Imperial College London


Faculty of Natural SciencesDepartment of Life Sciences

Senior Lecturer



+44 (0)20 7594 7463g.larrouy-maumus




3.42Flowers buildingSouth Kensington Campus






BibTex format

author = {Dortet, L and Bonnin, RA and Pennisi, I and Gauthier, L and Jousset, AB and Dabos, L and Furniss, RCD and Mavridou, DAI and Bogaerts, P and Glupczynski, Y and Potron, A and Plesiat, P and Beyrouthy, R and Robin, F and Bonnet, R and Naas, T and Filloux, A and Larrouy-Maumus, G},
doi = {jac/dky330},
journal = {Journal of Antimicrobial Chemotherapy},
pages = {3359--3367},
title = {Rapid detection and discrimination of chromosome-and MCR-plasmid-mediated resistance to polymyxins by MALDI-TOF MS in Escherichia coli: the MALDIxin test},
url = {},
volume = {73},
year = {2018}

RIS format (EndNote, RefMan)

AB - BackgroundPolymyxins are currently considered a last-resort treatment for infections caused by MDR Gram-negative bacteria. Recently, the emergence of carbapenemase-producing Enterobacteriaceae has accelerated the use of polymyxins in the clinic, resulting in an increase in polymyxin-resistant bacteria. Polymyxin resistance arises through modification of lipid A, such as the addition of phosphoethanolamine (pETN). The underlying mechanisms involve numerous chromosome-encoded genes or, more worryingly, a plasmid-encoded pETN transferase named MCR. Currently, detection of polymyxin resistance is difficult and time consuming.ObjectivesTo develop a rapid diagnostic test that can identify polymyxin resistance and at the same time differentiate between chromosome- and plasmid-encoded resistances.MethodsWe developed a MALDI-TOF MS-based method, named the MALDIxin test, which allows the detection of polymyxin resistance-related modifications to lipid A (i.e. pETN addition), on intact bacteria, in <15 min.ResultsUsing a characterized collection of polymyxin-susceptible and -resistant Escherichia coli, we demonstrated that our method is able to identify polymyxin-resistant isolates in 15 min whilst simultaneously discriminating between chromosome- and plasmid-encoded resistance. We validated the MALDIxin test on different media, using fresh and aged colonies and show that it successfully detects all MCR-1 producers in a blindly analysed set of carbapenemase-producing E. coli strains.ConclusionsThe MALDIxin test is an accurate, rapid, cost-effective and scalable method that represents a major advance in the diagnosis of polymyxin resistance by directly assessing lipid A modifications in intact bacteria.
AU - Dortet,L
AU - Bonnin,RA
AU - Pennisi,I
AU - Gauthier,L
AU - Jousset,AB
AU - Dabos,L
AU - Furniss,RCD
AU - Mavridou,DAI
AU - Bogaerts,P
AU - Glupczynski,Y
AU - Potron,A
AU - Plesiat,P
AU - Beyrouthy,R
AU - Robin,F
AU - Bonnet,R
AU - Naas,T
AU - Filloux,A
AU - Larrouy-Maumus,G
DO - jac/dky330
EP - 3367
PY - 2018///
SN - 0305-7453
SP - 3359
TI - Rapid detection and discrimination of chromosome-and MCR-plasmid-mediated resistance to polymyxins by MALDI-TOF MS in Escherichia coli: the MALDIxin test
T2 - Journal of Antimicrobial Chemotherapy
UR -
UR -
VL - 73
ER -