Ok. I know a little about this. My cultures always show pseudomonas Arigosa - sometimes shows sensitivity to cipro - sometimes show resistance - how can that be? Doc explained it like this. There are so many strains of the various infections that are in our lungs - and there are many different places the sputum you cough up can come from. For instance. My last culture showed 2 strains of pseudo - one res to cipro - one sensitive - so he said let's do the cipro any way and at least take down the one that is showing resistance. Won't do anything for the other. So it depends on where in your lung that sputum is coming from. The bacteria have little colonies built in there - so whichever one gave up the sputum - that's the one you are hearing about. Kind of silly way to explain - but gave me what I needed. You can tell that day I saw the cf pedia specialist and not the adult <img src="i/expressions/face-icon-small-smile.gif" border="0">