Bacterial Dilutions – Determination of Colony Forming Units from Gigas Bacterial challenge (from earlier today)

All dilutions were performed with 1x LB+ 1%NaCl. 100uL were plated of all dilutions (see below) on 1xLB+1%NaCL plates. Plates were incubated O/N @ 37C. Colonies will be counted tomorrow to determine CFU for each sample.

Plated 100uL of:

V.vulnificus, t=0, 1:1,000,000 and 1:10,000,000

V.vulnificus H2O sample, t=1 & 3, 1:10,000 and 1:1,000,000

V.tubiashii, t=0, 1:1,000,000

Control H2O sample, t=1 & 3, Undiluted

Samples tubes containing bacteria and dilutions were stored @ 4C.

UPDATE 20110112:

Colony counts and calculations

V.vulnificus 0hr = Both dilutions produced a total lawn of bacteria. Uncountable. Will plate higher dilutions, but this will now only be a rough estimate due to the time that has passed.

—UPDATE—

New serial dilutions (90uL plated) of V.vulnificus 0hr were performed, down to 10^12. The only countable plate was the 10^12 dilution.

V.vulnificus 0hr = 10^12 dilution x 410 CFU = 4.1×10^14 CFU/90uL = 4.56×10^12 CFU/uL x 8×10^6uL (8L H2O in oyster tank) = 3.64×10^19 CFU total in oyster tank/8L = 4.56×10^18 CFU/L

V.vulnificus 1hr = 1:1,000,000 dilution x 48 CFU = 4.8×10^7 CFU/100uL = 4.8×10^5 CFU/uL x 8×10^6uL (8L H2O in oyster tank) = 3.84×10^12 CFU total in oyster tank/8L = 4.8×10^11 CFU/L

V.vulnificus 3hr = 1:1,000,000 dilution x 23 CFU = 2.3×10^7 CFU/100uL = 2.3×10^5 CFU/uL x 8×10^6uL (8L H2O in oyster tank) = 1.84×10^12 CFU total in oyster tank/8L = 2.3×10^11 CFU/L

Control H2O (no significant growth occurred O/N, just tiny colonies; continued incubation to allow colonies to increase in size for easier counting)

Control H2O 1hr = Undiluted 146 CFU/100uL = 1.46 CFU/uL x 8×10^6uL (8L H2O in oyster tank) = 1.168×10^7 CFU total in oyster tank/8L = 1.46×10^6 CFU/L

Control H2O 3hr = Undiluted 106 CFU/100uL = 1.06 CFU/uL x 8×10^6uL (8L H2O in oyster tank) = 8.48×10^6 CFU total in oyster tank/8L = 1.06×10^5 CFU/L

V.tubiashii 0hr = 1:1,000,000 dilution x 31 CFU = 3.1×10^7 CFU/100uL = 3.1×10^5 CFU/uL x 5×10^4 (50mL total volume of bacteria) = 1.55×10^10 CFU total V.tubiashii

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