The "SciH" cluster

This cluster has at its core two hypothetical proteins that occur in Planctomycetes (fig|243090.1.peg.5361: Pirellula sp. 1) and numerous proteobacteria. Here is a pinned region depicting the situation.
The two genes have been called impB and sciH in many cases, although I have not located the origin of these designations.
There are discussions of the imp operon and someone clearly thinks about an sci operon. There are some suggestions that these relate to pathogenicity. I am basically clueless on this one.