SPADA Meeting Book

from different sources and are often not qualified/certified to the same set of standards, making it 24 difficult for results to be confidently compared. 25 One way to limit and monitor the genetic drift in laboratory handled strains is by encouraging 26 researchers and culture producers to carefully document the histories of bacterial cultures and 27 routinely screen them for divergent genotypic or phenotypic signatures. This guideline 28 establishes a framework for investigators to use in documenting the relationships among 29 microbial cultures used in well-documented studies. 30

2.0 Objectives

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These guidelines establish the roles and responsibilities for sponsors, performers, and culture 32 producers with respect to the verification of relatedness among test and index cultures used in an 33 extensible study. While not broadly enforceable, the guidelines are intended to create a 34 framework and set of expectations for properly qualifying and documenting the provenance of 35 microbial cultures used in scientific studies. 36

3.0 Concepts and Definitions

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( a ) An extensible study is a research program whose results and conclusions are expected to

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apply equally to test and index cultures.

( b ) In an extensible study, the test culture is the microbial culture that is being evaluated. 40 The index culture is the culture to which the assay results are to be applied. 41 42 well-documented number (e.g., lot/batch/subculture, etc., as appropriate) and propagation 43 history. 44 ( d ) Extensible studies are generally supported by: 45 ( c ) Both the test and index cultures must be traceable cultures , meaning that each has a

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