During July 7-11, 2023, CDC received reports of two patients in different states with a tuberculosis (TB) diagnosis following spinal surgical procedures that used bone allografts containing live cells from the same deceased donor. An outbreak associated with a similar product manufactured by the same tissue establishment (i.e., manufacturer) occurred in 2021. Because of concern that these cases represented a second outbreak, CDC and the Food and Drug Administration worked with the tissue establishment to determine that this product was obtained from a donor different from the one implicated in the 2021 outbreak and learned that the bone allograft product was distributed to 13 health care facilities in seven states. Notifications to all seven states occurred on July 12. As of December 20, 2023, five of 36 surgical bone allograft recipients received laboratory-confirmed TB disease diagnoses; two patients died of TB. Whole-genome sequencing demonstrated close genetic relatedness between positive Mycobacterium tuberculosis cultures from surgical recipients and unused product. Although the bone product had tested negative by nucleic acid amplification testing before distribution, M. tuberculosis culture of unused product was not performed until after the outbreak was recognized. The public health response prevented up to 53 additional surgical procedures using allografts from that donor; additional measures to protect patients from tissue-transmitted M. tuberculosis are urgently needed.

BACKGROUND: Mycobacterium tuberculosis transmission through solid organ transplantation has been well described, but transmission through transplanted tissues is rare. We investigated a tuberculosis outbreak in the USA linked to a bone graft product containing live cells derived from a single deceased donor. METHODS: In this outbreak report, we describe the management and severity of the outbreak and identify opportunities to improve tissue transplant safety in the USA. During early June, 2021, the US Centers for Disease Control and Prevention (CDC) worked with state and local health departments and health-care facilities to locate and sequester unused units from the recalled lot and notify, evaluate, and treat all identified product recipients. Investigators from CDC and the US Food and Drug Administration (FDA) reviewed donor screening and tissue processing. Unused product units from the recalled and other donor lots were tested for the presence of M tuberculosis using real-time PCR (rt PCR) assays and culture. M tuberculosis isolates from unused product and recipients were compared using phylogenetic analysis. FINDINGS: The tissue donor (a man aged 80 years) had unrecognised risk factors, symptoms, and signs consistent with tuberculosis. Bone was procured from the deceased donor and processed into 154 units of bone allograft product containing live cells, which were distributed to 37 hospitals and ambulatory surgical centres in 20 US states between March 1 and April 2, 2021. From March 3 to June 1, 2021, 136 (88%) units were implanted into 113 recipients aged 24-87 years in 18 states (some individuals received multiple units). The remaining 18 units (12%) were located and sequestered. 87 (77%) of 113 identified product recipients had microbiological or imaging evidence of tuberculosis disease. Eight product recipients died 8-99 days after product implantation (three deaths were attributed to tuberculosis after recognition of the outbreak). All 105 living recipients started treatment for tuberculosis disease at a median of 69 days (IQR 56-81) after product implantation. M tuberculosis was detected in all eight sequestered unused units tested from the recalled donor lot, but not in lots from other donors. M tuberculosis isolates from unused product and recipients were more than 99·99% genetically identical. INTERPRETATION: Donor-derived transmission of M tuberculosis via bone allograft resulted in substantial morbidity and mortality. All prospective tissue and organ donors should be routinely assessed for tuberculosis risk factors and clinical findings. When these are present, laboratory testing for M tuberculosis should be strongly considered. FUNDING: None.

