title: Rapid identification of carbapenemase genes in gram-negative bacteria with an oligonucleotide microarray-based assay.
abstract: Rapid molecular identification of carbapenemase genes in Gram-negative bacteria is crucial for infection control and prevention, surveillance and for epidemiological purposes. Furthermore, it may have a significant impact upon determining the appropriate initial treatment and greatly benefit for critically ill patients. A novel oligonucleotide microarray-based assay was developed to simultaneously detect genes encoding clinically important carbapenemases as well as selected extended (ESBL) and narrow spectrum (NSBL) beta-lactamases directly from clonal culture material within few hours. Additionally, a panel of species specific markers was included to identify Escherichia coli, Pseudomonas aeruginosa, Citrobacter freundii/braakii, Klebsiella pneumoniae and Acinetobacter baumannii. The assay was tested using a panel of 117 isolates collected from urinary, blood and stool samples. For these isolates, phenotypic identifications and susceptibility tests were available. An independent detection of carbapenemase, ESBL and NSBL genes was carried out by various external reference laboratories using PCR methods. In direct comparison, the microarray correctly identified 98.2% of the covered carbapenemase genes. This included blaVIM (13 out of 13), blaGIM (2/2), blaKPC (27/27), blaNDM (5/5), blaIMP-2/4/7/8/13/14/15/16/31 (10/10), blaOXA-23 (12/13), blaOXA-40-group (7/7), blaOXA-48-group (32/33), blaOXA-51 (1/1) and blaOXA-58 (1/1). Furthermore, the test correctly identified additional beta-lactamases [blaOXA-1 (16/16), blaOXA-2 (4/4), blaOXA-9 (33/33), OXA-10 (3/3), blaOXA-51 (25/25), blaOXA-58 (2/2), CTX-M1/M15 (17/17) and blaVIM (1/1)]. In direct comparison to phenotypical identification obtained by VITEK or MALDI-TOF systems, 114 of 117 (97.4%) isolates, including Acinetobacter baumannii (28/28), Enterobacter spec. (5/5), Escherichia coli (4/4), Klebsiella pneumoniae (62/63), Klebsiella oxytoca (0/2), Pseudomonas aeruginosa (12/12), Citrobacter freundii (1/1) and Citrobacter braakii (2/2), were correctly identified by a panel of species specific probes. This assay might be easily extended, adapted and transferred to point of care platforms enabling fast surveillance, rapid detection and appropriate early treatment of infections caused by multiresistant Gram-negative bacteria.
authors: Alere Technologies GmbH, Jena, Germany.
authors: Sascha D
authors: SD
authors: Braun
authors: Alere Technologies GmbH, Jena, Germany; Technische Universität Dresden, Medizinische Fakultät "Carl Gustav Carus", Dresden, Germany.
authors: Stefan
authors: S
authors: Monecke
authors: Technische Universität Dresden, Medizinische Fakultät "Carl Gustav Carus", Dresden, Germany.
authors: Alexander
authors: A
authors: Thürmer
authors: Technische Universität Dresden, Medizinische Fakultät "Carl Gustav Carus", Dresden, Germany.
authors: Antje
authors: A
authors: Ruppelt
authors: Center for Infectious Diseases and Infection Control and Center for Sepsis Care and Control, Jena University Hospital, Jena, Germany; Center for Sepsis Care and Control, Jena University Hospital, Jena, Germany.
authors: Oliwia
authors: O
authors: Makarewicz
authors: Center for Infectious Diseases and Infection Control and Center for Sepsis Care and Control, Jena University Hospital, Jena, Germany; Center for Sepsis Care and Control, Jena University Hospital, Jena, Germany.
authors: Mathias
authors: M
authors: Pletz
authors: Alere Technologies GmbH, Jena, Germany.
authors: Annett
authors: A
authors: Reiβig
authors: Alere Technologies GmbH, Jena, Germany.
authors: Peter
authors: P
authors: Slickers
authors: Alere Technologies GmbH, Jena, Germany.
authors: Ralf
authors: R
authors: Ehricht
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D006090:Gram-Negative Bacteria / Q000201:enzymology*; D020411:Oligonucleotide Array Sequence Analysis; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase