Open AccessDistribution, Functional Expression, and Genetic Organization of Cif, a Phage-Encoded Type III-Secreted Effector from Enteropathogenic and EnterohemorrhagicEscherichia coli
Author(s) -
Estelle Loukiadis,
Rika Nobe,
Sylvia Herold,
Clara Tramuta,
Yoshitoshi Ogura,
Tadasuke Ooka,
Stefano Morabito,
Monique Kérourédan,
Hubert Brugère,
Herbert Schmidt,
Tetsuya Hayashi,
Éric Oswald
Publication year - 2008
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.00844-07
Subject(s) - prophage , biology , effector , enteropathogenic escherichia coli , escherichia coli , population , pathogenicity island , genetics , microbiology and biotechnology , gene , type three secretion system , bacteriophage , virulence , demography , sociology
Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) inject effector proteins into host cells via a type III secretion system encoded by the locus of enterocyte effacement (LEE). One of these effectors is Cif, encoded outside the LEE by a lambdoid prophage. In this study, we demonstrated that the Cif-encoding prophage of EPEC strain E22 is inducible and produces infectious phage particles. We investigated the distribution and functional expression of Cif in 5,049 E. coli strains of human, animal, and environmental origins. A total of 115 E. coli isolates from diverse origins and geographic locations carried cif . The presence of cif was tightly associated with the LEE, since all the cif -positive isolates were positive for the LEE. These results suggested that the Cif-encoding prophages have been widely disseminated within the natural population of E. coli but positively selected within the population of LEE-positive strains. Nonetheless, 66% of cif -positive E. coli strains did not induce a typical Cif-related phenotype in eukaryotic cells due to frameshift mutations or insertion of an IS element in the cif gene. The passenger region of the prophages carrying cif was highly variable and showed various combinations of IS elements and genes coding for other effectors such as nleB , nleC , nleH , nleG , espJ , and nleA / espI (some of which were also truncated). This diversity and the presence of nonfunctional effectors should be taken into account to assess EPEC and EHEC pathogenicity and tropism.