New treatment approaches for Clostridioides difficile infections: alternatives to antibiotics and fecal microbiota transplantation

Figures & data

Figure 1. Schematic representation of four different groups of strategies for the treatment of C. difficile infections. Antibiotics, fecal microbiota transplantation (FMT), probiotics, and defined mixtures are discussed briefly in this review. The image was created with BioRender.

Figure 2. Selected TcdA and TcdB toxin-neutralizing antibodies and antibody alternatives. a. and b. Schematic representation and structural models of TcdA (merged from PDB IDs: 7POG and 2QJ6) and TcdB toxins (PDB ID: 6OQ5) with labeled binding sites of monoclonal antibodies actoxumab, bezlotoxumab, and PA41, the DLD-4 DARPin dimer, and small molecule compound ebselen. Toxin structures were visualized using ViewerLite 4.2 (Accelrys). GTD – glucosyltransferase domain, APD – autoprotease domain, DD – delivery domain, CROPS – combined repetitive oligopeptide sequences (receptor-binding domain). c. Schematic structures of various tandem V_HH constructs (nanobodies). Individual nanobodies bind to distinct epitopes on the TcdA (light gray) or TcdB (dark gray) domains. Trx – thioredoxin, ABP – albumin-binding peptide.

Table 1. Antibodies and antibody alternatives for neutralization of C. difficile toxins.

Agent	Target	Stage of development	Delivery route	Reference
Bezlotoxumab	TcdB	Approved	intravenous (infusion)	^Citation48–50
Actoxumab	TcdA	Phase III, discontinued	intravenous (infusion)	^Citation50,Citation51
PA41 (monoclonal antibody)	TcdB	Preclinical (cell model)	/	^Citation52
Three-monoclonal-antibody cocktail	TcdA and TcdB	Preclinical (mice, hamsters)	intraperitoneal (injection)	^Citation53,Citation54
Horse antiserum	C. difficile spores and TcdA/TcdB toxoids	Preclinical (mice)	intravenous (injection)	^Citation55
OraCAb (polyclonal anti-TcdA/TcdB ovine antibody formulation containing antacids and protease inhibitors)	TcdA and TcdB	Preclinical (hamsters)	oral	^Citation56
WPC-40 (hyperimmune whey protein concentrate from cow)	C. difficile cells and toxins	Uncontrolled human clinical trial	oral	^Citation57,Citation58
TcdB-specific bovine colostrum	TcdB	Preclinical (mice)	oral	^Citation59
Hyperimmune bovine whey protein concentrate	TcdA and TcdB	Preclinical (mice, hamsters)	oral	^Citation60,Citation61
Nanobodies and nanobody fusions	TcdA and TcdB	Preclinical (mice, hamsters, piglets)	oral (via engineered Lactobacillus paracasei); oral (via engineered Saccharomyces boulardii; intravenous (via adenoviral vector); intraperitoneal or intramuscular (injection)	^Citation62–67
DARPins and DARPin fusions	TcdA and TcdB	Preclinical (mice)	oral (gastrointestinal stability only)	^Citation68–70

Table 2. Antibacterial peptides against C. difficile toxins.

Agent	Target	Stage of development	Delivery route	Reference
α-defensin-1	TcdA, TcdB and CDTb	Preclinical (mice)	injection in isolated ileal loops	^Citation89
α-defensin-5	TcdA, TcdB and CDT	Preclinical (in vitro assay)	/	^Citation46
Periplanetasin-2	TcdA	Preclinical (mice)	injection in isolated ileal loops	^Citation90
Periplanetasin-4	TcdA	Preclinical (mice)	injection in isolated ileal loops	^Citation91
Cathelicidin LL-37	TcdA	Preclinical (mice)	injection in isolated ileal loops; intracolonic administration	^Citation92

Table 3. Agents for the neutralization of antibiotics in the colon lumen.

Agent	Target	Stage of development	Reference
Enteric-coated formulated activated-charcoal based DAV132	Antibiotics in the colon (e.g. fluoroquinolones)	Phase III	^Citation97–99
Ribaxamase (β-lactamase; formulated as oral capsules containing enteric-coated pellets)	β-lactam antibiotics	Phase IIb	^Citation100,Citation101
β-lactamase-secreting Lactococcus lactis	β-lactam antibiotics	Preclinical (mice)	^Citation102

Table 4. Phage-based therapies with the ability to cause lysis of C. difficile..

