Table 2.

Required Discriminatory Power and Need to Infer Genetic Relationships and/or Population Structure for Various Epidemiologic Applications of Bacterial Typing Techniques

Purpose	Example Research Goal	Discriminatory Power Needed	Need to infer genetic relationships and/or population structure
Confirm epidemiologic linkage	a. Determine if epidemiologically related cases share the identical organism. Result: either support or refute epidemiologic data.	Low	Low
Generate hypotheses about epidemiologic relationships between bacterial strains in the absence of epidemiologic data	a. Determine if time-space clustering surveillance isolates have identical or related genetic types. Result: trigger further epidemiologic investigation of related isolates. b. Determine if outbreak is propagated. Result: trigger investigation into how is spread and/or control actions to stop spread. c. Relate clinical outcomes to strain types or to the presence of transferable genetic material, e.g., antimicrobial resistance on a plasmid. Result: improve patient care.	Moderate to High	Moderate
Describe distribution of bacterial types and identify the determinants of that distribution	a. Test the hypothesis of clonal spread versus independent origin of a particular strain over disparate geographic areas. Result: Better predict emergence and spread of disease. b. Determine flow of infection from one group to another. Result: Public health intervention c. Identification of pathogenic factors. Result: Develop new interventions or therapies specific to those factors	Moderate to High	High