TABLE 2.
Effects of citrate on clinical, laboratory, and genetically defined strains
| Strain (description)a | Biofilm formation (A550) ± SDb
|
% Aggregationc | |
|---|---|---|---|
| Without citrate | With 0.2% citrate | ||
| WT | 0.65 ± 0.12 | 3.06 ± 0.04 | 94.5 ± 3.2 |
| sarA::aphA-3 | 0.28 ± 0.06 | 0.12 ± 0.03 | 0.8 ± 2.0 |
| sarA::Tn917 | 0.41 ± 0.17 | 0.315 ± 0.04 | ND |
| sarA::Tn917/pCL84-sarA | 0.19 ± 0.064 | 5.49 ± 0.24 | ND |
| DB clinical isolate | 0.92 ± 0.20 | 3.40 ± 0.08 | 70.2 ± 9.2 |
| DB sarA::Tn917 | 0.07 ± 0.01 | 0.08 ± 0.04 | 1.6 ± 3.0 |
| ica::tetK | 0.40 ± 0.1 | 3.50 ± 0.1 | ND |
| fnbA | 0.65 ± 0.06 | 0.66 ± 0.04 | 98.2 ± 2.0 |
| fnbB | 0.72 ± 0.03 | 0.70 ± 0.07 | 97.5 ± 2.6 |
| ΔgraR + pEPSa5 | 1.20 ± 0.14 | 1.26 ± 0.11 | 13.6 ± 2.8 |
| ΔgraR + pEPSAgraR | 0.86 ± 0.04 | 2.83 ± 0.04 | 97.8 ± 0.8 |
| ΔgraS + pEPSa5 | 0.97 ± 0.06 | 0.80 ± 0.04 | 30.1 ± 3.6 |
| ΔgraS + pEPSAgraRS | 0.89 ± 0.07 | 2.15 ± 0.05 | 99.9 ± 0.04 |
| ΔvraG | 1.28 ± 0.23 | 1.00 ± 0.06 | 25.8 ± 1.8 |
| Mu50 (VISA) | 0.12 ± 0.02 | 1.18 ± 0.16 | 25.8 ± 2.1 |
| Mu50 ΔgraR | 0.24 ± 0.03 | 0.30 ± 0.04 | 3.1 ± 0.5 |
| Mu50 ΔvraG | 0.19 ± 0.03 | 0.21 ± 0.02 | <1 |
a
Unless otherwise indicted, the strain is a derivative of RN6390.
b
Biofilm formation of biofilms grown for 6 to 8 h assayed by the microtiter biofilm assay. Each strain was tested at least twice, six to seven replicates were assayed per measurement, and one standard deviation is shown.
c
Aggregation was determined after 12 to 14 h in the presence of 0.2% sodium citrate. In the absence of citrate, aggregation was less than 7% for all strains. ND, not determined.