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.

Para-cresol production by Clostridium difficile affects microbial diversity and membrane integrity of Gram-negative bacteria / Passmore, I. J.; Letertre, M. P. M.; Preston, M. D.; Bianconi, I.; Harrison, M. A.; Nasher, F.; Kaur, H.; Hong, H. A.; Baines, S. D.; Cutting, S. M.; Swann, J. R.; Wren, B. W.; Dawson, L. F.. - In: PLOS PATHOGENS. - ISSN 1553-7366. - ELETTRONICO. - 14:9(2018), pp. e100719101-e100719131. [10.1371/journal.ppat.1007191]

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

Bianconi I.;
2018-01-01

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.
2018
9
Passmore, I. J.; Letertre, M. P. M.; Preston, M. D.; Bianconi, I.; Harrison, M. A.; Nasher, F.; Kaur, H.; Hong, H. A.; Baines, S. D.; Cutting, S. M.; ...espandi
Para-cresol production by Clostridium difficile affects microbial diversity and membrane integrity of Gram-negative bacteria / Passmore, I. J.; Letertre, M. P. M.; Preston, M. D.; Bianconi, I.; Harrison, M. A.; Nasher, F.; Kaur, H.; Hong, H. A.; Baines, S. D.; Cutting, S. M.; Swann, J. R.; Wren, B. W.; Dawson, L. F.. - In: PLOS PATHOGENS. - ISSN 1553-7366. - ELETTRONICO. - 14:9(2018), pp. e100719101-e100719131. [10.1371/journal.ppat.1007191]
File in questo prodotto:
File Dimensione Formato  
journal.ppat.1007191 (1).pdf

accesso aperto

Tipologia: Versione editoriale (Publisher’s layout)
Licenza: Creative commons
Dimensione 1.17 MB
Formato Adobe PDF
1.17 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/280567
Citazioni
  • ???jsp.display-item.citation.pmc??? 44
  • Scopus 90
  • ???jsp.display-item.citation.isi??? 79
  • OpenAlex ND
social impact