CHROMagar COL-APSE is a sensitive and specific medium for the growth of COL-resistant bacterial pathogens. Due to the low limit of detection (10 c.f.u.), it may be useful as a primary isolation medium in the surveillance and recovery of COL-resistant bacteria from complex human, veterinary and environmental samples, especially those with plasmid-mediated MCR-1 or novel mechanisms of polymyxin resistance.

We evaluated an immunochromatographic lateral flow assay to detect OXA-48-like carbapenemases (OXA-48 K-SeT) in Enterobacteriaceae (n ‫؍‬ 82). One hundred percent sensitivity and specificity were observed using bacteria recovered from both solid medium and spiked blood culture bottles, and the results were obtained in <10 min.T he identification, treatment, and control of multidrug-resistant (MDR) bacterial infections are global health priorities. Enterobacteriaceae with plasmids carrying genes encoding class A (Klebsiella pneumoniae carbapenemases [KPC]), B (IMP, VIM, and NDM), and D (OXA) carbapenemases (carbapenemase-producing Enterobacteriaceae [CPE]) are one of the most important groups of pathogens due to the burden of disease, lack of any new treatments, and potential for dissemination (1). Rapid and effective diagnostics therefore underpin any strategy aimed at tackling the problem of CPE. Considerable effort has been made to develop novel assays using both genotypic and phenotypic approaches. These approaches include the genetic detection of resistance gene profiles (PCR, loop-mediated isothermal amplification [LAMP], microarrays, and genome sequencing) (2), selective culture medium (chromogenic or supplemented) (3), combination disk testing (4), and direct or indirect detection of carbapenem-hydrolyzing enzymes (matrix-assisted laser desorption ionization-time of flight mass spectrometry [MALDI-TOF MS], acidometric Carba NP, and Blue-Carba) (5-7). These methods require varied levels of technical skill, investment into equipment, and quality assurance optimization. Strains producing OXA-48-like carbapenemhydrolyzing class D enzymes (CHDL) have proven to be particularly difficult to detect in clinical laboratories. This is due in part to relatively low MICs, conflicting interpretive rules associated with automated systems (8), and a lack of suitable inhibitor compounds for use in confirmatory tests. A novel means of detecting OXA-48-like enzymes using an antibody-mediated approach was recently developed (9). The OXA-48 K-SeT assay relies on the immunological capture of two epitopes specific to the OXA-48 enzyme using colloidal gold nanoparticles bound to a nitrocellulose membrane within a lateral flow device. Capture and detection antibodies were designed to bind all current CHDL OXA-48-like variants .In this study, we assessed the performance of the Coris OXA-48 K-SeT assay for detecting OXA-48-like-mediated carbapenem resistance in a large collection of carbapenem-resistant Enterobacteriaceae and also determined whether it could provide robust results when working directly with organisms recovered from blood culture bottles.Eighty-two enterobacterial isolates were used in the evaluation. Seventy-eight were clinical isolates (K. pneumoniae, n ϭ 60; Escherichia coli, n ϭ 11; Enterobacter cloacae, n ϭ 6; Enterobacter aerogenes, n ϭ 1) with resistance to one or more carbapenems (ertapenem, imipenem, and/or meropenem) along with a susceptible type strain as a representative control for each bacterial specie...

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