Table 4.

Quantitative Cultures for Clostridium difficile Total Counts, Spore Post–Alcohol Shock Counts, and C. difficile Cytotoxin B Titers in 89 Patients Randomly Assigned to Receive a 10-Day Course of Vancomycin or Fidaxomicin Therapy

	Day 0	Day 4	Day 10	Day 14	Day 21	Day 28	Day 42
Mean log10 CFU/g ± SD (spore ± SD)
VAN	6.2 ± 2.1	2.2 ± 0.9	2.0 ± 0.0	3.1 ± 2.2	4.5 ± 2.7	3.9 ± 2.2	4.5 ± 2.4
FDX	5.9 ± 2.8	2.0 ± 0.1	2.0 ± 0.1	2.7 ± 1.9	4.2 ± 2.4	3.9 ± 2.3	3.0 ± 1.9
Mean log10 spore count (±SD)a
VAN	4.8 ± 1.7	2.7 ± 1.1b	2.2 ± 0.6	3.2 ± 2.0	4.0 ± 1.9	3.3 ± 1.5	3.2 ± 1.6
FDX	4.7 ± 1.8	2.0 ± 0.0b	2.1 ± 0.7	2.3 ± 1.2	3.3 ± 1.8	3.1 ± 1.4	2.7 ± 1.3
Mean toxin B titer ± SEM	Day 0	Day 4	Day 10	Pooled for Days 14, 21, 28, 42c
VAN	2800 ± 1250	Negative	Negative	1260 ± 350
FDX	2250 ± 600	Negative	Negative	2400 ± 1400d

A total of 44 patients received VAN, and 45 received FDX.

Abbreviations: CFU, colony forming units; FDX, fidaxomicin; SD, standard deviation; SEM, standard error of the mean; VAN, vancomycin.

^a Several values were higher than total counts, reflecting several samples for which spore counts appeared higher than total counts, which could represent variation near the lower limit of detection and possibly less competition after alcohol shock–treatment cultures.

^b P = .001.

^c Data are for positive titers only. For the VAN group, 7 of 30 specimens tested from day 14, 15 of 30 from day 21, 3 of 22 from day 28, and 1 of 12 from day 42 were positive. For the FDX group, 1 of 23 specimens tested from day 14, 6 of 27 from day 21, 5 of 20 from day 28, and 1 of 21 from day 42 were positive.

^d The value was 1140 ± 770 if the outlier toxin titer of 1/16 000 was excluded.