ETEST Imipenem/Relebactam P. aeruginosa (IRPA) (0.008/4-128/4 µg/mL)

ETEST Imipenem/Relebactam P. aeruginosa (IRPA) is a manual, quantitative antimicrobial susceptibility test that uses a plastic strip with a predefined antibiotic gradient to determine the Minimum Inhibitory Concentration (MIC) of imipenem/relebactam against Pseudomonas aeruginosa on agar media after overnight incubation. The test is indicated for determining susceptibility of P. aeruginosa isolates per FDA criteria.

The new device uses imipenem/relebactam (0.008–128/4 μg/mL) while the predicate uses meropenem/vaborbactam (0.004–64/8 μg/mL). Both are ETEST strips with identical methodology: quantitative testing via inoculated agar plates with a preformed antibiotic gradient. The indicated organism differs (P. aeruginosa only for IRPA versus multiple Enterobacteriaceae and P. aeruginosa for the predicate). Performance metrics and reproducibility are essentially identical.

CLSI M07-11th Edition (January 2018) broth microdilution reference method; CLSI M100 34th Edition (February 2024) for specifications; FDA Class II Special Controls Guidance Document for Antimicrobial Susceptibility Test Systems (August 28, 2009).

The device uses identical ETEST methodology and manufacturing to the predicate, with equivalent quantitative design, inoculum approach, and test type. Clinical and challenge performance data demonstrate 97.7% essential agreement and 91.1% category agreement with the CLSI reference method across 437 P. aeruginosa strains, meeting FDA guidance requirements. Reproducibility (99.6%) and quality control (>95% pass rate) match the predicate's performance, supporting that differences in the specific antimicrobial agent formulation do not affect the fundamental safety or effectiveness of the susceptibility testing platform.