TABLE 2

Nucleotide similarities of O-processing genes wzx and wzy and the corresponding known cross-reactions using rabbit antisera

Category and O groups% similarityCross-reaction using rabbit antiseraa
wzxwzyKnownAdditional
Identity in either wzx and/or wzy gene(s)
    O153/O178100100NoO153 * O54
    O28ac/O42b100100YesO28ab * O28ac
    O2/O5010099.90YesFour with O2; 11 with O50c
    O17/O7710099.92Yesd
    O118/O15110099.91O118-O151eO174-O151
    O169/O183NAf100YesO30 * O169; O105 * O183
    O141ab/O141ac10099.82Yes
    O13/O13599.68100O135-O13e12 with O13; Seven with O135g
    O17/O4499.92100Yesd
    O123/O18699.86–99.93100YesO12 * O123; O116 * O123; O4 * O186; O116 * O186; O124 * O186
High similaritiy on one gene but different sizes on the other
    O62/O6899.92Diff. sizesYesO62 * O73; O62 * O106; O62 * O125ab/ac; O68 * O73; O68 * O125abh
    O36/O134Diff. sizes99.82NoO36 * O43; O134 * O17; O134 * O171
    O124/O164Diff. sizes99.82YesO124 * O186; O4 * O164; O25 * O164i
High similarities on both genes
    O90/O12799.76–99.9299.14–99.23YesO86 * O90; O127 * O128ab
    O107/O11799.7599.77–99.85YesTen with O107, nine with O117j
    O20/O13799.8699.84No
    O13/O135/O12999.60–99.9298.96–100YesO50 * O129
O135-O13, only one wayO129 * O133
  • a Two-way cross-reactions are shown as “Yes” or with an asterisk, and one-way cross reactions are shown with a hyphen, e.g., “O118-O151.” These are cross-reactions as known by the WHOCC as of 24 March 2015.

  • b Only one of the O28ac variants is 100% identical.

  • c O2 also cross-reacts with O53, O74, O117, and O138; O50 also cross-reacts with O1, O13, O19, O53, O107, O117, O129, O133, O135, O147, and O149.

  • d —, O17, O44, O73, O77, and O106 form a special O complex, which is very closely related both phenotypically and genotypically. All five O groups show phenotypic two way cross-reactions except for O77 which does not cross-react with O73 or O106. Outside this complex, two-way cross-reactions between O17, O44, O73, and O77 and five, four, seven and one other O groups are presently recorded at the WHOCC.

  • e Only the one way cross-reaction is known.

  • f NA, not applicable. Similarity on wzx genes is very low, sizes are different, and the pairwise BLAST results in a match only over 17 bp (see Table S2 in the supplemental material).

  • g O13 also cross-reacts with O4, O18ac, O19, O23, O25, O44, O50, O62, O73, O125ab, O129 and O147; O135 also cross-reacts with O4, O16, O17, O18ac, O44, O50 and O129.

  • h Fifteen O antigens react with O68 antiserum: O3, O4, O7, O13, O18ab, O19, O23, O36, O44, O102, O138, O141, O142, O147 and O148.

  • i O164 also reacts in O18ac.

  • j O107 also cross-reacts with O1, O14, O50, O92, O102, O108, O116, O139, O159, and O185; O117 also cross-reacts with O2, O26, O50, O53, O101, O112ac, O120, O149, and O185.