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Calculation of Total % Adhered Bacteria

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Pankaj Jyoti Barua

Sep 23, 2020, 3:02:03 PM9/23/20
Hello friends:
I need to calculate the Total % Adhered Bacteria for E.coli

I counted the CFUs and they were
566 at 10-2 dilution and 68 at 10-3 dilution

Now to calculate the Total % Adhered Bacteria I am using the following formula

Number of colonies adhered X dilution factor X 100/ Original inoculum

Also to calculate the original inoculum I am using the following formula:
(OD600 x 7.65) – 0.3 =? X 10^9 CFU/mL
For E.coli the ED600 value I got was 0.183
and after calculation the value I got was 1.09 X 10^9 CFU/mL

Now coming back to the calculation of Total % Adhered Bacteria
For 10-2 dilution I am doing this:

566 X 0.01 X 100/1.09 X 10^9 CFU/mL

Where 566 is the CFU count I counted after incubation
0.01 is the dilution factor and 1.09 X 10^9 is the original inoculum.

Please let me know if I am doing it right.

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