Foreign-born Cases Research Articles

Individual- and neighborhood-level contextual factors are associated with Mycobacterium tuberculosis transmission: genotypic clustering of cases in Michigan, 2004–2012

PurposeUsing genotyping data of Mycobacterium tuberculosis isolates from new cases reported to the tuberculosis (TB) surveillance program, we evaluated risk factors for recent TB transmission at both the individual- and neighborhood- levels among U.S.-born and foreign-born populations. MethodsTB cases (N = 1236) reported in Michigan during 2004 to 2012 were analyzed using multivariable Poisson regression models to examine risk factors for recent transmission cross-sectionally for U.S.-born and foreign-born populations separately. Recent transmission was defined based on spoligotype and 12-locus-mycobacterial interspersed repetitive unit–variable number tandem repeat typing matches of bacteria from cases that were diagnosed within 1 year of each other. Four classes of predictor variables were examined: demographic factors, known TB risk factors, clinical characteristics, and neighborhood-level factors. ResultsOverall, 22% of the foreign-born cases resulted from recent transmission. Among the foreign-born, race and being a contact of an infectious TB case were significant predictors of recent transmission. More than half (52%) of U.S.-born cases resulted from recent transmission. Among the U.S.-born, recent transmission was predicted by both individual- and neighborhood-level sociodemographic characteristics. ConclusionsInterventions aimed at reducing TB incidence among foreign-born should focus on reducing reactivation of latent infection. However, reducing TB incidence among the U.S.-born will require decreasing transmission among socially disadvantaged groups at the individual- and neighborhood- levels. This report fills an important knowledge gap regarding the contemporary social context of TB in the United States, thereby providing a foundation for future studies of public health policies that can lead to the development of more targeted, effective TB control.

Immigrant Arrival and Tuberculosis among Large Immigrant- and Refugee-Receiving Countries, 2005-2009.

Objective. Tuberculosis control in foreign-born populations is a major public health concern for Australia, Canada, New Zealand, United Kingdom, and the United States, large immigrant- and refugee-receiving countries that comprise the Immigration and Refugee Health Working Group (IRHWG). Identifying and comparing immigration and distribution of foreign-born tuberculosis cases are important for developing targeted and collaborative interventions. Methods. Data stratified by year and country of birth from 2005 to 2009 were received from these five countries. Immigration totals, tuberculosis case totals, and multidrug-resistant tuberculosis (MDR TB) case totals from source countries were analyzed and compared to reveal similarities and differences for each member of the group. Results. Between 2005 and 2009, there were a combined 31,785,002 arrivals, 77,905 tuberculosis cases, and 888 MDR TB cases notified at the federal level in the IRHWG countries. India, China, Vietnam, and the Philippines accounted for 41.4% of the total foreign-born tuberculosis cases and 42.7% of the foreign-born MDR tuberculosis cases to IRHWG. Interpretation. Collaborative efforts across a small number of countries have the potential to yield sizeable gains in tuberculosis control for these large immigrant- and refugee-receiving countries.

Estimating tuberculosis cases and their economic costs averted in the United States over the past two decades.

Following a concerted public health response to the resurgence of tuberculosis (TB) in the United States in the late 1980s, annual TB incidence decreased substantially. However, no estimates exist of the number and cost savings of TB cases averted. TB cases averted in the United States during 1995-2014 were estimated: Scenario 1 used a static 1992 case rate; Scenario 2 applied the 1992 rate to foreign-born cases, and a pre-resurgence 5.1% annual decline to US-born cases; and a statistical model assessed human immunodeficiency virus and TB program indices. We applied the cost of illness to estimate the societal benefits (costs averted) in 2014 dollars. During 1992-2014, 368 184 incident TB cases were reported, and cases decreased by two thirds during that period. In the scenarios and statistical model, TB cases averted during 1995-2014 ranged from approximately 145 000 to 319 000. The societal benefits of averted TB cases ranged from US$3.1 to US$6.7 billion, excluding deaths, and from US$6.7 to US$14.5 billion, including deaths. Coordinated efforts in TB control and prevention in the United States yielded a remarkable number of TB cases averted and societal economic benefits. We illustrate the value of concerted action and targeted public health funding.

