Do add a macrolide for immunomodulatory effect in patients with macrolide-resistant M. abscessus?

I think using azithromycin is something that definitely can be considered, but on an individual basis; if there is significant bronchiectasis with exacerbations, then it makes sense to consider azithromycin; more likely to consider also if there are other microorganisms, especially Pseudomonas drivi...

Not routinely. Many patients with NTM lung disease - including abscessus - are at high risk of co-infection with other NTM pathogens (including MAC). Routinely prescribing azithromycin for macrolide-resistant Mabs raises the risk of emerging macrolide resistance in these other non-Mabs NTM organisms...