TABLE 3.
Effect of iron transport mutations on Henle cell invasion and plaque formation
| Strain | Phenotype | Percent invasiona | No. of plaquesb |
|---|---|---|---|
| SDU378 | Wild type | 41 ± 3.5 | 107 ± 13 |
| SDU380 | TonB− | 44 ± 11 | 0 |
| SDU380/pYUK1 | TonB+ | 52 ± 6.1 | 112 ± 12 |
| SDU400 | ShuA− | 56 ± 5.5c | 72 ± 7.5d |
| SDU400/pHTL116 | ShuA+ | 52 ± 5.6 | 82 ± 13 |
| SDU402 | ShuA− EntB− | 42 ± 9.3 | 73 ± 11 |
| SDU402/pHTL116 | EntB− | 39 ± 8.5 | 99 ± 3.1 |
| SDU402/pHEB1 | ShuA+ EntB+ | 47 ± 13 | 117 ± 21 |
a
After a 2-h incubation, Henle cells containing three or more intracellular bacteria were scored as positive for invasion. Values represent the mean ± standard deviation of three independent invasion assays.
b
Confluent Henle cell monolayers were infected with 104 bacteria per 35-mm-diameter plate. Plaques were counted after 48 h of incubation. The number of plaques reported is the mean ± standard deviation of three independent experiments.
c
Significantly different (P < 0.0001) compared to the wild type.
d
Of those strains that produced plaques, only SDU400 was significantly different from the wild type (P < 0.02).