In vitro Antibiotic Susceptibility of Bacterial Isolates from Polish patients with Cystic Fibrosis: A Non-Interventional Study

This non-interventional study was conducted at three cystic fibrosis (CF) treatment centers in Poland from August 2022 to July 2023. The aim was to assess the etiology of bacterial infection and evaluate antimicrobial susceptibility in CF patients. Prevalent pathogens were identified and their <i>in vitro</i> susceptibility to commonly prescribed antibiotics was assessed, highlighting potential needs in CF antibiotic therapy. Results indicated that <i>Staphylococcus aureus</i> was the most frequently isolated strain and was highly susceptible to tigecycline, linezolid, vancomycin, co-trimoxazole, and ceftaroline. <i>Pseudomonas aeruginosa</i>, the second most common strain, was susceptible to colistin, ceftazidime/avibactam, and tobramycin but exhibited high resistance to ciprofloxacin and cefepime. Coinfections of <i>S. aureus</i> and <i>P. aeruginosa</i> were notably more prevalent in adult CF patients. Although bacterial diversity was comparable between adults and children, limited sample sizes for specific species constrained the statistical analysis. Notably, comprehensive resistance data were lacking for most samples; however, many <i>P. aeruginosa</i> strains were classified as multidrug-resistant. Additionally, methicillin-resistant <i>S. aureus</i> and extended-spectrum β-lactamase-producing strains of <i>Enterobacter cloacae</i> and <i>Klebsiella</i> species were identified. This study highlights the importance of ongoing surveillance of bacterial pathogens and their resistance patterns in CF patients, as such information is essential for optimizing antibiotic therapy and improving clinical outcomes.