TABLE 1.
Expected and observed recovery of bacterial inocula from experimentally contaminated bladesa
| Inoculum level and organism | No. of recovered organisms (CFU):
|
||||
|---|---|---|---|---|---|
| Calculatedc | After direct inoculation on solid medium
|
After indirect inoculation (BHI)b
|
|||
| Expectedd (95% CI) | Observede | Expectedd (95% CI) | Observede | ||
| Low | |||||
| S. pneumoniae | 1 | 0-5 | 0, 0, 1 | 0 | 0, 0, 0 |
| H. influenzae | 3 | 0-10 | 0, 0, 1 | 0-1 | 0, 1, 1 |
| S. aureus | 6 | 2-20 | 7, 12, 19 | 0-2 | 0, 0, 0 |
| P. aeruginosa | 26 | 5-50 | 6, 24, 29 | 0-6 | 0, 0, 1 |
| High | |||||
| S. pneumoniae | 380 | >250f | >250f | 20-40 | 34, 45, 50-100 |
| H. influenzae | 52 | 20-100 | 50-100f | 1-8 | 4, 5, 5 |
| S. aureus | 120 | 50-200 | 18, 25, 50-100 | 4-17 | 5, 5, 20 |
| P. aeruginosa | 186 | 100-250 | 50-100 | 8-20 | 44, 50-100g |
a
Results represent recoveries in triplicate experiments.
b
Indirect inoculation, dilution in BHI followed by plating on solid medium.
c
Calculated results differed according to the inoculum used.
d
Expected results represent 95% CI for 100% CFU recovery.
e
Observed results correspond to actual colony counts.
f
The same numbers of CFU were expected and/or observed in triplicate experiments.
g
The same numbers of CFU were observed in duplicate experiments.