

This three-center collaborative study was conducted to evaluate samples of the Microbial Profile System (MPS) antimicrobial microdilution panels [previously produced by Minnesota Mining & Manufacturing Co., (3M Co.), St. Paul, Minn. and currently produced by Flow Laboratories, Inc., Rockville, Md.). This was a three-phase study. In phase I, the inter- and intralaboratory agreement was determine...

We performed Etest, disk diffusion, and broth microdilution susceptibility testing of 2,171 clinical isolates of Candida spp. against posaconazole. By using provisional breakpoints for comparison purposes only, the categorical agreement between the agar-based methods and broth microdilution results ranged from 93 to 98%, with <1% very major errors. The essential agreement (within 2 well dilutio...

Inoculum size and incubation time were varied during broth microdilution testing of the susceptibilities of 35 strains of lactic acid bacteria to six antibiotics. An increase in either parameter resulted in elevated MICs for all species. An inoculum of 3 x 10(5) CFU/ml is recommended to assess the antibiotic susceptibilities of these bacteria by using broth microdilution.

We describe the ScanMIC method, a colorimetric MIC method for susceptibility testing of gram-negative fermentative bacteria. The method is a slight modification of the National Committee for Clinical Laboratory Standards (NCCLS) recommended broth microdilution method that uses a redox indicator 2,3,5-triphenyltetrazolium chloride (TTC) to enhance the estimate of bacterial growth inhibition in a...

Minimum inhibitory concentrations (MICs) of daptomycin, linezolid, and vancomycin against 212 isolates of Listeria monocytogenes, Pediococcus, Leuconostoc, Rhodococcus and Nocardia species were determined by the broth microdilution method and the Etest (daptomycin only). Except for Leuconostoc species, daptomycin Etest MICs showed >90% agreement with MICs by the broth microdilution method.

The effect of hypoxic conditions on the in vitro efficacy of amphotericin B and posaconazole against Mucorales was evaluated by defining MICs with Etest and broth microdilution and identifying minimal fungicidal concentrations (MFCs). With Etest, oxygen-dependent changes were detected, while the MIC and the MFC determined with broth microdilution remained unaltered with reduced oxygen levels. T...

Agar dilution and broth microdilution are widely recommended quantitative antimicrobial susceptibility test methods, but they are tedious and time consuming to implement as routine tests in many clinical laboratories. Therefore, this study aimed at comparing the broth microdilution and the M.I.C Evaluator method which has been validated for its high accuracy and easy performance for routine dia...