VITEK 2 AST-Streptococcus Cefuroxime (<=0.125 - >=8 µg/mL)

The VITEK 2 AST-Streptococcus Cefuroxime is an automated antimicrobial susceptibility test card used with VITEK 2 Systems to determine in vitro susceptibility of Streptococcus pneumoniae to cefuroxime. The device contains 64 wells with premeasured cefuroxime concentrations and uses automated growth pattern analysis to generate MIC values and interpretive results for clinical laboratory use.

The device uses cefuroxime as the antimicrobial agent with concentrations of 0.25, 0.5, 1, and 2 μg/mL, employs growth pattern analysis algorithms, and uses Modified ST1 broth. The predicate uses penicillin with different concentrations (0.06, 0.12, 0.5, 2), discriminant analysis algorithms, and ST4 broth. Both are automated quantitative microdilution tests using saline-suspended organisms on identical test card platforms.

The performance comparison was conducted against the CLSI broth microdilution reference method as defined in the FDA Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems (issued August 28, 2009). Testing was validated with fresh and stock clinical isolates and challenge strains.

Substantial equivalence is based on identical test methodology (automated quantitative antimicrobial susceptibility testing), same test card platform, same organism (Streptococcus pneumoniae), comparable inoculation procedure, and equivalent performance metrics (95.5% essential agreement and 95.5-97.7% category agreement with CLSI reference method). The only differences are the antimicrobial agent and breakpoints used, which are application-specific but do not affect the fundamental safety and effectiveness of the device.