Descriptive Study of Gut Microbiota in Infected and Colonized Subjects by Clostridiodes difficile.

Pedro Sánchez-Pellicer,Vicente Navarro-López,Laura Navarro-Moratalla,Eva Núñez-Delegido,Juan Agüera-Santos,Beatriz Ruzafa-Costas,Ruth González-Tamayo,Coral Llopis-Ruiz

doi:10.3390/microorganisms9081727

Abstract

Clostridiodes difficile can lead to a range of situations from the absence of symptoms (colonization) to severe diarrhea (infection). Disruption of gut microbiota provides an ideal environment for infection to occur. Comparison of gut microbiota of infected and colonized subjects could provide relevant information on susceptible groups or protectors to the development of infection, since the presence of certain genera could be related to the inhibition of transition from a state of colonization to infection. Through high-throughput sequencing of 16S rDNA gene, we performed alpha and beta diversity and composition studies on 15 infected patients (Group CDI), 15 colonized subjects (Group P), and 15 healthy controls (Group CTLR). A loss of alpha diversity and richness and a different structure have been evidenced in the CDI and P groups with respect to the CTRL group, but without significant differences between the first two. In CDI and P groups, there was a strong decrease in phylum Firmicutes and an expansion of potential pathogens. Likewise, there was a loss of inhibitory genus of C. difficile germination in infected patients that were partially conserved in colonized subjects. Therefore, infected and colonized subjects presented a gut microbiota that was completely different from that of healthy controls, although similar to each other. It is in composition where we found that colonized subjects, especially in minority genera, presented differences with respect to those infected.

Highlights

Clostridioides difficile is a Gram-positive bacillus that is strictly anaerobic and sporeforming [1]
A case of C. difficile infection (CDI) was defined as one that presented diarrhea (3 stools or more cataloged from type 5 on the Bristol scale in the last 24 h), clinical diagnosis of pseudomembranous colitis, or toxic megacolon where the presence of toxigenic C. difficile was evidenced by the following laboratory tests [15]: Detection of C. difficile TcdA and/or TcdB toxins and/or glutamate dehydrogenase (GDH) in feces by immunochromatography (C. difficile GDH-toxins A-B MonlabTests, Monlab, Barcelona, Spain)
Samples from a group of healthy controls formed a distinct cluster from the samples from infected and colonized subjects

Summary

Introduction

Clostridioides difficile is a Gram-positive bacillus that is strictly anaerobic and sporeforming [1]. It is one of the main causes of nosocomial diarrhea in hospitalized patients. Intestinal colonization of C. difficile can lead to a range of situations such as an absence of symptoms (colonized subjects) to severe diarrhea or fulminating pseudomembranous colitis (infected subjects) [5,6]. C. difficile infection (CDI) is an especially important problem in terms of mortality, morbidity, and associated costs. Apart from an increase in mortality and morbidity generated by the CDI, existence of many cases from the community has begun to be described [7]

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