Deciphering microbiome and fungi-bacteria interactions in chronic wound infections using metagenomic sequencing.

Purpose: Chronic wounds caused by infections impose a considerable global healthcare burden. The microbial features of these infections and possible correlations between bacteria and fungi may influence wound healing. However, metagenomic next-generation sequencing (mNGS) analyses of these features remain sparse. Therefore, we performed mNGS on chronic wound infection samples to investigate features and correlations between the bacteriome and mycobiome in 66 patients (28: chronic wounds; 38: non-chronic wounds).

Methods: Microbial community characteristics in patients with wound infections, microbiome-systemic inflammation associations, and bacteria-fungi correlations were analyzed.

Results: Infections constituted the primary cause of wounds in this study. Nontuberculous mycobacteria (23%) and Mycobacterium tuberculosis (13%) were the most common pathogens associated with chronic wounds, whereas Staphylococcus aureus (15%) was the most prevalent in non-chronic wound infections. Patients with chronic wound infections had a higher abundance of Pseudomonas aeruginosa than those without chronic wounds. Microbes with a high relative abundance in chronic wound infections were less significantly associated with plasma inflammatory factors than those in non-chronic wound infections. Additionally, a positive correlation between Candida glabrata and P. aeruginosa and an association between Malassezia restricta and anaerobic species were detected in patients with chronic wound infections.

Conclusion: Our results further support the hypothesis that P. aeruginosa is a microbial biomarker of chronic wound infection regardless of the causative pathogens. Moreover, we propose a positive correlation between C. glabrata and P. aeruginosa in chronic wound infections, which advances the current understanding of fungi-bacteria correlations in patients with chronic wound infections.