Growth of Yersinia pseudotuberculosis in human plasma: impacts on virulence and metabolic gene expression.
BACKGROUND
In man, infection by the Gram-negative enteropathogen Yersinia pseudotuberculosis is usually limited to the terminal ileum. However, in immunocompromised patients, the microorganism may disseminate from the digestive tract and thus cause a systemic infection with septicemia.


RESULTS
To gain insight into the metabolic pathways and virulence factors expressed by the bacterium at the blood stage of pseudotuberculosis, we compared the overall gene transcription patterns (the transcriptome) of bacterial cells cultured in either human plasma or Luria-Bertani medium. The most marked plasma-triggered metabolic consequence in Y. pseudotuberculosis was the switch to high glucose consumption, which is reminiscent of the acetogenic pathway (known as "glucose overflow") in Escherichia coli. However, upregulation of the glyoxylate shunt enzymes suggests that (in contrast to E. coli) acetate may be further metabolized in Y. pseudotuberculosis. Our data also indicate that the bloodstream environment can regulate major virulence genes (positively or negatively); the yadA adhesin gene and most of the transcriptional units of the pYV-encoded type III secretion apparatus were found to be upregulated, whereas transcription of the pH6 antigen locus was strongly repressed.


CONCLUSIONS
Our results suggest that plasma growth of Y. pseudotuberculosis is responsible for major transcriptional regulatory events and prompts key metabolic reorientations within the bacterium, which may in turn have an impact on virulence.
Rosso
Marie-Laure
ML
Inserm U801, Lille, F-59019, Université Lille II, Faculté de Médecine Henri Warembourg), Lille, France. mlrosso@pasteur.fr
Chauvaux
Sylvie
S
Dessein
Rodrigue
R
Laurans
Caroline
C
Frangeul
Lionel
L
Lacroix
Céline
C
Schiavo
Angèle
A
Dillies
Marie-Agnès
MA
Foulon
Jeannine
J
Coppée
Jean-Yves
JY
Médigue
Claudine
C
Carniel
Elisabeth
E
Simonet
Michel
M
Marceau
Michaël
M
D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism; D002952:Citric Acid Cycle / Q000235:genetics; D003470:Culture Media; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism; D006019:Glycolysis / Q000235:genetics; D006801:Humans; D007501:Iron / Q000378:metabolism; D010949:Plasma / Q000382:microbiology*; D015854:Up-Regulation; D014774:Virulence; D015011:Yersinia pseudotuberculosis / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity*; D015012:Yersinia pseudotuberculosis Infections / Q000378:metabolism / Q000382:microbiology
D018829:Adhesins, Bacterial; D003470:Culture Media; C064832:YadA protein, Yersinia; D007501:Iron; D005947:Glucose