Hypervirulent Clostridium difficile ribotypes are CpG depleted

Figures & data

Figure 1. (a) CpG dinucleotides are depleted in C.difficile: Graph illustrating mean ± SD (the continuous black line indicates the mean and the broken black lines indicate standard deviation) of dinucleotide O/E ratio for C.difficile (both hypervirulent and non hypervirulent) (1 ± 0.213). All dinucleotides except the CpG dinucleotides (red) lie within the confidence interval of (0.787–1.213). (b) CpG dinucleotides are the most variable dinucleotides between hypervirulent and non-hypervirulent C.difficile strains: The difference in dinucleotide O/E ratios between hypervirulent (HV) and non-hypervirulent (NHV) C.difficile strains in percentage is shown in the Y-axis (A positive value for a given dinucleotide implies higher O/E ratios for the hypervirulent strains as compared to the non-hypervirulent strains). The complete genome sequences were analyzed. The differences between the hypervirulent and the non-hypervirulent strains were less than 1% except for the CpG dinucleotide for which the difference is about 9% (red bar). (c) Hypervirulent C.difficile strains are more CpG depleted than the non-hypervirulent strains: Box-plot diagram showing the CpG (O/E) in the whole genome sequence in non-hypervirulent and hypervirulent strains of C.difficile. The relative abundance of CpG dinucleotides was significantly higher in non-hypervirulent strains (Median = 0.341) as compared to the hypervirulent strains (Median = 0.298) [p < 0.05].

Figure 2. (a) Within the coding regions CpG dinucleotides are the most variable dinucleotides between hypervirulent and non-hypervirulent C.difficile strains: The difference in dinucleotide O/E ratios between hypervirulent (HV) and non-hypervirulent (NHV) C.difficile strains within the coding region (in percentage) is shown in the Y-axis (A positive value for a given dinucleotide implies higher O/E ratios for the hypervirulent strains as compared to the non-hypervirulent strains). The differences between the hypervirulent and the non-hypervirulent strains were less than 1% except for the CpG dinucleotide for which the difference is about 11.5% (red bar). (b) Within the coding region CpG depletion is more pronounced in the hypervirulent C.difficile strains as compared to the non-hypervirulent strains: Box-plot diagram showing the CpG (O/E) in the coding region in non-hypervirulent and hypervirulent strains of C.difficile. The relative abundance of CpG dinucleotides was significantly lower in the hypervirulent strains (Median = 0.263) as compared to the non-hypervirulent strains (Median = 0.298) [p < 0.05].