Ronnie Houston at St Mary's Hospital in Richmond (no kin!) Virginia asks 
about Helicobacter pylori controls.

I think most labs just use known positives as controls, since they are rather 
common in ordinary GI pathology practice. I notice that controls often don't 
contain any bacteria, or have a motley collection of cocci but no curved 
bacilli.

The elegant solution is to obtain a gastrectomy specimen that has the bacilli 
teeming in the antrum. Such specimens aren't very common, but they do occur, 
and it would only take one of them to supply the world with controls into the 
foreseeable future. For this reason, I prepare and check every gastrectomy 
specimen as a possible control. I actually had one a few years ago, but the 
lab I was working in wasn't interested, and threw the specimen out.

Bob Richmond
Samurai Pathologist
Knoxville TN