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Background: Directly observed therapy (DOT) is a widely recommended and promoted strategy to manage tuberculosis (TB), however, there is still disagreement about the role of DOT in TB control and the impact it has on reducing the acquisition and transmission of drug resistant TB. This study compares the portion of drug resistant genotype clusters, representing recent transmission, within and between communities implementing programs differing only in their directly observed therapy (DOT) practices., Methods: Genotype clusters were defined as 2 or more patient members with matching IS6110 restriction fragment length polymorphism (RFLP) and spoligotype patterns from all culture-positive tuberculosis cases diagnosed between January 1, 1995 and December 31, 2001. Logistic regression was used to compute maximum-likelihood estimates of odds ratios (ORs) and 95% confidence intervals (CIs) comparing cluster members with and without drug resistant isolates. In the universal DOT county, all patients received doses under direct observation of health department staff; whereas in selective DOT county, the majority of received patients doses under direct observation of health department staff, while some were able to self-administer doses., Results: Isolates from 1,706 persons collected during 1,721 episodes of tuberculosis were genotyped. Cluster members from the selective DOT county were more than twice as likely than cluster members from the universal DOT county to have at least one isolate resistant to isoniazid, rifampin, and/or ethambutol (OR = 2.3, 95% CI: 1.7, 3.1). Selective DOT county isolates were nearly 5 times more likely than universal DOT county isolates to belong to clusters with at least 2 resistant isolates having identical resistance patterns (OR = 4.7, 95% CI: 2.9, 7.6)., Conclusions: Universal DOT for tuberculosis is associated with a decrease in the acquisition and transmission of resistant tuberculosis.

Rationale and Objectives: Identifying and treating persons with latent tuberculosis (TB) infection (LTBI) at high risk for developing TB is part of the current TB elimination strategy. There are no specific criteria, other than medical risks, to designate groups as high risk for developing TB. We hypothesized that, if location-based screenings were done in communities where persons with genotypically clustered Mycobacterium tuberculosis resided, then persons with LTBI from recent transmission and with undiagnosed TB could be identified., Methods: Location-based TB screenings were done in partnership with multiple community-based organizations using resources previously used for other types of screening., Main Results: Location-based screenings identified one person with TB for every 83 screened, and one person with LTBI for every five screened. The yield of this targeted screening program for discovering persons with TB and LTBI exceeded what would be expected from nontargeted screening in a county with a TB incidence of 5.7 per 100,000 population., Conclusions: Genotyping combined with geographic information systems analysis can potentially be used to define high-risk status and to define areas for location-based TB screenings.

Purpose: Evaluation improves efficiency and effectiveness. Current U.S. tuberculosis (TB) control policies emphasize the treatment of latent TB infection (LTBI). However, this policy, if not targeted, may be inefficient. We determined the efficiency of a state-law mandated TB screening program and a non state-law mandated one in terms of cost, morbidity, treatment, and disease averted., Methods: We evaluated two publicly funded metropolitan TB prevention and control programs through retrospective analyses and modeling. Main outcomes measured were TB incidence and prevalence, TB cases averted, and cost., Results: A non state-law mandated TB program for homeless persons in Tarrant County screened 4.5 persons to identify one with LTBI and 82 persons to identify one with TB. A state-law mandated TB program for jail inmates screened 109 persons to identify one with LTBI and 3274 persons to identify one with TB. The number of patients with LTBI treated to prevent one TB case was 12.1 and 15.3 for the homeless and jail inmate TB programs, respectively. Treatment of LTBI by the homeless and jail inmate TB screening programs will avert 11.9 and 7.9 TB cases at a cost of 14,350 US dollars and 34,761 US dollars per TB case, respectively., Conclusions: Mandated TB screening programs should be risk-based, not population-based. Non mandated targeted testing for TB in congregate settings for the homeless was more efficient than state-law mandated targeted testing for TB among jailed inmates.

Setting: Urban county health department in Tarrant County, Texas, USA., Objective: To determine the yield of associate investigations in non-bacille Calmette-Guerin (BCG) immunized children with positive tuberculin skin tests (TSTs)., Design: We compared the results of associate investigations of the contacts of 38 TST-positive, non-BCG-immunized pre-school children with the results of contact investigations of 290 culture-confirmed persons with tuberculosis (TB)., Results: Associate investigations were more likely than contact investigations to identify persons with culture-confirmed TB and positive TSTs. Contacts identified through associate investigation of non-BCG-immunized pre-school children were 9.4 (95%CI 4.2-22.5) times more likely to have culture-confirmed TB and 2.3 (95%CI 2.0-2.7) times more likely to have positive TSTs than contacts of persons with culture-confirmed TB., Conclusion: While conducting associate investigations is labor intensive, these data indicate that associate investigation of pre-school non-BCG-immunized children should be assigned priority in TB control activities, at least equal to the importance of investigating the contacts of culture-proven TB.