I posted here pre Christmas re a cough I had had since October 2014. I was x rayed and ct scanned which showed up bacterial infection. Fortunately my local teaching hospital was running a drug trial for this 'unknown' cough so I am on a 3 month x 3 times a week antibiotics. I still have over a month to go but although I have made great strides to being my old self, I still have a morning chesty productive cough. Pre going on the trial I had 3 courses of antibiotics. I wondered if anyone else had experienced this 'unknown' cough which is so very stubborn.