Why do microbiologists use serial dilution?

In microbiology, serial dilutions (log dilutions) are used to decrease a bacterial concentration to a required concentration for a specific test method, or to a concentration which is easier to count when plated to an agar plate.

How do you do a dilution in microbiology?

To find a dilution of a single tube, use the formula: sample/(diluent + sample). The sample is the amount you are transferring into the tube, and the diluent is the liquid already in the tube. When you transfer 1 ml into 9 mls, the formula would be: 1/(1+9) = 1/10.

What is serial dilution technique?

A serial dilution is the stepwise dilution of a substance in solution. Usually the dilution factor at each step is constant, resulting in a geometric progression of the concentration in a logarithmic fashion. A ten-fold serial dilution could be 1 M, 0.1 M, 0.01 M, 0.001 M …

What is dilution test in microbiology?

The tube dilution test is the standard method for determining levels of resistance to an antibiotic. Serial dilutions of the antibiotic are made in a liquid medium which is inoculated with a standardized number of organisms and incubated for a prescribed time.

What are the advantages of using serial dilution?

The Advantages of Serial Dilution

  • Errors.
  • Easier and Faster Preparation of Calibration Standards.
  • Calibrations Solutions More Evenly Spaced.
  • Greater Variability in Calibration Range.

What is a 5 fold serial dilution?

“It was a 5 fold dilution” “It was diluted 1/5″ These all mean the same thing, that there is 1 volume part of sample and 4 volume parts of whatever liquid is being used to dilute the sample for a total of 5 volume parts.

Why is saline used for serial dilution?

Serial dilution or culture suspension used saline solution (0.9% Nacl) because 0.9% sodium chloride (Nacl) solution is isotonic in nature. In isotonic solution the concentration of solutes remains the same both inside and outside of the microbial cell and cells remains at their usual osmotic pressure.

How do you perform a dilution test?

Use-Dilution Test For this test, a cylinder of stainless steel is dipped in a culture of the targeted microorganism and then dried. The cylinder is then dipped in solutions of disinfectant at various concentrations for a specified amount of time.

How dilution is done?

Dilution is the process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to the solution. To dilute a solution means to add more solvent without the addition of more solute.

What is serial dilution in microbiology?

A serial dilution is a series of sequential dilutions used to reduce a dense culture of cells to a more usable concentration. The easiest method is to make a series of 1 in 10 dilutions.

What is the purpose of the dilution protocol?

The following protocol is a step-by-step procedure to working dilution problems, and includes some practice problems at the end. The purpose can be determination of bacterial, fungal, or viral counts (commonly called colony – forming units, CFUs, for bacterial or fungal counts, or plaque – forming units, PFUs, for viral counts).

How do I dilute my original bacterial culture?

To start, we need 10 milliliters (10 ml) of your original bacterial culture (labeled OBC). Before we start diluting, we need to prepare several dilution blanks, which are tubes containing your diluting liquid in exact quantities. Your liquid could be growth media, saline, sterile water, or any other appropriate liquid.

What does 1 in 10 dilution mean?

You just performed a 1 in 10 dilution, or it could be written 1/10. 1 is the volume you transferred, and 10 is the final volume of the tube after the transfer. Now, you are done with tube OBC, and Tube 1 becomes the next tube to be diluted.