Efa-1/LifA mediates intestinal colonization of calves by enterohaemorrhagic Escherichia coli O26 : H- in a manner independent of glycosyltransferase and cysteine protease motifs or effects on type III secretion.
Enterohaemorrhagic Escherichia coli (EHEC) comprise a group of animal and zoonotic pathogens of worldwide importance. Our previous research established that intestinal colonization of calves by EHEC serotypes O5 : H- and O111 : H- requires EHEC factor for adherence (Efa-1), also known as lymphostatin (LifA). Towards an understanding of the mode of action of Efa-1/LifA, chromosomal in-frame deletions of predicted glycosyltransferase (DXD) and cysteine protease (CHD) motifs were created in a Deltastx1 derivative of EHEC O26 : H-. The magnitude and duration of faecal excretion of EHEC O26 : H- were significantly reduced by null mutation of efa-1/lifA, but were not impaired by DeltaDXD or DeltaCHD mutations, in contrast to observations made with truncated Efa-1/LifA mutants of Citrobacter rodentium in mice. Although C. rodentium Efa-1/LifA influences the induction of colonic hyperplasia in mice, EHEC O26 : H- Efa-1/LifA was not required for fluid accumulation or neutrophil recruitment in bovine ileal loops. In contrast to observations with EHEC O5 : H- or O111 : H- mutants, inactivation of efa-1/lifA in EHEC O26 : H- did not significantly affect adherence or secretion of type III secreted proteins that play pivotal roles in calf colonization. Lymphostatin activity could not be reliably demonstrated in lysates of EHEC O26 : H-; however, deletion of the glycosyltransferase and cysteine protease motifs in Efa-1/LifA from enteropathogenic E. coli O127 : H6 abolished lymphostatin activity. Our data uncouple the role of Efa-1/LifA in calf colonization from effects on type III secretion and reinforce the potential for pathotype- and serotype-specific phenotypes.
Deacon
Victoria
V
Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College, London SW7 2AZ, UK.|Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, UK.
Dziva
Francis
F
Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, UK.
van Diemen
Pauline M
PM
Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, UK.
Frankel
Gad
G
Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College, London SW7 2AZ, UK.
Stevens
Mark P
MP
Enteric Bacterial Pathogens Laboratory, Institute for Animal Health, Compton, Berkshire RG20 7NN, UK.
D020816:Amino Acid Motifs; D000818:Animals; D001422:Bacterial Adhesion; D001427:Bacterial Toxins / Q000378:metabolism*; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D057056:Cysteine Proteases / Q000378:metabolism; D054324:Enterohemorrhagic Escherichia coli / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D005243:Feces / Q000382:microbiology; D016695:Glycosyltransferases / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D008297:Male; D016254:Mutagenesis, Insertional; D017384:Sequence Deletion
D001427:Bacterial Toxins; C404907:Efa1 protein, E coli; D029968:Escherichia coli Proteins; C406587:lymphostatin protein, E coli; D016695:Glycosyltransferases; D057056:Cysteine Proteases