Agent	Target	Stage of development	Benefits	Limitations	Reference
ΦCD140	C. difficile	Preclinical (hamsters)	Specific lytic activity	Occurrence of phage-resistant clones	^Citation105
ΦCD27	C. difficile NCTC11204 ribotype 001	Preclinical (multi-vessel gut model)	Strong lytic activity; reduction of toxin production	Occurrence of phage-resistant clones	^Citation107
Four phage cocktail CDHM1, 2, 5, and 6	Collection of 80 C. difficile strains	Preclinical (in vitro assay, hamsters, wax moth larvae)	Reduced risk of the emergence of resistance; more effective in preventing biofilm formation; no negative effect on commensals; increase in specific commensals	Occurrence of resistance to multiple phages from the cocktail	^Citation108,Citation109
Broad host phage ΦCD1801	Collection of 15 strains of C. difficile ribotype 078	Preclinical (in vitro assay)	Expanded lysis spectrum; reduced risk of the emergence of resistance	Less specific	^Citation110
Engineered phage with redirected CRISPR-Cas3	C. difficile	Preclinical (mice)	Improved lysogenic activity; eligible for intellectual property protection	Occurrence and regrowth of phage-resistant clones	^Citation111
Phage tail-like particles	Collection of 16 strains of C. difficile ribotype 027 and 40 other bacterial isolates from 23 different ribotypes	Preclinical (in vitro assay)	Absence of viral genetic material or antibiotic resistance genes; killing is highly specific and efficient	Optimization of pharmacokinetic properties of oral formulation is needed	^Citation112,Citation113
PlyCD1–174	Collection of C. difficile, including ribotypes 087, 001 and 017	Preclinical (mice)	Broader lysis spectrum; no risk of resistance; no negative effect on commensals	Intrarectal delivery	^Citation114
Endolysins seq_1, seq_5 and seq_10	Collection of C. difficile	Preclinical (mice)	Protection from CDI	Intrarectal delivery	^Citation115
CD27L	Collection of 30 strains of C. difficile, including strain 027	Preclinical (in vitro assay)	Broader lysis spectrum; no risk of resistance; no negative effect on commensals; wide pH range stability	Challenging oral delivery, potential short term increase in symptoms due to toxin release	^Citation116
ΦC2 lysin-human defensin HD5 fusion protein	Collection of C. difficile strains, including 027, 078, 012 and 087	Preclinical (mice)	Broader lysis spectrum; concomitant lysis and TcdB neutralization	Challenging oral delivery	^Citation117

Figure 3. Phage-based therapies against C. difficile infections. a. Conventional phage therapy: phages specifically dock to bacterial surface receptors (not shown) via tail fibers and inject their genomic DNA into host bacteria. Progeny phages are released upon bacterial wall disruption by phage-encoded endolysins which gain access to peptidoglycan through holin pores. b. Phages can be exploited as vehicles to deliver guide RNA (gRNA) which combines with the endogenous Cas nuclease of C. difficile to catalyze cleavage of the bacterial chromosome. c. Tailocins (phage tail-like particles) have no capsid head and therefore no phage genetic material. Nevertheless, they still selectively attach to bacterial surface receptors and puncture the cell, thereby disrupting the membrane potential. d. Recombinant phage endolysins degrade the peptidoglycan wall from the outside. The image was created with BioRender.

Table 5. Cytokines and anti-cytokine antibodies that facilitate clearance of C. difficile by modulating the immune system.

Agent	Target	Stage of development	Reference
IL-27	IL-27 receptor	Preclinical (mice)	^Citation139
Anti-IL-22 and anti-CD160 antibodies	IL-22, CD160	Preclinical (mice)	^Citation140
IL-33	IL-33 receptor	Preclinical (mice)	^Citation141
Anti MIP-1α antibody	MIP-1α	Preclinical (mice)	^Citation142
Anti IL-23 antibody	IL-23	Preclinical (mice)	^Citation143

Table 6. Small-molecule agents against C. difficile that prevent the activity of C. difficile toxins, activate the immune system, affect bile acid synthesis, or exert their effects via other mechanisms.

