High-throughput sequencing of microbial diversity in implant-associated infection

• Metagenomic results indicated that the microbial diversity in different patients and sites are obviously different.
• The microbial diversity in positive patients were predominant by specific bacteria, while is well distributed in negative patients.
• The reduced number of bacterial species and the overgrowth of some specific pathogens in positive patients maybe the cause of the implant-associated infection.

Few molecular studies have shown that the number of bacterial species in implant-associated infection may have been underestimated. To determine the actual microbial diversity in implant-associated infection, a high-throughput sequencing method was adopted to sequence the DNAs extracted from the tissues of infected and uninfected patients. Principal component analysis (PCA) and β diversity showed an obvious divergence of infected and uninfected groups, and that the overgrowth of Proteobacteria (80.87%), Firmicutes (13.41%) in the positive deep infection group (P.d, via biopsy) and Proteobacteria (91.68%) in the positive surface infection group (P.s, via swabs) might be the causative factors in implant-associated infection. Moreover, Venn results indicated that a mean of 330 common operational taxonomic units (OTUs) was obtained in all groups, of which 113, 109, 45, 20, 13 and 12 OTUs belonging to Proteobacteria, Actinobacteria, Acidobacteria, Planctomycetes, Gemmatimonadetes and Chloroflexi were identified. In conclusion, many traditional “pathogenic bacteria” were identified as the common bacteria in operation sites, and the disruption of their complex interaction caused infection; therefore, further work is need to illustrate the aetiology of implant-associated infection using in-depth systems-level analyses.