Table 3.
Comparative analysis of curli and cellulose production and adherence to HT-29 cells by EPEC E2348/69 and EHEC EDL933strains.
| Strain | Curli* | Cellulose** | Adherence to HT-29 cells CFUs × 107/ml ±SD (%) |
Adherence to bovine gut tissue CFUs × 107/ml ±SD (%) |
||
|---|---|---|---|---|---|---|
| E2348/69 | EDL933 | E2348/69 | EDL933 | |||
| Wild type | + | + | 4.9 ±0.3 (100) | 1.43±0.09 (100) | 1.09 ±0.09 (100) | 1.11 ±0.07 (100) |
| ΔcsgA | − | ++ | 2.2 ±0.2 (45) | 0.75±0.04 (52) | 0.49 ±0.04 (45) | 0.23 ±0.04 (21) |
| ΔcsgA(pCsgA) | + | + | 5.6 ±0.7 (114) | 2.55±0.04 (178) | ND | ND |
| ΔcsgA(pCP994) | − | ++ | 6.9 ±0.8 (141) | 1.22±0.08 (85) | ND | ND |
| ΔbcsA | + | − | 3.9 ±1.2 (81) | 0.34±0.07 (24) | 0.63 ±0.06 (58) | 0.62 ±0.14 (56) |
| ΔbcsA(pBcsA) | + | + | 4.8 ±0.5 (98) | 1.47±0.12 (103) | ND | ND |
| ΔbcsA(pCP994) | ++ | − | 3.6 ±0.3 (73) | 0.77±0.13 (54) | ND | ND |
| ΔcsgAΔbcsA | − | − | 7.0 ±0.3 (15) | 0.18±0.08 (12) | 0.10 ±0.04 (9) | 0.21 ±0.03 (20) |
| ΔcsgAΔbcsA(pBcsA) | − | + | 3.6 ±1.6 (74) | 1.42±0.55 (99) | ND | ND |
| ΔcsgD | − | − | 4.4 ±0.4 (89) | 0.92±0.02 (65) | 0.82 ±0.07 (75) | 0.88 ±0.10 (79) |
| ΔcsgD(pCP994) | ++ | ++ | 32.7 ±4.3 (667) | 7.22±0.63 (505) | ND | ND |
The experiments were performed three times in triplicate and the results represent the mean of the averages obtained from those three experiments ± standard deviations. The data correspond to 6 h of incubation. +, Positive expression; −, negative expression; ++ high levels of expression.
*
Phenotypic production of curli as demonstrated by EM, Congo red staining and immunoblotting;
**
Production of cellulose as determined by calcofluor binding.