Para-cresol production by Clostridium difficile affects microbial diversity and membrane integrity of Gram-negative bacteria

Abstract

Clostridium difficile is a Gram-positive spore-forming anaerobe and a major cause of antibiotic-associated diarrhoea. Disruption of the commensal microbiota, such as through treatment with broad-spectrum antibiotics, is a critical precursor for colonisation by C. difficile and subsequent disease. Furthermore, failure of the gut microbiota to recover colonisation resistance can result in recurrence of infection. An unusual characteristic of C. difficile among gut bacteria is its ability to produce the bacteriostatic compound para-cresol (p-cresol) through fermentation of tyrosine. Here, we demonstrate that the ability of C. difficile to produce p-cresol in vitro provides a competitive advantage over gut bacteria including Escherichia coli, Klebsiella oxytoca and Bacteroides thetaiotaomicron. Metabolic profiling of competitive co-cultures revealed that acetate, alanine, butyrate, isobutyrate, p-cresol and p-hydroxyphenylacetate were the main metabolites responsible for differentiating the parent strain C. difficile (630Δerm) from a defined mutant deficient in p-cresol production. Moreover, we show that the p-cresol mutant displays a fitness defect in a mouse relapse model of C. difficile infection (CDI). Analysis of the microbiome from this mouse model of CDI demonstrates that colonisation by the p-cresol mutant results in a distinctly altered intestinal microbiota, and metabolic profile, with a greater representation of Gammaproteobacteria, including the Pseudomonales and Enterobacteriales. We demonstrate that Gammaproteobacteria are susceptible to exogenous p-cresol in vitro and that there is a clear divide between bacterial Phyla and their susceptibility to p-cresol. In general, Gram-negative species were relatively sensitive to p-cresol, whereas Gram-positive species were more tolerant. This study demonstrates that production of p-cresol by C. difficile has an effect on the viability of intestinal bacteria as well as the major metabolites produced in vitro. These observations are upheld in a mouse model of CDI, in which p-cresol production affects the biodiversity of gut microbiota and faecal metabolite profiles, suggesting that p-cresol production contributes to C. difficile survival and pathogenesis.

Phytotoxic metabolites produced by Diaporthe eres involved in cane blight of grapevine in Italy

“…These latter were identified by TLC analysis carried out in different conditions, in comparison with the corresponding standard and also by cochromatography. Furthermore, their spectroscopic properties (essentially 1 H NMR and MS) were very similar to those previously reported for 1 (Avent et al 1992), for 2 (Venkatasubbaiah et al 1991;Zhang et al 2012), for 3 (Kasthuraiah et al 2004;Passmore et al 2018) for 4 (Kimura and Tamura 1973;Venkatasubbaiah et al 1991;Capasso et al 1992) for 5 (Zhang et al 2012;Cimmino et al 2017). For 1 we carried out a complete 1 H and 13 C NMR study for the first time using 1 D and 2 D NMR experiments (COSY, HSCQ and HMBC) ( Figures S1-S5, Supplementary materials) that allowed to unambiguously assign the chemical shifts to all the carbons and the corresponding protons as reported in Table S1 of Supplementary materials, in respect to the data previously reported using only 1 D NMR (Avent et al 1992).…”

“…4-Hydroxybenzaldehyde (2) was first reported as phytotoxin produced by Phaeomoniella chlamydospora involved in the esca complex disease of grapevine (Tabacchi et al 2000) and later from Spencermartinsia viticola, one of the causal agents of grapevine Botryosphaeria dieback in Australia (Reveglia et al 2018). p-Cresol (3), which has been recently isolated from the culture of Clostridium difficile, a Gram-positive spore-forming anaerobe and a major cause of antibiotic-associated diarrhoea.1had bacteriostatic activity against microorganisms including Escherichia coli, Klebsiella oxytoca and Bacteroides thetaiotaomicron (Passmore et al 2018). However, this is the first time that p-cresol was detected as a secondary phytotoxic metabolite from a fungus pathogenic for grapevine.…”

NAFLD as a driver of chronic kidney disease

“…The metabolism of the amino acids tyrosine and phenylalanine by a variety of obligate or facultative anaerobes, including the genera Bacteroides, Lactobacillus, Enterobacter, Bifidobacterium, and especially Clostridium difficile, results in the increased production of para-cresyl and the conjugate para-cresyl sulfate. 94,95 Escherichia coli has been shown to metabolise tryptophan, resulting in the production of indole that is metabolised in the liver to the uraemic toxin indoxyl sulfate. 94,95 A variety of other potentially nephrotoxic metabolites are also produced, such as ammonia, thiols and phenols.…”

“…94,95 Escherichia coli has been shown to metabolise tryptophan, resulting in the production of indole that is metabolised in the liver to the uraemic toxin indoxyl sulfate. 94,95 A variety of other potentially nephrotoxic metabolites are also produced, such as ammonia, thiols and phenols. 83 A complex interaction also exists between the gut microbiota and BA metabolism in NAFLD, 89 wherein a diverse range of BAs can be detected in the plasma and have the potential to influence development and progression of the disease.…”

Metabolomic and Lipidomic Biomarkers for Premalignant Liver Disease Diagnosis and Therapy

“…Fxr-null and WT mice dosed with the FXR ligands CA or LCA generated metabolites indicative of intrahepatic cholestasis. These included the sulfate and β-D-glucuronic acid conjugates of p-cresol [78], a fermentation product of tyrosine produced by Clostridium difficile in the gut [79], thereby providing further evidence of gut microbiota-liver crosstalk. Other metabolites related to cholestasis included corticosterone and CA metabolites, with the latter being produced by induced CYP3A11 [78].…”