TABLE 3.
Comparison of effectiveness of CNA buffered at a range of pH values in suppressing different types of anti-S. pyogenes BLIS activity
| Test medium | Degree of S. pyogenes positivity in BLIS-negative saliva coseeded with prototype BLIS-positive S. salivarius strainsa
|
|||||
|---|---|---|---|---|---|---|
| Min5 | 20P3 | N | F | K-33 (BLIS negative) | None | |
| SBA | 0 | 1+ | 0 | 0 | 3+ | 3+ |
| CNA | 0 | 1+ | 1+ | 0 | 3+ | 3+ |
| SBA-PIPES (pH 7.5) | 2+ | 3+ | 1+ | 2+ | 3+ | 3+ |
| CNA-PIPES (pH 6.5) | 1+ | 1+ | 1+ | 1+ | 3+ | 3+ |
| CNA-PIPES (pH 7.0) | 1+ | 3+ | 2+ | 3+ | 3+ | 3+ |
| CNA-PIPES (pH 7.5) | 2+ | 3+ | 3+ | 3+ | 3+ | 3+ |
| CNA-PIPES (pH 8.0) | 1+ | 2+ | 3+ | 3+ | 3+ | 3+ |
a
Each BLIS-producing S. salivarius strain or negative control was added to BLIS-negative saliva together with S. pyogenes, and the sample was then plated on each medium. After overnight incubation, the degree of positivity of S. pyogenes was graded from 0 to 4+.