Optimization of the MALDIxin test for the rapid identification of colistin resistance in Klebsiella pneumoniae using MALDI-TOF MS.

Abstract

BACKGROUND:

With the dissemination of carbapenemase producers, a revival of colistin was observed for the treatment of infections caused by MDR Gram-negatives. Unfortunately, the increasing usage of colistin led to the emergence of resistance. In Klebsiella pneumoniae, colistin resistance arises through addition of 4-amino-l-arabinose (l-Ara4N) or phosphoethanolamine (pEtN) to the native lipid A. The underlying mechanisms involve numerous chromosome-encoded genes or the plasmid-encoded pEtN transferase MCR. Currently, detection of colistin resistance is time-consuming since it still relies on MIC determination by broth microdilution. Recently, a rapid diagnostic test based on MALDI-TOF MS detection of modified lipid A was developed (the MALDIxin test) and tested on Escherichia coli and Acinetobacter baumannii.

OBJECTIVES:

Optimize the MALDIxin test for the rapid detection of colistin resistance in K. pneumoniae.

METHODS:

This optimization consists of an additional mild-acid hydrolysis of 15 min in 1% acetic acid. The optimized method was tested on a collection of 81 clinical K. pneumoniae isolates, including 49 colistin-resistant isolates (45 with chromosome-encoded resistance, 3 with MCR-related resistance and 1 with both mechanisms).

RESULTS:

The optimized method allowed the rapid (<30 min) identification of l-Ara4N- and pEtN-modified lipid A of K. pneumoniae, which are known to be the real triggers of polymyxin resistance. At the same time, it discriminates between chromosome-encoded and MCR-related polymyxin resistance.

CONCLUSIONS:

The MALDIxin test has the potential to become an accurate tool for the rapid determination of colistin resistance in clinically relevant Gram-negative bacteria.

• Authors: Laurent Dortet, Agnieszka Broda, Sandrine Bernabeu, Youri Glupczynski, Pierre Bogaerts, Rémy Bonnin, Thierry Naas, Alain Filloux, Gerald Larrouy-Maumus
• Journal: The Journal of antimicrobial chemotherapy (J Antimicrob Chemother) Vol. 75 Issue 1 Pg. 110-116 (01 01 2020) ISSN: 1460-2091 [Electronic] England
• PMID: 31580426 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

Chemical References

• Anti-Bacterial Agents
• Lipid A
• Colistin

Topics

• Anti-Bacterial Agents (pharmacology)
• Colistin (pharmacology)
• Drug Resistance, Bacterial
• Humans
• Klebsiella pneumoniae (drug effects)
• Lipid A (chemistry)
• Microbial Sensitivity Tests
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization