Differential Role of the T6SS in Acinetobacter baumannii Virulence

Guillermo D Repizo; Stéphanie Gagné; Marie-Laure Foucault-Grunenwald; Vitor Borges; Xavier Charpentier; Adriana S Limansky; João Paulo Gomes; Alejandro M Viale; Suzana P Salcedo

doi:10.1371/journal.pone.0138265

Differential Role of the T6SS in Acinetobacter baumannii Virulence

PLoS One. 2015 Sep 24;10(9):e0138265. doi: 10.1371/journal.pone.0138265. eCollection 2015.

Authors

Guillermo D Repizo¹, Stéphanie Gagné¹, Marie-Laure Foucault-Grunenwald², Vitor Borges³, Xavier Charpentier², Adriana S Limansky⁴, João Paulo Gomes³, Alejandro M Viale⁴, Suzana P Salcedo¹

Affiliations

¹ Bases Moléculaires et Structurales des Systèmes Infectieux, CNRS UMR 5086, Université Lyon 1, Institut de Biologie et Chimie des Protéines, Lyon, France.
² Unité de Microbiologie, Adaptation et Pathogénie, CNRS UMR 5240, Université Lyon 1, Villeurbanne, France.
³ Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal.
⁴ Instituto de Biologia Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiologia, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Rosario, Argentina.

Abstract

Gram-negative bacteria, such as Acinetobacter baumannii, are an increasing burden in hospitals worldwide with an alarming spread of multi-drug resistant (MDR) strains. Herein, we compared a type strain (ATCC17978), a non-clinical isolate (DSM30011) and MDR strains of A. baumannii implicated in hospital outbreaks (Ab242, Ab244 and Ab825), revealing distinct patterns of type VI secretion system (T6SS) functionality. The T6SS genomic locus is present and was actively transcribed in all of the above strains. However, only the A. baumannii DSM30011 strain was capable of killing Escherichia coli in a T6SS-dependent manner, unlike the clinical isolates, which failed to display an active T6SS in vitro. In addition, DSM30011 was able to outcompete ATCC17978 as well as Pseudomonas aeruginosa and Klebsiella pneumoniae, bacterial pathogens relevant in mixed nosocomial infections. Finally, we found that the T6SS of DSM30011 is required for host colonization of the model organism Galleria mellonella suggesting that this system could play an important role in A. baumannii virulence in a strain-specific manner.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Acinetobacter Infections / microbiology
Acinetobacter baumannii / pathogenicity*
Acinetobacter baumannii / physiology*
Animals
Biofilms
Biomass
Gene Expression Regulation, Bacterial
Gene Order
Genetic Complementation Test
Genetic Loci
Humans
Microbial Interactions
Molecular Sequence Data
Moths / microbiology
Mutation
Phenotype
Type VI Secretion Systems / genetics*
Virulence / genetics

Substances

Type VI Secretion Systems

Associated data

GENBANK/KT334324
GENBANK/KT334325
GENBANK/KT334326
GENBANK/KT334327
GENBANK/KT334328

Grants and funding

This work was supported by a FINOVI Young Researcher Grant. SS is supported by an INSERM researcher contract and SG by Région Rhône-Alpes ARC1 Santé fellowship. XC and MLG are supported by grants from the CNRS-Inserm ATIP-Avenir program and Sanofi (awarded to XC). AV is a Staff Member of CONICET, Argentina, and AL a Staff Member of the Universidad Nacional de Rosario, Argentina. Both researchers are supported by grants from ANPCyT, CONICET, and Secretaría de Ciencia, Tecnología e Innovación, Provincia de Santa Fe, Argentina. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.