Table 2.
Prevalence of Antibiotic Exposures in the Nursing Home Resident Cohort
| Variable | Cohort resident-days (000s)a | Mean Days of Antibiotic in Prior 90 da | C. difficile Infection (N, %) | Incidence Rate per 100 000 resident-days (95% CI) |
|---|---|---|---|---|
| Antibiotic exposure in prior 90 d | ||||
| None | 106 766 (79.6%) | 0 | 883 (51.7%) | 0.83 (.77, .88) |
| Any | 27 379 (20.4%) | 11.6 | 825 (48.3%) | 3.01 (2.81, 3.23) |
| Type of antibiotic | ||||
| Cephalexin | 3641 (2.7%) | 11.0 | 123 (7.2%) | 3.38 (2.81, 4.03) |
| Ciprofloxacin | 3405 (2.5%) | 9.6 | 123 (7.2%) | 3.61 (3.00, 4.31) |
| Amoxicillin | 3409 (2.5%) | 9.6 | 57 (3.3%) | 1.67 (1.27, 2.17) |
| Cotrimoxazole | 2932 (2.2%) | 15.7 | 65 (3.8%) | 2.22 (1.71, 2.83) |
| Nitrofurantoin | 2667 (2.0%) | 19.7 | 35 (2.0%) | 1.31 (.91, 1.83) |
| Moxifloxacin | 2343 (1.7%) | 8.4 | 140 (8.2%) | 5.98 (5.03, 7.05) |
| Levofloxacin | 1814 (1.4%) | 8.2 | 42 (2.5%) | 2.32 (1.67, 3.13) |
| Amoxicillin-clavulanate | 1508 (1.1%) | 9.3 | 67 (3.9%) | 4.44 (3.44, 5.64) |
| Azithromycin | 1140 (0.8%) | 8.8 | 34 (2.0%) | 2.98 (2.07, 4.17) |
| Cefuroxime | 848 (0.6%) | 8.6 | 36 (2.1%) | 4.25 (2.97, 5.88) |
| Norfloxacin | 742 (0.6%) | 13.0 | 8 (0.5%) | 1.08 (.47, 2.12) |
| Clarithromycin | 602 (0.4%) | 8.6 | 8 (0.5%) | 1.33 (.57, 2.62) |
| Clindamycin | 526 (0.4%) | 8.6 | 32 (1.9%) | 6.08 (4.16, 8.59) |
| Cloxacillin | 440 (0.3%) | 10.8 | 13 (0.8%) | 2.95 (1.57, 5.05) |
| Cefprozil | 352 (0.3%) | 9.3 | 11 (0.6%) | 3.13 (1.56, 5.59) |
| Tetracycline | 174 (0.1%) | 45.6 | 0 (0%) | 0.00 (.00, 2.12) |
| Cefixime | 144 (0.1%) | 8.6 | 14 (0.8%) | 9.72 (5.32, 16.3) |
| Trimethoprim | 152 (0.1%) | 72.0 | 1–5 (0.0–0.3%)b | NA |
| Other c | 539 (0.4%) | 14.6 | 15 (0.9%) | 2.78 (1.56, 4.59) |
Abbreviation: CI, confidence interval; NA, not applicable.
a Weighted to reflect the source population (case weight = 1, control weight = 1000).
b Exact value suppressed.
c Includes penicillin V, ceftriaxone, and other less frequently prescribed antibiotics.