Genomic Markers for Differentiation of Francisella tularensis subsp. Tularensis A.I and A.II

Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO., Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO

^* To whom correspondence should be addressed. Email: JPetersen{at}cdc.gov.

	Abstract

Tularemia is caused primarily by two subspecies of Francisella tularensis, tularensis (type A) and holarctica (type B). F. tularensis subsp. tularensis is further subdivided into two genetically distinct populations (A.I and A.II) that differ with respect to geographical location, anatomical source of recovered isolates, and disease outcome. Using two human clinical isolates, genomic suppression subtractive hybridization (SSH) was performed to identify thirteen genomic regions of difference (RDs) between A.I and A.II strains. Two PCR assays, one to identify A.I and A.II as well as to discriminate from F. tularensis subsp. holarctica and F. novicida, and another specific for A.I were developed. This is the first report to identify and characterize conserved genomic differences between A.I and A.II.