1. Group-1 KLPS has few K-antigen repeats and group 4 has long chains of K antigen repeat units. Some isolates are given O-antigen status (examples include O26, O55, O100, O111, O113, and O127) and others have K-antigen status (e.g., K40) because they (like group 1 K antigens) are found in isolates that co express an additional neutral O antigen (i.e., one of O8, O9, O9a, O20, and O101 group)
2. The distribution between the capsular and KLPS forms point to complex interplay in surface polymers that may be critical in understanding the pathogenicity.

Regulation of Colanic Acid production

1. In contrast to the serotype-specific group 1 capsules, an exopolysaccharide is colonic acid produced upon active transcription of cps locus
2. The genes are regulated based on altered conditions like osmotic shock, damaged cell envelope structure etc. Colanic acid helps to withstand dessication, by forming biofilms. But, they don't have a role in virulence.
3. The location of this locus is upstream of galF in group 2, 3, 4 capsules and E.coli K12 isolates
4. The colanic acid locus is similar to group-1 locus with homologs wza, wzb and wzc (wzi absent) at 5' end. Stem loop transcriptional attenuator separates wzx and (biosynthetic region) from region1.
5. The Rcs system plays a major role in controlling the regulation of colanic acid transcription. It is a complex phosphorelay system that encodes for proteins involved in capsular synthesis.
6. Due to genetic rearrangement in these regions colanic acid genes are absent incase of group1(Whitfield et al., 2006)