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1. (WO2018158573) METHOD OF DETECTION

Pub. No.:    WO/2018/158573    International Application No.:    PCT/GB2018/050522
Publication Date: Sat Sep 08 01:59:59 CEST 2018 International Filing Date: Thu Mar 01 00:59:59 CET 2018
IPC: C12Q 1/02
C12Q 1/04
C12Q 1/10
Applicants: IMPERIAL INNOVATIONS LIMITED
Inventors: LARROUY-MAUMUS, Gerald
DORTET, Laurent
FILLOUX, Alain
Title: METHOD OF DETECTION
Abstract:
The present invention is directed to a method for detecting the presence or absence of a bacterium resistant to a cyclic cationic polypeptide antibiotic, comprising: (a) subjecting a test sample to mass spectrometry analysis and generating a mass spectrum output; wherein said test sample comprises a bacterial membrane or a fragment thereof, wherein the fragment comprises a non- Lipid A component; (b) identifying in said mass spectrum output a first defined peak indicative of the presence of Lipid A modified by phosphoethanolamine, wherein said first defined peak is a peak present in a mass spectrum output for Lipid A modified by phosphoethanolamine and wherein said first defined peak is absent from a corresponding mass spectrum output for native Lipid A; and (c) wherein the presence of said first defined peak indicates the presence of a bacterium resistant to a cyclic cationic polypeptide antibiotic, and wherein the absence of said first defined peak indicates the absence of a bacterium resistant to a cyclic cationic polypeptide antibiotic. This method is also used in a screening method to identify an inhibitor of cyclic cationic polypeptide antibiotic resistance in a bacterium. The matrix solution can contain 2,5-dihydroxybenzoic acid and aids in the selective extraction, co-crystallisation and ionisation of native Lipid A and/or modified Lipid A as an integral part of a bacterial membrane.