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Patricia Martin - Jeudi 9 novembre 2017 10h

Amphi. J. Poly - Bât. 440 - Séminaire Micalis

Patricia Martin - Jeudi 9 novembre 2017 10h
Interplay between siderophores and colibactin in emerging pathogenic clones of Enterobacteriacae

Interplay between siderophores and colibactin in emerging pathogenic clones of Enterobacteriacae


Patricia Martin 

Institut de Recherche en Santé Digestive 
INSERM  UMR1220, INRA UMR1416, Toulouse 

There is an increased prevalence of highly pathogenic Escherichia coli strains that belong to the phylogenetic group B2 over the last 30 years in the intestinal microbiota in industrialized countries.These E. coli strains have developed a greater ability to acquire iron (heme receptor and siderophores) and to produce the genotoxin colibactin.The biosynthesis of both siderophores and colibactin requires a 4'-phosphopantetheinyl transferase (PPTase). The EntD PPTase is involved in the synthesis of siderophores enterobactin, salmochelins and yersiniabactin. The ClbA PPTase is involved in the synthesis of the genotoxin colibactin.We evidenced the connection between the pathways leading to the synthesis of siderophores and colibactin, via the PPTase ClbA. We demonstrated that clbA transcription is regulated by iron concentration, and by the two major regulators of iron homeostasis: the small regulatory non-coding RNA RyhB and the ferric uptake regulator (Fur) leading to a fine-tuning regulation of colibactin production.Integrating the regulation of fitness/virulence factors, such as siderophores and colibactin into networks that respond to specific environmental signals, such as the local iron concentration, could result in an accurate production of specific fitness/virulence factors, so that E. coli can adapt to the competitive environment that is the gut and/or the blood.Because this connection exists not only in extraintestinal pathogenic E. coli strains causing neonatal meningitis and urinary infections but also in hypervirulent Klebsiella pneumoniae, PPTases are promising new therapeutic targets. 

Jeudi 9 novembre 2017 10h

Amphi. J. Poly - Bât. 440

INRA, Jouy en Josas 

Invitée par Alexandra Gruss