Fig 1.
The O antigen gene clusters from the 60 Proteus serotypes.
The sequences of the 60 Proteus O antigen gene clusters have been deposited to GenBank with accession numbers KY710685 to KY710739.
Fig 2.
Biosynthesis pathways for the sugars in Proteus O antigens.
GalU, UTP-glucose-1-phosphate uridylyltransferase; GalE, UDP-glucose-4-epimerase; Ugd, UDP-glucose 6-dehydrogenase; Gla, UDP-glucuronate 4-epimerase; GlmS, glutamine:fructose-6-phosphate transaminase; GlmM, phosphoglucosamine mutase; GlmU, UDP-N-acetyl-glucosamine pyrophosphorylase; Gne, UDP-N-acetylglucosamine-4-epimerase; RmlA, glucose-1-phosphate thymidylyltransferase; RmlB, dTDP-D-glucose 4,6-dehydratase; RmlC, dTDP-6-deoxy-α-D-xylo-hexos-4-ulose 3,5-epimerase; RmlD, dTDP-6-deoxy-β-L-lyxo-hexos-4-ulose 4-reductase; FdtA, dTDP-6-deoxy-α-D-xylo-hexos-4-ulose 3,4-isomerase; FdtB, dTDP-6-deoxy-α-D-xylo-hexos-3-ulose aminase; FdtC, dTDP-D-Fuc3N acetylase; QdtA, dTDP-6-deoxy-α-D-xylo-hexos-4-ulose 3,4-isomerase; QdtB, dTDP-6-deoxy-α-D-ribo-hexos-3-ulose aminase; QdtC, dTDP-D-Qui3N acetylase; FnlA, UDP-D-GlcNAc 4,6-dehydratase, 3- and 5-epimerase; FnlB, UDP-2-acetamido-2,6-dideoxy-β-L-lyxo-hexos-4-ulose 4-reductase; FnlC, UDP-2-acetamido-2,6-dideoxy-L-talose 2-epimerase; QnlA, UDP-2-acetamido-2,6-dideoxy-β-L-lyxo-hexos-4-ulose 4-reductase; QnlB, UDP-L-RhaNAc 2-epimerase; * indicates the genes located outside the O antigen gene cluster (all enzymes encoded by these genes can be found in the 68 Proteus genomes; the amino acid sequence identities of GalU to the homolog in E. coli K12 are 75.44–76.43%, the amino acid sequence identities of GalE to the homolog in E. coli K12 are 59.13–65.26%, the amino acid sequence identities of Rib to the homolog in E. coli K12 are 94.29–94.6%, the amino acid sequence identities of GlmS to the homolog in E. coli K12 are 78.89–82.79%, the amino acid sequence identities of GlmM to the homolog in E. coli K12 are 80.97–88.12%, the amino acid sequence identities of GlmU to the homolog in E. coli K12 are 73.94–79.8%, data not shown).
Fig 3.
The phylogenetic trees for wzx and wzy genes from the 60 Proteus serotypes.
The wzx (A) and wzy (B) trees were constructed using wzx and wzy genes. The sequences were aligned using ClustalW v2.0, and the trees were constructed using the JC69 substitution model and the phyML v3.0.
Fig 4.
The hybridization results of the 31 Proteus strains.
The suspension arrays were divided into 3 groups: (A) O1, O2, O9, O17, O20, O21, O23ac, O30, O32 and O47; (B) O5, O6, O8, O11, O12, O27, O29a, O31ab and O45; (C) O3ab, O10, O13, O14ab, O18, O19a, O24, O33, O34, O36, O40 and O42; no cross reactions were observed for any probe tested in this study, and the Blank was a negative control; the x-axis represents the PCR products of different serotypes, the y-axis represents the MFI values, and the z-axis represents the specific probes used for detection.