TABLE 1.
Aggressiveness index values of populations of isolates producing a zone of inhibition on different media
| Medium or test | Soil source | Value witha: |
P valueb | |||||
|---|---|---|---|---|---|---|---|---|
| No ZOI |
ZOI |
|||||||
| AI | SEM | No. of isolates | AI | SEM | No. of isolates | |||
| % TSA | ||||||||
| 100 | GS | −0.8 | 3.6 | 19 | 0.4 | 2.0 | 29 | NS |
| FSS | −2.3 | 3.4 | 8 | 1.2 | 1.4 | 15 | 0.2 > P > 0.1 | |
| 50 | GS | −3.5 | 2.0 | 24 | 3.4 | 3.0 | 24 | P < 0.05 |
| FSS | −2.6 | 3.9 | 7 | 1.5 | 1.4 | 15 | 0.2 > P > 0.1 | |
| 10 | GS | −1.3 | 1.9 | 42 | 8.7 | 6.7 | 6 | P < 0.05 |
| FSS | 0.3 | 1.9 | 12 | −0.3 | 2.4 | 11 | NS | |
| 10% TSA plus: | ||||||||
| Glucose | GS | −1.2 | 2.4 | 20 | 0.7 | 2.7 | 28 | NS |
| FSS | −3.4 | 2.7 | 8 | 1.8 | 1.6 | 15 | P < 0.05 | |
| NH4NO3 | GS | 0.4 | 2.1 | 42 | −4 | 2.3 | 5 | NS |
| FSS | −4.7 | 1.8 | 9 | 3 | 1.7 | 14 | P < 0.01 | |
| K3PO4 | GS | 0.7 | 1.9 | 43 | −3.6 | 9.6 | 4 | NS |
| FSS | −3.2 | 1.9 | 12 | 3.5 | 1.9 | 11 | P < 0.02 | |
| DNA platec | ||||||||
| Test for killing | GS | −3.1 | 4.2 | 10 | 0.7 | 2.1 | 38 | NS |
| FSS | 1.4 | 2.3 | 11 | −1.3 | 1.9 | 12 | 0.2 > P > 0.1 | |
| Test for DNase activity | GS | −5 | 4.1 | 10 | 1.2 | 2.1 | 38 | 0.1 > P > 0.05 |
| FSS | 1.3 | 2.6 | 10 | −1 | 1.8 | 13 | NS | |
| Test for killing in DNase producing populations | GS | −19 | 1 | 2 | 1.1 | 2 | 36 | P < 0.02 |
| FSS | 10 | NA | 1 | −0.8 | 1.1 | 12 | ||
a
ZOI, zone of inhibition; AI, aggressiveness index.
b
Return is from the homoscedastic, one-sided t test. NS, not significant with P > 0.2.
c
Using DNA-plates seeded with Staphylococcus CWZ226 allows to test for a ZOI and the ability to hydrolyze DNA in the whole populations, as well as the exDNase producing populations.