Hi all,

This lab about testing the effect of disinfectants and antibiotics on the growth of microorganisms. Please study the Exercise in the lab manual. In this exercise, a bacterial culture is spread over a plate completely and various paper discs, each saturated with a different disinfectant or antibiotic, are disposed on the plate in an equidistance fashion and the plate is incubated overnight. The plate is then analyzed for the growth of culture with respect to a given disc. If bacterial strain is sensitive, meaning it is killed/inhibited by what is in this disc, then bacteria will not grow around the disc forming a large “no-growth-zone” or “growth-inhibition-zone.” If the bacterial strain is resistant to the disinfectant/antibiotic, it will grow close to/into the disc forming a very small “no-growth-zone.” The diameter of this zone is then measured in millimeter (mm) and recorded. This data is then compared to a reference table to identify if the microorganism is resistant or sensitive to the disinfectant/antibiotic in that particular disc. See example-1 and example-2plates.

In the lab, each group would culture a separate bacterial strain on 4 plates and dispense various discs on each plate: two plates would get 8 discs each with a different antibiotics and the other two plates would get 8 discs each with a different disinfectants (see the names of each antibiotic and disinfectant in the first two tables). For the assignment, download this Lab Exercise 10 worksheet, answer the questions and fill the tables according to the data populated in the first two tables. Make sure you calculate the averages in last columns and last rows also. Then, upload your file to this assignment.

Hope you enjoy it.