Comprehensive guidelines for treatment of latent tuberculosis infection (LTBI) among persons living in the United States were last published in 2000 (American Thoracic Society. CDC targeted tuberculin testing and treatment of latent tuberculosis infection. Am J Respir Crit Care Med 2000;161:S221-47). Since then, several new regimens have been evaluated in clinical trials. To update previous guidelines, the National Tuberculosis Controllers Association (NTCA) and CDC convened a committee to conduct a systematic literature review and make new recommendations for the most effective and least toxic regimens for treatment of LTBI among persons who live in the United States.The systematic literature review included clinical trials of regimens to treat LTBI. Quality of evidence (high, moderate, low, or very low) from clinical trial comparisons was appraised using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. In addition, a network meta-analysis evaluated regimens that had not been compared directly in clinical trials. The effectiveness outcome was tuberculosis disease; the toxicity outcome was hepatotoxicity. Strong GRADE recommendations required at least moderate evidence of effectiveness and that the desirable consequences outweighed the undesirable consequences in the majority of patients. Conditional GRADE recommendations were made when determination of whether desirable consequences outweighed undesirable consequences was uncertain (e.g., with low-quality evidence).These updated 2020 LTBI treatment guidelines include the NTCA- and CDC-recommended treatment regimens that comprise three preferred rifamycin-based regimens and two alternative monotherapy regimens with daily isoniazid. All recommended treatment regimens are intended for persons infected with Mycobacterium tuberculosis that is presumed to be susceptible to isoniazid or rifampin. These updated guidelines do not apply when evidence is available that the infecting M. tuberculosis strain is resistant to both isoniazid and rifampin; recommendations for treating contacts exposed to multidrug-resistant tuberculosis were published in 2019 (Nahid P, Mase SR Migliori GB, et al. Treatment of drug-resistant tuberculosis. An official ATS/CDC/ERS/IDSA clinical practice guideline. Am J Respir Crit Care Med 2019;200:e93-e142). The three rifamycin-based preferred regimens are 3 months of once-weekly isoniazid plus rifapentine, 4 months of daily rifampin, or 3 months of daily isoniazid plus rifampin. Prescribing providers or pharmacists who are unfamiliar with rifampin and rifapentine might confuse the two drugs. They are not interchangeable, and caution should be taken to ensure that patients receive the correct medication for the intended regimen. Preference for these rifamycin-based regimens was made on the basis of effectiveness, safety, and high treatment completion rates. The two alternative treatment regimens are daily isoniazid for 6 or 9 months; isoniazid monotherapy is efficacious but has higher toxicity risk and lower treatment completion rates than shorter rifamycin-based regimens.In summary, short-course (3- to 4-month) rifamycin-based treatment regimens are preferred over longer-course (6-9 month) isoniazid monotherapy for treatment of LTBI. These updated guidelines can be used by clinicians, public health officials, policymakers, health care organizations, and other state and local stakeholders who might need to adapt them to fit individual clinical circumstances.

Although considerable progress has been made in reducing US tuberculosis incidence, the goal of eliminating the disease from the United States remains elusive. A continued focus on preventing new tuberculosis infections while also identifying and treating persons with existing tuberculosis infection is needed. Continued vigilance to ensure ongoing control of tuberculosis transmission remains key.

Treatment of latent tuberculosis infection (LTBI) is critical to the control and elimination of tuberculosis disease (TB) in the United States. In 2011, CDC recommended a short-course combination regimen of once-weekly isoniazid and rifapentine for 12 weeks (3HP) by directly observed therapy (DOT) for treatment of LTBI, with limitations for use in children aged <12 years and persons with human immunodeficiency virus (HIV) infection (1). CDC identified the use of 3HP in those populations, as well as self-administration of the 3HP regimen, as areas to address in updated recommendations. In 2017, a CDC Work Group conducted a systematic review and meta-analyses of the 3HP regimen using methods adapted from the Guide to Community Preventive Services. In total, 19 articles representing 15 unique studies were included in the meta-analysis, which determined that 3HP is as safe and effective as other recommended LTBI regimens and achieves substantially higher treatment completion rates. In July 2017, the Work Group presented the meta-analysis findings to a group of TB experts, and in December 2017, CDC solicited input from the Advisory Council for the Elimination of Tuberculosis (ACET) and members of the public for incorporation into the final recommendations. CDC continues to recommend 3HP for treatment of LTBI in adults and now recommends use of 3HP 1) in persons with LTBI aged 2-17 years; 2) in persons with LTBI who have HIV infection, including acquired immunodeficiency syndrome (AIDS), and are taking antiretroviral medications with acceptable drug-drug interactions with rifapentine; and 3) by DOT or self-administered therapy (SAT) in persons aged >/=2 years.

We agree with the excellent summary provided by Reves and Benjamin of the important, but insufficient, progress toward tuberculosis (TB) elimination (<1 case per million population) in the United States over the past two decades. Furthermore, we concur with the need to advance the argument in favor of additional investments required to eliminate TB by providing an estimate of future expected benefits. | | While we did not model future projected savings in our report,1 we have undertaken relatively simple retrospective modeling to estimate the reduction in TB cases and societal benefits had TB elimination been achieved in 1995 and sustained through 2014. From this we estimate that during 1995–2014 from 430 397 to 604 494 TB cases would have been averted (Figure 1), at estimated benefits of US $19.9 billion to $27.7 billion, including the value of deaths prevented and the costs to treat drug-resistant TB disease (Figure 2). Projected cases averted and cost savings for two decades into the future would also be anticipated to be substantial, although somewhat less, because even with a flat case rate the projected case counts for the next two decades would be less than those that actually occurred between 1995 and 2014.

