1.
Inoculation: In
this procedure a small sample of microbes, called the inoculum,
is transferred into a container of sterile culture medium that consists of
nutrients that will sustain their growth. The transfer can be made with
sterile swabs, pipettes, syringes, or inoculating wires. The microbial
specimen can come from many different sources. These include water, food,
soil, sewage, air, inanimate objects, body fluids, discharges, tissues, or prepared
stock cultures.
2.
Incubation:
After inoculation, microbial cultures are usually placed into a
temperature-controlled environment to facilitate their growth. The
instrument used for this procedure is called an incubator. The
length of time for incubation will vary depending on how rapidly the microbes
multiply at a given temperature. Periods of incubation could last hours,
days, or even
weeks.
3.
Isolation:
This procedure involves separating out individual cells from one another so
each can be grown into separate, observable colonies on a nutrient
surface. Isolation is commonly used to separate species from samples that
may contain a mixture of species. Methods used to do this include the streak
plate method and the loop dilution (or pour plate) method.
4.
Inspection:
This involves either macroscopic or microscopic observations.
Cultures can be visually inspected to analyze growth characteristics such as
the size, color, and texture of colonies .
Microscopically, morphological information can be gathered by observing
microbes mounted on glass slides. This includes determining cell size,
cell shape, cell arrangements, and motility.
5.
Identification: This procedure involves
collecting several types of data to identify microbes down to the species
level. The information used during this
procedure may include cultural characteristics, morphological traits, staining
reactions, biochemical tests, immunological tests, and DNA analysis.