Performance of ceftriaxone susceptibility testing on the Accelerate Pheno® system of ESBL-producing isolates

The correlation of ceftriaxone nonsusceptibility and ESBL production was evaluated in 40 characterized isolates. Performance of ceftriaxone susceptibility testing on the Accelerate Pheno was evaluated and compared with reference broth microdilution in triplicate. The CLSI ESBL confirmatory test was also evaluated. Ceftriaxone categorical agreement of the Accelerate Pheno was 97.5% with 1 minor error. The ESBL confirmatory disk test resulted in 4 false-negatives and 1 false positive. The Accelerate Pheno provides an expedited and accurate method of ceftriaxone susceptibility testing allowing for optimization of antimicrobial regimens sooner. These data indicate that ESBL production has a high likelihood of ceftriaxone non-susceptibility.