TABLE 2.
Phenotypic characteristics of mutants
| GAS | Hemolytic units of the following toxin/ml of culture
|
Hyaluronic acid (fg/CFU) | Streptokinase (U/ml of culture) | Protease (mm)c | Multiplicity index in human blood from donord
|
||||
|---|---|---|---|---|---|---|---|---|---|
| SLOa
|
SLSb
|
A | B | ||||||
| TB | CH | TB | CH | ||||||
| Wild type | >1,000 | 0 | 0 | 136 | 16.1 ± 3.4 | 9.8 ± 0.7 | 8.8 ± 1.3 | 21.8 | 24.1 |
| sloΔ1 mutant | 0 | 0 | 0 | 136 | 16.9 ± 1.1 | 9.5 ± 0.6 | 8.6 ± 1.0 | 21.7 | 37.8 |
| sagBΔ1 mutant | >1,000 | 0 | 0 | 0 | 18.4 ± 2.9 | 10.0 ± 0.7 | 6.6 ± 1.5 | 45.3 | 47.1 |
| sloΔ1 sagBΔ1 mutant | 0 | 0 | 0 | 0 | 16.0 ± 2.0 | 9.9 ± 0.7 | 6.4 ± 1.9 | 27.9 | 32.3 |
a
Precipitated from cell-free supernatants of pH-controlled late-log-phase cultures. Tested in the presence of trypan blue (TB) and cholesterol (CH).
b
Cell-bound activity determined for cells from 50-ml early-stationary-phase cultures. Tested as described for SLO.
c
Diameters of cleared zones on casein plates, determined as described by Wheeler et al. (61).
d
The multiplicity index is the output CFU after 3 h of rotation in fresh human blood divided by the input CFU at time zero. In these assays, an M protein-deficient mutant of strain Manfredo had an index of <1.0.