Comparative nutritional and chemical phenome of Clostridium difficile isolates determined using phenotype microarrays

• To study the effect of phenotype diversity on Clostridium difficile virulence, global phenome of historic and recent hypervirulent strains were determined using Biolog Phenotype Microarrays.
• Of the 760 nutrient sources tested, 285 compounds were utilized by at least one strain.
• Compared to other strains, C. difficile R20291, a recent hypervirulent outbreak associated strain, appears to have an expanded nutrient utilization profile.
• The nutritional utilization profile of C. difficile strains identified in this profile study could be used to design tube feeding formulas that reduce the risk of CDI.

SummaryObjectivesClostridium difficile infection (CDI) is the leading cause of infectious diarrhea in North America and Europe. The risk of CDI increases significantly in the case where antimicrobial treatment reduces the number of competing bacteria in the gut, thus leading to the increased availability of nutrients and loss of colonization resistance. The objective of this study was to determine comprehensive nutritional utilization and the chemical sensitivity profile of historic and newer C. difficile isolates and to examine the possible role of the phenotype diversity in C. difficile virulence.MethodsPhenotype microarrays (PMs) were used to elucidate the complete nutritional and chemical sensitivity profile of six C. difficile isolates.ResultsOf the 760 nutrient sources tested, 285 compounds were utilized by at least one strain. Among the C. difficile isolates compared, R20291, a recent hypervirulent outbreak-associated strain, appears to have an expanded nutrient utilization profile when compared to all other strains.ConclusionsThe expanded nutritional utilization profile of some newer C. difficile strains could be one of the reasons for infections in patients who are not exposed to the hospital environment or not undergoing antibiotic treatment. This nutritional profile could be used to design tube feeding formulas that reduce the risk of CDI.