The cutoff for significant number of colony forming units to differentiate between colonization and infection depends on the diagnostic test:
- tracheobronchial secretion, 10–5 CFU/ ml;
- BAL, 10–4 CFU/ml
- protected specimen brush, 10–3 CFU/ml
Bein, Thomas et al. “The Standard Of Care Of Patients With ARDS: Ventilatory Settings And Rescue Therapies For Refractory Hypoxemia”. Intensive Care Med 42.5 (2016): 699-711. Web. 14 May 2016.