Preparation of Bacterial Smear

Preparation of Bacterial Smear 

Aim

To prepare a bacterial smear for staining

Principle

For staining preparation of a thin uniform smear is essential.  The purpose of smear preparation is to fix the bacteria onto the slide and to prevent the bacterial cells from being lost during the staining procedure. A smear can be prepared from either from a solid or broth culture.

Materials required

Clean glass slide, Bacterial culture, Inoculation loop, Bunsen Burner, etc

Procedure

1.      A microscopic slide was cleaned thoroughly and was labelled and a central area was marked by drawing a circle with a diameter about 2 cm using a marker at the bottom side of the slide

2.      An inoculation loop was sterilized by flaming it until making it red hot and then allowed to cool down.

3.      If the bacterial culture is a broth, the culture was shaken well and using the sterilized loop a loopful of broth was transferred to the center of the slide and spread over the target circle. If the bacteria were grown on solid medium, a loopful of water was placed on the center of the slide to which a loopful of inoculum was transferred and mixed completely and spread into a smear.

4.      After spreading the smear, the loop was again flame sterilized.

5.      The smear was left at room temperature to air dry.

6.      After air drying, the slide was gently passed over the flame to heat fix the smear.

Results

A bacterial smear was prepared.