Related Experiment Video
Updated: Jul 20, 2025
One-day Workflow Scheme for Bacterial Pathogen Detection and Antimicrobial Resistance Testing from Blood Cultures
Published on: July 9, 2012
Rapid detection of imipenem/relebactam susceptibility/resistance in Enterobacterales
Maxime Bouvier1, Otávio Hallal Ferreira Raro2, Auriane Kerbol3
1Medical and Molecular Microbiology, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland; Swiss National Reference Center for Emerging Antibiotic Resistance (NARA), University of Fribourg, Fribourg, Switzerland.
Objectives:
The treatment options for infections caused by carbapenem-resistant Enterobacterales are scarce and the development of new antibiotics is an urgent necessity. Imipenem/relebactam (IPR) has been recently introduced for treating severe infections related to multidrug-resistant bacteria. However, IPR resistance has already been reported in Enterobacterales, thus its rapid detection may be interesting for clinical decision-making. The aim of the study was to develop a rapid and accurate test, namely the Rapid IPR Nordmann Poirel (NP) test, for the identification of IPR resistance among multidrug-resistant Enterobacterales.
Methods:
The Rapid IPR NP test is based on the detection of glucose metabolization because of bacterial growth in the presence of IPR. Bacterial growth is visually detectable by a colour change of the red phenol pH indicator, turning from red to yellow subsequent to the acidification of the medium upon bacterial growth. Cultures of a total of 94 Enterobacterales isolates were selected for evaluating the performance of the Rapid IPR NP test.
Results:
The sensitivity and specificity of the test were found to be 95.2% (95.2%, CI 84.2-98.7%) and 100% (100%, CI 93.1-100%), respectively. All the results were obtained within 3 hours incubation time at 35°C ± 2°C, which is a gain of time of at least 15 hours when compared with currently used antimicrobial susceptibility. The test showed two very major errors corresponding to OXA-48-producing Klebsiella pneumoniae isolates with MICs of IPR at 8 mg/L.
Discussion:
The Rapid IPR NP test is simple to perform and interpret, and shows excellent performances. Thus, it may suitable for implementation in clinical microbiology routine laboratories.
Insights
A new Rapid Imipenem/relebactam (IPR) Nordmann Poirel (NP) test quickly identifies resistance in carbapenem-resistant Enterobacterales. This simple test offers high accuracy, aiding clinical decisions for multidrug-resistant infections.
Area of Science:
- Clinical microbiology
- Antimicrobial resistance
- Infectious diseases
Background:
- Carbapenem-resistant Enterobacterales (CRE) pose a significant threat due to limited treatment options.
- Imipenem/relebactam (IPR) is a crucial antibiotic for severe multidrug-resistant bacterial infections.
- Emergence of IPR resistance in Enterobacterales necessitates rapid detection methods for effective patient management.
Purpose of the Study:
- To develop and evaluate a rapid, accurate diagnostic test for identifying imipenem/relebactam resistance in Enterobacterales.
- The study aimed to create the Rapid IPR Nordmann Poirel (NP) test for timely clinical decision-making.
Main Methods:
- The Rapid IPR NP test detects bacterial growth via glucose metabolism in the presence of IPR.
- A colorimetric pH indicator (red phenol) signals bacterial growth through a color change from red to yellow.
- Ninety-four Enterobacterales isolates were used to assess the test's performance.
Main Results:
- The Rapid IPR NP test demonstrated high sensitivity (95.2%) and perfect specificity (100%).
- Results were available within 3 hours, significantly faster than conventional antimicrobial susceptibility testing (at least 15 hours faster).
- Two very major errors were noted with OXA-48-producing Klebsiella pneumoniae isolates.
Conclusions:
- The Rapid IPR NP test is a simple, accurate, and rapid method for detecting imipenem/relebactam resistance.
- Its excellent performance suggests suitability for routine implementation in clinical microbiology laboratories.
- This test can aid in the timely management of infections caused by multidrug-resistant Enterobacterales.
