Tips On How To Carry Out Culture And Sensitivity Test

Culture and sensitivity test

A culture is a test used for germs diagnosis (such as bacteria or a fungus) that can cause an infection.

A sensitivity test is to check what kind of medicine, such as an antibiotic, will work best to treat the illness or infection.

For culture to take place, sample from body fluid or tissue is added to a substance that promotes the growth of germs. If no germs grow, the culture is negative. If germs grows, the culture is positive. The type of germ is known using a microscope or chemical tests. Bacteria usually grow quickly in a culture (48hrs), while other types of organisms, such as a fungus, can take longer.

Culture and sensitivity test can be carried out on many different body fluids, such as urine, mucus, blood, pus, saliva, breast milk, spinal fluid, or discharge from the vagina or penis.
An organism is cultured in a media which serves as food and it incubated, there are different type of media which are made of differ agar which includes
  • Blood agar 
  • Chocolate agar 
  • Neomycin agar 
  •  Sabouraud agar 
  • Thayer-Martin agar 
  • XLD agar 
  • Nutrient agar 
  • Hay Infusion agar 
  • MacConkey agar - growth of Gram positive bacteria.

 Material used in preparation of media

1) Agar (powdered)
2) Conical flask
3)distilled water
4) Bunsen burner
6) Tube holder
7) Petri dish

 Procedure in making a media

1) Put the conical flask on a weighing balance
2) According to the quantity of media needed measure a certain amount of agar into the conical flask
3) Pour the corresponding amount of distilled water into the conical flask
4) Allow mixture to dissolve properly
5) Heat slolution for about twenty (20) minutes
6) Distribute into different sterile petri dish and close
7) Allow solution to solidify
8) Place properly into the incubator
9) When is dried completely store in the refrigerator

 Precautions taken

1) I made sure I handle the glassware properly to avoid accident.
2) I made sure I didn't handle the conical flask with my bare hands after it has been heated.
3) I made sure I didn't talk while pouring the solution into the sterile petri dish and also while placing it in the incubator.
How to culture a sample

Material used

1) Body fluid sample
2) Media
3) Inoculating loop


1) Deep the inoculating loop into the sample and put it on the prepared media then sterilize the loop by burning or sample can be put using swab stick.
2) Put in the incubator allow for 48hrs to 72hrs.
3) Observation and identification of pathogens.

Post a Comment