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Subtyping of Campylobacter jejuni ssp. doylei Isolates Using Mass Spectrometry-based PhyloProteomics MSPP
Published on: October 30, 2016
Clinical evaluation of advanced MALDI-TOF MS for carbapenemase subtyping in Gram-negative isolates
Dong Huey Cheon1, Heejung Jang1, Yoon Kyung Choi1
1R&D Center for Clinical Mass Spectrometry, Seegene Medical Foundation, Seoul, Republic of Korea.
Abstract:
The spread of carbapenemase-producing Enterobacterales (CPE) is emerging as a significant clinical concern in tertiary hospitals and, in particular, long-term care facilities with deficiencies in infection control. This study aims to evaluate an advanced matrix-assisted laser desorption/ionization (A-MALDI) mass spectrometry method for the identification of carbapenemases and further discrimination of their subtypes in clinical isolates. The A-MALDI method was employed to detect CPE target proteins. Enhancements were made to improve detectability and mass accuracy through the optimization of MALDI-TOF settings and internal mass calibration. A total of 581 clinical isolates were analyzed, including 469 CPE isolates (388 Klebsiella pneumoniae carbapenemases [KPC], 51 NDM, 40 OXA, and 2 GES) and 112 carbapenemase-negative isolates. Clinical evaluation of the A-MALDI demonstrated 100% accuracy and precision in identifying all the collected CPE isolates. Additionally, A-MALDI successfully discriminated individual carbapenemase subtypes (KPC-2 or KPC-3/KPC-4, OXA-48 or OXA-181 or OXA-232, GES-5 or GES-24) and also differentiated co-producing carbapenemase strains (KPC and NDM, KPC and OXA, KPC and GES, and NDM and OXA), attributed to its high mass accuracy and simultaneous detection capability. A-MALDI is considered a valuable diagnostic tool for accurately identifying CPE and carbapenemase's subtypes in clinical isolates. It may also aid in selecting appropriate antibiotics for each carbapenemase subtype. Ultimately, we expect that the A-MALDI method will contribute to preventing the spread of antibiotic resistance and improving human public health.
Importance:
A-MALDI clearly demonstrated excellent ability to identify CPEs such as KPC, NDM, OXA, and GES when carbapenemase is present in the strain (100% accuracy and precision). The method also successfully discriminated carbapenemase subtypes and simultaneous detection of co-producing multiple carbapenemases in a single strain. This is the first report for simultaneous and multiple detection of intact carbapenemases of KPC, NDM, OXA, and GES using matrix-assisted laser desorption/ionization mass spectrometry in a clinical isolate.
Insights
Advanced matrix-assisted laser desorption/ionization mass spectrometry accurately identifies carbapenemase-producing Enterobacterales (CPE) and their subtypes. This method aids in combating antibiotic resistance and improving public health outcomes.
Area of Science:
- Clinical microbiology
- Mass spectrometry
- Infectious disease diagnostics
Background:
- Carbapenemase-producing Enterobacterales (CPE) pose a significant clinical threat, particularly in healthcare settings with infection control challenges.
- Accurate and rapid identification of CPE and their specific carbapenemase enzymes is crucial for effective treatment and infection control.
Purpose of the Study:
- To evaluate an advanced matrix-assisted laser desorption/ionization (A-MALDI) mass spectrometry method for identifying carbapenemases and their subtypes in clinical isolates.
- To assess the accuracy, precision, and discriminatory power of A-MALDI for CPE detection.
Main Methods:
- Analysis of 581 clinical isolates, including 469 CPE and 112 carbapenemase-negative strains.
- Optimization of A-MALDI-TOF settings and internal mass calibration to enhance detectability and mass accuracy.
- Detection of specific carbapenemase target proteins (KPC, NDM, OXA, GES).
Main Results:
- A-MALDI demonstrated 100% accuracy and precision in identifying all CPE isolates.
- The method successfully discriminated individual carbapenemase subtypes (e.g., KPC-2 vs. KPC-3/4) and co-producing strains (e.g., KPC and NDM).
- High mass accuracy and simultaneous detection capabilities attributed to the method's success.
Conclusions:
- A-MALDI is a valuable tool for accurate identification of CPE and carbapenemase subtypes in clinical settings.
- This method can aid in selecting appropriate antibiotic therapies, contributing to antibiotic stewardship.
- The A-MALDI method shows promise in preventing the spread of antibiotic resistance and enhancing public health.
