New algorithm of antibiotic selection reveals the abundance and reduces bacterial load in sputum of adult patients with cystic fibrosis

Objectives: Traditional antibiotic selection tests take days and fail to select effective antibiotics against Multidrug-resistant strains (MDR-strains) because they do not account for critical characteristics of “real-life” infections. AtbFinder – a novel culture-based test system addresses these realities by using a novel principle of antibiotic selection, named “populational response”. Methods: 30 CF patients aged 18 to 65 years, with known chronic infection, receiving prophylactic antibiotic therapy with antibiotics selected based on AtbFinder results were monitored over 3 years. Sputum was obtained during yearly check-ups and the presence of several pathogens was assessed with (i)AtbFinder or (ii)standard microbiological media. Results: First we analyzed the effect of antibiotic therapy selected with the AtbFinder on eradication of P.aeruginosa. By year 1 and 2 after the switch, eradication of P.aeruginosa were noted in 16 (53%) and 22 (73%) out of 30 subjects who had P.aeruginosa infection respectively (p<0.001). The use of AtbFinder resulted in the growth of broader bacterial diversity in 97.1% patients compared to routine diagnostics methods and contributed to the isolation of critical for patients with CF pathogens missed by conventional microbiology lab. Along with P.aeruginosa S.aureus, A.xylosoxidans, S.maltophila including MDR strains, were isolated and successfully eradicated in patients following a switch to antibiotic therapy selected with the AtbFinder. Conclusion: Antibiotic optimization with therapy prescribed using AtbFinder results in progressive eradication of different MDR bacteria from airways of adults with CF.