Table 2.

Molecular and phenotypic characteristics of C. difficile isolates

CDI clinical outcomeStrainRibotypeTRSTCDTatcdCbToxins at 48 hcSpores at 48 hd
TcdATcdB
Complicated3832727++466H616HL
3902727++467H559HL
3912727++579**H474HL
3981819+wt106L240LL
4032727++571**H423HL
Severe3952727++725***H500HL
3962727++171L242LL
384533wt104L132LH
3922314wt277L217LH***
39962wt95L156LH
Mild to moderate3862727++670**H662*HL
3882727++647**H551HL
3892727++445H474HL
3932727++605**H425HL
3942727++503H416HL
3972727++447H445HH
3872727++425H379HL
4012727++352L408HL
3851819+wt204L431HH
4002465wt86L76LH
40262wt187L19LH***
  • a Presence (+) or absence (−) of the cdtA and cdtB genes, encoding the binary toxin CDT.

  • b wt, wild-type tcdC sequence identical to that of the reference strain VPI 10463; +, presence of the common 18-bp deletion in addition to the 1-bp deletion at nucleotide 117.

  • c Relative amounts of toxins detected by immunodot blotting; numbers indicate the mean density of the spots (arbitrary units [AU]) calculated from three independent blots. Letters indicate low (L) and high (H) toxin production compared to the mean densities for TcdA (387 AU [range, 292 to 483]) and TcdB (373 AU [292 to 455]). Asterisks indicate individual values that are significantly different from mean values for non-R027 isolates: *, = P < 0.05; **, P < 0.01; ***, P < 0.001.

  • d L and H, isolates with spore counts at 48 h (spores/ml) below or above the mean for all isolates (1.4 × 107 spores/ml [range, 8.3 × 106 to 2.0 × 107]), respectively. Asterisks indicate isolates that produced significantly more spores than R027 isolates (***, P < 0.001).