title: Contributions of molecular epidemiology to the understanding of infectious disease transmission, pathogenesis, and evolution.
abstract: OBJECTIVE
  Describe the contributions of molecular genetics to our understanding of the molecular epidemiology of infectious diseases caused by bacteria.
  
  
  METHODS
  Synthesize the literature, highlighting work on Escherichia coli and Group B streptococcus.
  
  
  RESULTS
  1) Commensal bacteria are genetically and phenotypically diverse. 2) Disease-causing strains of commensal bacteria often have special characteristics than allow them to be distinguished from common inhabitants. 3) Colonization by commensal bacteria is dynamic. 4) Commensal bacteria are transmitted between individuals.
  
  
  CONCLUSIONS
  Applications of epidemiologic principles to bacterial populations gives insight into the natural history of colonization and transmission in the human host.
authors.affiliation: Center for Molecular and Clinical Epidemiology of Infectious Diseases, Department of Epidemiology, University of Michigan School of Public Health, 109 Observatory Street, Ann Arbor, MI 48109, USA. bfoxman@umich.edu
authors.forename: Betsy
authors.initials: B
authors.lastname: Foxman
mesh_terms: D001424:Bacterial Infections / Q000235:genetics / Q000473:pathology / Q000635:transmission; D006801:Humans; D017720:Molecular Epidemiology; D014481:United States