Study Notes: Flow Chart of Identification Process for Bacteria
The processes involved in the identification of bacteria can be
standardised and systematised to follow a logical progression.
In this example you will follow the process for the identification
of the organism responsible for the food infection of Barbara Bunter
(sample SL2004/4). Barbara was apparently affected after eating
a number of cream and custard filled buns.
Gram-positive cocci were isolated from an uneaten bun. This result
excludes a number of other possible organisms such as Escherichia
coli, Shigella sp. and Salmonella sp. (gram-negative
rods), Clostridium perfringens (gram-positive rods) and Campylobacter
sp. (gram-negative thin curved rods). From the details of the
case including the symptoms, rapid onset of symptoms and type of
food, it is likely to be caused by Staphylococcus aureus
but we cannot guess in diagnostic microbiology.
The following flow chart demonstrates the process of identifying
the causative agent in this case. Click to start, then click on
the name of each test as they appear in the flow chart, to view
the results for that test, to complete the identification process.
Take note of the results, as you will need these in the next activity.