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BACKGROUND: Understanding the etiology of recurrent tuberculosis (rTB) is important for effective TB control. Prior to the advent of whole genome sequencing (WGS), attributing rTB to relapse or reinfection using genetic information was complicated by the limited resolution of conventional genotyping methods. METHODS: We applied a systematic method of evaluating whole genome single nucleotide polymorphism (wgSNP) distances and results of phylogenetic analyses to characterize the etiology of rTB in American Indian and Alaska Native (AIAN) persons in Alaska during 2008-2020. We contextualized our findings through descriptive analyses of surveillance data and results of a literature search for investigations that characterized rTB etiology using WGS. RESULTS: The percentage of TB cases in AIAN persons in Alaska classified as recurrent episodes (11.8%) was three times the national percentage (3.9%). Of 38 recurrent episodes included in genetic analyses, we attributed 25 (65.8%) to reinfection based on wgSNP distances and phylogenetic analyses; this proportion was the highest among 16 published point estimates identified through the literature search. By comparison, we attributed 11 of 38 (28.9%) and 6 of 38 (15.8%) recurrent episodes to reinfection based on wgSNP distances alone and on conventional genotyping methods, respectively. CONCLUSIONS: WGS and attribution criteria involving genetic distances and patterns of relatedness can provide an effective means of elucidating rTB etiology. Our findings indicate that rTB occurs at high proportions among AIAN persons in Alaska and is frequently attributable to reinfection, reinforcing the importance of active surveillance and control measures to limit the spread of TB disease in Alaskan AIAN communities.
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Esputo , Tuberculosis Pulmonar , Humanos , Esputo/microbiología , Estados Unidos , Tuberculosis Pulmonar/diagnóstico , Tuberculosis Pulmonar/epidemiología , Tuberculosis Pulmonar/microbiología , Adolescente , Masculino , Persona de Mediana Edad , Adulto , Adulto Joven , Femenino , Anciano , Niño , Preescolar , Lactante , Modelos Logísticos , Mycobacterium tuberculosis/aislamiento & purificaciónRESUMEN
BACKGROUND: American Indian and Alaska Native (AIAN) populations are frequently associated with the highest rates of tuberculosis (TB) disease of any racial/ethnic group in the USA. We systematically investigated variation in patterns and potential drivers of TB epidemiology among geographically distinct AIAN subgroups. METHODS: Using data reported to the National Tuberculosis Surveillance System during 2010-2020, we applied a geographic method of data disaggregation to compare annual TB incidence and the frequency of TB patient characteristics among AIAN persons in Alaska with AIAN persons in other states. We used US Census data to compare the prevalence of substandard housing conditions in AIAN communities in these two geographic areas. RESULTS: The average annual age-adjusted TB incidence among AIAN persons in Alaska was 21 times higher than among AIAN persons in other states. Compared to AIAN TB patients in other states, AIAN TB patients in Alaska were associated with significantly higher frequencies of multiple epidemiologic TB risk factors (e.g., attribution of TB disease to recent transmission, previous diagnosis of TB disease) and significantly lower frequencies of multiple clinical risk factors for TB disease (e.g., diagnosis with diabetes mellitus, end-stage renal disease). Occupied housing units in AIAN communities in Alaska were associated with significantly higher frequencies of multiple measures of substandard housing conditions compared to AIAN communities in other states. CONCLUSIONS: Observed differences in patient characteristics and substandard housing conditions are consistent with contrasting syndromes of TB epidemiology in geographically distinct AIAN subgroups and suggest ways that associated public health interventions could be tailored to improve efficacy.
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BACKGROUND: In the United States, over 80% of tuberculosis (TB) disease cases are estimated to result from reactivation of latent TB infection (LTBI) acquired more than 2 years previously ("reactivation TB"). We estimated reactivation TB rates for the US population with LTBI, overall, by age, sex, race-ethnicity, and US-born status, and for selected comorbidities (diabetes, end-stage renal disease, and HIV). METHODS: We collated nationally representative data for 2011-2012. Reactivation TB incidence was based on TB cases reported to the National TB Surveillance System that were attributed to LTBI reactivation. Person-years at risk of reactivation TB were calculated using interferon-gamma release assay (IGRA) positivity from the National Health and Nutrition Examination Survey, published values for interferon-gamma release assay sensitivity and specificity, and population estimates from the American Community Survey. RESULTS: For persons aged ≥6 years with LTBI, the overall reactivation rate was estimated as 0.072 (95% uncertainty interval: 0.047, 0.12) per 100 person-years. Estimated reactivation rates declined with age. Compared to the overall population, estimated reactivation rates were higher for persons with diabetes (adjusted rate ratio [aRR] = 1.6 [1.5, 1.7]), end-stage renal disease (aRR = 9.8 [5.4, 19]), and HIV (aRR = 12 [10, 13]). CONCLUSIONS: In our study, individuals with LTBI faced small, non-negligible risks of reactivation TB. Risks were elevated for individuals with medical comorbidities that weaken immune function.
