Using a set of 55 Staphylococcus aureus challenge organisms, we evaluated six routine methods (broth microdilution, disk diffusion, oxacillin agar screen, MicroScan conventional panels, MicroScan rapid panels, and Vitek cards) currently used in many clinical laboratories and two new rapid methods, Velogene and the MRSA-Screen, that require less than a day to determine the susceptibility of S. a...

The MicroScan MICroSTREP panel is a recently marketed frozen broth microdilution panel for susceptibility testing of various streptococci, including Streptococcus pneumoniae. The panel contains 10 antimicrobial agents in cation-adjusted Mueller-Hinton broth supplemented with 3% lysed horse blood, similar in concept to the National Committee for Clinical Laboratory Standards (NCCLS) reference br...

Quality control ranges were developed for broth microdilution testing of Campylobacter jejuni ATCC 33560 against 14 antimicrobials. Cation-adjusted Mueller-Hinton broth containing 2.5% laked horse blood was the preferred medium, with incubation in a microaerobic atmosphere of 10% CO(2), 5% O(2), and 85% N(2) at 36 degrees C for 48 h or 42 degrees C for 24 h.

The activities of ampicillin, ampicillin-sulbactam, amoxicillin, amoxicillin-clavulanic acid, ticarcillin, ticarcillin-clavulanic acid, piperacillin, piperacillin-tazobactam, aztreonam, and aztreonam-clavulanic against Stenotrophomonas maltophilia strains for which the MICs of penicillins and commercially available b-lactam– b-lactamase inhibitor combinations were higher than the breakpoints us...

Brucella broth without supplementation is the recommended medium for broth microdilution susceptibility tests of Brucella abortus, B. melitensis, and B. suis. Based on an eight-laboratory collaborative study using a pH-adjusted modification of this medium, we propose MIC quality control ranges for three control strains against 10 antimicrobials that are potentially efficacious for treating infe...

For broth microdilution susceptibility tests of Francisella tularensis, Mueller-Hinton broth with 2% Isovitalex is recommended. Using that medium, we studied three standard control strains tested with nine antimicrobial agents potentially efficacious for treating tularemia. An eight-laboratory collaborative study generated the data needed to propose appropriate MIC control limits.