One hundred clinical isolates of Candida albicans were tested for amphotericin B and fluconazole susceptibilities by the National Committee for Clinical Laboratory Standards (NCCLS) broth microdilution test at center 1 (C1). The same isolates were tested blinded at center 2 (C2) by NCCLS and flow cytometry (FC) methods. The agreement between NCCLS and FC methods ranged from 96 to 99%.

The in vitro activity of LY303366, a new echinocandin derivative, was evaluated with 191 yeast isolates by a broth microdilution method. The MICs at which 50% of the isolates were inhibited were 0.125 microg/ml for Candida albicans and C. tropicalis, 0.25 microg/ml for C. krusei, C. kefyr, and C. glabrata, and 2.0 microg/ml for C. parapsilosis.

Twelve isolates of Streptococcus pneumoniae with decreased susceptibility by oxacillin screen were susceptible by the FOX panel (Micro Media Systems, Cleveland, Ohio), a commercial microdilution system designed for fastidious organisms. These organisms were found to be moderately susceptible or resistant by broth macrodilution and agar dilution methods. This discrepancy indicates that the FOX p...

We assessed the effect of increasing manganese concentrations in test media (0.001 to 1,024 mg/liter) on MICs of tigecycline. For both broth microdilution (BMD) and Etests, this effect was negligible for physiological concentrations, but MICs increased when concentrations exceeded 8 mg/liter. Susceptibility testing should be performed on media with standardized low manganese content.

We studied six methods for preparation of inoculum to use in susceptibility tests of anaerobic bacteria to determine viable counts of 15 different species of anaerobes. We counted viable bacteria for each method-organism combination. Methods studied included those used for the more routine tests (broth microdilution and broth-disk elution) and for the National Committee for Clinical Laboratory ...

Agar and broth microdilution MICs of Ro 23-9424 that inhibited 90% of 22 Legionella clinical isolates tested were 0.64 and 0.08 micrograms/ml, respectively; respective erythromycin values were 1.0 and 0.12 micrograms/ml. Ro 23-9424 (1 microgram/ml) was slightly more active than the same erythromycin concentration in a macrophage system, for both Legionella pneumophila strains studied.

Susceptibilities to beta-lactam antibiotics of five VIM-1-producing Klebsiella pneumoniae isolates were determined by broth microdilution, Etest, disk diffusion, and the automated systems Vitek 2, Phoenix, and MicroScan. Significant discrepancies were observed in the determination of susceptibility to imipenem and meropenem. Interpretation problems by the automated systems were also noted.

MICs and minimum fungicidal concentrations of amphotericin B, miconazole, itraconazole, ketoconazole, fluconazole, and flucytosine against 17 isolates of Scopulariopsis spp. were determined by a broth microdilution method. All the isolates were resistant to itraconazole, fluconazole, and flucytosine, and amphotericin B, miconazole, and ketoconazole MICs were low for only a few.

Linezolid was tested by broth microdilution against 140 clinical Nocardia isolates belonging to seven species. The MIC at which 50% of the strains are inhibited (MIC50) and MIC90 for all species other than Nocardia farcinica were 2 and 4 microg/ml. Linezolid is the first antimicrobial agent demonstrated to be active against all Nocardia species.