Agent	Target	Stage of development	Reference
VB-82252	Inhibition of UDP-glucose hydrolytic activity of TcdA and TcdB	Preclinical (mice)	^Citation149
Ebselen	Inhibition of toxin cysteine protease domain	Preclinical (mice)	^Citation150
Inositol hexakisphosphate	Toxin TcdB auto-proteolysis induction	Preclinical (mice)	^Citation151
Niclosamide	Increase of pH of endosomes, prevention of toxin entry	Preclinical (mice)	^Citation152
Indole-3-carbinol	Activation of aryl hydrocarbon receptor	Preclinical (mice)	^Citation153
SR1001	Inhibition of (ROR)γt	Preclinical (mice)	^Citation154
Amoxapine, doxapram, trifluoperazine	Induction of chemokines, IL-33 and IL-22	Preclinical (mice)	^Citation155
MRS2578	Inhibition of P2Y6 receptor	Preclinical (mice)	^Citation156
CamSA	Inhibition of spore germination	Preclinical (mice, hamsters)	^Citation157–159
Obeticholic acid	Inhibition of bile acid synthesis	Preclinical (mice)	^Citation160
Auranofin	Inhibition of thioredoxin reductase	Preclinical (mice)	^Citation161,Citation162
Misoprostol	PGE1 analog	Preclinical (mice)	^Citation163
5FDQD	Riboflavin analog, riboswitch activation	Preclinical (mice)	^Citation164

Wilcox MH, Gerding DN, Poxton IR, Kelly C, Nathan R, Birch T, Cornely OA, Rahav G, Bouza E, Lee C. et al. Bezlotoxumab for Prevention of Recurrent Clostridium difficile Infection. N Engl J Med. 2017;376(4):305–317. doi:10.1056/NEJMoa1602615.

 PubMed Web of Science ®Google Scholar

Hernandez LD, Kroh HK, Hsieh E, Yang X, Beaumont M, Sheth PR, DiNunzio E, Rutherford SA, Ohi MD, Ermakov G. et al. Epitopes and mechanism of action of the Clostridium difficile Toxin A-Neutralizing antibody Actoxumab. J Mol Biol. 2017;429(7):1030–1044. doi:10.1016/j.jmb.2017.02.010.

 PubMed Web of Science ®Google Scholar

Kroh HK, Chandrasekaran R, Zhang Z, Rosenthal K, Woods R, Jin X, Nyborg AC, Rainey GJ, Warrener P, Melnyk RA. et al. A neutralizing antibody that blocks delivery of the enzymatic cargo of Clostridium difficile toxin TcdB into host cells. J Biol Chem. 2018;293(3):941–952. doi:10.1074/jbc.M117.813428.

 PubMed Web of Science ®Google Scholar

Davies NL, Compson JE, Mackenzie B, O’Dowd VL, Oxbrow AK, Heads JT, Turner A, Sarkar K, Dugdale SL, Jairaj M. et al. A mixture of functionally oligoclonal humanized monoclonal antibodies that neutralize Clostridium difficile TcdA and TcdB with high levels of in vitro potency shows in vivo protection in a hamster infection model. Clin Vaccine Immunol. 2013;20(3):377–390. doi:10.1128/CVI.00625-12.

 PubMedGoogle Scholar

Qiu H, Cassan R, Johnstone D, Han X, Joyee AG, McQuoid M, Masi A, Merluza J, Hrehorak B, Reid R. et al. Novel Clostridium difficile Anti-Toxin (TcdA and TcdB) humanized monoclonal antibodies demonstrate in vitro neutralization across a broad spectrum of clinical strains and in vivo potency in a Hamster Spore Challenge Model. PLOS ONE. 2016;11(6):e0157970. doi:10.1371/journal.pone.0157970.

 PubMed Web of Science ®Google Scholar

Yan W, Shin KS, Wang SJ, Xiang H, Divers T, McDonough S, Bowman J, Rowlands A, Akey B, Mohamed H. et al. Equine hyperimmune serum protects mice against Clostridium difficile spore challenge. J Vet Sci. 2014;15(2):249–258. doi:10.4142/jvs.2014.15.2.249.

 PubMed Web of Science ®Google Scholar

Roberts AK, Harris HC, Smith M, Giles J, Polak O, Buckley AM, Clark E, Ewin D, Moura IB, Spitall W. et al. A Novel, Orally Delivered Antibody Therapy and Its Potential to Prevent Clostridioides difficile Infection in Pre-clinical Models. Front Microbiol. 2020;11:578903. doi:10.3389/fmicb.2020.578903.

