Clostridioides (Clostridium) difficile

General Information

• GeneBank Accessions: CP003939, CP010905


• Scientific Name: Clostridioides difficile


• Common Name: C. difficile


• Characteristics:

• Gram-positive


• Anaerobic


• Spore-forming


• Motile

Pathogenicity and Virulence

Clostridioides (Clostridium) difficile is challenging to diagnose and treat as it forms spores and can persist asymptomatically within the gut. Some strains express multiple virulence factors, including adhesins and toxins (21).

Clostridioides difficile is a bacterial pathogen that causes a range of clinical diseases, from mild to moderate diarrhea to more severe conditions such as pseudomembranous colitis and toxic megacolon (2). The virulence of C. difficile is strain-dependent, with particularly virulent strains like the Clostridioides (Clostridium) difficile Hypervirulent Clade 2(brain://KZitF6GUVUC14XOu8XP2nw/ClostridioidesDifficileFormerlyNamedClostridiumDifficileHypervirule) (1).

Clostridioides (Clostridium) difficile is the most common healthcare-associated infectious agent in the US, causing over 460,000 infections and 20,000 deaths annually (16).

Clostridioides (Clostridium) difficile is acquired from the environment through fecal-oral transmission (15).

Virulence Factors

Several virulence factors have been identified, the most important of which are:

• TcdA


• TcdB

These toxins disrupt the Rho family of GTPases in host cells, leading to disease (8). TcdB is considered a dominant virulence factor (1)

Impact on Host

Clostridioides (Clostridium) difficile induces the expression of numerous transcripts associated with inflammation and extracellular matrix (ECM) degradation. The toxin activity of C. difficile suppresses the Bacteroidaceae, which compete with C. difficile for amino acids. Additionally, toxin-mediated degradation of collagen supports C. difficile growth in vitro (2)

Epidemiology

Clostridioides (Clostridium) difficile is part of the normal gut microbiota and is present in 2–5% of the adult population (12). In the healthy human gut, its abundance is about 2.10% of all species (7). It is the most common identifiable infectious agent of nosocomial antibiotic-associated diarrhea (8, 10).

Germination and Growth

Clostridioides (Clostridium) difficile spores exhibit a remarkable resistance to both oxygen and chemicals. The primary pathway for infection is through the ingestion of these spores. Consequently, strains that lack the ability to form spores are incapable of surviving in these conditions and spreading among hosts. Notably, the process of sporulation is opposed by the host and the commensal microbes. The spo0A gene of Clostridium difficile acts as a factor for persistence and transmission (13, 14).

When nutrients are limited, Clostridioides (Clostridium) difficile cells cease their growth and initiate the process of sporulation. The spores then develop into toxin-producing vegetative cells. This transformation takes place in the small intestine when taurocholate is present. This well-documented and regulated process is initiated by sensor histidine kinases, which subsequently lead to the phosphorylation and activation of the transcription factor Spo0A (17, 18).

Clostridioides (Clostridium) difficile spores are absorbed by intestinal epithelial cells (IECs) and macrophages, maintaining their ability to remain viable and capable of germination. Spores entering intestinal epithelial cells play a role in the recurrence of Clostridioides difficile infection (19, 20).

The conjugated primary bile acids taurocholate and taurochenodeoxycholate are powerful germinants for Clostridioides (Clostridium) difficile spores, with taurochenodeoxycholate being a weaker stimulant (11).

References

(1) Luo et al. 2022 Cell 185: 980-994
(2) Fletcher et al. 2021
(3) Lyras et al. 2009 Nature 458: 1176-1179
(4) Kuehne et al. 2010 Nature 467: 711-713
(5) Carter et al. 2012 Trends Microbiol 20: 21-29
(6) Carter et al. 2015 MBio 6: e00551
(7) King et al. 2019
(8) Mileto et al. 2019 Microbiol Spectrum 7(3): GPP3- 0015-2018
(9) Buffie & Pamer 2013
(10) Belizário & Faintuch 2018 In: Silvestre, R., Torrado, E. (eds) Metabolic Interaction in Infection. Experientia Supplementum 109 Springer, Cham. https://doi.org/10.1007/978-3-319-74932-7_13
(11) Sorg & Sonenshein 2008 J. Bacteriol. 190: 2505–2512
(12) Hsu et al. 2006 J Microbiol Immunol Infect 39: 242-248
(13) Deakin et al. 2012 Infect Immun 80: 2704-2711
(14) Paredes-Sabja et al. 2014 Trends Microbiol 22: 406-416
(15) Smits et al. 2016 Nat Rev Dis Primers 2: 16020
(16) Guh et al. 2020 N Engl J Med 382(14): 1320-1330
(17) Saujet et al. 2014 FEMS Microbiol Lett 358: 1-10
(18) Shen 2020 Annu Rev Microbiol 74: 545-566
(19) Paredes-Sabja et al. 2012 PLoS One 7: e43635
(20) Castro-Córdova et al. 2021 Nat Commun 12: 1140
(21) Chilton et al. 2026 Nat Rev Microbiol 24: 215-232

see also:
Bile salts / Bile acids & Clostridioides (Clostridium) difficile
Clostridioides difficile infection (CDI)
Clostridioides (Clostridium) difficile toxins
Sporulation / Spore