Demonstrating laboratory proficiency in bacterial mutagenicity assays for regulatory submission

Introduction:
This text outlines the steps and recommendations for laboratories to demonstrate proficiency in conducting the bacterial reverse mutation assay, also known as the ames test, for regulatory submissions. The text includes detailed guidelines for test conduct, quality control, and data interpretation. By following these recommendations, laboratories can establish usable historical control databases and gain sufficient experience in conducting the assay, including practice with challenging test articles.

Key Points:

* The bacterial reverse mutation assay is a microbial mutagenesis test used to evaluate the mutagenic potential of a test substance and predict its carcinogenic potential.
* The assay uses mutant strains of Salmonella typhimurium and/or Escherichia coli and tests the substance alone and in parallel with a liver microsomal enzyme activation system.
* Laboratories should establish genotype and proper strain growth conditions, create a laboratory cell bank, and use growth curves to demonstrate the ability to generate cells in early stationary phase.
* Performance of each batch of metabolic activation mix should be demonstrated by evaluating the enzymatic capability of the batch and the performance of in-house positive controls.
* Laboratories should establish historical control databases for positive and solvent/vehicle controls, with and without metabolic activation.
* Test proficiency compounds should be used to obtain expected results and generate data for historical control ranges.
* Careful attention to bacterial strain management and optimal culture conditions are essential for generating reliable and robust ames test data.

Main Message:
The bacterial reverse mutation assay is a critical test for regulatory submissions to evaluate the mutagenic potential of a test substance. The recommendations outlined in this text provide detailed guidelines for laboratories to establish usable historical control databases and gain sufficient experience in conducting the assay. By following these recommendations, laboratories can ensure the reliability and robustness of their ames test data and meet regulatory requirements.

Levy, Dan D., atsushi hakura, Rosalie K. Elespuru, Patricia a. Escobar, Masayuki Kato, Jasmin Lott, Martha M. Moore, and Kei-ichi Sugiyama. “Demonstrating Laboratory Proficiency in Bacterial Mutagenicity assays for Regulatory Submission.” Mutation Research/Genetic Toxicology and Environmental Mutagenesis 848 (December 2019): 403075. https://doi.org/10.1016/j.mrgentox.2019.07.005.