In continuation with last week's experiment result (which proved that my current extract is contaminated), another extract is used to repeat the experiment. This time I used an older extract, which is much more dark, concentrated and viscous (therefore cannot be poured using a pipette).
The method is still the same, that is:
Prepare a 24 hour culture suspension of the selected microbes: S. aureus, E. Coli, L. monocytogenes, S. typhi, and S. I.
An agar-well test is made using the selected microbes. Three holes of .7mm are plugged out on each plate and poured with samples. (Samples are used at 100% conc to see their effectiveness first) The plates are incubated 18hr in 37C.
Results are in as follows:
 |
| ST-no zone |
 |
| SA-no zone |
 |
| LM- clear zone |
 |
| EC-clear zone |
 |
| I-not much growth, but not very clear zone |
Therefore, after much measurement, we have:
 |
| Average inhibition zone, in mm |
Looking at
I plate sets, the zone are not that clear, but the microbe growth is not that vigorous either. There are spots of microbe in the "zone" around the plates. This either due to 1) microbes in I are slow-growing (not so) or 2) it's very effective that no microbe has grown. The little growth seen are probably lucky few contaminant/resistant ones.
In conclusion, the sample is very effective on
L.monocytogenes, E.coli, and not effective on
S.aureus and
S.typhi. More test should be done to confirm I.
No comments:
Post a Comment