Table 2.
Geometric mean titers (and standard deviations) of serum IgG and IgA antibody levels against toxin A and B of Clostridium difficile among cases according to Clostridium difficile infection (CDI) disease severity.
| Toxin A | Toxin B | Toxin A | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Variable | IgG | Mean Difference (95% CI) | p Value a | IgA | Mean Difference (95% CI) | p Value a | IgG | Mean Difference (95% CI) | p Value a | IgA | Mean Difference (95% CI) | p Value a |
| GMT (SD) | GMT (SD) | GMT (SD) | GMT (SD) | |||||||||
| Disease severity | ||||||||||||
| Mild (n = 31) | 23.4 (1.1) | 0.39 (−0.13, 0.92) | 0.12 b | 7.6 (0.9) | 0.30 (−0.13, 0.74) | 0.14 c | 20.5 (1.0) | 0.34 (−0.22, 0.91) | 0.11 d | 9.2 (1.0) | 0.63 (0.10, 1.15) | 0.023 e |
| Severe (n = 19) | 15.8 (0.5) | Reference | 5.6 (0.7) | Reference | 14.6 (0.9) | Reference | 4.9 (0.6) | Reference | ||||
| Disease severity in the time period, 7–14 days | ||||||||||||
| Mild (n = 9) | 35.5 (1.1) | 0.90 (0.07, 1.74) | 0.004 f | 8.1 (0.5) | 0.33 (−0.20, 0.87) | 0.23 g | 30.1 (1.1) | 0.77 (−0.40, 1.95) | 0.036 h | 9.0 (1.2) | 0.63 (−0.32, 1.57) | 0.27 i |
| Severe (n = 8) | 14.4 (0.4) | Reference | 5.8 (0.6) | Reference | 13.9 (1.2) | Reference | 4.8 (0.5) | Reference |
CDI: Clostridium difficile infection; GMT: geometric mean titer; IgA: Immunoglobulin A; IgG: Immunoglobulin G; SD: standard deviation. The results are expressed in ELISA units. a p value was obtained by Mann Whitney test for the difference between patients with mild vs. severe CDI. p value adjusted for multiple comparisons: b 0.19, c 0.14, d 0.19, e 0.09, f 0.032, g 0.26, h 0.09, i 0.27.