TABLE 2.
Acinetobacter baumannii strains used in this study
| Strain IDa | BEI designationb | Isolate informationc | Log10 CFUd |
Differencee | ||
|---|---|---|---|---|---|---|
| Untreated | Tobramycin only | Tobramycin and PEG 400 | ||||
| ATCC 17978 | NA | NA | 7.53 ± 0.13 | 5.24 ± 0.30 | 1.15 ± 0.26 | 4.09 |
| ATCC 19606 | NA | Urine isolate, 1948 | 8.19 ± 0.12 | 5.70 ± 0.12 | 1.92 ± 0.17 | 3.78 |
| Isolate 9 | NR-13382 | Blood isolate 2008 | 8.10 ± 0.14 | 6.17 ± 0.18 | 3.05 ± 0.12 | 3.12 |
| 3-137 (OIFC137) | NR-17777 | Catheter isolate, 2003 | 8.02 ± 0.13 | 5.89 ± 0.20 | 2.95 ± 0.36 | 2.94 |
| 5-032 (OIFC132)f | NR-17778 | Wound isolate, 2003 | 8.04 ± 0.22 | 5.46 ± 0.14 | 3.64 ± 0.15 | 1.82 |
| 5-143 (OIFC134)f | NR-17781 | Wound isolate, 2003 | 8.09 ± 0.06 | 6.65 ± 0.18 | 3.80 ± 0.13 | 2.85 |
| H72721 | NR-9667 | Sputum isolate, 2006 | 7.83 ± 0.10 | 5.46 ± 0.14 | 1.77 ± 0.09 | 3.69 |
| 5-189 (OIFC189) | NR-17782 | Human isolate, no yr | 7.94 ± 0.08 | 6.17 ± 0.11 | 4.50 ± 0.17 | 1.67 |
| BC-5 | NR-17783 | Nosocomial isolate, 2007 | 8.20 ± 0.18 | 5.76 ± 0.15 | 2.11 ± 0.08 | 3.65 |
| Naval-18f | NR-17785 | Wound isolate, 2006 | 7.97 ± 0.12 | 5.81 ± 0.17 | 3.80 ± 0.25 | 2.01 |
| IS-123 | NR-17787 | Wound isolate, 2009 | 8.11 ± 0.09 | 6.15 ± 0.19 | 4.46 ± 0.19 | 1.69 |
ATCC strains were obtained from the American Type Culture Collection (www.atcc.org). All others were obtained from BEI Resources, NIAID, NIH (www.beiresources.org). ID, identification. All strains were resistant to ampicillin and sensitive to tobramycin in broth culture.
Strain designation from BEI Resources.
Basic information about strains as supplied by vendors.
Log10 CFU expresses the log10-transformed average number of CFU (± standard error of the mean) recovered from untreated biofilms and those treated with 50 μg/ml tobramycin or 50 μg/ml tobramycin and PEG 400 (26.6 mM).
Difference is the log10 CFU for biofilms treated only with tobramycin minus the log10 CFU for biofilms treated with tobramycin and PEG 400 (mean, 2.72 log10 CFU), which was significantly greater than zero (t = 10.027, df = 9, P < 0.0001). The difference for ATCC 17978 was not used for statistical comparisons.
Strains that form a pellicle according to the methods of Nait Chabane et al. (22). The treatment effect was not different between pellicle-forming (n = 3; mean, 2.23 log10 CFU difference) and non-pellicle-forming (n = 7; mean, 2.9 log10 CFU) strains (t = −1.83, df = 6.5, P = 0.18).