3 years ago

Evaluation of the Rapid Polymyxin NP Test for Polymyxin B Resistance Detection Using Enterobacter cloacae and Enterobacter aerogenes Isolates.

Pankey G, Ashcraft D, Sibley D, Simar S
Background: Polymyxin resistance is an increasing problem worldwide. Currently, determining susceptibility to polymyxins is problematic and lengthy. Polymyxins diffuse poorly into agar, potentially giving inaccurate disk diffusion and Etest results. A rapid screening test (2 h) for detection of polymyxin-resistance in Enterobacteriaceae, developed by Nordmann and Poirel (Rapid Polymyxin NP Test, 2016), detects glucose metabolization in the presence of polymyxins E and B via pH-induced color change. Sensitivity/specificity were 99.3%/95.4%, respectively, with results obtained in ≤2 h. Our goal was to evaluate this test using polymyxin B (PB) against larger numbers of EnterobacterMethods: 143 non-duplicate Enterobacter isolates (102 E. cloacae complex, 41 E. aerogenes) were tested, including 136 collected from Ochsner Health System patients from March-May 2016 and 7 previously determined PB-resistant E. cloacae isolates from JMI Laboratories. MICs were determined via broth microdilution. For the rapid polymyxin NP test, a color change from orange to yellow was positive; a weak/no color change, negative after 4 h.Results: 25/143 Enterobacter isolates were PB-resistant by broth microdilution (MIC >2μg/mL), including all 7 JMI isolates. Of these 25, 7 were positive by the rapid polymyxin NP test (included 3/7 JMI isolates). All 118 isolates PB-susceptible by broth microdilution were NP test negative. Sensitivity/specificity for the rapid polymyxin NP test were 25%/100%, respectively, compared to broth microdilution.Conclusions: While the rapid polymyxin NP test is a much faster method (2-4 h) for polymyxin-resistance determination compared with broth microdilution (16-20 h), our study indicates that it may be subject to limitations when testing Enterobacter.

Publisher URL: https://www.ncbi.nlm.nih.gov/pubmed/28747375

DOI: PubMed:28747375

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.