Table 2.
Results of four weekly challenges with A. baumannii NB893, showing on each challenge rising bacterial counts in the control catheter to the point where they became obstructed by biofilm by Day 7
| Day 1 | Day 2 | Day 3 | Day 6 | Day 7 | |
|---|---|---|---|---|---|
| Day 0, challenge 1 | |||||
| control | 1.3 × 107 | 1.8 × 107 | 2.9 × 108 | 4.3 × 108 | blocked |
| test 1 | 0 | 0 | 0 | 0 | 0 |
| test 2 | 0 | 0 | 0 | 0 | 0 |
| test 3 | 0 | 0 | 0 | 0 | 0 |
| Day 0, challenge 2 | |||||
| control | 2.8 × 107 | 3.2 × 107 | 2.3 × 107 | 1.9 × 108 | blocked |
| test 1 | 80 | 5 | 0 | 0 | 0 |
| test 2 | 275 | 65 | 0 | 0 | 0 |
| test 3 | 65 | 15 | 0 | 0 | 0 |
| Day 0, challenge 3 | |||||
| control | 2.7 × 107 | 1.5 × 108 | 5.4 × 108 | 4.9 × 108 | blocked |
| test 1 | 225 | 0 | 0 | 0 | 0 |
| test 2 | 155 | 0 | 0 | 0 | 0 |
| test 3 | 185 | 0 | 0 | 0 | 0 |
| Day 0, challenge 4 | |||||
| control | 2.7 × 107 | 3.2 × 107 | 5.0 × 107 | 1.8 × 108 | blocked |
| test 1 | 160 | 0 | 0 | 0 | 0 |
| test 2 | 115 | 0 | 0 | 0 | 0 |
| test 3 | 105 | 0 | 0 | 0 | 0 |
A value of 0 corresponds to a value that was below the lower limit of detection.
There was no growth from the antimicrobial catheters at 24 h after the first challenge and though cultures were positive on monitoring on Day 1 after challenges 3 and 4, and Day 2 after challenge 2, they were negative by Day 3 and cultures remained negative thereafter in the antimicrobial catheters throughout the four weekly challenges and each post-challenge perfusion (7 days).