Essential Agreement Susceptibility Testing

Although not part of the specific Class II controls, the FDA recommends that you follow the following in your approach to QSR compliance. The method you use to validate reproducibility and stability should be able to detect a power change of at least 50% for each antibiotic. For example, if the organisms you select for such tests have stable PEMs on the scale, then a sufficient number of replications of these organisms could detect changes in the mode of the test organism. Although fda recognizes that the methodology has good variability, each antimicrobial should be evaluated by you for minor trends to ensure that the product remains safe and effective and works as intended. ViteK 2 reported a categorical agreement of 93.0% and a substantial agreement of 92.0% with the results of the micro-dilution tests of broth. The only very significant error with the isolate S. aureus 3213 (documented mutation of G2576T) (MIC – 4 g/ml) was corrected by VITEK 2 in further testing (MIC, >8 g/ml). Only one major error was observed with the 1909 S. aureus isolate, which had no documented sequence analysis mutation (VITEK 2 MIC, >8 g/ml; MIC reference – 4 g/ml); This error was duplicated in new tests (data is not displayed).

Five minor errors were observed in enterococci (two E. faecium and three E. faecalis strains); Only two of the defects (both with sensitive F. Fukalis isolates) were corrected in further testing. The VITEK-2 system revealed eight major errors, five with staph and three with enterococcal disease. VITEK 2 also did not provide an interpretation of the results that were not receptive to staph. Surprisingly, the advanced expert system VITEK 2 announced that all non-sensitive linezolid results for staphylococci as vulnerable. However, the expert results were not used in the error calculations for this study. In summary, our results show a significant discrepancy between the vulnerability results between the methods tested and the BMD, without meeting the criteria for acceptable AST performance.

Each system has inherent advantages and limitations, and the results have been widely used by antimicrobials, software versions and maps. However, the Vitek-2 system appeared to provide a relatively accurate and conservative assessment of MNIs for most antimicrobials, with the exception of FEP and MEM.