Tuberculosis in native- and foreign-born populations in Portugal.

Tuberculosis (TB) is a major global health problem, and during the last 20 years, industrialised countries have shown similar patterns in TB notifications: decreasing TB incidence in native populations and increasing incidence in foreign-born populations. To characterise risk factors associated with TB among native- and foreign-born TB patients in Portugal and identify barriers to the management of foreign cases. Analysis of the data from the national tuberculosis surveillance system and data from an online survey of physicians managing TB cases in the country. Risk factors in the two populations differed. Foreign-born patients were younger, less likely to use drugs or alcohol and had fewer comorbidities. They were also more likely to be human immunodeficiency virus positive, to be employed and to be homeless/living in shelters. The outcome of the disease and the time to diagnosis were not significantly different between the two populations. The most important barriers to the management of foreign-born TB cases were language and fear of deportation. As there are significant differences between the two populations, different TB control strategies should be implemented in the two populations.

Mind the gap: TB trends in the USA and the UK, 2000–2011

BackgroundTB remains a major public health concern, even in low-incidence countries like the USA and the UK. Over the last two decades, cases of TB reported in the USA have...

Recommended drug use after acute myocardial infarction by migration status and education level.

The purpose of this study is to investigate the association between migration status and education level and the use of recommended drugs after first acute myocardial infarction (MI). A nationwide cohort study performed in Sweden from January 1, 2006 to August 1, 2008. The cohort consisted of 49,037 incident cases of first acute MI. In total, 37,570 individuals survived 180 days after MI, of whom 4782 (12.7%) were foreign-born. We used logistic regression to estimate the odds ratio (OR) with 95% confidence interval (CI) of the association between migration status and education level and prescribed drugs after MI. One third of the patients who were not on any recommended cardiovascular drugs before MI continued to be without recommended cardiovascular drugs after MI. Among those with no cardiovascular drugs before MI, we found no difference in recommended drug use after MI by migration status (OR 1.00, 95% CI 0.89-1.12). Among those with some but not all recommended cardiovascular drugs before MI, foreign-born cases had a slightly non-significant lower use of recommended drugs (OR 0.92, 95% CI 0.83-1.03). Foreign-born patients with low education had a slightly lower use of recommended drug compared to Sweden-born. Women with low education had a lower use of drugs after MI (Sweden born, OR 0.85; 95% CI 0.74-0.96 and foreign born OR 0.51; 95% CI 0.34-0.77). There is no apparent difference between foreign-born and Sweden-born in recommended drug use after MI. However, our study reveals an inequity in secondary prevention therapy after myocardial infarction by education level.

Genotypic characterization and historical perspective of Mycobacterium tuberculosis among older and younger Finns, 2008–2011

The Mycobacterium tuberculosis genotypes obtained from elderly Finns were assessed and compared with those obtained from younger Finns to comprehend the epidemiology of tuberculosis (TB) in Finland. From 2008 to 2011, a total of 1021 M. tuberculosis isolates were characterized by spoligotyping and 15-locus mycobacterial interspersed repetitive units–variable number tandem repeat typing. In total, 733 Finnish-born cases were included in the study, of which 466 (64%) were born before 1945 (older Finns). Of these, 63 (14%) shared an M. tuberculosis genotype with foreign-born or younger Finnish cases (born after 1945), and 59 (13%) shared a genotype with older Finnish cases. Eighty-five per cent had a unique genotypic profile while 70% belonged to T or Haarlem families, suggesting that ongoing transmission is infrequent among young and elderly Finns. Simultaneous reactivation of TB among older Finns was the most likely cause for clustering. As most isolates belonged to Haarlem or T, Finland was most likely affected by a similar TB epidemic at the beginning of the twentieth century as that seen in Sweden and Norway. Younger Finns were significantly more likely to be clustered (56% versus 27%, p <0.001), have pulmonary TB (87% versus 71%, p <0.001) and to be sputum smear positive (57% versus 48%, p <0.05) indicating that the risk of TB transmission from younger Finns is likely to be larger than from older Finns. The M. tuberculosis isolates from elderly Finns were associated with dominant lineages of the early twentieth century and differed from the heterogeneous lineages found among younger TB patients. Additionally, younger TB patients were more likely to transmit TB than elderly Finns.

