Gut microbiota in immunocompromised patients: reappraisal of pathogenesis of bloodstream infections
Currently understanding of pathogenesis of infections in immunosuppressed patients with hematological diseases was based on exogenous infections. In this clinical research paper we show the microbiome-associated factors leading to bloodstream infections in immunosuppressed patients.Aim. The aim of this large study was to evaluate the characteristics of gut microbiome leading to bloodstream infections in immunosuppressed patients.Materials and methods. 765 recipients of allogeneic hematopoietic stem cells were included in the study during period of 2012-2018. PCR-amplification of V4-V5 region of 16S rRNA was performed using modified universal bacterial primers, using 5988 stool samples collected. Primary outcome was estimated as an episode of bloodstream infection. Statistical analysis was performed using R programming language with methods of linear discriminant analysis of effect size, time-dependent regression analysis.Results. Proteobacteria phylum gut domination over 30% is an independent predictor of subsequent gram-negative bloodstream infections, with most of effect based on E. coli, Klebsiella spp., and this effect observed on various taxonomic levels. The increase in relative abundance of Proteobacteria in gut leading to bloodstream infections has changed the understanding of pathogenesis of infections in immunosuppressed hosts, what may be used for future preventive and therapeutic measures.