Download Bacterial cultivation

Lab 10Colony 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 @ 37oc
 From
unknown / student

NA, BHI, DSA @ 37oc

NA, BHI, DSA @ room temperature (RT)