Chronic obstructive pulmonary disease (COPD) appears to be a reservoir of antimicrobial resistance genes (ARGs), a study led by the University of Leicester suggests.
The study used quantitative PCR targeting 279 specific ARGs to profile the resistomes in sputum from subjects with COPD at stable, exacerbation and recovery visits (n=55; COPD-BEAT study), healthy controls with (n=7) or without (n=22) exposure to antibiotics in the preceding 12 months (EXCEED study) and in bronchial brush samples from COPD (n=8) and healthy controls (n=7) (EvA study).
The analysis found ARG mean (SEM) prevalence was greater in stable COPD samples (35.2 [1.6]) than in healthy controls (27.6 [1.7]; P=.004) and correlated with total bacterial abundance (r2=0.23; P<.001).
The prevalence of ARG positive signals in individuals was not related to COPD symptoms, lung function or changes at exacerbation.
In the COPD subgroups designated high γ-Proteobacteria and high Firmicutes, ARG prevalence was not different at stable state but significantly declined from stable through exacerbation to recovery in the former (P=.011), without changes in total bacterial abundance.
The ARG patterns were similar in COPD versus health, COPD microbiome subgroups and between sputum and bronchoscopic samples, independent of antibiotic exposure in the last 12 months.
The authors concluded that ARGs are highly prevalent in sputum, broadly in proportion to bacterial abundance in both healthy and COPD subjects. COPD appears to be an ARG reservoir due to high levels of bacterial colonisation, they said.