Características de la tuberculosis en la población inmigrante en el Área de Salud Sur de Granada

IntroductionThe incidence of tuberculosis (TB) among the native population in Spain continues to decrease, resulting in a higher proportion of foreign-born cases. The aim of this study was to identify the differential TB characteristics within the immigrant population with respect to the native population in the South Granada Health Area, Spain. MethodsThis was a descriptive study, including all cases of TB diagnosed during the period 2003-2010. Cases were identified through a prospective database. A logistic regression analysis was performed to determine differential characteristics. ResultsFrom 319 TB cases diagnosed, 247 were natives and 72 (22.6%) immigrants, and 272 were pulmonary tuberculosis. The following variables were significantly associated with immigrant TB cases: age<35 years (OR=4.75, CI: 2.72-8.31), higher percentage of cavitated chest X-ray (OR=2.26, CI: 1.20-4.20), higher percentage of smear-positive cases (OR=1.80, CI: 1.02-3.16), longer diagnostic delay in smear-positive pulmonary TB (median 32 days vs. 21 days P=.043), and lower total lethality (OR=0.12; CI: 0.01-0.89). ConclusionsThe incidence of TB has remained constant in the South Granada Health Area due to the increase in cases among immigrants. Compared with native TB patients, immigrant patients were younger and had more advanced disease (higher percentage of smear-positive cases and higher percentage of cavitated chest X-ray) and longer diagnostic delay in smear-positive pulmonary TB, indicating poorer TB control. Strategies for earlier diagnosis of TB in immigrants are essential.

Four year longitudinal study of Mycobacterium tuberculosis complex isolates in a region of North-Eastern Italy

Recent reports have suggested a change of Mycobacterium tuberculosis complex genetic diversity in Western Europe due to an increasing proportion of imported cases of tuberculosis (TB). This study analyzed a total of 705 M. tuberculosis strains isolated from 2006 to 2009 in Veneto, a North-Eastern Italian region, to see the impact of foreign-born cases vs. Italian patients on prevailing TB epidemiology. Strains were genotyped using spoligotyping followed by comparison with international genotyping database SITVIT2. Six spoligotyping clusters with suspected phylogeographical specificity for imported cases, were typed by 15-loci MIRUs for a finer characterization. Overall, 410 (58.16%) strains were isolated from foreign-born patients, while 295 (41.84%) were isolated from Italian patients. Older patients (>70years, i.e., 46.4% of cases) predominated among Italians while younger age groups prevailed among foreign-born patients. Our results suggest that despite a high proportion of reactivation of latent TB infection in elderly Italian-born patients, active TB transmission between foreign-born and Italian patients may be ongoing, and argue in favor of an increased TB surveillance among immigrants to combat TB epidemic in Italy.

Trend of microbiologically-confirmed tuberculosis in a low-incidence setting with high immigration rates