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Diabetes Mellitus , Infecciones por VIH , Fallo Renal Crónico , Mycobacterium tuberculosis , Tuberculosis , Humanos , Estados Unidos/epidemiología , Encuestas Nutricionales , Tuberculosis/epidemiología , Tuberculosis/diagnóstico , Fallo Renal Crónico/epidemiología , Infecciones por VIH/epidemiologíaRESUMEN
OBJECTIVE: This study describes characteristics of large tuberculosis (TB) outbreaks in the United States detected using novel molecular surveillance methods during 2014-2016 and followed for 2 years through 2018. METHODS: We developed 4 genotype-based detection algorithms to identify large TB outbreaks of ≥10 cases related by recent transmission during a 3-year period. We used whole-genome sequencing and epidemiologic data to assess evidence of recent transmission among cases. RESULTS: There were 24 large outbreaks involving 518 cases; patients were primarily U.S.-born (85.1%) racial/ethnic minorities (84.1%). Compared with all other TB patients, patients associated with large outbreaks were more likely to report substance use, homelessness, and having been diagnosed while incarcerated. Most large outbreaks primarily occurred within residences among families and nonfamilial social contacts. A source case with a prolonged infectious period and difficulties in eliciting contacts were commonly reported contributors to transmission. CONCLUSION: Large outbreak surveillance can inform targeted interventions to decrease outbreak-associated TB morbidity.
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Personas con Mala Vivienda , Mycobacterium tuberculosis , Tuberculosis , Brotes de Enfermedades , Genotipo , Humanos , Mycobacterium tuberculosis/genética , Tuberculosis/diagnóstico , Tuberculosis/epidemiología , Estados Unidos/epidemiologíaRESUMEN
Objectives. To understand the frequency, magnitude, geography, and characteristics of tuberculosis outbreaks in US state prisons. Methods. Using data from the National Tuberculosis Surveillance System, we identified all cases of tuberculosis during 2011 to 2019 that were reported as occurring among individuals incarcerated in a state prison at the time of diagnosis. We used whole-genome sequencing to define 3 or more cases within 2 single nucleotide polymorphisms within 3 years as clustered; we classified clusters with 6 or more cases during a 3-year period as tuberculosis outbreaks. Results. During 2011 to 2019, 566 tuberculosis cases occurred in 41 state prison systems (a median of 3 cases per state). A total of 19 tuberculosis genotype clusters comprising 134 cases were identified in 6 state prison systems; these clusters included a subset of 5 outbreaks in 2 states. Two Alabama outbreaks during 2011 to 2017 totaled 20 cases; 3 Texas outbreaks during 2014 to 2019 totaled 51 cases. Conclusions. Only Alabama and Texas reported outbreaks during the 9-year period; only Texas state prisons had ongoing transmission in 2019. Effective interventions are needed to stop tuberculosis outbreaks in Texas state prisons. (Am J Public Health. 2022;112(8):1170-1179. https://doi.org/10.2105/AJPH.2022.306864).
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Prisioneros , Tuberculosis , Brotes de Enfermedades , Genotipo , Humanos , Prisiones , Texas , Tuberculosis/epidemiología , Estados Unidos/epidemiologíaRESUMEN
BACKGROUND: Reductions in tuberculosis (TB) transmission have been instrumental in lowering TB incidence in the United States. Sustaining and augmenting these reductions are key public health priorities. METHODS: We fit mechanistic transmission models to distributions of genotype clusters of TB cases reported to the Centers for Disease Control and Prevention during 2012-2016 in the United States and separately in California, Florida, New York, and Texas. We estimated the mean number of secondary cases generated per infectious case (R0) and individual-level heterogeneity in R0 at state and national levels and assessed how different definitions of clustering affected these estimates. RESULTS: In clusters of genotypically linked TB cases that occurred within a state over a 5-year period (reference scenario), the estimated R0 was 0.29 (95% confidence interval [CI], .28-.31) in the United States. Transmission was highly heterogeneous; 0.24% of simulated cases with individual R0 >10 generated 19% of all recent secondary transmissions. R0 estimate was 0.16 (95% CI, .15-.17) when a cluster was defined as cases occurring within the same county over a 3-year period. Transmission varied across states: estimated R0s were 0.34 (95% CI, .3-.4) in California, 0.28 (95% CI, .24-.36) in Florida, 0.19 (95% CI, .15-.27) in New York, and 0.38 (95% CI, .33-.46) in Texas. CONCLUSIONS: TB transmission in the United States is characterized by pronounced heterogeneity at the individual and state levels. Improving detection of transmission clusters through incorporation of whole-genome sequencing and identifying the drivers of this heterogeneity will be essential to reducing TB transmission.
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Mycobacterium tuberculosis , Tuberculosis , California/epidemiología , Florida/epidemiología , Genotipo , Humanos , Mycobacterium tuberculosis/genética , New York/epidemiología , Texas/epidemiología , Tuberculosis/diagnóstico , Estados UnidosRESUMEN
BACKGROUND: Older age is a risk factor for tuberculosis (TB) in low incidence settings. Using data from the US National TB Surveillance System and American Community Survey, we estimated trends and racial/ethnic differences in TB incidence among US-born cohorts aged ≥50 years. METHODS: In total, 42 000 TB cases among US-born persons ≥50 years were reported during 2001-2019. We used generalized additive regression models to decompose the effects of birth cohort and age on TB incidence rates, stratified by sex and race/ethnicity. Using genotype-based estimates of recent transmission (available 2011-2019), we implemented additional models to decompose incidence trends by estimated recent versus remote infection. RESULTS: Estimated incidence rates declined with age, for the overall cohort and most sex and race/ethnicity strata. Average annual percentage declines flattened for older individuals, from 8.80% (95% confidence interval [CI] 8.34-9.23) in 51-year-olds to 4.51% (95% CI 3.87-5.14) in 90-year-olds. Controlling for age, incidence rates were lower for more recent birth cohorts, dropping 8.79% (95% CI 6.13-11.26) on average between successive cohort years. Incidence rates were substantially higher for racial/ethnic minorities, and these inequalities persisted across all birth cohorts. Rates from recent infection declined at approximately 10% per year as individuals aged. Rates from remote infection declined more slowly with age, and this annual percentage decline approached zero for the oldest individuals. CONCLUSIONS: TB rates were highest for racial/ethnic minorities and for the earliest birth cohorts and declined with age. For the oldest individuals, annual percentage declines were low, and most cases were attributed to remote infection.
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Tuberculosis , Niño , Estudios de Cohortes , Etnicidad , Humanos , Incidencia , Vigilancia de la Población , Tuberculosis/epidemiología , Estados Unidos/epidemiologíaRESUMEN
BACKGROUND: Populations of indigenous persons are frequently associated with pronounced disparities in rates of tuberculosis (TB) disease compared to co-occurring nonindigenous populations. METHODS: Using data from the National Tuberculosis Surveillance System on TB cases in U.S.-born patients reported in the United States during 2009-2019, we calculated incidence rate ratios and risk ratios for TB risk factors to compare cases in American Indian or Alaska Native (AIAN) and Native Hawaiian or other Pacific Islander (NHPI) TB patients to cases in White TB patients. RESULTS: Annual TB incidence rates among AIAN and NHPI TB patients were on average ≥10 times higher than among White TB patients. Compared to White TB patients, AIAN and NHPI TB patients were 1.91 (95% confidence interval (CI): 1.35-2.71) and 3.39 (CI: 1.44-5.74) times more likely to have renal disease or failure, 1.33 (CI: 1.16-1.53) and 1.63 (CI: 1.20-2.20) times more likely to have diabetes mellitus, and 0.66 (CI: 0.44-0.99) and 0.19 (CI: 0-0.59) times less likely to be HIV positive, respectively. AIAN TB patients were 1.84 (CI: 1.69-2.00) and 1.48 (CI: 1.27-1.71) times more likely to report using excess alcohol and experiencing homelessness, respectively. CONCLUSION: TB among U.S. indigenous persons is associated with persistent and concerning health disparities.
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Tuberculosis , Humanos , Incidencia , Pueblos Indígenas , Nativos de Hawái y Otras Islas del Pacífico , Tuberculosis/epidemiología , Estados Unidos/epidemiologíaRESUMEN
CONTEXT: Resistance to isoniazid (INH) only (monoresistance), with drug susceptibility to rifampin, pyrazinamide, and ethambutol at diagnosis of tuberculosis (TB) disease, can increase the length of treatment. OBJECTIVE: To describe US trends in INH monoresistance and associated patient characteristics. DESIGN: We performed trend and cross-sectional analyses of US National Tuberculosis Surveillance System surveillance data. We used Joinpoint regression to analyze annual trends in INH monoresistance and logistic regression to identify patient characteristics associated with INH monoresistance. PARTICIPANTS: Culture-positive cases reported to National Tuberculosis Surveillance System during 1993-2016 with drug susceptibility test results to INH, rifampin, pyrazinamide, and ethambutol. MAIN OUTCOME MEASURES: (1) Trends in INH monoresistance; (2) odds ratios for factors associated with INH monoresistance. RESULTS: Isoniazid monoresistance increased significantly from 4.1% of all TB cases in 1993 to 4.9% in 2016. Among US-born patients, INH monoresistance increased significantly from 2003 onward (annual percentage change = 2.8%; 95% confidence interval: 1.4-4.2). During 2003-2016, US-born persons with INH-monoresistant TB were more likely to be younger than 65 years; to be Asian; to be human immunodeficiency virus-infected; or to be a correctional facility resident at the time of diagnosis. Among non-US-born persons, INH resistance did not change significantly during 1993-2016 (annual percentage change = -0.3%; 95% confidence interval: -0.7 to 0.2) and was associated with being aged 15 to 64 years; being Asian, black, or Hispanic; or having a previous history of TB. CONCLUSIONS: INH-monoresistant TB has been stable since 1993 among non-US-born persons; it has increased 2.8% annually among US-born persons during 2003-2016. Reasons for this increase should be further investigated.
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Mycobacterium tuberculosis , Tuberculosis , Antituberculosos/uso terapéutico , Estudios Transversales , Humanos , Isoniazida/uso terapéutico , Factores de Riesgo , Tuberculosis/diagnóstico , Tuberculosis/tratamiento farmacológico , Tuberculosis/epidemiología , Estados Unidos/epidemiologíaRESUMEN
INTRODUCTION: To describe diabetes trends among adults with incident tuberculosis (TB) disease and examine diabetes-associated TB characteristics and patient outcomes in the USA. RESEARCH DESIGN AND METHODS: We examined all 71 855 persons aged ≥20 years with incident TB disease reported to the National Tuberculosis Surveillance System during 2010-2017. We performed multivariable logistic regression, comparing characteristics and outcomes among patients with TB reported to have diabetes and those whose diabetes status was unknown. RESULTS: An overall 18% (n=13 281) of the 71 855 adults with incident TB disease were reported as also having diabetes; the annual proportion increased from 15% in 2010 to 22% in 2017. Among patients aged ≥45 years with both TB and diabetes, the adjusted OR for cavitary or sputum smear-positive TB was 1.7 and 1.5, respectively (95% CIs 1.5 to 1.8 and 1.4 to 1.6). Patients with TB and diabetes had 30% greater odds of dying and took longer to achieve negative Mycobacterium tuberculosis cultures and complete treatment. CONCLUSIONS: The prevalence of reported diabetes among adults with TB disease has increased. Having diabetes as a comorbidity negatively affects patient outcomes. In accordance with national recommendations, all patients aged ≥45 years and all younger patients who have risk factors for diabetes should be screened for diabetes at the start of TB treatment.
