Hello bbeers, sending samples after bronchoscopy to lab for bacteria growing and if something grows for a susceptibility should be a norm. When I first had bronchoscopy the pulmonologist sent my samples for types of bacteria growth, and MAC grew, but as my id doctor found out, she never order the susceptibility test. So it cost me another few months to get it ( sputum induction and wait) before I could be treated and I coughed nonstop. I am not a doctor but my pulmonologist said that she always order it after the bronchoscopy. Good luck. One more thing. From what I know azithromycin should not be taken long time alone so ask your doctor about it.