MTS Sulbactam-Durlobactam 0.004/4 - 64/4 µg/mL (SUD)

The MTS Sulbactam-Durlobactam 0.004/4–64/4 µg/mL is a paper strip impregnated with a gradient of sulbactam and fixed durlobactam used to measure the minimum inhibitory concentration (MIC) of these antibiotics against bacteria. It is intended for quantitative in vitro determination of antimicrobial susceptibility of Acinetobacter baumannii calcoaceticus complex, with results read manually after 16–20 hours of incubation on Mueller Hinton agar.

The device uses high-quality paper impregnated with a predefined gradient of sulbactam across 15 two-fold dilutions plus fixed durlobactam at 4 µg/mL, tested on Mueller Hinton agar with manual reading. The predicate (Liofilchem MTS Vancomycin K153687) uses the same strip material, plate media, inoculation method, and manual reading approach but differs in the antimicrobial agent (vancomycin) and incubation time (24 hours versus 16–20 hours for this device).

Clinical testing followed CDRH Guidance for Class II Special Controls on Antimicrobial Susceptibility Test (AST) Systems (August 28, 2009). Reference testing used CLSI broth microdilution guidelines (CLSI M7-A11) and results were compared to CLSI reference ranges (CLSI M100-S34).

The device is substantially equivalent because it uses the same fundamental MTS strip technology, plate media, inoculation procedures, and manual reading methodology as the predicate. The differences—different antimicrobial agent and incubation duration—arise from the different bacterial species being tested (Acinetobacter baumannii versus gram-positive organisms) and are appropriately documented in labeling. Clinical performance data demonstrated 97.3% essential agreement with reference broth microdilution methodology across 588 isolates, with quality control results within expected CLSI ranges, establishing comparable safety and effectiveness.