French AL, Welber SF, Dietrich SE, et al. Use of DNA fingerprinting to assess tuberculosis infection control. Ann Intern Med 1998; 129:856-861.

Because it illustrates genetic relatedness among strains of Mycobacterium tuberculosis, DNA fingerprinting has been used to confirm outbreaks of disease and laboratory cross-contamination. The authors hypothesized that routine DNA fingerprinting, done by using restriction fragment length polymorphism analysis, could be used to enhance hospital infection control surveillance for patient-to-patient transmission of TB.

The authors used DNA fingerprinting to analyze 173 TB isolates over a one-year period. Ana lysis revealed that five isolates represented false-positive cultures and that 91 (54%) of the remaining 168 isolates were in 15 DNA fingerprinting clusters, which ranged in size from two to 29 isolates. However, retrospective epidemiologic analysis of inpatient and outpatient visits by the 91 patients who had clustered isolates revealed only one possible instance of patient-to-patient transmission.

"However, these results did not lead to changes in infection-control practices or in clinical care," the authors note. "The study findings do not support the use of DNA fingerprinting for nosocomial tuberculosis surveillance, but they suggest that compliance with the CDC tuberculosis infection-control guidelines may control patient-to-patient transmission in high-risk urban hospitals."