Table 2.
Resistance to human serum, proteolytic activity, pyocyanin production, cytotoxicity, twitching motility and biofilm production of the 12 isolates. Arrows indicate lasR mutants. Stars indicate exoU positive isolates.
| Isolate | Grades of response in serum bactericidal assaysa | Proteolytic activity: clear zone diameter (mm) | Pyocyanin quantification (mg/L) | Cytotoxicity on A549 cells (%) | Twitching: motility areab | Biofilm production: OD 560 nm |
|---|---|---|---|---|---|---|
| Patient 1 ( Strain PA-VAP-1 ) | ||||||
| 1A*← | 1 | 9.0 ± 0.0 | 0.00 ± 0.00 | 104.00 ± 4.00 | 0 | 0.13 ± 0.06 |
| 1B*← | 1 | 9.0 ± 0.0 | 0.02 ± 0.02 | 100.20 ± 9.19 | 0 | 0.40 ± 0.36 |
| 1C*← | 1 | 9.0 ± 0.0 | 0.15 ± 0.05 | 104.20 ± 10.48 | 0 | 1.85 ± 0.37 |
| Patient 2 ( Strain PA-VAP-2 ) | ||||||
| 2A | 4 | 12.7 ± 0.6 | 3.28 ± 1.64 | 26.53 ± 10.27 | + | 0.45 ± 0.12 |
| 2B | 4 | 12.5 ± 0.5 | 3.05 ± 1.47 | 62.78 ± 31.31 | + | 0.63 ± 0.17 |
| 2C | 4 | 14.3 ± 0.3 | 3.35 ± 1.22 | 75.25 ± 43.76 | ++ | 0.55 ± 0.11 |
| Patient 3 ( Strain PA-VAP-3 ) | ||||||
| 3A* | 1 | 15.2 ± 1.0 | 6.73 ± 0.67 | 107.70 ± 8.45 | ++ | 1.57 ± 0.36 |
| 3B*← | 1 | 9.0 ± 0.0 | 0.38 ± 0.66 | 109.47 ± 13.99 | 0 | 0.62 ± 0.35 |
| 3C*← | 1 | 9.0 ± 0.0 | 0.31 ± 0.44 | 104.90 ± 11.30 | 0 | 0.53 ± 0.35 |
| Patient 4 ( Strain PA-VAP-4 ) | ||||||
| 4A | 6 | 14.2 ± 1.3 | 3.18 ± 0.56 | 82.3 ± 17.91 | ++ | 0.90 ± 0.16 |
| 4B← | 3 | 9.0 ± 0.0 | 0.02 ± 0.04 | 6.86 ± 5.72 | 0 | 0.77 ± 0.14 |
| 4C | 6 | 13.0 ± 0.0 | 3.74 ± 0.72 | 81.03 ± 6.52 | ++ | 0.64 ± 0.35 |
aSensitive = grades 1 and 2; Intermediate = grades 3 and 4; Resistant = grades 5 and 6.
b0, no twitching motility; +, 1–10 mm; ++, 10–20 mm.