They are distinguished by the presence of a hitherto unknown combination of type O-factor I
and group O-factor 7,8, both associated with lateral a-D-glucosyl groups on the basal linear O-polysaccharide.
A serologically identical strain, 036_1d, has been constructed in the laboratory by sequential infection
of serotype Y by serotype-converting bacteriophages SfX and SfI.