 | The 131st Annual Meeting (November 15-19, 2003) of APHA |
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| The 131st Annual Meeting (November 15-19, 2003) of APHA |
Teresa N. Quitugua, PhD1, R. Scott Spurgiesz, BS2, Kimothy L Smith, DVM, PhD3, James L Schupp, PhD2, Rebecca A. Cox, PhD1, and Paul Keim, PhD2. (1) Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245, 210-562-5035, quitugua@uthscsa.edu, (2) Department of Biological Sciences, Northern Arizona University, 500 South Beaver Street, Flagstaff, AZ 86011, (3) Biodefense Division, Lawrence Livermore National Laboratory, 7000 East avenue, L-452, Livermore, CA 94550
Rapid genotyping of Mycobacterium tuberculosis isolates is needed to track transmission and investigate cases of specimen cross-contamination. Investigations are currently hampered by techniques that do not attain the level of strain discrimination required, or do not lend themselves to fast, simple assays. We identified 87 short sequence repeat (SSR) loci within the genome of M. tuberculosis and screened them across a set of 122 clinical M. tuberculosis isolates from persons residing in Texas. Nine of the SSRs were variable across this limited strain set. These SSRs differentiate a variety of M. tuberculosis strains, including strains difficult to distinguish by other PCR-based methods. Although Beijing strains share the same spoligotype, SSR analysis grouped 10 Beijing family strains into seven distinct genotypes. Similarly, SSR analysis differentiated isolates having one of three 4-band IS6110 RFLP patterns. These isolates shared spoligotypes that predominate across a broad range of strains having less than 6 IS6110 insertions. The isolates were split into eight groups by spoligotyping, nine by SSR analysis, and 14 by combining the methods. Since we aim to identify genetic elements whose mutation rate coincides with transmission and disease progression, we analyzed 66 isolates from persons with and without personal contact, and previously genotyped via IS6110 RFLP and spoligotyping by other investigators. Our groupings were consistent with previous genotyping and contact investigation results. SSR loci provide a useful extension of variable nucleotide tandem repeat (VNTR) typing methods for application to molecular epidemiologic studies of M. tuberculosis, particularly when used in combination with spoligotyping.
Learning Objectives:
Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: University of Texas Health Science Center at San Antonio, Northern Arizona University, Lawrence Livermore National Lab, Public Health Research Institute, Baylor University, California Department of Health, University of North Texas Health Science Center
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.