Premium
Characterizing mucus‐based biofilms in human Clostridium difficile infection
Author(s) -
Engevik Melinda A.,
Danhof Heather A.,
Auchtung Jennifer,
Endres Bradley T.,
Bassères Eugénie T.,
Garey Kevin T.,
Britton Robert A.,
Versalovic James
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.04534
Subject(s) - microbiology and biotechnology , fusobacterium nucleatum , clostridium difficile , biofilm , mucus , biology , fusobacterium , mucin , antibiotics , bacteria , bacteroides , porphyromonas gingivalis , ecology , biochemistry , genetics
Background Clostridium difficile infection (CDI) is a major nosocomial disease associated with antibiotic use throughout the globe. Limited therapies are available for the treatment of CDI. As a result, understanding the mechanisms of CDI and developing novel therapeutics is a high priority. C. difficile has been observed in the MUC2 mucus layer of mice and patients, indicating that C. difficile may establish a mucus‐related niche and interact with members of the mucus‐associated microbiome. We hypothesized that certain mucus‐associated microbes would promote C. difficile colonization and biofilm formation. Methods & Results To address this hypothesis, we utilized a human centered approach. We found that C. difficile adhered to O‐glycan structures on human MUC2 using mucin‐producing cells lines and human colonoid monolayers. To identify other microbes residing with C. difficile in the mucus layer during infection, we seeded bioreactors with healthy human stool, added antibiotics and C. diffiicle to mirror patient infection. We then inserted human MUC2‐coated coverslips and examined the community structure. 16S rRNA sequencing revealed a unique biofilm profile with substantial co‐colonization with Fusobacterium . Chemotaxis assays revealed that motile C. diffiicle was chemoattracted to Fusobacterium nucleatum subspecies nucleatum , polymorphum , and animalis . We also observed that C. difficile co‐aggregated with all F. nucleatum subspecies ; an effect that was mediated by the F. nucleatum adhesin RadD. Moreover, addition of F. nucleatum enhanced C. difficile biofilm formation as denoted by ruby red biofilm staining, crystal violet and SEM. These biofilms were more resistant to standard dispersion methods and the antibiotic vancomycin. Consistent with our biofilm findings, RNAseq data revealed significant changes in C. difficile surface adhesion and antimicrobial resistance genes following exposure to F. nucleatum metabolites. Finally, publicly available datasets and patient stool samples revealed that a subset of patients with C. difficile infection exhibited high levels of Fusobacterium OTUs. C. difficile and F. nucleatum were found to co‐localize by FISH in CDI positive adult stool and pediatric IBD stool, as well as in the mucus layer of CDI patients in surgical resections. Conclusions Together, these data demonstrate the unique role of mucus‐associated bacteria such as F. nucleatum in enhancing C. difficile mucus‐associated biofilms.Clostridium difficile adheres to human intestinal MUC2 (left) and aggregates with another mucus‐associated microbe Fusobacterium nucleatum in a RadD dependent manner (right).