Smita Ghosh

Using Genotyping and Geospatial Scanning to Estimate Recent Mycobacterium tuberculosis Transmission, United States

These tools may enable direction of resources to populations with high transmission rates.

Tuberculosis genotyping information management system: enhancing tuberculosis surveillance in the United States.

Molecular characterization of Mycobacterium tuberculosis complex isolates (genotyping) can be used by public health programs to more readily identify tuberculosis (TB) transmission. The Centers for Disease Control and Preventions National Tuberculosis Genotyping Service has offered M. tuberculosis genotyping for every culture-confirmed case in the United States since 2004. The TB Genotyping Information Management System (TB GIMS), launched in March 2010, is a secure online database containing genotype results linked with case characteristics from the national TB registry for state and local TB programs to access, manage and analyze these data. As of September 2011, TB GIMS contains genotype results for 89% of all culture-positive TB cases for 2010. Over 400 users can generate local and national reports and maps using TB GIMS. Automated alerts on geospatially concentrated cases with matching genotypes that may represent outbreaks are also generated by TB GIMS. TB genotyping results are available to enhance national TB surveillance and apply genotyping results to conduct TB control activities in the United States.

Epidemiology of Tuberculosis in Young Children in the United States

OBJECTIVES: To estimate tuberculosis (TB) rates among young children in the United States by children’s and parents’ birth origins and describe the epidemiology of TB among young children who are foreign-born or have at least 1 foreign-born parent. METHODS: Study subjects were children <5 years old diagnosed with TB in 20 US jurisdictions during 2005–2006. TB rates were calculated from jurisdictions’ TB case counts and American Community Survey population estimates. An observational study collected demographics, immigration and travel histories, and clinical and source case details from parental interviews and health department and TB surveillance records. RESULTS: Compared with TB rates among US-born children with US-born parents, rates were 32 times higher in foreign-born children and 6 times higher in US-born children with foreign-born parents. Most TB cases (53%) were among the 29% of children who were US born with foreign-born parents. In the observational study, US-born children with foreign-born parents were more likely than foreign-born children to be infants (30% vs 7%), Hispanic (73% vs 37%), diagnosed through contact tracing (40% vs 7%), and have an identified source case (61% vs 19%); two-thirds of children were exposed in the United States. CONCLUSIONS: Young children who are US born of foreign-born parents have relatively high rates of TB and account for most cases in this age group. Prompt diagnosis and treatment of adult source cases, effective contact investigations prioritizing young contacts, and targeted testing and treatment of latent TB infection are necessary to reduce TB morbidity in this population.

Tuberculosis among the homeless, United States, 1994–2010

OBJECTIVES 1) To describe homeless persons diagnosed with tuberculosis (TB) during the period 1994-2010, and 2) to estimate a TB incidence rate among homeless persons in the United States. METHODS TB cases reported to the National Tuberculosis Surveillance System were analyzed by origin of birth. Incidence rates were calculated using the US Department of Housing and Urban Development homeless population estimates. Analysis of genotyping results identified clustering as a marker for transmission among homeless TB patients. RESULTS Of 270,948 reported TB cases, 16,527 (6%) were homeless. The TB incidence rate among homeless persons ranged from 36 to 47 cases per 100,000 population in 2006-2010. Homeless TB patients had over twice the odds of not completing treatment and of belonging to a genotype cluster. US- and foreign-born homeless TB patients had respectively 8 and 12 times the odds of substance abuse. CONCLUSIONS Compared to the general population, homeless persons had an approximately 10-fold increase in TB incidence, were less likely to complete treatment and more likely to abuse substances. Public health outreach should target homeless populations to reduce the excess burden of TB in this population.

Does Alcohol Consumption during Multidrug-resistant Tuberculosis Treatment Affect Outcome?. A Population-based Study in Kerala, India

RATIONALE India reports the largest number of multidrug-resistant tuberculosis cases in the world; yet, no longitudinal study has assessed factors related to treatment outcomes under programmatic conditions in the public sector. OBJECTIVES To describe demographic, clinical, and risk characteristics associated with treatment outcomes for all patients with multidrug-resistant tuberculosis registered in the Revised National Tuberculosis Control Programme, Kerala State, India from January 1, 2009 to June 30, 2010. METHODS Cox regression methods were used to calculate adjusted hazard ratios with 95% confidence intervals (CIs) to assess factors associated with an unsuccessful treatment outcome. MEASUREMENTS AND MAIN RESULTS Of 179 patients with multidrug-resistant tuberculosis registered, 112 (63%) had successful treatment outcomes (77 bacteriologically cured, 35 treatment completed) and 67 (37%) had unsuccessful treatment outcomes (30 died, 26 defaulted, 9 failed treatment, 1 stopped treatment because of drug-related adverse events, and 1 developed extensively drug-resistant tuberculosis). The hazard for unsuccessful outcome was significantly higher among patients who consumed alcohol during treatment (adjusted hazard ratio, 4.3; 95% CI, 1.1-17.6) than those who did not. Persons who consumed alcohol during treatment, on average, missed 18 more intensive-phase doses (95% CI, 13-22) than those who did not. Although many patients had diabetes (33%), were ever smokers (39%), or had low body mass index (47%), these factors were not associated with outcome. CONCLUSION Overall treatment success was greater than global and national averages; however, outcomes among patients consuming alcohol remained poor. Integration of care for multidrug-resistant tuberculosis and alcoholism should be considered to improve treatment adherence and outcomes.

Transmission of multidrug-resistant tuberculosis in the USA: a cross-sectional study

BACKGROUND Multidrug-resistant (MDR) tuberculosis is a potential threat to tuberculosis elimination, but the extent of MDR tuberculosis disease in the USA that is attributable to transmission within the country is unknown. We assessed transmission of MDR tuberculosis and potential contributing factors in the USA. METHODS In a cross-sectional study, clinical, demographic, epidemiological, and Mycobacterium tuberculosis genotype data were obtained during routine surveillance of all verified cases of MDR tuberculosis reported from eight states in the USA (California from Jan 1, 2007, to Dec 31, 2009; Texas from Jan 1, 2007, to March 31, 2009; and the states of Colorado, Maryland, Massachusetts, New York, Tennessee, and Washington from Jan 1, 2007 to Dec 31, 2008). In-depth interviews and health-record abstraction were done for all who consented to ascertain potential interpersonal connections. FINDINGS 168 cases of MDR tuberculosis were reported in the eight states during our study period. 92 individuals (55%) consented to in-depth interview. 20 (22%) of these individuals developed MDR tuberculosis as a result of transmission in the USA; a source case was identified for eight of them (9%). 20 individuals (22%) had imported active tuberculosis (ie, culture-confirmed disease within 3 months of entry into the USA). 38 (41%) were deemed to have reactivation of disease, of whom 14 (15%) had a known previous episode of tuberculosis outside the USA. Five individuals (5%) had documented treatment of a previous episode in the USA, and so were deemed to have relapsed. For nine cases (10%), insufficient evidence was available to definitively classify reason for presentation. INTERPRETATION About a fifth of cases of MDR tuberculosis in the USA can be linked to transmission within the country. Many individuals acquire MDR tuberculosis before entry into the USA. MDR tuberculosis needs to be diagnosed rapidly to reduce potential infectious periods, and clinicians should consider latent tuberculosis infection treatment-tailored to the results of drug susceptibility testing of the putative source case-for exposed individuals. FUNDING Centers for Disease Control and Prevention.

Preventing Infectious Pulmonary Tuberculosis Among Foreign-Born Residents of the United States

OBJECTIVES We described risk factors associated with infectious tuberculosis (TB) and missed TB-prevention opportunities in foreign-born US residents, who account for almost two thirds of the nations TB patients. METHODS In a cross-sectional study at 20 US sites of foreign-born persons diagnosed with TB in 2005 through 2006, we collected results of sputum smear microscopy for acid-fast bacilli (a marker for infectiousness) and data on visa status, sociodemographics, TB-related care seeking, and latent TB infection (LTBI) diagnosis opportunities. RESULTS Among 980 persons with pulmonary TB who reported their visa status, 601 (61%) were legal permanent residents, 131 (13.4%) had temporary visas, and 248 (25.3%) were undocumented. Undocumented persons were more likely than permanent residents to have acid-fast bacilli-positive smears at diagnosis (risk ratio = 1.3; 95% confidence interval = 1.2, 1.4). Of those diagnosed 1 year or more after arrival, 57.3% reported LTBI screening opportunities; fewer than 25% actually were. Undocumented persons reported fewer LTBI screening opportunities and were less likely to be tested. CONCLUSIONS Progress toward TB elimination in the United States depends upon expanding opportunities for regular medical care and promotion of LTBI screening and treatment among foreign-born persons.

Prioritizing Tuberculosis Clusters by Genotype for Public Health Action, Washington, USA

Groups of tuberculosis cases with indistinguishable Mycobacterium tuberculosis genotypes (clusters) might represent recent transmission. We compared geospatial concentration of genotype clusters with independent priority rankings determined by local public health officials; findings were highly correlated. Routine use of geospatial statistics could help health departments identify recent disease transmission.

Photovoice: A Novel Approach to Improving Antituberculosis Treatment Adherence in Pune, India

We compared antituberculosis treatment (ATT) adherence and outcomes among patients exposed to Photovoice (video of previously cured TB patients sharing experiences about TB treatment) versus those not exposed. The odds of successful outcome (i.e., cured or completing treatment) for the 135 patients who watched Photovoice were 3 times greater (odds ratio: 2.8; 95% CI: 1.3–6.1) than for patients who did not watch Photovoice. The comparison group, on average, missed more doses (10.9 doses; 95% CI: 6.6–11.1) than the intervention group who saw Photovoice (5.5 doses; 95% CI: 3.7–6.1). Using Photovoice at initiation of ATT has the potential to improve treatment adherence and outcomes.

Molecular Epidemiology of Mycobacterium tuberculosis in the United States–Affiliated Pacific Islands

The United States–Affiliated Pacific Islands (USAPI) are part of the US National Tuberculosis (TB) Surveillance System and use laboratory services contracted through a cooperative agreement with the Centers for Disease Control and Prevention (CDC). In 2004, the CDC established the National Tuberculosis Genotyping Service, a system to genotype 1 isolate from each culture-confirmed case of TB. To describe the molecular epidemiology of TB in the region, we examined all Mycobacterium tuberculosis isolates submitted for genotyping from January 1, 2004, to December 31, 2008. Over this time period, the USAPI jurisdictions reported 1339 verified TB cases to the National Tuberculosis Surveillance System. Among 419 (31%) reported culture-confirmed TB cases, 352 (84%) had complete genotype results. Routine TB genotyping allowed, for the first time, an exploration of the molecular epidemiology of TB in the USAPI.