OECD Guideline for Testing of Chemicals: Bacterial Reverse Mutation Test

Introduction:
This text outlines the OECD guideline for the bacterial reverse mutation test, also known as the ames test, which is used to detect point mutations in bacteria caused by exposure to a test substance. The test is widely used as an initial screen for genotoxic activity, particularly for point mutation-inducing activity. The guideline covers the test methodology, including the use of Salmonella typhimurium and Escherichia coli strains, metabolic activation, and data interpretation.

Key Points:

* The ames test uses amino-acid requiring strains of Salmonella typhimurium and Escherichia coli to detect point mutations.
* The test detects mutations that revert mutations present in the test strains and restore the functional capability of the bacteria to synthesize an essential amino acid.
* The test strains have features that make them more sensitive for the detection of mutations, including responsive DNa sequences at the reversion sites, increased cell permeability to large molecules, and elimination of DNa repair systems.
* The test is rapid, inexpensive, and relatively easy to perform and has a very large data base of results for a wide variety of structures.
* The test does not provide direct information on the mutagenic and carcinogenic potency of a substance in mammals.
* The guideline outlines the test methodology, including the use of Salmonella typhimurium and Escherichia coli strains, metabolic activation, and data interpretation.
* The test may not be appropriate for the evaluation of certain classes of chemicals, such as highly bactericidal compounds and those that interfere specifically with the mammalian cell replication system.

Main Message:
The OECD guideline for the bacterial reverse mutation test provides a standardized methodology for detecting point mutations in bacteria caused by exposure to a test substance. The test is widely used as an initial screen for genotoxic activity, but it is important to note that it does not provide direct information on the mutagenic and carcinogenic potency of a substance in mammals. additionally, the test may not be appropriate for the evaluation of certain classes of chemicals, and it is crucial to consider the limitations and appropriate use of the test.

“OECD Guideline for Testing of Chemicals: Bacterial Reverse Mutation Test.” OECD, 1997.