Binary Toxin Expression by <i>Clostridioides difficile</i> Is Associated With Worse Disease

Young, Mary K.; Leslie, Jhansi L.; Madden, Gregory R; Lyerly, David M.; Carman, Robert J.; Lyerly, Matthew W.; Stewart, David B.; Abhyankar, Mayuresh M.; Petri, William A.

doi:10.1093/ofid/ofac001

Cited by 23 publications

(14 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of a binary toxin locus has been associated with epidemic strains and hypervirulence of C. difficile . 44,45 CDT belongs to the family of ADP-ribosylating toxins that consist of two components: CDTa ( cdtA ), the enzymatic active ADP-ribosyltransferase which modifies cellular actin, and CDTb ( cdtB ), the binding component facilitates CDTa translocation. However, despite knowing their enzymatic activities, experimental evidence is very limited to support critical roles of CDT in C. difficile virulence.…”

Section: Discussionmentioning

confidence: 99%

Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027)Clostridioides difficile

Dong

Lin

Allen

et al. 2023

Preprint

View full text Add to dashboard Cite

Clostridioides difficile (C. difficile), a leading cause of nosocomial infection, produces toxins that damage the colonic epithelium and results in colitis that varies from mild to fulminant. Variation in disease severity is poorly understood and has been attributed to host factors (age, immune competence and intestinal microbiome composition) and/or virulence differences between C. difficile strains, with some, such as the epidemic BI/NAP1/027 (MLST1) strain, being associated with greater virulence. We tested 23 MLST1(ST1) C. difficile clinical isolates for virulence in antibiotic-treated C57BL/6 mice. All isolates encoded a complete Tcd pathogenicity locus and achieved similar colonization densities in mice. Disease severity varied, however, with 5 isolates causing lethal infections, 16 isolates causing a range of moderate infections and 2 isolates resulting in no detectable disease. The avirulent ST1 isolates did not cause disease in highly susceptible Myd88-/- or germ-free mice. Genomic analysis of the avirulent isolates revealed a 69 base-pair deletion in the N-terminus of the cdtR gene, which encodes a response regulator for binary toxin (CDT) expression. Genetic deletion of the 69 base-pair cdtR sequence in the highly virulent ST1 R20291 C. difficile strain rendered it avirulent and reduced toxin gene transcription in cecal contents. Our study demonstrates that a natural deletion within cdtR attenuates virulence in the epidemic ST1 C. difficile strain without reducing colonization and persistence in the gut. Distinguishing strains on the basis of cdtR may enhance the specificity of diagnostic tests for C. difficile colitis.

show abstract

Section: Discussionmentioning

confidence: 99%

Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027)Clostridioides difficile

Dong

Lin

Allen

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…In this study, we developed and used a strain of C difficile expressing CDTb but not CDTa to further investigate the role of CDTb during infection, and we found that expression of CDTb alone is sufficient to enhance virulence. Previous work has shown that CDT holotoxin expression has been associated with increased mortality in both humans [ 10 ] and mice [ 11 ]. In addition, although not common, clinical strains of C difficile that are negative for the primary clostridial toxins TcdA and TcdB but positive for CDT have been isolated from symptomatic patients [ 21 ], further supporting that the binary toxin CDT plays a significant role in the pathogenesis of CDI.…”

Section: Discussionmentioning

confidence: 99%

“…Similarly, it is possible that the epithelial damage induced by CDTb promotes the translocation of microbes across the gut barrier, leading to bloodstream infections such as candidemia [ 24 , 25 ]. This may be another potential reason behind the increased clinical severity seen in hypervirulent strains [ 10 ], further emphasizing the need to study the effects of CDTb during infection.…”

