The effect of oral bacterial lysates on the respiratory microbiome in patients with chronic obstructive pulmonary disease exacerbations – A pilot study

Background

Increasing evidence suggests that the airway microbiome plays an important role in chronic obstructive pulmonary disease (COPD). While oral bacterial lysates were found to reduce the number of acute exacerbations of COPD (AECOPD), little is known regarding the effects of bacterial lysates on COPD airway microbiome.

Methods

Sixteen patients with AECOPD were enrolled in this pilot, prospective study from November 2020 to June 2021. Patients were randomly divided into two groups to receive conventional treatment (n ​= ​8) or conventional treatment combined with bacterial lysates (n ​= ​8), respectively. Sputum samples were collected upon hospital admission and at discharge. Patients were followed-up over 6 months after discharge.

Results

The α-diversity was not significantly different pre- and post-treatment between the two treatment groups. There was a significantly greater weighted UniFrac distance between the paired pre- and post-treatment samples for patients receiving bacterial lysates compared to those receiving conventional treatment (P ​= ​0.021). Among all taxa, a significantly decrease of Pseudomonadaceae was observed for patients receiving bacterial lysates group, while this trend was non-significant for the conventional treatment group. The frequency of acute exacerbations during the 6-month follow-up period was significantly lower for patients receiving bacterial lysates compared to those receiving conventional treatment (P ​= ​0.042).

Conclusions

Bacterial lysates resulted in greater alteration of the airway microbiota compared to conventional treatment. Pseudomonadaceae was significantly decreased in sputum samples of patients receiving bacterial lysate, which may be a microbiome-related mechanism by which bacterial lysates reduce COPD exacerbations.