title: Evaluation of brilliance CRE agar for the detection of carbapenem-resistant gram-negative bacteria.
abstract: The aim of this work was to evaluate the performance of the new chromogenic medium BrillianceTM CREAgar (Thermo Fisher Scientific) for determining the limit of detection of carbapenem-resistant enterobacteria (CRE). A total of 70 clinical isolates were studied. Of these, 30 were well-characterized CRE, including Klebsiella pneumoniae strains producing KPC-, VIM-, and OXA-type enzymes, VIM-positive Enterobacter cloacae and Escherichia coli, NDM-positive E. coli, and enterobacterial isolates characterized by porin loss associated with ESBL production or AmpC hyperproduction. Ten carbapenem-resistant non-fermentative isolates were also included as well as 30 carbapenem-susceptible isolates. Carbapenem-resistant strains were inoculated at three different concentrations onto Brilliance CRE Agar (from 1.5x101 CFU/ml up to 1.5x104 CFU/ml) whereas carbapenem-susceptible isolates were inoculated at a concentration of 1.5x102 CFU/ml. The medium sustained the growth of carbapenem-resistant isolates, showing detection limits from 1.5x101 CFU/ml (in 31/40 cases) to 1.5x104 CFU/ml. No growth was observed with carbapenem-sensitive control strains. Our results indicate that the Brilliance CRE Agar allows the growth of carbapenem-resistant isolates with low detection limits and could represent a useful screening medium for both enterobacteria and non-fermentative Gram-negative strains resistant to carbapenems.
authors.affiliation: Laboratory of Microbiology, A. Manzoni Hospital, Lecco, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Bracco
authors.forename: Roberta
authors.initials: R
authors.lastname: Migliavacca
authors.forename: Beatrice
authors.initials: B
authors.lastname: Pini
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Corbo
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Nucleo
authors.forename: Gioconda
authors.initials: G
authors.lastname: Brigante
authors.forename: Aurora
authors.initials: A
authors.lastname: Piazza
authors.forename: Piero
authors.initials: P
authors.lastname: Micheletti
authors.forename: Francesco
authors.initials: F
authors.lastname: Luzzaro
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015780:Carbapenems / Q000494:pharmacology*; D015169:Colony Count, Microbial / Q000295:instrumentation / Q000379:methods*; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000254:growth & development* / Q000302:isolation & purification*; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems