Geo-epidemiologic and molecular characterization to identify social, cultural, and economic factors where targeted tuberculosis control activities can reduce incidence in Maryland, 2004-2010.

OBJECTIVES: Tuberculosis (TB) disproportionately affects members of socioeconomically disadvantaged and minority populations in the U.S. We describe the geospatial distribution of TB cases in Maryland, identify areas at high risk for TB, and compare the geospatial clustering of cases with genotype clustering and demographic, socioeconomic, and TB risk-factor information. METHODS: Addresses of culture-positive, genotyped TB cases reported to the Maryland Department of Health and Mental Hygiene from January 1, 2004, to December 31, 2010, were geocoded and aggregated to census tracts. Geospatial clusters with higher-than-expected case numbers were identified using Poisson spatial cluster analysis. Case distribution and geospatial clustering information were compared with (1) genotype clustering (spoligotypes and 12-locus MIRU-VNTR), (2) individual-level risk and demographic data, and (3) census tract-level demographic and socioeconomic data. RESULTS: We genotoyped 1,384 (98%) isolates from 1,409 culture-positive TB cases. Two geospatial clusters were found: one in Baltimore City and one in Montgomery and Prince George's counties. Cases in these geospatial clusters were equally or less likely to share genotypes than cases outside the geospatial clusters. The two geospatial clusters had poverty and crowding in common but differed significantly by risk populations and behaviors. CONCLUSIONS: Genotyping results indicated that recent transmission did not explain most geospatial clustering, suggesting that geospatial clustering is largely mitigated by social determinants. Analyses combining geospatial, genotyping, and epidemiologic data can help characterize populations most at risk for TB and inform the design of targeted interventions.

Tuberculosis control in a large urban jail: discordance between policy and reality.

OBJECTIVE: This study evaluated adherence to tuberculosis control guidelines, published by the Centers for Disease Control and Prevention in 1996, in a large urban jail. Jails are a critical locale because of high risk for tuberculosis transmission in a congregate setting. METHODS: Symptom screening at intake into the facility was systematically observed. Medical records were reviewed to measure timing of tuberculin skin testing (TST) and chest radiograph (CXR) screening. Isolation records were examined for airborne infectious isolation practices. Contact investigation practices were evaluated for ease of data retrieval and adherence to CDC guidelines. RESULTS: A TB symptom screening question was asked correctly during 28/97 of intake health interviews. Median time from intake to TST was 3 days for men and 2 days for women. Median time from referral to CXR was 2 days for men and 7 days for women. Delays were noted in diagnostic testing of 51 detainees isolated for suspected TB. Contact investigations lacked comprehensive procedures, data collection forms, and databases for managing information. CONCLUSION: Findings were used to refine protocols for TB control. This evaluation illustrated the need for ongoing assessment of adherence to TB control protocols in short-term correctional settings to prevent the spread of TB.

Improved adherence and less toxicity with rifampin vs isoniazid for treatment of latent tuberculosis: a retrospective study.

BACKGROUND: Treatment of latent tuberculosis infection (LTBI) is an important aspect of tuberculosis control in the United States, but the effectiveness of this strategy is compromised by poor adherence to the recommended 9-month isoniazid regimen. In this study, we compared treatment completion and clinically recognized adverse drug reactions in patients prescribed 9 months of isoniazid therapy or 4 months of rifampin therapy for LTBI. METHODS: Retrospective chart review of patients who received LTBI treatment at a public health clinic. RESULTS: A total of 770 patients were prescribed 9 months of isoniazid therapy, and 1379 patients were prescribed 4 months of rifampin therapy. The percentages of patients who completed 80% or more of their prescribed treatment were 52.6% and 71.6% in the isoniazid and rifampin groups, respectively (P<.001). In multivariate logistic regression analysis, treatment regimen was independently associated with treatment completion (adjusted odds ratio for treatment completion, 2.88 for rifampin group vs isoniazid group; 95% confidence interval, 2.27-3.66). Clinically recognized adverse reactions resulting in permanent treatment discontinuation occurred in 4.6% and 1.9% of patients in the isoniazid and rifampin groups, respectively (P<.001). Clinically recognized hepatotoxicity was more common in the isoniazid group (1.8%) than in the rifampin group (0.08%, P<.001). CONCLUSIONS: Compared with a 9-month isoniazid regimen, a 4-month rifampin regimen was associated with a higher percentage of patients completing treatment and a lower percentage of patients with clinically recognized adverse reactions. Additional studies are warranted to determine efficacy and effectiveness of rifampin therapy for LTBI.