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Diabetes Mellitus , Tuberculosis , Adulto , Antituberculosos/uso terapéutico , Diabetes Mellitus/tratamiento farmacológico , Diabetes Mellitus/epidemiología , Humanos , Prevalencia , Esputo , Tuberculosis/tratamiento farmacológico , Tuberculosis/epidemiología , Estados Unidos/epidemiologíaRESUMEN
The US Centers for Disease Control and Prevention recommends screening populations at increased risk for tuberculosis (TB), including persons born in countries with high TB rates. This approach assumes that TB risk for expatriates living in the United States is representative of TB risk in their countries of birth. We compared US TB rates by country of birth with corresponding country rates by calculating incidence rate ratios (IRRs) (World Health Organization rate/US rate). The median IRR was 5.4. The median IRR was 0.5 for persons who received a TB diagnosis <1 year after US entry, 4.9 at 1 to <10 years, and 10.0 at >10 years. Our analysis suggests that World Health Organization TB rates are not representative of TB risk among expatriates in the United States and that TB testing prioritization in the United States might better be based on US rates by country of birth and years in the United States.
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Emigrantes e Inmigrantes , Tuberculosis Pulmonar/epidemiología , Humanos , Incidencia , India/etnología , México/etnología , Filipinas/etnología , Tuberculosis Pulmonar/etnología , Tuberculosis Pulmonar/etiología , Estados Unidos/epidemiologíaRESUMEN
OBJECTIVE: To determine risk factors for multidrug-resistant tuberculosis (MDR-TB) and describe MDR-TB according to three characteristics: previous TB disease, recent transmission of MDR-TB, and reactivation of latent MDR-TB infection.SETTING and DESIGN: We used 2011-2016 surveillance data from the US National Tuberculosis Surveillance System and National Tuberculosis Genotyping Service and used logistic regression models to estimate risk factors associated with MDR-TB.RESULTS: A total of 615/45 209 (1.4%) cases were confirmed as MDR-TB; 111/615 (18%) reported previous TB disease; 41/615 (6.7%) were attributed to recent MDR-TB transmission; and 449/615 (73%) to reactivation. Only 12/41 (29%) patients with TB attributed to recent transmission were known to be contacts of someone with MDR-TB. For non-US-born patients, the adjusted odds ratios of having MDR-TB were 32.6 (95%CI 14.6-72.6) among those who were known to be contacts of someone with MDR-TB and 6.5 (95%CI 5.1-8.3) among those who had had previous TB disease.CONCLUSION: The majority of MDR-TB cases in the United States were associated with previous TB disease or reactivation of latent MDR-TB infection; only a small proportion of MDR-TB cases were associated with recent transmission.
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Mycobacterium tuberculosis , Tuberculosis Resistente a Múltiples Medicamentos , Tuberculosis , Antituberculosos/uso terapéutico , Humanos , Modelos Logísticos , Oportunidad Relativa , Factores de Riesgo , Tuberculosis/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Estados Unidos/epidemiologíaRESUMEN
We used tuberculosis genotyping results to derive estimates of prevalence of latent tuberculosis infection in the United States. We estimated <1% prevalence in 1,981 US counties, 1%-<3% in 785 counties, and >3% in 377 counties. This method for estimating prevalence could be applied in any jurisdiction with an established tuberculosis surveillance system.
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Tuberculosis Latente/epidemiología , Genotipo , Geografía Médica , Historia del Siglo XXI , Humanos , Incidencia , Tuberculosis Latente/historia , Tuberculosis Latente/microbiología , Mycobacterium/clasificación , Mycobacterium/genética , Vigilancia de la Población , Prevalencia , Estados Unidos/epidemiologíaRESUMEN
The U.S. Centers for Disease Control and Prevention (CDC) uses a combination of spacer oligonucleotide typing (spoligotyping) and mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) analyses as part of the National TB Genotyping Service (NTGS). The NTGS expansion from 12-locus MIRU-VNTR (MIRU12) to 24-locus MIRU-VNTR (MIRU24) in 2009 enhanced the ability to discriminate Mycobacterium tuberculosis strains. In the current study, we investigated the MIRU24 concordance among epidemiologic-linked tuberculosis (TB) patients in four U.S. health jurisdictions. We also evaluated the programmatic benefits of combining MIRU24 and spoligotyping with epidemiologic evidence in identifying potential recent TB transmission. We examined 342 TB patients in 42 spoligotype/MIRU12 (PCRType) clusters (equivalent to 46 spoligotype/MIRU24 [GENType] clusters) to identify epidemiologic links among cases. GENType clusters, when compared to PCRType clusters, had 12 times higher odds of epidemiologic links being identified if patients were younger than 25 years and 3 times higher odds if patients resided in the same zip code, or had HIV infection. Sixty (18%) fewer PCRType-clustered patients would need investigations if clusters are defined using GENType instead of PCRType. An important advantage of defining clusters by MIRU24 is resource savings related to the reduced number of clustered cases needing investigation.
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Técnicas Bacteriológicas , Sitios Genéticos , Secuencias Repetitivas Esparcidas , Repeticiones de Minisatélite , Técnicas de Diagnóstico Molecular , Mycobacterium tuberculosis/genética , Tuberculosis/diagnóstico , Adulto , Análisis por Conglomerados , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Epidemiología Molecular , Mycobacterium tuberculosis/patogenicidad , Fenotipo , Valor Predictivo de las Pruebas , Tuberculosis/epidemiología , Tuberculosis/microbiología , Estados Unidos/epidemiología , Adulto JovenRESUMEN
INTRODUCTION: Treatment completion is the cornerstone of tuberculosis (TB) control strategy globally. Although the majority of reported TB cases in the U.S. have documented treatment completion, individuals diagnosed while incarcerated are less likely to have documentation of whether or not they completed treatment. This study assessed trends and correlates of no documented treatment completion among individuals incarcerated at diagnosis. METHODS: U.S. National TB Surveillance System (1999-2011) data on cases eligible for treatment completion were analyzed during 2014-2015. Treatment outcomes and trends in no documented completion were assessed by incarceration status. Multivariable logistic regression identified correlates of no documented completion among people incarcerated at diagnosis. RESULTS: A lower proportion of individuals incarcerated at diagnosis had documented TB treatment completion than non-incarcerated individuals (75.6% vs 93.7%), and a higher proportion were lost to follow-up (10.7% vs 2.2%) or moved (9.4% vs 2.3%) during treatment (p<0.001). The 1999-2011 trend in no documented completion significantly increased among those incarcerated at diagnosis and declined among non-incarcerated individuals. Being foreign born was the strongest correlate of no documented completion among people incarcerated at diagnosis (AOR=2.86, 95% CI= 2.35, 3.49). Social risk factors for TB (e.g., homelessness, substance abuse), although common among incarcerated individuals, did not emerge as correlates of no documented completion. CONCLUSIONS: People diagnosed with TB disease at U.S. correctional facilities, especially the foreign born, require enhanced strategies for documenting TB treatment completion. Strengthened collaboration between correctional and public health agencies could improve continuity of care among released inmates.
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Prisioneros/estadística & datos numéricos , Tuberculosis/terapia , Adolescente , Adulto , Anciano , Niño , Preescolar , Femenino , Disparidades en Atención de Salud , Humanos , Lactante , Masculino , Persona de Mediana Edad , Vigilancia en Salud Pública , Adulto JovenRESUMEN
BACKGROUND: Tracking the dissemination of specific Mycobacterium tuberculosis (Mtb) strains using genotyped Mtb isolates from tuberculosis patients is a routine public health practice in the United States. The present study proposes a standardized cluster investigation method to identify epidemiologic-linked patients in Mtb genotype clusters. The study also attempts to determine the proportion of epidemiologic-linked patients the proposed method would identify beyond the outcome of the conventional contact investigation. METHODS: The study population included Mtb culture positive patients from Georgia, Maryland, Massachusetts and Houston, Texas. Mtb isolates were genotyped by CDC's National TB Genotyping Service (NTGS) from January 2006 to October 2010. Mtb cluster investigations (CLIs) were conducted for patients whose isolates matched exactly by spoligotyping and 12-locus MIRU-VNTR. CLIs were carried out in four sequential steps: (1) Public Health Worker (PHW) Interview, (2) Contact Investigation (CI) Evaluation, (3) Public Health Records Review, and (4) CLI TB Patient Interviews. Comparison between patients whose links were identified through the study's CLI interviews (Step 4) and patients whose links were identified earlier in CLI (Steps 1-3) was conducted using logistic regression. RESULTS: Forty-four clusters were randomly selected from the four study sites (401 patients in total). Epidemiologic links were identified for 189/401 (47 %) study patients in a total of 201 linked patient-pairs. The numbers of linked patients identified in each CLI steps were: Step 1 - 105/401 (26.2 %), Step 2 - 15/388 (3.9 %), Step 3 - 41/281 (14.6 %), and Step 4 - 28/119 (30 %). Among the 189 linked patients, 28 (14.8 %) were not identified in previous CI. No epidemiologic links were identified in 13/44 (30 %) clusters. CONCLUSIONS: We validated a standardized and practical method to systematically identify epidemiologic links among patients in Mtb genotype clusters, which can be integrated into the TB control and prevention programs in public health settings. The CLI interview identified additional epidemiologic links that were not identified in previous CI. One-third of the clusters showed no epidemiologic links despite being extensively investigated, suggesting that some improvement in the interviewing methods is still needed.
