Sequence of the E-coli O104 antigen gene cluster and identification of O104 specific genes

The Escherichia coli O104 polysaccharide is an important antigen, which con tains sialic acid and is often associated with EHEC clones. Sialic acid is a component of many animal tissues, and its presence in bacterial polysacch arides may contribute to bacterial pathogenicity. Wr sequenced the genes re sponsible for O104 antigen synthesis and have found genes which from their sequences are identified as an O antigen polymerase gene, an O antigen flip pase gene, three CMP-sialic acid synthesis genes, and three potential glyco syl transferase genes. The E. coli K9 group IB capsular antigen has the sam e structure as the 0104 O antigen, and we find using gene by gene PCR that the K9 gene cluster is essentially the same as that for 0104. It appears th at the distinction between presence as group IB capsule or O antigen for th is structure does not involve any difference in genes present in the O anti gen gene cluster. By PCR testing against representative strains for the 166 E. coli O antigens and some randomly selected Gram-negative bacteria, we i dentified three O antigen genes which are highly specific to 0104/K9. This work; provides the basis for a sensitive test for rapid detection of O104 E . coli. This is important both for decisions on patient care as early treat ment may reduce the risk of life-threatening complications and for a faster response in control of food borne outbreaks. (C) 2001 Elsevier Science B.V . All rights reserved.