 PubMed Web of Science ®Google Scholar

van Dissel JT, de Groot N, Hensgens CM, Numan S, Kuijper EJ, Veldkamp P, van ’t Wout J. Bovine antibody-enriched whey to aid in the prevention of a relapse of Clostridium difficile-associated diarrhoea: preclinical and preliminary clinical data. J Med Microbiol. 2005;54(2):197–205. doi:10.1099/jmm.0.45773-0.

 PubMed Web of Science ®Google Scholar

Numan SC, Veldkamp P, Kuijper EJ, van den Berg RJ, van Dissel JT. Clostridium difficile-associated diarrhoea: bovine anti-Clostridium difficile whey protein to help aid the prevention of relapses. Gut. 2007;56(6):888–889. doi:10.1136/gut.2006.119016.

 PubMed Web of Science ®Google Scholar

Hutton ML, Cunningham BA, Mackin KE, Lyon SA, James ML, Rood JI, Lyras D. Bovine antibodies targeting primary and recurrent Clostridium difficile disease are a potent antibiotic alternative. Sci Rep. 2017;7(1):3665. doi:10.1038/s41598-017-03982-5.

 PubMed Web of Science ®Google Scholar

Heidebrecht HJ, Weiss WJ, Pulse M, Lange A, Gisch K, Kliem H, Mann S, Pfaffl MW, Kulozik U, von Eichel-Streiber C. et al. Treatment and prevention of recurrent clostridium difficile infection with functionalized bovine antibody-enriched whey in a Hamster Primary Infection Model. Toxins. 2019;11(2):11. doi:10.3390/toxins11020098.

 PubMed Web of Science ®Google Scholar

Heidebrecht HJ, Lagkouvardos I, Reitmeier S, Hengst C, Kulozik U, Pfaffl MW. Alteration of intestinal microbiome of Clostridioides difficile-Infected Hamsters during the Treatment with Specific Cow Antibodies. Antibiotics. 2021;10(6):10. doi:10.3390/antibiotics10060724.

 Google Scholar

Fischer S, Uckert AK, Landenberger M, Papatheodorou P, Hoffmann-Richter C, Mittler AK, Ziener U, Hägele M, Schwan C, Müller M. et al. Human peptide α-defensin-1 interferes with Clostridioides difficile toxins TcdA, TcdB, and CDT. FASEB J. 2020;34(5):6244–6261. doi:10.1096/fj.201902816R.

 PubMed Web of Science ®Google Scholar

Korbmacher M, Fischer S, Landenberger M, Papatheodorou P, Aktories K, Barth H. Human alpha-Defensin-5 Efficiently Neutralizes Clostridioides difficile Toxins TcdA, TcdB, and CDT. Front Pharmacol. 2020;11:1204. doi:10.3389/fphar.2020.01204.

 PubMed Web of Science ®Google Scholar

Hong J, Zhang P, Yoon IN, Hwang JS, Kang JK, Kim H. The American Cockroach Peptide Periplanetasin-2 Blocks Clostridium Difficile Toxin A-Induced Cell Damage and Inflammation in the Gut. J Microbiol Biotechnol. 2017;27(4):694–700. doi:10.4014/jmb.1612.12012.

 PubMed Web of Science ®Google Scholar

Yoon IN, Lu LF, Hong J, Zhang P, Kim DH, Kang JK, Hwang JS, Kim H. The American cockroach peptide periplanetasin-4 inhibits Clostridium difficile toxin A-induced cell toxicities and inflammatory responses in the mouse gut. J Pept Sci. 2017;23(11):833–839. doi:10.1002/psc.3046.

 PubMed Web of Science ®Google Scholar

Hing TC, Ho S, Shih DQ, Ichikawa R, Cheng M, Chen J, Chen X, Law I, Najarian R, Kelly CP. et al. The antimicrobial peptide cathelicidin modulates Clostridium difficile-associated colitis and toxin A-mediated enteritis in mice. Gut. 2013;62(9):1295–1305. doi:10.1136/gutjnl-2012-302180.