BackgroundThe metropolitan area of Bologna, a city in Northern Italy (Emilia Romagna region), is considered a low incidence setting for TB, but has a high rate of foreign immigration (13.5% official resident immigrants relative to the whole population in 2011). The aim of this study was to describe the epidemiological trend of TB, focusing on differences between Italian and foreign-born cases.MethodsWe examined all bacteriologically confirmed TB cases identified in the Microbiology Unit of Bologna University Hospital from January 2008 and December 2011. We compared demographic, clinical and microbiological data for Italian vs. foreign-born TB cases.ResultsOut of 255 TB cases identified during the study period, 168 (65.9%) were represented by foreign-born cases. The proportion of immigrants with TB progressively increased over the study period (from 60.8% in 2008 to 67.5% in 2011). Although foreign-born cases were significantly younger than Italian cases (mean age 32.3 ± 14.4 years vs 61.9 ± 21.5 years), the mean age among the latter decreased from 71.2 in 2008 to 54.6 years in 2011 (p = 0.036).Concerning TB localization, 65.9% (n = 168) had pulmonary TB (P-TB) and 34.1% (n = 87) extra-pulmonary TB (EP-TB). In this study, 35.6% of Italian-born P-TB cases were smear positive, versus 51.4% of foreign-born P-TB cases. The highest proportion of high-grade positive microscopy P-TB was among subjects between 25–34 years old (36.9%; p = 0.004).Mono-resistance to isoniazid (mono-H) was found among 9.2% and 10.1% of Italian and foreign-born cases, respectively. Among Italian cases, resistance to H and any other first line drug (poly-H) and Multidrug resistant TB (MDR-TB) were 4.6% and 1.2%, respectively. In foreign-born cases poly-H (12.8%) and MDR-TB (6.9%) significantly increased over the time (p = 0.003 and p = 0.007, respectively). The proportion of MDR-TB was significantly higher among immigrants from Eastern Europe (10.9%) compared to Italian-born patients (p = 0.043). All (n = 9) MTB strains resistant to four or five first line drugs and Extensively drug resistant (XDR-TB) strains were from foreign-born cases.ConclusionsTB epidemiology in a low incidence setting is strongly influenced by immigration rates. Ethnicity, mean age, and incidence of MDR-TB among foreign-born cases reflect immigration trends in Northern Italy.

Preventing tuberculosis in the foreign-born population of Canada: a mathematical modelling study

Foreign-born persons in Canada contribute 67% of all tuberculosis (TB) cases annually, but represent only 21% of the total population. Molecular epidemiological studies suggest that most foreign-born TB cases result from the reactivation of latent tuberculous infection (LTBI) acquired before immigration. To estimate the effect on incidence of a prevention strategy that would screen selected immigrants at arrival for LTBI and offer preventive treatment to those who test positive. A deterministic model was developed to quantify the incidence of active TB in immigrants to Canada and validated with national immigration and TB case data. Model simulations suggested that it would be optimal to screen and treat LTBI in new immigrants from countries of birth with an estimated TB incidence rate in excess of 50 per 100 000 person-years. If this strategy had been implemented in 1986, the national TB incidence rate would have fallen by 18.5%, from 5.4 to 4.4 cases per 100 000 population by 2002. This study suggests that screening and treating LTBI in foreign-born persons from high TB incidence countries is the most effective strategy in terms of total persons screened and treated and percentage reduction in national incidence.

Molecular Epidemiology of Tuberculosis in Finland, 2008-2011

In industrialized countries the majority of tuberculosis (TB) cases are linked to immigration. In Finland, most cases are still Finnish born but the number of foreign born cases is steadily increasing. In this 4-year population based study, the TB situation in Finland was characterized by a genotypic analysis of Mycobacterium tuberculosis isolates. A total of 1048 M. tuberculosis isolates (representing 99.4% of all culture positive cases) were analyzed by spoligotyping and MIRU. Spoligotype lineages belonging to the Euro-American family were predominant among the Finnish isolates, particularly T (n=346, 33.0%) and Haarlem (n=237, 22.6%) strains. The lineage signature was unknown for 130 (12.4%) isolates. Out of the 17 multi-drug resistant TB strains, 10 (58.8%) belonged to the Beijing lineage. In total, 23 new SIT designations were given and 51 orphan strains were found, of which 58 patterns were unique to Finland. Phylogeographical TB mapping as compared to neighboring countries showed that the population structure in Finland most closely resembled that observed in Sweden. By combining spoligotyping and MIRU results, 98 clusters comprising 355 isolates (33.9%) were found. Only 10 clusters contained both Finnish and foreign born cases. In conclusion, a large proportion of the M. tuberculosis isolates were from Finnish born elderly patients. Moreover, many previously unidentified spoligotype profiles and isolates belonging to unknown lineages were encountered.

