Determining CFU/mL from colony count formula/equation:
[# colonies counted / volume pipetted onto plate in uL] * [ 1 / serial dilution made (ie 10^-2)] * [1000 uL / 1 mL] = CFU/mL
Results:
| BHI | ||
| No Heat | Heat | |
| CFU/ml | 1.11x10^6 | 5.5x10^4 |
| H2O | ||
| No Heat | Heat | |
| CFU/ml | 9.3x10^5 | 8.9x10^5 |
| BAD | ||
| No Heat | Heat | |
| CFU/ml | 2.25x10^6 | 1.65x10^6 |
The results indicate that P. larvae spores germinate in the BHI + 1ug/ml Thiamine media, but do not in the H2O and BAD medias. The CFU/mL concentration of P. larvae that was observed growing on the MYPGP agar decreased after the sample had been heated to 65C for 15 minutes in the BHI treatment group. This indicates that vegetative cells that had germinated from the P. larvae spores were destroyed at such high temperatures (only the spores are so heat resistant). This results makes sense since BHI is what P. larvae is brothed in for growth.
The CFU/mL concentrations remained relatively the same in the H2O and BAD treatment groups.This indicates that the P. larvae spores did not germinate in those medias since it appears that CFU didn't decrease due to the heating like seen in the BHI treatment groups.
I would like to repeat these experiments in the future with different spore stocks to confirm these findings.
//EWW
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