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Updated: Oct 2, 2026
DNA Fingerprinting of Mycobacterium leprae Strains Using Variable Number Tandem Repeat (VNTR) - Fragment Length Analysis (FLA)
Published on: July 15, 2011
Restriction fragment length polymorphism screening of Mycobacterium tuberculosis isolates: population surveillance
M E Kimerling1, W H Benjamin, K H Lok
1Division of International Health, School of Public Health, University of Alabama at Birmingham, 35294-0022, USA. kimerlin@uab.edu
Setting:
Alabama State Tuberculosis Control Program, USA.
Objective:
To combine molecular screening data with routine information to assess transmission of Mycobacterium tuberculosis and improve control efforts.
Design:
Since January 1994, samples from tuberculosis cases statewide have been systematically analyzed by IS6110 restriction fragment length polymorphism (RFLP). All cases during 1994-1995 with a predominate RFLP pattern were evaluated and risk factors assessed. pTBN12 was used to evaluate a large cluster in the Birmingham-Jefferson County (BJC) area.
Results:
Statewide, a common two-band pattern was found, named JH2 (99/566, 17.5%). The most important risk associated with this pattern was homelessness (odds ratio, 8.9; P < 0.001). In the BJC area, the homeless accounted for 29% (51/175) of new cases diagnosed during the study period. For the BJC homeless, there were 13 unique RFLP patterns, and JH2 was predominant (29/33, 88%) among three clusters. Secondary analysis of the homeless JH2 cluster revealed a large group that included 19 of 24 (79%) isolates analyzed. Compared with the BJC non homeless (n = 124), the homeless were younger (P < 0.001), of male gender (P < 0.001), black race (P = 0.002), and were heavy alcohol (P < 0.001) and non-injection drug (P = 0.001) users.
Conclusions:
By screening tuberculosis cases statewide, a common two-band RFLP pattern was identified. Its predominance is explained by an ongoing tuberculosis epidemic among Birmingham's homeless population, highlighting RFLP as a tool for population surveillance. The pattern differences observed by pTBN12 typing clearly demonstrate that the isolates might be related but are not clonal.
