Rapid Carbapenemase Detection With Xpert Carba-R V2 Directly On Positive Blood Vials

Abstract

Aurélie Cointe,1,2 Violaine Walewski,1,3 Claire Amaris Hobson,1 Catherine Doit,1,2 Philippe Bidet,1,2 Laurent Dortet,4–6 Stéphane Bonacorsi,1,2 André Birgy1,2 1IAME, UMR 1137, INSERM, Université Paris Diderot, Sorbonne Paris Cité, AP-HP, Service de Microbiologie, Hôpital Robert-Debré, AP-HP, Paris, France; 2Service de Microbiologie, Centre National de Référence associé Escherichia coli, Hôpital Robert-Debré, AP-HP, Paris, France; 3Service de Microbiologie, Hôpitaux Universitaires de Paris Seine Denis (HUPSSD), site Avicenne, AP-HP, Bobigny, France; 4EA7361, Université Paris-Sud, Université Paris-Saclay, LabEx Lermit, Service de Bactériologie-Hygiène, Hôpital Bicêtre, AP-HP, Le Kremlin-Bicêtre, France; 5Centre National de Référence associé de la résistance aux antibiotiques: Entérobactéries productrices de carbapénémases, Le Kremlin-Bicêtre, France; 6Evolution et Ecologie de la résistance aux antibiotiques, Institut Pasteur - APHP -Université Paris Sud, Paris, FranceCorrespondence: André BirgyService de Microbiologie, Hôpital Robert Debré, 48 Boulevard Serrurier Paris F75019, FranceTel [phone]Fax [phone]Email [email protected]: The rapid detection of carbapenemase allows implementation of infection control measures and adaptation of antibiotic therapy. We evaluated the performances of the Xpert Carba-R V2® assay for the direct detection and identification of carbapenemase on positive blood cultures. We focused our evaluation on its detection capacity and on the risks of interference due to the patient’s blood. Isolates of several variants of OXA-48-like (n=10), KPC (n=10), NDM (n=11), VIM (n=7), IMP-1 (n=1) carbapenemases and 14 non carbapenemase-producing Enterobacteriaceae were tested. For each isolate (n=53), an aerobic vial was seeded, and incubated in Bactec Fx (Becton Dickinson®) automate. When positive, the Xpert® Carba-R-V2 assay was assessed for carbapenemase detection using 40 μl aliquot. Reproducibility tests were performed on a subset of 23 isolates using aerobic and anaerobic vials. Longer incubation time was also evaluated on 6 isolates. A complementary prospective study in real-time testing of patient-derived clinical samples on 20 additional positive blood vials with Gram negative bacilli on direct examination was performed. Perfect sensitivity and specificity (100%) were observed regardless of the carbapenemase type, the blood vials used and the time of incubation. Xpert® Carba-R-V2 assay is suitable for the rapid detection of the main carbapenemase genes directly on positive blood vials. Its performances and rapid time analysis allow its use in routine to guide therapeutic choices and to implement infection control measures.Keywords: carbapenemase, rapid detection, positive blood culture, GeneXpert, antibiotic therapy, infection control measures

Keywords

• Carbapenemase
• Rapid detection
• Positive blood culture
• GeneXpert
• Antibiotic therapy
• Infection control measures