Pseudomonas selective cetrimide agar

Sputum samples were collected after patients rinsed their mouths out with sterile water. If spontaneous sputum was not possible, induced sputum was systematically performed according to international recommendations [31 (link), 32 ].
Extended culture analysis was performed on the sputum. After liquefaction by N-acetylcysteine, serial dilutions (1/1000, 1/10,000, and 1/100,000) were made and cultured in Columbia blood agar, chocolate agar, Schaedler agar, and Pseudomonas selective cetrimide agar (Thermo Fisher Scientific, USA), at 37 °C for 48 h for aerobic and 5% CO₂ cultures and 5 days for anaerobic cultures. All colonies that appeared to be morphologically distinct were quantified as colony-forming unit (CFU) per milliliter and identified by matrix-associated laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MALDI Biotyper®, Bruker Daltonics, Bremen, Germany). The α-diversity of the airway microbiota was evaluated with the Shannon index (a marker of intra-individual diversity).
Chronic P. aeruginosa infection was defined by the isolation of P. aeruginosa in two or more cultures, at least 3 months apart in a consecutive period of 12 months at a stable state [33 (link)].

Endobronchial samples (bronchial aspiration or BALF, n = 15) were collected, and extended microbiological culture was performed, as previously described [26 (link),27 (link)]. The samples and their dilutions (1/1.000 for bronchial aspiration) were cultured in Columbia blood agar, chocolate agar, Schaedler agar, and Pseudomonas selective cetrimide agar (Thermo Fisher Scientific, Waltham, MA, USA), at 37 ℃ for 48 h for aerobic and 5% CO₂ cultures and 5 days for anaerobic cultures. All colonies that appeared to be morphologically distinct were quantified as colony-forming unit (CFU) per mL and identified using MALDI-TOF mass spectrometry (MALDI Biotyper^®, Bruker Daltonics, Billerica, MA, USA). The α-diversity of the airway microbiota was evaluated with the Shannon index (a marker of intra-individual diversity).