All pathogenic Y. enterocolitica strains harbor ail, which is different from the inv sequence (which encodes a protein of similar function), and renders Y. enterocolitica capable of invading the intestinal epithelium. In addition, the Ail protein confers a serum resistance phenotype on Y. enterocolitica [5]. In contrast to inv, which exists in non-pathogenic as well as pathogenic strains of Y. enterocolitica, ail only exists in Y. enterocolitica strains epidemiologically

related to human disease [6], and is therefore an important virulence marker. CB-5083 molecular weight Environmental isolates not associated with disease have a non-functional inv and no ail [7]. Ferric ion uptake is essential for bacterial growth and survival. The supply of iron and production of the siderophore transport system is a central factor in infections with Yesinia pestis and Y. enterocolitica. BAY 1895344 molecular weight Pathogenic Y. enterocolitica can be divided into 2 groups, those producing the siderophore, such as biotype 1B/O:8, and those producing no siderophore, as in serotypes O:3 and O:9 [8]; the latter take up ferric ion using ectogenic siderophores, such as ferrioxamin B and ferrioxamin E [9]. The 2 groups have different

ferric ion uptake abilities, which may explain the differences in virulence among serotypes [10]. A 77 kDa receptor on the Y. enterocolitica outer membrane [11] combines with ferrioxamin to take up ferric ion rapidly [12]. This process is energy-dependent and requires the action of the TonB protein, part of a complex known as the Ton system. This complex undergoes a conformational change driven by the proton motive force (PMF), which interacts with the outer membrane receptors and activates www.selleck.co.jp/products/Paclitaxel(Taxol).html transport [13]. The FoxA receptor of Y. enterocolitica, the ferrochrome receptor and the TonB-dependent receptor share high amino acid homology [14, 15]. The foxA was chosen for study because it exists in all Y. enterocolitica strains. Using polymorphic gene analysis,

we show that combined detection of ail and foxA confirms the identity of pathogenic Y. enterocolitica. Methods Bacterial strains and identification of biotype and serotype We chose 271 pathogenic and 27 non-pathogenic Y. enterocolitica strains isolated from diarrhea patients, animals, food and the environment in China. They included 205 strains of serotype O:9, 72 of serotype O:3, 10 of serotype O:8, 5 of serotype O:5, 3 of serotype O:6, 30 and 3 of undetermined serotype (Table 1), together with 11 reference strains from Europe, the United States and Japan (Table 2). The serotypes, biotypes and pathogenesis of these strains were determined as previously described [16–18]. Table 1 Bio-serotypes of the 298 Y.