 PubMed Web of Science ®Google Scholar

Kokai-Kun JF, Roberts T, Coughlin O, Le CX, Whalen H, Stevenson R, Wacher VJ, Sliman J. Use of ribaxamase (SYN-004), a β-lactamase, to prevent Clostridium difficile infection in β-lactam-treated patients: a double-blind, phase 2b, randomised placebo-controlled trial. Lancet Infect Dis. 2019;19(5):487–496. doi:10.1016/S1473-3099(18)30731-X.

 PubMed Web of Science ®Google Scholar

Kokai-Kun JF, Le C, Trout K, Cope JL, Ajami NJ, Degar AJ, Connelly S. Ribaxamase, an Orally Administered β-Lactamase, Diminishes Changes to Acquired Antimicrobial Resistance of the Gut Resistome in Patients Treated with Ceftriaxone. Infect Drug Resist. 2020;13:2521–2535. doi:10.2147/IDR.S260258.

 PubMed Web of Science ®Google Scholar

Cubillos-Ruiz A, Alcantar MA, Donghia NM, Cardenas P, Avila-Pacheco J, Collins JJ. An engineered live biotherapeutic for the prevention of antibiotic-induced dysbiosis. Nat Biomed Eng. 2022;6(7):910–921. doi:10.1038/s41551-022-00871-9.

 PubMed Web of Science ®Google Scholar

Ramesh V, Fralick JA, Rolfe RD. Prevention of Clostridium difficile-induced ileocecitis with bacteriophage. Anaerobe. 1999;5(2):69–78. doi:10.1006/anae.1999.0192.

 Web of Science ®Google Scholar

Meader E, Mayer MJ, Steverding D, Carding SR, Narbad A. Evaluation of bacteriophage therapy to control Clostridium difficile and toxin production in an in vitro human colon model system. Anaerobe. 2013;22:25–30. doi:10.1016/j.anaerobe.2013.05.001.

 PubMed Web of Science ®Google Scholar

Nale JY, Spencer J, Hargreaves KR, Buckley AM, Trzepinski P, Douce GR, Clokie MRJ. Bacteriophage Combinations Significantly Reduce Clostridium difficile Growth in vitro and Proliferation in vivo. Antimicrob Agents Chemother. 2016;60(2):968–981. doi:10.1128/AAC.01774-15.

 PubMed Web of Science ®Google Scholar

Nale JY, Redgwell TA, Millard A, Clokie MRJ. Efficacy of an Optimised Bacteriophage Cocktail to Clear Clostridium difficile in a Batch Fermentation Model. Antibiotics. 2018;7(1):13. doi:10.3390/antibiotics7010013.

 Google Scholar

Whittle MJ, Bilverstone TW, van Esveld RJ, Lucke AC, Lister MM, Kuehne SA, Minton NP. A Novel Bacteriophage with Broad Host Range against Clostridioides difficile Ribotype 078 Supports SlpA as the Likely Phage Receptor. Microbiol Spectr. 2022;10(1):e0229521. doi:10.1128/spectrum.02295-21.

 PubMed Web of Science ®Google Scholar

Selle K, Fletcher JR, Tuson H, Schmitt DS, McMillan L, Vridhambal GS, Rivera AJ, Montgomery SA, Fortier L-C, Barrangou R. et al. In vivo Targeting of Clostridioides difficile Using Phage-Delivered CRISPR-Cas3 Antimicrobials. mBio. 2020;11(2):11. doi:10.1128/mBio.00019-20.

 Web of Science ®Google Scholar

Gebhart D, Williams SR, Bishop-Lilly KA, Govoni GR, Willner KM, Butani A, Sozhamannan S, Martin D, Fortier L-C, Scholl D. et al. Novel high-molecular-weight, R-type bacteriocins of Clostridium difficile. J Bacteriol. 2012;194(22):6240–6247. doi:10.1128/JB.01272-12.

 PubMed Web of Science ®Google Scholar

Gebhart D, Lok S, Clare S, Tomas M, Stares M, Scholl D, Donskey CJ, Lawley TD, Govoni GR. et al. A modified R-type bacteriocin specifically targeting Clostridium difficile prevents colonization of mice without affecting gut microbiota diversity. mBio. 2015;6(2):6. doi:10.1128/mBio.02368-14.