Molecular epidemiology of pleural and other extrapulmonary tuberculosis: a Maryland state review.

BACKGROUND: Limited information exists about the current epidemiological characteristics of extrapulmonary tuberculosis. However, pleural tuberculosis is usually considered to be a manifestation of primary tuberculosis. Our objective was to use molecular epidemiological techniques to describe the occurrence of pleural and other extrapulmonary tuberculosis in Maryland, a state with moderate tuberculosis incidence. METHODS: We surveyed tuberculosis cases reported with a single site of disease in Maryland from 1996 through 2001. Genotyping of Mycobacterium tuberculosis isolates was performed with an IS6110-based restriction fragment-length polymorphism analysis. DNA clustering of strains with >5 IS6110 bands, with supporting epidemiologic information on patients, served as a proxy for recent transmission. RESULTS: A total of 1811 patients with tuberculosis were reported (incidence, 5.9 cases per 100,000 population). Of 1411 patients (77.9%) with cultures positive for M. tuberculosis, 1246 (88.3%) had a single site of disease, with 934 (75.0%) of these isolates having >5 IS6110 bands. Of the 934 patients included in the analyses, 729 (78.0%) had pulmonary tuberculosis, and 205 (22.0%) had extrapulmonary tuberculosis; of the latter group, 46 patients had pleural disease, and 159 patients had nonrespiratory disease. In multivariate analyses, patients with pleural tuberculosis were not significantly associated with clustered strains, compared with patients with nonrespiratory or pulmonary tuberculosis disease. Having a DNA-clustered strain was negatively associated with nonrespiratory tuberculosis, compared with pulmonary disease (adjusted odds ratio, 0.48; P = .003). CONCLUSIONS: Nonrespiratory extrapulmonary tuberculosis is less likely than pulmonary tuberculosis to be a result of recent infection. Pleural tuberculosis is not an appropriate indicator for recent transmission among our population.

Cross-jurisdictional transmission of Mycobacterium tuberculosis in Maryland and Washington, D C, 1996-2000, linked to the homeless.

From 1996 to 2000, 23 Maryland and Washington, D.C., tuberculosis cases were identified in one six-band DNA cluster. Cases were clustered on the basis of their Mycobacterium tuberculosis isolates. Medical record reviews and interviews were conducted to identify epidemiologic linkages. Eighteen (78%) of the 23 case-patients with identical restriction fragment length polymorphism patterns were linked to another member; half the patients were associated with a Washington, D.C., homeless shelter. Molecular epidemiology defined the extent of this large, cross-jurisdictional outbreak.

Molecular epidemiology of tuberculosis in a low- to moderate-incidence state: are contact investigations enough?

To assess the circumstances of recent transmission of tuberculosis (TB) (progression to active disease <2 years after infection), we obtained DNA fingerprints for 1172 (99%) of 1179 Mycobacterium tuberculosis isolates collected from Maryland TB patients from 1996 to 2000. We also reviewed medical records and interviewed patients with genetically matching M. tuberculosis strains to identify epidemiologic links (cluster investigation). Traditional settings for transmission were defined as households or close relatives and friends; all other settings were considered nontraditional. Of 436 clustered patients, 115 had recently acquired TB. Cluster investigations were significantly more likely than contact investigations to identify patients who recently acquired TB in nontraditional settings (33/42 vs. 23/72, respectively; p<0.001). Transmission from a foreign-born person to a U.S.-born person was rare and occurred mainly in public settings. The time from symptom onset to diagnosis was twice as long for transmitters as for nontransmitters (16.8 vs. 8.5 weeks, respectively; p<0.01). Molecular epidemiologic studies showed that reducing diagnostic delays can prevent TB transmission in nontraditional settings, which elude contact investigations.