Rapid detection of carbapenemase-producing Acinetobacter baumannii and carbapenem-resistant Enterobacteriaceae using a bioluminescence-based phenotypic method.

Accurate detection of carbapenem-resistant Enterobacteriaceae (CRE) and carbapenemase-producing carbapenem-resistant Acinetobacter spp . (CP-CRA) constitutes a major challenge in laboratory diagnostics. We developed a bioluminescence-based carbapenem susceptibility detection assay (BCDA) which allows identification of CRE (carbapenemase-producing-CRE (CP-CRE) as well as non-carbapenemase-producing-CRE (non-CP-CRE) and CP-CRA in 2.5 h from culture media. This laboratory method was evaluated with CP-CRE and CP-CRA isolates producing different β-lactamases of different Ambler classes (A, n  = 16; B, n  = 25; D, n  = 67) and 22 non-CP-CRE. The results were correlated with those obtained by BD Phoenix™ and genotypic analysis results. The performance of BCDA on 123 validated CRE (except C . freundii isolates) and CP-CPA isolates revealed that 122 of 123 isolates were identified correctly. Only one OXA-48-producing Klebsiella pneumoniae was falsely classified. Among 45 meropenem susceptible Enterobacteriaceae (except C . freundii isolates) and meropenem susceptible Acinetobacter spp. strains tested, 44 were confirmed as susceptible by our BCDA. Overall, our BCDA had a sensitivity of 99% and a specificity of 98% and is a rapid and accurate assay which distinguished CRE/CP-CRA from meropenem susceptible Enterobacteriaceae and Acinetobacter spp . [ABSTRACT FROM AUTHOR]