title: Evaluation of ROSCO Neo-Sensitabs for phenotypic detection and subgrouping of ESBL-, AmpC- and carbapenemase-producing Enterobacteriaceae.
abstract: The increasing prevalence of ESBL-, AmpC- and carbapenemase-producing Enterobacteriaceae necessitates reliable phenotypic tests for detection and categorization. The main objective of this study was to evaluate ROSCO Neo-Sensitabs with different β-lactam-β-lactam inhibitor combinations for phenotypic detection and categorization of β-lactamases in Enterobacteriaceae. Using standard CLSI/EUCAST methodology, differences in zones of inhibitions between a β-lactam alone compared with the combination with a β-lactamase inhibitor as well as subjective synergy observations were determined for 172 well characterized Enterobacteriaceae strains with defined resistance mechanisms. The results showed that for all ESBL-positive strains (n = 66), combinations of clavulanic acid synergy with cefotaxime, ceftazidime or cefepime, were observed. All acquired AmpC β-lactamases (n = 17) were detected using cloxacillin combined with cefotaxime and/or ceftazidime (both combinations were required). Carbapenemase producers (n = 59) with the exception of one KPC-producer were correctly grouped using the combination of meropenem ± aminophenylboronic acid (APBA) or dipicolinic acid (DPA). Ethylene diamine tetraacetic acid (EDTA) also inhibited all metallo-β-lactamases, but as with DPA, one false positive result was observed. Based upon these data, we propose a tablet layout for 14 cm agar plates, which could be used as a whole or in a targeted approach for detection and categorizing of relevant acquired β-lactamases in Enterobacteriaceae.
authors.affiliation: Statens Serum Institut, Copenhagen S, Denmark. fha@ssi.dk
authors.forename: Frank
authors.initials: F
authors.lastname: Hansen
authors.forename: Anette M
authors.initials: AM
authors.lastname: Hammerum
authors.forename: Robert L
authors.initials: RL
authors.lastname: Skov
authors.forename: Christian G
authors.initials: CG
authors.lastname: Giske
authors.forename: Arnfinn
authors.initials: A
authors.lastname: Sundsfjord
authors.forename: Orjan
authors.initials: O
authors.lastname: Samuelsen
mesh_terms: D001426:Bacterial Proteins / Q000302:isolation & purification*; D004755:Enterobacteriaceae / Q000201:enzymology* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D006801:Humans; D011933:Reagent Kits, Diagnostic; D001618:beta-Lactamases / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; D011933:Reagent Kits, Diagnostic; C048795:AmpC beta-lactamases; D001618:beta-Lactamases; C063912:carbapenemase