The Environmental Health Center -- Dallas works wonders with problems like this. If they can't figure it out, I'd be surprised.
It eventually turned out to be strep B. From what Im told, its not normally tested for because “it isn’t serious” and “it just goes away” except that it was causing problems and wasn’t just going away for my daughter. Given the original post, maybe someone needs to rewrite that part of the medical texts.
see 1843, 1844, 1848