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Mycobacterium tuberculosis/genética , Tuberculosis/epidemiología , Tuberculosis/microbiología , Centers for Disease Control and Prevention, U.S. , Genotipo , Georgia/epidemiología , Humanos , Modelos Logísticos , Maryland/epidemiología , Massachusetts/epidemiología , Repeticiones de Minisatélite , Mycobacterium tuberculosis/aislamiento & purificación , Texas/epidemiología , Estados Unidos/epidemiologíaRESUMEN
Tuberculosis is an infectious disease that may result from recent transmission or from an infection acquired many years in the past; there is no diagnostic test to distinguish the two causes. Cases resulting from recent transmission are particularly concerning from a public health standpoint. To describe recent tuberculosis transmission in the United States, we used a field-validated plausible source-case method to estimate cases likely resulting from recent transmission during January 2011-September 2014. We classified cases as resulting from either limited or extensive recent transmission based on transmission cluster size. We used logistic regression to analyze patient characteristics associated with recent transmission. Of 26,586 genotyped cases, 14% were attributable to recent transmission, 39% of which were attributable to extensive recent transmission. The burden of cases attributed to recent transmission was geographically heterogeneous and poorly predicted by tuberculosis incidence. Extensive recent transmission was positively associated with American Indian/Alaska Native (adjusted prevalence ratio [aPR] = 3.6 (95% confidence interval [CI] 2.9-4.4), Native Hawaiian/Pacific Islander (aPR = 3.2, 95% CI 2.3-4.5), and black (aPR = 3.0, 95% CI 2.6-3.5) race, and homelessness (aPR = 2.3, 95% CI 2.0-2.5). Extensive recent transmission was negatively associated with foreign birth (aPR = 0.2, 95% CI 0.2-0.2). Tuberculosis control efforts should prioritize reducing transmission among higher-risk populations.
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Mycobacterium tuberculosis/genética , Tuberculosis/transmisión , Adolescente , Adulto , Anciano , Técnicas de Tipificación Bacteriana , Población Negra , Niño , Preescolar , Control de Enfermedades Transmisibles , Emigración e Inmigración , Femenino , Genotipo , Personas con Mala Vivienda , Humanos , Indígenas Norteamericanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Tuberculosis/epidemiología , Tuberculosis/etnología , Estados Unidos/epidemiología , Adulto JovenRESUMEN
SETTING: Even among persons who have completed a course of treatment for their first tuberculosis (TB) episode, patients with a history of TB are at higher risk for having TB. OBJECTIVE: To describe factors from the initial TB episode associated with recurrent TB among patients who completed treatment and remained free of TB for at least 12 months. DESIGN: During 1993-2006, US TB cases stratified by birth origin were examined. Cox proportional hazards regression was used to assess the association of factors during the initial episode with recurrence at least 12 months after treatment completion. RESULTS: Among 632 US-born patients, TB recurrence was associated with age 25-44 years (adjusted hazard ratio [aHR] 1.77, 99% confidence interval [CI] 1.02-3.09, attributable fraction [AF] 1-34%), substance use (aHR 1.57, 99%CI 1.23-2.02, AF 8-22%), and treatment supervised by health departments (aHR 1.42, 99%CI 1.03-1.97, AF 2-28%). Among 211 foreign-born patients, recurrence was associated with human immunodeficiency virus infection (aHR 2.24, 99%CI 1.27-3.98, AF 2-9%) and smear-positive TB (aHR 1.56, 99%CI 1.06-2.30, AF 3-33%). CONCLUSION: Factors associated with recurrence differed by origin of birth, and might be useful for anticipating greater risk for recurrent TB among certain patients with a history of TB.