Guideline for phenotypic screening and confirmation of carbapenemases in Enterobacteriaceae.
Adequate detection of carbapenemase-producing Enterobacteriaceae is crucial for infection control measures and appropriate choice of antimicrobial therapy. This guideline aims to improve the detection of carbapenemase-producing Enterobacteriaceae in the routine setting of clinical microbiology laboratories. Detection of carbapenemases in Enterobacteriaceae includes a screening step followed by a genotypic and optional phenotypic confirmatory step. For all Enterobacteriaceae, the meropenem screening breakpoint to detect carbapenemases is set at >or=0.5mg/L or a zone diameter of <or=23 mm (10 microg disk loading). For Escherichia coli, Klebsiella spp., Salmonella spp., Enterobacter spp. and Citrobacter spp., the imipenem screening breakpoint is set at >or=2mg/L or a zone diameter <or=21 mm. Ertapenem is not advised as an indicator carbapenem as it has a lower specificity compared with imipenem and meropenem. On the first isolate from a patient with a positive carbapenemase screen test, a polymerase chain reaction (PCR)-based test should be performed to detect carbapenemase genes. However, if genotypic confirmation is not immediately available, phenotypic confirmation tests should be performed to avoid delayed reporting of carbapenemase-producers to the clinic. Recommended phenotypic confirmation tests are the modified Hodge test as well as carbapenemase inhibition tests with boronic acid for Ambler class A carbapenemases and with ethylene diamine tetra-acetic acid (EDTA) or dipicolinic acid for metallo-carbapenemases.
Cohen Stuart
James
J
Department of Medical Microbiology, University Medical Centre Utrecht, Utrecht, The Netherlands. j.cohenstuart@umcutrecht.nl
Leverstein-Van Hall
Maurine A
MA
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics; D015780:Carbapenems / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008826:Microbial Sensitivity Tests / Q000379:methods; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000032:analysis* / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D001618:beta-Lactamases; C063912:carbapenemase