 Web of Science ®Google Scholar

Wang Q, Euler CW, Delaune A, Fischetti VA. Using a Novel Lysin to Help Control Clostridium difficile Infections. Antimicrob Agents Chemother. 2015;59(12):7447–7457. doi:10.1128/AAC.01357-15.

 PubMed Web of Science ®Google Scholar

Fujimoto K, Kimura Y, Shimohigoshi M, Satoh T, Sato S, Tremmel G, Uematsu M, Kawaguchi Y, Usui Y, Nakano Y. et al. Metagenome Data on Intestinal Phage-Bacteria Associations Aids the Development of Phage Therapy against Pathobionts. Cell Host & Microbe. 2020;28(3):380–389.e9. doi:10.1016/j.chom.2020.06.005.

 PubMed Web of Science ®Google Scholar

Mayer MJ, Narbad A, Gasson MJ. Molecular characterization of a Clostridium difficile bacteriophage and its cloned biologically active endolysin. J Bacteriol. 2008;190(20):6734–6740. doi:10.1128/JB.00686-08.

 PubMed Web of Science ®Google Scholar

Peng Z, Wang S, Gide M, Zhu D, Lamabadu Warnakulasuriya Patabendige HM, Li C, Cai J, Sun X. A Novel Bacteriophage Lysin-Human Defensin Fusion Protein Is Effective in Treatment of Clostridioides difficile Infection in Mice. Front Microbiol. 2018;9:3234. doi:10.3389/fmicb.2018.03234.

 PubMed Web of Science ®Google Scholar

Xu B, Wu X, Gong Y, Cao J. IL-27 induces LL-37/CRAMP expression from intestinal epithelial cells: implications for immunotherapy of Clostridioides difficile infection. Gut Microbes. 2021;13(1):1968258. doi:10.1080/19490976.2021.1968258.

 PubMed Web of Science ®Google Scholar

Sadighi Akha AA, McDermott AJ, Theriot CM, Carlson PE Jr., Frank CR, McDonald RA, Falkowski NR, Bergin IL, Young VB, Huffnagle GB. Interleukin-22 and CD160 play additive roles in the host mucosal response to Clostridium difficile infection in mice. Immunology. 2015;144(4):587–597. doi:10.1111/imm.12414.

 PubMed Web of Science ®Google Scholar

Frisbee AL, Saleh MM, Young MK, Leslie JL, Simpson ME, Abhyankar MM, Cowardin CA, Ma JZ, Pramoonjago P, Turner SD. et al. IL-33 drives group 2 innate lymphoid cell-mediated protection during Clostridium difficile infection. Nat Commun. 2019;10(1):2712. doi:10.1038/s41467-019-10733-9.

 PubMed Web of Science ®Google Scholar

Wang J, Ortiz C, Fontenot L, Mukhopadhyay R, Xie Y, Chen X, Feng H, Pothoulakis C, Koon HW. Therapeutic Mechanism of Macrophage Inflammatory Protein 1 α Neutralizing Antibody (CCL3) in Clostridium difficile Infection in Mice. J Infect Dis. 2020;221(10):1623–1635. doi:10.1093/infdis/jiz640.

 PubMed Web of Science ®Google Scholar

Buonomo EL, Madan R, Pramoonjago P, Li L, Okusa MD, Petri WA Jr. Role of interleukin 23 signaling in Clostridium difficile colitis. J Infect Dis. 2013;208(6):917–920. doi:10.1093/infdis/jit277.

 PubMed Web of Science ®Google Scholar

Stroke IL, Letourneau JJ, Miller TE, Xu Y, Pechik I, Savoly DR, Ma L, Sturzenbecker LJ, Sabalski J, Stein PD. et al. Treatment of Clostridium difficile Infection with a Small-Molecule Inhibitor of Toxin UDP-Glucose Hydrolysis Activity. Antimicrob Agents Chemother. 2018;62(5):62. doi:10.1128/AAC.00107-18.

 Web of Science ®Google Scholar

Bender KO, Garland M, Ferreyra JA, Hryckowian AJ, Child MA, Puri AW, Solow-Cordero DE, Higginbottom SK, Segal E, Banaei N. et al. A small-molecule antivirulence agent for treating Clostridium difficile infection. Sci Transl Med. 2015;7(306):306ra148. doi:10.1126/scitranslmed.aac9103.

