First name: Guilhem
  Last name: Royer
  Position: PhD Student
  Email: guilhem.royer

Research interest

I am currently studying strain of Escherichia coli responsible for bacteraemia. Thanks to large-scale NGS analysis I will focus on the link between the severity of infection or a specific portal of entry  on one side and with particular bacterial characters or specific metabolic pathway on the other hand. Given the importance of Escherichia coli in human medicin, we hope to find bacterial determinant which may help clinician in estimating bactaeriamia prognostic and/or treatment.  



2016 : Ph D. student – INSERM UMR 1137 (Iame team2 -EVRest)
2016 : Pharm. D., Aix-Marseille University
2015 : Master 2, Montpellier II university
2009 : Second cycle of pharmaceutical studies, Paris XI university
2005 : First cycle of pharmaceutical studies, Paris XI university

Academic positions

2013-2016 : Resident, CHRU Montpellier
2011-2013 : Resident, AP-HM, Marseille

Exhaustive list of publications


Royer G, Fourreau F, Boulanger B, Mercier-Darty M, Ducellier D, Cizeau F, Potron A, Podglajen I, Mongardon N, Decousser JW
Local outbreak of extended-spectrum β-lactamase SHV2a-producing Pseudomonas aeruginosa reveals the emergence of a new specific sub-lineage of the international ST235 high-risk clone.
The Journal of Hospital Infection 2020, 104, 33-39.

Coppry M, Leroyer C, Saly M, Venier AG, Slekovec C, Bertrand X, Parer S, Alfandari S, Cambau E, Megarbane B, Lawrence C, Clair B, Lepape A, Cassier P, Trivier D, Boyer A, Boulestreau H, Asselineau J, Dubois V, Thiébaut R, Rogues AM
Exogenous acquisition of Pseudomonas aeruginosa in intensive care units: a prospective multi-centre study (DYNAPYO study).
The Journal of Hospital Infection 2020, 104, 40-45.

Woerther PL, Royer G, Decousser JW, Fihman V, Lepeule R
Emergence of Resistance to Carbapenems Should not be considered as the only Marker of Good Practices in Antibiotic Stewardship.
Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America 2020


Royer G, Melloul E, Roisin L, Courbin V, Jacquier H, Lepeule R, Coutte L, Darty M, Fihman V, Lim P, Decousser JW, Rodriguez C, Woerther PL
Complete genome sequencing of Enterococcus faecalis strains suggests role of Ebp deletion in infective endocarditis relapse.
Clinical Microbiology and Infection: The Official Publication of the European Society of Clinical Microbiology and Infectious Diseases 2019, 25, 1565-1567.

Royer G, Fourreau F, Gomart C, Maurand A, Hacquin B, Ducellier D, Cizeau F, Lo S, Cordonnier-Jourdin C, Mercier-Darty M, Decousser JW
Outbreak of an uncommon rifampicin resistant blaNDM-1Citrobacter amalonaticus strain in a digestive rehabilitation center: the putative role of rifaximin.
Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America 2019

Bourrel AS, Poirel L, Royer G, Darty M, Vuillemin X, Kieffer N, Clermont O, Denamur E, Nordmann P, Decousser JW, IRG
Colistin resistance in Parisian inpatient faecal Escherichia coli as the result of two distinct evolutionary pathways.
The Journal of Antimicrobial Chemotherapy 2019, 74, 1521-1530.

Billard-Pomares T, Clermont O, Castellanos M, Magdoud F, Royer G, Condamine B, Fouteau S, Barbe V, Roche D, Cruveiller S, Médigue C, Pognard D, Glodt J, Dion S, Rigal O, Picard B, Denamur E, Branger C
The Arginine Deiminase Operon Is Responsible for a Fitness Trade-Off in Extended-Spectrum-β-Lactamase-Producing Strains of Escherichia coli.
Antimicrobial Agents and Chemotherapy 2019, 63,

Kieffer N, Royer G, Decousser JW, Bourrel AS, Palmieri M, Ortiz De La Rosa JM, Jacquier H, Denamur E, Nordmann P, Poirel L
mcr-9, an Inducible Gene Encoding an Acquired Phosphoethanolamine Transferase in Escherichia coli, and Its Origin.
Antimicrobial Agents and Chemotherapy 2019, 63,


Royer G, Decousser JW, Branger C, Dubois M, Médigue C, Denamur E, Vallenet D
PlaScope: a targeted approach to assess the plasmidome from genome assemblies at the species level.
Microbial Genomics 2018

Desroches M, Clermont O, Lafeuillade B, Rodriguez C, Darty M, Royer G, Bouvet O, Ounnoughene N, Noizat-Pirenne F, Denamur E, Decousser JW
Genotypic and phenotypic characteristics of Escherichia coli involved in transfusion-transmitted bacterial infections: implications for preventive strategies.
Transfusion 2018, 58, 1940-1950.

Desroches M, Royer G, Roche D, Mercier-Darty M, Vallenet D, Médigue C, Bastard K, Rodriguez C, Clermont O, Denamur E, Decousser JW
The Odyssey of the Ancestral Escherich Strain through Culture Collections: an Example of Allopatric Diversification.
mSphere 2018


Edouard S, Million M, Royer G, Giorgi R, Grisoli D, Raoult D
Reduction in incidence of Q fever endocarditis: 27 years of experience of a national reference center.
The Journal of Infection 2014, 68, 141-148.