Tuberculosis transmission between foreign- and native-born populations in the EU/EEA: a systematic review

Tuberculosis (TB) control programmes of many low TB incidence countries of the European Union/European Economic Area (EU/EEA) perceive challenges in controlling TB due to high numbers of TB in migrants from high-incidence countries.To assess the extent of TB transmission from the foreign-born to the native-born population, we quantitatively investigated the dynamics of TB transmission between these populations in the EU/EEA, using published molecular epidemiological studies. We searched PubMed and EMBASE databases from 1990 to August 2012.We identified 15 studies performed during 1992–2007 covering 12,366 cases, of which median (range) 49.2% (17.7%–86.4%) were foreign-born. The proportion of clustered isolates ranged between 8.5% and 49.1% of the total number of TB cases genotyped and among these, foreign-born cases were equally or more likely to have unique isolates compared to native-born cases. One third of the clusters were “mixed”, i.e. composed of foreign- and native-born cases, involving 0–34.2% of all genotyped cases. Cross-transmission among foreign and native populations was bidirectional, with wide differences across studies.This systematic review provides evidence that TB in a foreign-born population does not have a significant influence on TB in the native population in EU/EEA.

Use of genotyping based clustering to quantify recent tuberculosis transmission in Guadeloupe during a seven years period: analysis of risk factors and access to health care

BackgroundThe present study aimed to characterize Mycobacterium tuberculosis population structure and to identify transmission chains and risk factors by prospective molecular typing in conjunction with conventional epidemiological investigations in the French overseas department of Guadeloupe.MethodsThe study included all the culture-positive TB cases (1 clinical isolate per patient; n = 129) diagnosed between a seven year period (April 4th, 1999 to December 31st, 2005). Prospective molecular typing was performed using spoligotyping and VNTRs, and a subset of 44 M. tuberculosis isolates found to be clustered was retrospectively typed using 12-loci MIRUs. Data were compared using the SITVIT2 database, followed by analysis of risk factors in function of clustering of the isolates and available demographic and socioeconomic data.ResultsThe study sample was characterized by a majority of new cases (87.4%); a moderate proportion of drug-resistance (7.8%); a high level of immigration (51.2% foreign-born) originating from high TB/HIV incidence neighboring islands such as Haiti or Dominican Republic; lower socioeconomic conditions (70.7% of jobless, average income 824 EUR/month); and a significantly higher proportion of TB/HIV co-infected cases (38.2% vs. 8.5%; p < 0.001), and extrapulmonary disease (18.2% vs. 4.8%; p < 0.02) among migrants as compared to French patients. The study revealed an important delay in access to healthcare with a median delay of 74.5 days between the 1st symptoms and clinical suspicion of TB. Prospective molecular typing based on spoligotyping and 5-loci VNTRs showed that evolutionary recent Euro-American lineages predominated in Guadeloupe (91.5% of isolates). In conjunction with epidemiological data, it allowed to estimate a recent transmission rate of 18.6%, which was close to the rate of 16.7% estimated using retrospective 12-loci MIRU typing. Although a higher proportion of cases in older age-group were apparently linked to reactivation; univariate analysis of risk factors did not allow pinpointing specific risk factors for a patient to belong to a TB transmission group.ConclusionsOngoing TB transmission in the insular, low TB-incidence setting of Guadeloupe can be defined as follows: (i) a significant proportion of imported cases of the disease from neighboring islands; (ii) significantly higher TB/HIV coinfection among foreign-born cases; and, (iii) a higher proportion of cases affecting older age-group among French patients due to reactivation. This study emphasizes the need for universal typing using spoligotyping and 15-loci MIRUs in prospective studies.