 PubMed Web of Science ®Google Scholar

Ivarsson ME, Durantie E, Huberli C, Huwiler S, Hegde C, Friedman J, Altamura F, Lu J, Verdu EF, Bercik P. et al. Small-Molecule Allosteric Triggers of Clostridium difficile Toxin B Auto-proteolysis as a Therapeutic Strategy. Cell Chem Biol. 2019;26(1):17–26.e13. doi:10.1016/j.chembiol.2018.10.002.

 PubMed Web of Science ®Google Scholar

Tam J, Hamza T, Ma B, Chen K, Beilhartz GL, Ravel J, Feng H, Melnyk RA. Host-targeted niclosamide inhibits C. difficile virulence and prevents disease in mice without disrupting the gut microbiota. Nat Commun. 2018;9(1):5233. doi:10.1038/s41467-018-07705-w.

 PubMedGoogle Scholar

Julliard W, De Wolfe TJ, Fechner JH, Safdar N, Agni R, Mezrich JD. Amelioration of Clostridium difficile Infection in Mice by Dietary Supplementation with Indole-3-carbinol. Annals Of Surgery. 2017;265(6):1183–1191. doi:10.1097/SLA.0000000000001830.

 PubMed Web of Science ®Google Scholar

Wang S, Deng W, Li F, Chen YE, Wang PU. Blockade of T helper 17 cell function ameliorates recurrent Clostridioides difficile infection in mice. Acta Biochim Biophys Sin (Shanghai). 2021;53(10):1290–1299. doi:10.1093/abbs/gmab107.

 PubMed Web of Science ®Google Scholar

Andersson JA, Peniche AG, Galindo CL, Boonma P, Sha J, Luna RA, Savidge TC, Chopra AK, Dann SM. et al. New Host-Directed Therapeutics for the Treatment of Clostridioides difficile Infection. mBio. 2020;11(2):11. doi:10.1128/mBio.00053-20.

 Web of Science ®Google Scholar

Hansen A, Alston L, Tulk SE, Schenck LP, Grassie ME, Alhassan BF, Veermalla AT, Al-Bashir S, Gendron F-P, Altier C. et al. The P2Y6 receptor mediates Clostridium difficile toxin-induced CXCL8/IL-8 production and intestinal epithelial barrier dysfunction. PLoS ONE. 2013;8(11):e81491. doi:10.1371/journal.pone.0081491.

 PubMed Web of Science ®Google Scholar

Jose S, Mukherjee A, Horrigan O, Setchell KDR, Zhang W, Moreno-Fernandez ME, Andersen H, Sharma D, Haslam DB, Divanovic S. et al. Obeticholic acid ameliorates severity of Clostridioides difficile infection in high fat diet-induced obese mice. Mucosal Immunol. 2021;14(2):500–510. doi:10.1038/s41385-020-00338-7.

 PubMed Web of Science ®Google Scholar

Hutton ML, Pehlivanoglu H, Vidor CJ, James ML, Thomson MJ, Lyras D. Repurposing auranofin as a Clostridioides difficile therapeutic. J Antimicrob Chemother. 2020;75:409–417. doi:10.1093/jac/dkz430.

 PubMed Web of Science ®Google Scholar

Abutaleb NS, Seleem MN. Auranofin, at clinically achievable dose, protects mice and prevents recurrence from Clostridioides difficile infection. Sci Rep. 2020;10(1):7701. doi:10.1038/s41598-020-64882-9.

 PubMed Web of Science ®Google Scholar

Zackular JP, Kirk L, Trindade BC, Skaar EP, Aronoff DM. Misoprostol protects mice against severe Clostridium difficile infection and promotes recovery of the gut microbiota after antibiotic perturbation. Anaerobe. 2019;58:89–94. doi:10.1016/j.anaerobe.2019.06.006.

 PubMed Web of Science ®Google Scholar

Blount KF, Megyola C, Plummer M, Osterman D, O’Connell T, Aristoff P, Quinn C, Chrusciel RA, Poel TJ, Schostarez HJ. et al. Novel riboswitch-binding flavin analog that protects mice against Clostridium difficile infection without inhibiting cecal flora. Antimicrob Agents Chemother. 2015;59(9):5736–5746. doi:10.1128/AAC.01282-15.

 PubMed Web of Science ®Google Scholar

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.