Characterization of Pseudomonas aeruginosa from subjects with diffuse panbronchiolitis.

UNLABELLED: Diffuse panbronchiolitis (DPB) is a rare, idiopathic inflammatory disease primarily diagnosed in East Asian populations. DPB is characterized by diffuse pulmonary lesions, inflammation of the respiratory bronchioles, and bacterial infections of the airway. Historically, sputum cultures reveal Pseudomonas aeruginosa in 22% of DPB patients, increasing to 60% after 4 years from disease onset. Although DPB patients have a known susceptibility to respiratory P. aeruginosa infections, as is observed in other chronic lung diseases such as cystic fibrosis (CF), the characterization of DPB P. aeruginosa strains is limited. In this study, we characterized 24 strains obtained from a cohort of DPB patients for traits previously associated with virulence, including growth, motility, antibiotic susceptibility, lipopolysaccharide structure, and genomic diversity. Our cohort of DPB P. aeruginosa strains exhibits considerable genomic variability when compared with isolates from people with cystic fibrosis chronically colonized with P. aeruginosa and acute P. aeruginosa infection isolates. Similar to CF, DPB P. aeruginosa strains produce a diverse array of modified lipid A structures. Antibiotic susceptibility testing revealed increased resistance to erythromycin, a representative agent of the macrolide antibiotics used to manage DPB patients. Differences in the O-antigen type among P. aeruginosa strains collected from these different backgrounds were also observed. Ultimately, the characterization of DPB P. aeruginosa strains highlights several unique qualities of P. aeruginosa strains collected from chronically diseased airways, underscoring the challenges in treating DPB, CF, and other obstructive respiratory disease patients with P. aeruginosa infections.

IMPORTANCE: Diffuse panbronchiolitis (DPB), a chronic lung disease characterized by persistent P. aeruginosa infection, serves as an informative comparator to more common chronic lung diseases, such as cystic fibrosis (CF). This study aimed to better address the interplay between P. aeruginosa and chronically compromised airway environments through the examination of DPB P. aeruginosa strains, as existing literature regarding DPB is limited to case reports, case series, and clinical treatment guidelines. The evaluation of these features in the context of DPB, in tandem with prevailing knowledge of P. aeruginosa strains collected from more common chronic lung diseases (e.g., CF), can aid in the development of more effective strategies to combat respiratory P. aeruginosa infections in patients with chronic lung diseases.