CF, Bronchiectasis Antimicrobial Resistance Varies Widely by Region

News | Articles | November 5, 2026 Antimicrobial resistance in bronchiectasis and cystic fibrosis varied widely in a study spanning 11 centers on 3 continents. Patients with cystic fibrosis (CF) or bronchiectasis across the world showed differences in antimicrobial resistance (AMR) based on geographic location, according to a recent study published in Thorax .

1 AMR is a global threat for patients with CF or bronchiectasis, yet it is poorly characterized in these specific patient populations. This study aimed to characterize differences in AMR between patients with CF and bronchiectasis to inform treatment management. Because both conditions are commonly associated with chronic lung infection , antibiotics are used in 2 ways: episodically for acute exacerbations and as long-term suppressive approaches.

Both increase the risk of AMR. The World Health Organization (WHO) has identified a list of priority AMR bacterial pathogens, many of which are prognostically relevant in chronic lung infection, such as Pseudomonas aeruginosa . 1 All 5 pathogens analyzed in this study appear on the WHO's 2024 Bacterial Priority Pathogens List , which ranks carbapenem- and third-generation cephalosporin–resistant Enterobacterales—the family that includes Klebsiella pneumoniae and Escherichia coli —as critical priorities, carbapenem-resistant P. aeruginosa and methicillin-resistant Staphylococcus aureus as high priorities, and ampicillin-resistant Haemophilus influenzae as a medium priority.

1,2 Analyzing Respiratory Samples Across 3 Continents The study assessed patients from 11 centers across 8 countries on 3 continents: the United Kingdon, Italy, Germany, the Czech Republic, Turkey, Egypt, the United Arab Emirates (UAE), and China (Hong Kong). Researchers used collated retrospective microbiological data, including pathogen growth and antimicrobial susceptibility data, from sputum, bronchoalveolar lavage, and pediatric cough swab samples.

The study focused on 5 high-priority bacteria: P. aeruginosa , S. aureus , E. coli , H. influenzae , and K. pneumoniae . The study analyzed 110,323 respiratory samples from 19,143 individuals—10,568 with bronchiectasis and 8575 with CF—between 2011 and 2024. Centers interpreted antimicrobial susceptibility testing results using either Clinical and Laboratory Standards Institute breakpoints (China, UAE, and Turkey) or European Committee on Antimicrobial Susceptibility Testing guidelines (the UK, Italy, Germany, and the Czech Republic).

To sync results across datasets, isolates were grouped as susceptible or nonsusceptible. P. aeruginosa was the predominant pathogen in both diseases. K. pneumoniae was more commonly isolated in individuals with bronchiectasis (8.0%) compared with CF (0.7%).

H. influenzae was found more commonly in the UK in bronchiectasis and K. pneumoniae more frequently in Hong Kong. Antimicrobial Sensitivity and Resistance Profiles Varied by Region In bronchiectasis, P. aeruginosa isolates frequently showed fluoroquinolone resistance across all sites, while resistance to other antibiotic classes varied by geography.

Cephalosporin and carbapenem resistance reached 20.3% and 20.1%, respectively, in Berlin, Germany, and 33.3% and 26.5% in Istanbul, Turkey, compared with about 5% in London. Resistance also varied within countries, with H. influenzae cephalosporin resistance at 17.0% in Liverpool vs 2.7% in London.

In CF, a high AMR burden was seen for P. aeruginosa and S. aureus across all centers. Overall, CF had a significantly higher AMR burden than bronchiectasis for all pathogens except H. influenzae . Multidrug resistance (MDR) was highest in E. coli (CF: 32.6%; bronchiectasis: 39.2%), followed by K. pneumoniae (CF: 22.7%; bronchiectasis: 13.4%).

Among P. aeruginosa isolates, 18.7% were MDR in CF compared with 3.2% in bronchiectasis. Geographically, the highest AMR burden was in Turkey and Egypt, followed by Liverpool, Berlin, and Milan. At 4 European centers, P. aeruginosa resistance in bronchiectasis rose significantly from 2018 to 2023 across 5 antibiotic classes.

Antipseudomonal aminoglycosides rose the highest across the 4 centers (OR per year, 1.44; 95% CI, 1.24-1.67). K. pneumoniae resistance rose for cephalosporins and carbapenems. In people with CF who remained culture positive after starting triple CF transmembrane conductance regulator modulator therapy, the multiple antibiotic resistance index rose from 0.09 to 0.19 ( P < .001), although the authors cautioned that this may reflect selection bias.

Limitations and the Need for Respiratory AMR Surveillance The study had several limitations. Because it was retrospective, researchers could not fully assess AMR risk factors or distinguish colonization from acute infection. Samples skewed toward patients who produced sputum, so true pathogen and AMR prevalence could not be determined.

Centers also did not follow a shared protocol for collecting data and samples, and they used different susceptibility testing standards, which made comparisons between countries harder. Still, the researchers found a significant and increasing international AMR burden in bronchiectasis and CF.

They also identified emerging MDR pathogens, such as K. pneumoniae and E. coli , for which there is currently no evidence base for treating chronic lung infection. "These findings underscore the necessity for geographically stratified approaches to antimicrobial prescribing, management, and the design of clinical trials," the authors wrote.

They called for further international prospective AMR surveillance in chronic lung disease to support robust antimicrobial stewardship. 1 References 1. Pitts O, Premuda C, Yuan Z, et al.

International epidemiology of antimicrobial resistance in people living with chronic lung infection. Thorax . Published online September 21, 2026. doi:10.1136/thorax-2026-225527 2.

WHO updates list of drug-resistant bacteria most threatening to human health. News release. World Health Organization.

May 17, 2024. Accessed November 5, 2026. https://www.who.int/news/item/17-05-2024-who-updates-list-of-drug-resistant-bacteria-most-threatening-to-human-health Related to this article