Section: Discussionmentioning

confidence: 99%

“…Clostridioides difficile transferase also induces the formation of microtubule protrusions at the apical surface, which are thought to aid in bacterial adherence to host epithelial cells [ 9 ]. Previous work from our group demonstrated that CDT expression is associated with increased mortality in patients [ 10 ] and can enhance virulence in a mouse model of CDI through suppression of protective eosinophilic responses [ 11 ]. In addition, it has been shown that CDTb alone is sufficient to induce cytotoxicity in vitro [ 12 , 13 ], although it remains unknown whether this contributes to disease pathogenesis in vivo.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Clostridioides difficileBinary Toxin Binding Component Increases Virulence in a Hamster Model

Simpson

Bilverstone

Leslie

et al. 2023

Open Forum Infectious Diseases

View full text Add to dashboard Cite

Background Clostridioides difficile is the leading cause of hospital-acquired gastrointestinal infection, in part due to the existence of binary toxin (CDT)-expressing hypervirulent strains. While the effects of the CDT holotoxin on disease pathogenesis have been previously studied, we sought to investigate the role of the individual components of CDT during in vivo infection. Methods To determine the contribution of the separate components of CDT during infection, we developed strains of C. difficile expressing either CDTa or CDTb individually. We then infected both mice and hamsters with these novel mutant strains and monitored them for development of severe illness. Results While expression of CDTb without CDTa did not induce significant disease in a mouse model of C. difficile infection, we found that complementation of a CDT-deficient C. difficile strain with CDTb alone restored virulence in a hamster model of C. difficile infection. Conclusions Overall, this study demonstrates that the binding component of C. difficile binary toxin, CDTb, contributes to virulence in a hamster model of infection.

show abstract

“…The presence of this CDT toxin is associated with increased lethality, indicating additive pathomechanisms. Thus, the presence of the binary toxin increases the risk for severe disease progression, complications, recurrence of infection, and mortality [ 4 , 5 ]. The underlying mechanisms of hypervirulence remain unclear.…”

Section: Introductionmentioning

confidence: 99%

CDT of Clostridioides difficile Induces MLC-Dependent Intestinal Barrier Dysfunction in HT-29/B6 Epithelial Cell Monolayers

Heils

Schneemann

Gerhard

et al. 2023

Toxins

View full text Add to dashboard Cite

Background: Clostridioides difficile binary toxin (CDT) defines the hypervirulence of strains in nosocomial antibiotic-induced colitis with the highest mortality. The objective of our study was to investigate the impact of CDT on the intestinal epithelial barrier and to enlighten the underlying molecular mechanisms. Methods: Functional measurements of epithelial barrier function by macromolecular permeability and electrophysiology were performed in human intestinal HT-29/B6 cell monolayers. Molecular analysis of the spatial distribution of tight junction protein and cytoskeleton was performed by super-resolution STED microscopy. Results: Sublethal concentrations of CDT-induced barrier dysfunction with decreased TER and increased permeability for 332 Da fluorescein and 4 kDa FITC-dextran. The molecular correlate to the functional barrier defect by CDT was found to be a tight junction protein subcellular redistribution with tricellulin, occludin, and claudin-4 off the tight junction domain. This redistribution was shown to be MLCK-dependent. Conclusions: CDT compromised epithelial barrier function in a human intestinal colonic cell model, even in sublethal concentrations, pointing to barrier dysfunction in the intestine and leak flux induction as a diarrheal mechanism. However, this cannot be attributed to the appearance of apoptosis and necrosis, but rather to an opening of the paracellular leak pathway as the result of epithelial tight junction alterations.

show abstract

Binary Toxin Expression by Clostridioides difficile Is Associated With Worse Disease

Cited by 23 publications

References 24 publications

Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027)Clostridioides difficile

Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027)Clostridioides difficile

Clostridioides difficileBinary Toxin Binding Component Increases Virulence in a Hamster Model

CDT of Clostridioides difficile Induces MLC-Dependent Intestinal Barrier Dysfunction in HT-29/B6 Epithelial Cell Monolayers

Contact Info

Product

Resources

About