Sorry, never heard of these.
I've been on colistyn for about 3 years and still have the same cultures nearly every visit. I think it mostly depends on how you feel and whether your exaccerbations have lessened. I think many people just ALWAYS culture things like pseudo and it doesn't matter what meds. they use (like me).
Good luck finding someone who can tell you more about the meds.... I just wanted you to know that some inhaled meds don't actually change your cultures, and that may not mean they're not working. <img src="i/expressions/face-icon-small-smile.gif" border="0">