Predicting U.S. Tuberculosis Case Counts through 2020

In 2010, foreign-born persons accounted for 60% of all tuberculosis (TB) cases in the United States. Understanding which national groups make up the highest proportion of TB cases will assist TB control programs in concentrating limited resources where they can provide the greatest impact on preventing transmission of TB disease. The objective of our study was to predict through 2020 the numbers of U.S. TB cases among U.S.-born, foreign-born and foreign-born persons from selected countries of birth. TB case counts reported through the National Tuberculosis Surveillance System from 2000–2010 were log-transformed, and linear regression was performed to calculate predicted annual case counts and 95% prediction intervals for 2011–2020. Data were analyzed in 2011 before 2011 case counts were known. Decreases were predicted between 2010 observed and 2020 predicted counts for total TB cases (11,182 to 8,117 [95% prediction interval 7,262–9,073]) as well as TB cases among foreign-born persons from Mexico (1,541 to 1,420 [1,066–1,892]), the Philippines (740 to 724 [569–922]), India (578 to 553 [455–672]), Vietnam (532 to 429 [367–502]) and China (364 to 328 [249–433]). TB cases among persons who are U.S.-born and foreign-born were predicted to decline 47% (4,393 to 2,338 [2,113–2,586]) and 6% (6,720 to 6,343 [5,382–7,476]), respectively. Assuming rates of declines observed from 2000–2010 continue until 2020, a widening gap between the numbers of U.S.-born and foreign-born TB cases was predicted. TB case count predictions will help TB control programs identify needs for cultural competency, such as languages and interpreters needed for translating materials or engaging in appropriate community outreach.

A snapshot of genetic lineages of Mycobacterium tuberculosis in Ireland over a two-year period, 2010 and 2011

Mycobacterial interspersed repetitive-unit-variable-number tandem repeat typing alone was used to investigate the genetic lineages among 361 Mycobacterium tuberculosis strains circulating in Ireland over a two-year period, 2010 and 2011. The majority of isolates, 63% (229/361), belonged to lineage 4 (Euro-American), while lineages 1 (Indo-Oceanic), 2 (East-Asian) and 3 (East-African–Indian) represented 12% of isolates each (42/361, 45/361, and 45/361, respectively). Sub-lineages Beijing (lineage 2), East-African–Indian (lineage 1) and Delhi/central-Asian (lineage 3) predominated among foreign-born cases, while a higher proportion of Euro-American lineages were identified among cases born in Ireland. Eighteen molecular clusters involving 63 tuberculosis (TB) cases were identified across four sub-lineages of lineage 4. While the mean cluster size was 3.5 TB cases, the largest cluster (involving 12 Irish-born cases) was identified in the Latin American–Mediterranean sub-lineage. Clustering of isolates was higher among Irish-born TB cases (47 of 63 clustered cases), whereas only one cluster (3/63) involved solely foreign-born individuals. Four multidrug-resistant cases identified during this period represented lineages 2 and 4. This study provides the first insight into the structure of the M. tuberculosis population in Ireland.

Increase in multidrug-resistant tuberculosis (MDR-TB) in Alberta among foreign-born persons: implications for tuberculosis management.

Globally, the prevalence of anti-tuberculosis drug resistance has been increasing. This study sought to identify trends in multidrug-resistant tuberculosis (MDR-TB) among foreign-born persons in Alberta, a major immigrant-receiving province of Canada. A retrospective cohort study design was used to investigate the prevalence of MDR-TB in foreign-born culture-positive TB cases between 1982 and 2011. Relevant demographic, clinical and laboratory data were abstracted from the TB Registry, individual medical records and the Provincial Laboratory for Public Health. Of the 2,234 foreign-born culture-positive TB cases in Alberta in 1982-2011, 27 (1.2%) had MDR-TB. Overall, MDR was associated with age &lt;65 years (p=0.025), TB relapse/retreatment, and diagnosis and arrival in the last decade (2002-2011). The prevalence of MDR-TB in 2002-2011 was 2.1%, a significant increase from 0.65% in 1982-1991 (p=0.022) and 0.56% in 1992-2001 (p=0.009). Only immigrants from the Philippines and Vietnam showed a significant increase in the prevalence of MDR-TB between the first two decades and the last. Compared to MDR-TB cases reported in the first two decades, those reported in the last decade were more frequently younger than 35 years of age, new active versus relapse/retreatment cases and diagnosed with non-respiratory versus respiratory TB. In 1992-2011, MDR-TB strains had unique DNA fingerprints. Recent trends in the prevalence and clinical characteristics of foreign-born MDR-TB cases have important implications for TB case management in Canada. Early diagnosis of MDR-TB, using genotypic drug susceptibility testing, is suggested in foreign-born TB cases at increased risk of being MDR.

