Table 2. Zones of clearing for A. baumannii ATCC 17978 and deletion mutants grown on Mueller-Hinton agar with the addition or chelation of iron after pentamidine exposure.
| Zone of clearing (mm)ab | |||||
|---|---|---|---|---|---|
| Strain | WT | ΔadeRS | ΔadeAB | ΔadeA | ΔadeB |
| Mediumc | |||||
| MHA control | 1.4 ± 0.3 | 6.9 ± 0.5 | 6.9 ± 0.3 | 6.9 ± 0.4 | 7.2 ± 0.4 |
| + 2.5 mM FeSO4 | 0.8 ± 0.1* | 5.4 ± 0.2* | 5.6 ± 0.3* | 5.4 ± 0.1*** | 5.6 ± 0.1*** |
| + 5 mM FeSO4 | 0.7 ± 0.2* | 2.5 ± 0.8*** | 2.8 ± 0.3*** | 3.2 ± 0.3*** | 2.9 ± 0.6*** |
| + 7.5 mM FeSO4 | NG | NG | NG | NG | NG |
| + 100 μM DIP | 1.7 ± 0.1 | 6.7 ± 0.2 | 6.9 ± 0.1 | 6.2 ± 0.2 | 6.6 ± 0.2 |
| + 200 μM DIP | 5 ± 0.3*** | 6.7 ± 0.4 | 6.6 ± 0.4 | 6.1 ± 0.1 | 6.4 ± 0.1 |
aAveraged values are displayed ± SD. Statistical analyses were performed by Student’s t-test, two-tailed, unpaired
* = P <0.0005 and
*** = P <0.000001.
bValues given in bold indicate a significant difference between a strain grown under iron-rich or iron-limited conditions versus its respective MHA control.
cMHA, Mueller-Hinton agar; FeSO4, ferrous sulphate; DIP, 2’,2’ dipyridyl; NG, no growth due to iron toxicity.