<it>tkt1</it>, located on a novel pathogenicity island, is prevalent in avian and human extraintestinal pathogenic <it>Escherichia coli</it>

• Main Authors: Li Ganwu, Kariyawasam Subhashinie, Tivendale Kelly A, Wannemuehler Yvonne, Ewers Christa, Wieler Lothar H, Logue Catherine M, Nolan Lisa K
• Format: Article
• Language: English
• Published: BMC 2012-04-01
• Series: BMC Microbiology
• Online Access: http://www.biomedcentral.com/1471-2180/12/51

<p>Abstract</p> <p>Background</p> <p>Extraintestinal pathogenic <it>Escherichia coli </it>are important pathogens of human and animal hosts. Some human and avian extraintestinal pathogenic <it>E. coli </it>are indistinguishable on the basis of diseases caused, multilocus sequence and phylogenetic typing, carriage of large virulence plasmids and traits known to be associated with extraintestinal pathogenic <it>E. coli </it>virulence.</p> <p>Results</p> <p>The gene <it>tkt1 </it>identified by a previous signature-tagged transposon mutagenesis study, was found on a 16-kb genomic island of avian pathogenic <it>Escherichia coli </it>(APEC) O1, the first pathogenic <it>Escherichia coli </it>strain whose genome has been completely sequenced. <it>tkt1 </it>was present in 39.6% (38/96) of pathogenic <it>Escherichia coli </it>strains, while only 6.25% (3/48) of <it>E. coli </it>from the feces of apparently healthy chickens was positive. Further, <it>tkt1 </it>was predominantly present in extraintestinal pathogenic <it>E. coli </it>belonging to the B2 phylogenetic group, as compared to extraintestinal pathogenic <it>E. coli </it>of other phylogenetic groups. The <it>tkt1</it>-containing genomic island is inserted between the <it>metE </it>and <it>ysgA </it>genes of the <it>E. coli </it>K12 genome. Among different extraintestinal pathogenic <it>E. coli </it>of the B2 phylogenetic group, 61.7% of pathogenic <it>Escherichia coli</it>, 80.6% of human uropathogenic <it>E.coli </it>and 94.1% of human neonatal meningitis-causing <it>E. coli</it>, respectively, harbor a complete copy of this island; whereas, only a few avian fecal <it>E. coli </it>strains contained the complete island. Functional analysis showed that Tkt1 confers very little transketolase activity but is involved in peptide nitrogen metabolism.</p> <p>Conclusion</p> <p>These results suggest <it>tkt1 </it>and its corresponding genomic island are frequently associated with avian and human ExPEC and are involved in bipeptide metabolism.</p>