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...

The growing number of fungal infections, coupled with emerging resistance to classical antifungal agents, has led to the development of new agents, among them voriconazole. Susceptibility to voriconazole was tested by using two microdilution techniques: the reference method described in National Committee for Clinical Laboratory Standards document M27-A2 and a colorimetric method, Sensititre Ye...

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...

Seven commonly used antimicrobial susceptibility testing methods were used to test the susceptibility of 150 isolates of Pseudomonas aeruginosa against gentamicin, tobramycin, amikacin, carbenicillin, and piperacillin. Results were compared with respect to the susceptibility characteristics of the population of isolates as defined by each method. Conventional methods included agar disk diffusio...