Virulence factors of the human opportunistic pathogen Serratia marcescens identified by in vivo screening.
The human opportunistic pathogen Serratia marcescens is a bacterium with a broad host range, and represents a growing problem for public health. Serratia marcescens kills Caenorhabditis elegans after colonizing the nematode's intestine. We used C.elegans to screen a bank of transposon-induced S.marcescens mutants and isolated 23 clones with an attenuated virulence. Nine of the selected bacterial clones also showed a reduced virulence in an insect model of infection. Of these, three exhibited a reduced cytotoxicity in vitro, and among them one was also markedly attenuated in its virulence in a murine lung infection model. For 21 of the 23 mutants, the transposon insertion site was identified. This revealed that among the genes necessary for full in vivo virulence are those that function in lipopolysaccharide (LPS) biosynthesis, iron uptake and hemolysin production. Using this system we also identified novel conserved virulence factors required for Pseudomonas aeruginosa pathogenicity. This study extends the utility of C.elegans as an in vivo model for the study of bacterial virulence and advances the molecular understanding of S.marcescens pathogenicity.
Kurz
C Léopold
CL
Centre d'Immunologie de Marseille Luminy, INSERM/CNRS/Université de la Méditerranée, Case 906, 13288 Marseille cedex 9, France.
Chauvet
Sophie
S
Andrès
Emmanuel
E
Aurouze
Marianne
M
Vallet
Isabelle
I
Michel
Gérard P F
GP
Uh
Mitch
M
Celli
Jean
J
Filloux
Alain
A
De Bentzmann
Sophie
S
Steinmetz
Ivo
I
Hoffmann
Jules A
JA
Finlay
B Brett
BB
Gorvel
Jean-Pierre
JP
Ferrandon
Dominique
D
Ewbank
Jonathan J
JJ
D000818:Animals; D017173:Caenorhabditis elegans / Q000382:microbiology*; D008969:Molecular Sequence Data; D009154:Mutation; D012706:Serratia marcescens / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence