TABLE 3.
Comparison of contamination rates and methods for fecal culture
| Group | Contamination rate (%) (total no. of samples)a | Sampling-to-receipt interval (days) | Settling time for 1st sedimentation step (min) | Tube used to suspend feces for 1st sedimentation step | Mixing for 1st sedimentation step | Decanting supernatant for 1st sedimentation step | Time of decontamination in VAN (days) |
|---|---|---|---|---|---|---|---|
| 1 | 22 (1,535) | 1-7 (85% within 4 days) | 15 | Fixed swab stick | Gentle inversion | Decanted 5 ml | 2 or 3 |
| 2 | 1.6 (386) | 0-5 (85% within 3 days) | 30 | Retractable swab stick | Shaken | Decanted a variable amt of supernatant to avoid sediment | 3 |
| 3 | 9.3 (4,619) | Not recorded | 30 | Retractable swab stick | Shaken | Aspirated up to 5 ml without disturbing sediment | 3 |
a
Measured as growth-index-positive, PCR-negative cultures.