Lucca F, et al. - Researchers assessed the evolution of antibiotic resistance in cystic fibrosis (CF) patients with chronic colonization with P aeruginosa, from 2010-2013. Researchers also looked for the features of this evolution in patients younger than 20 years, utilizing clinical and microbiological data from two electronic databases. Antibiotic resistance was defined according to European Committee of Antimicrobial Susceptibility Testing for levofloxacin, ciprofloxacin, meropenem, amikacin and ceftazidime. A significant decrease was noted in P. aeruginosa antibiotic sensitivity for fluoroquinolones, primarily in patients aged <20 years, while it increased for amikacin and colistin. In the 4-year period studied, an evolution in P aeruginosa antibiotic resistances was observed. In CF, responsible and informed use of antibiotics is compulsory.