Exploring genotype concordance in epidemiologically linked cases of tuberculosis in New York City.

Comparing genotype results of tuberculosis (TB) isolates from individuals diagnosed with TB can support or refute transmission; however, these conclusions are based upon the criteria used to define a genotype match. We used a genotype-match definition which allowed for variation in IS6110 restriction fragment length polymorphism (RFLP) to support transmission between epidemiologically linked persons. Contacts of individuals with infectious TB (index cases) diagnosed in New York City from 1997 to 2003 who subsequently developed TB (contact cases) from 1997 to 2007 were identified. For each contact case and index case (case-pair), isolate genotypes (spoligotype and RFLP results) were evaluated. Isolates from case-pairs were classified as exact or non-exact genotype match. Genotypes from non-exact match case-pairs were reviewed at the genotyping laboratory to determine if the isolates met the near-genotype-match criteria (exactly matching spoligotype and similar RFLP banding patterns). Of 118 case-pairs identified, isolates from 83 (70%) had exactly matching genotypes and 14 (12%) had nearly matching genotypes (supporting transmission), while the remaining 21 (18%) case-pairs had discordant genotypes (refuting transmission). Using identical genotype-match criteria for isolates from case-pairs epidemiologically linked through contact investigation may lead to underestimation of transmission. TB programmes should consider the value of expanding genotype-match criteria to more accurately assess transmission between such cases.

Health care provider perspectives on tuberculosis care for foreign-born populations in New York City.

BACKGROUND: Tuberculosis (TB) in foreign-born patients is a key determinant of TB epidemiology in low-burden settings. In New York City (NYC), foreign-born TB populations are heterogeneous and face diverse challenges in accessing care. OBJECTIVE: To characterize barriers and facilitators to health care services and identify potential mechanisms to improve TB care for foreign-born patients in NYC. DESIGN: Semi-structured interviews with health care providers identified through the NYC TB registry and snowball sampling. Transcripts were analyzed using a modified grounded theory approach. RESULTS: Fourteen providers from private practice (21%), community clinic (36%), and hospitals (43%) were interviewed. Barriers clustered into thematic areas: interrelated social and economic issues that impact TB care and treatment (documentation status, poverty, mental/behavioral health issues), challenges of fragmented health system (care continuity, costs), latent tuberculous infection, and relative lack of resources and significant barriers for clinic and private practice providers. Health care providers' deep commitment to foreign-born TB patients was evidenced by their attitudes and actions. CONCLUSION: Improving access to TB care for foreign-born patients in NYC requires strategies that address specific social, economic and structural barriers. Improving linkages between private providers and public health initiatives is a key challenge. Health care providers' commitment to foreign-born communities is a significant resource.