Lab 10 Colony isolation

Mixed culture and unknown

Cultivation

 The process of growing microorganisms in culture by taking bacteria from the infection site (in vivo or environment) and grow them in artificial environment in the laboratory (in vitro).

Colony- (clone)

 Colony- A bacterial population derived from one bacterial cell. The cells within the colony have identical, genus, species, genetic and phenotypic characteristics.

 Mixed culture- contains more than one type of colony  Pure bacteria/ culture - derived from a single colony.

Isolation of bacteria - Dilution

 Selection of a pure colony from a mixed culture most important for bacterial identification  The inoculum is spread on the surface of an agar plate in such a pattern so that individual bacterial colonies are obtained.  Dilution of the original inoculum such that the colonies grow separate from each other

Streak Plate technique

Mixed culture

Example 1: Good single colony isolation?

Example 2: Good single colony isolation?

Example 3: Good single colony isolation?

Lab activities:

 Streaking bacteria for isolation : 

From a mixed culture / student

 2xNA plates /student @ 37 o c 

From unknown / student

 NA, BHI, DSA @ 37 o c  NA, BHI, DSA @ room temperature (RT)