Increase in Multidrug-resistant Tuberculosis (MDR-TB) in Alberta Among Foreign-born Persons: Implications for Tuberculosis Management

Globally, the prevalence of anti-tuberculosis drug resistance has been increasing. This study sought to identify trends in multidrug-resistant tuberculosis (MDR-TB) among foreign-born persons in Alberta, a major immigrant-receiving province of Canada.A retrospective cohort study design was used to investigate the prevalence of MDR-TB in foreign-born culture-positive TB cases between 1982 and 2011. Relevant demographic, clinical and laboratory data were abstracted from the TB Registry, individual medical records and the Provincial Laboratory for Public Health.Of the 2,234 foreign-born culture-positive TB cases in Alberta in 1982-2011, 27 (1.2%) had MDR-TB. Overall, MDR was associated with age &lt;65 years (p=0.025), TB relapse/retreatment, and diagnosis and arrival in the last decade (2002-2011). The prevalence of MDR-TB in 2002-2011 was 2.1%, a significant increase from 0.65% in 1982-1991 (p=0.022) and 0.56% in 1992-2001 (p=0.009). Only immigrants from the Philippines and Vietnam showed a significant increase in the prevalence of MDR-TB between the first two decades and the last. Compared to MDR-TB cases reported in the first two decades, those reported in the last decade were more frequently younger than 35 years of age, new active versus relapse/retreatment cases and diagnosed with non-respiratory versus respiratory TB. In 1992-2011, MDR-TB strains had unique DNA fingerprints.Recent trends in the prevalence and clinical characteristics of foreign-born MDR-TB cases have important implications for TB case management in Canada. Early diagnosis of MDR-TB, using genotypic drug susceptibility testing, is suggested in foreign-born TB cases at increased risk of being MDR.

Understanding Disparity on the Canadian Prairies: A Step toward Improving Tuburculosis Outcomes

Understanding Disparity on the Canadian Prairies: A Step toward Improving Tuburculosis Outcomes

Prevalence of Anti-Tuberculosis Drug Resistance in Foreign-Born Tuberculosis Cases in the U.S. and in Their Countries of Origin

BackgroundForeign-born individuals comprise >50% of tuberculosis (TB) cases in the U.S. Since anti-TB drug resistance is more common in most other countries, when evaluating a foreign-born individual for TB, one must consider the risk of drug resistance. Naturally, clinicians query The Global Project on Anti-tuberculosis Drug Resistance Surveillance (Global DRS) which provides population-based data on the prevalence of anti-TB drug resistance in 127 countries starting in 1994. However, foreign-born persons in the U.S. are a biased sample of the population of their countries of origin, and Global DRS data may not accurately predict their risk of drug resistance. Since implementing drug resistance surveillance in 1993, the U.S. National TB Surveillance System (NTSS) has accumulated systematic data on over 130,000 foreign-born TB cases from more than 200 countries and territories. Our objective was to determine whether the prevalence of drug resistance among foreign-born TB cases correlates better with data from the Global DRS or with data on foreign-born TB cases in the NTSS.Methods and FindingsWe compared the prevalence of resistance to isoniazid and rifampin among foreign-born TB cases in the U.S., 2007–2009, with US NTSS data from 1993 to 2006 and with Global DRS data from 1994–2007 visually with scatterplots and statistically with correlation and linear regression analyses. Among foreign-born TB cases in the U.S., 2007–2009, the prevalence of isoniazid resistance and multidrug resistance (MDR, i.e. resistance to isoniazid and rifampin), correlated much better with 1993–2006 US surveillance data (isoniazid: r = 0.95, P<.001, MDR: r = 0.75, P<.001) than with Global DRS data, 1994–2007 (isoniazid: r = 0.55, P = .001; MDR: r = 0.50, P<.001).ConclusionSince 1993, the US NTSS has accumulated sufficient data on foreign-born TB cases to estimate the risk of drug resistance among such individuals better than data from the Global DRS.