Since 1989, the USA has been pursuing the goal of tuberculosis elimination. After substantial progress during the past two decades, the rate of tuberculosis cases in the USA each year has now levelled off and remains well above the elimination threshold. Both epidemiological data and modelling underline the necessity of addressing latent tuberculosis infection if further progress is to be made in eliminating the disease. In this Personal View we explore next steps towards elimination. Given the estimated prevalence of latent tuberculosis infection, compared with the limited testing and treatment that currently occur, a major new effort is required. This effort should consist of a surveillance system or registry to monitor progress, scale-up of targeted testing for latent tuberculosis infection in at-risk populations, scale-up of short-course treatment regimens, engagement of affected communities and medical providers who serve those communities, and increased public health staffing for implementation and oversight. Such an effort would benefit greatly from the development of new tools, such as tests that better indicate reactivation risk, and even shorter latent tuberculosis infection treatment regimens than currently exist.

Because tuberculosis is caused by an infectious organism that is spread from person to person through the air, public health measures are essential to control the disease. There are three priority strategies for tuberculosis prevention and control in the United States: (i) identifying and treating persons who have tuberculosis disease; (ii) finding persons exposed to infectious tuberculosis patients, evaluating them for Mycobacterium tuberculosis infection and disease, and providing subsequent treatment, if appropriate; and (iii) testing populations at high risk for latent tuberculosis infection (LTBI) and treating those persons who are infected to prevent progression to disease. These strategies for prevention and control of tuberculosis are discussed in a framework containing the following important topics: historical and epidemiological context of tuberculosis control, organization of public health tuberculosis control programs, legal basis for public health authority, conducting overall planning and development of policy, identifying persons who have clinically active tuberculosis, evaluation of immigrants, managing persons who have or who are suspected of having disease, medical consultation, interjurisdictional referrals, identifying and managing persons infected with Mycobacterium tuberculosis, providing laboratory and diagnostic services, collecting and analyzing data, and providing training and education. This chapter describes the role of the health department in the context of these components. This discussion is primarily applicable to tuberculosis prevention and control programs in the United States.

Current US guidelines recommend longer treatment for tuberculosis (TB) caused by pyrazinamide-resistant organisms (e.g., Mycobacterium bovis) than for M. tuberculosis TB. We compared treatment response times for patients with M. bovis TB and M. tuberculosis TB reported in the United States during 2006-2013. We included culture-positive, pulmonary TB patients with genotyping results who received standard 4-drug treatment at the time of diagnosis. Time to sputum-culture conversion was defined as time between treatment start date and date of first consistently culture-negative sputum. We analyzed 297 case-patients with M. bovis TB and 30,848 case-patients with M. tuberculosis TB. After 2 months of treatment, 71% of M. bovis and 65% of M. tuberculosis TB patients showed conversion of sputum cultures to negative. Likelihood of culture conversion was higher for M. bovis than for M. tuberculosis, even after controlling for treatment administration type, sex, and a composite indicator of bacillary burden.

BACKGROUND: Individuals infected with Mycobacterium tuberculosis (Mtb) may develop symptoms and signs of disease (tuberculosis disease) or may have no clinical evidence of disease (latent tuberculosis infection [LTBI]). Tuberculosis disease is a leading cause of infectious disease morbidity and mortality worldwide, yet many questions related to its diagnosis remain. METHODS: A task force supported by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America searched, selected, and synthesized relevant evidence. The evidence was then used as the basis for recommendations about the diagnosis of tuberculosis disease and LTBI in adults and children. The recommendations were formulated, written, and graded using the Grading, Recommendations, Assessment, Development and Evaluation (GRADE) approach. RESULTS: Twenty-three evidence-based recommendations about diagnostic testing for latent tuberculosis infection, pulmonary tuberculosis, and extrapulmonary tuberculosis are provided. Six of the recommendations are strong, whereas the remaining 17 are conditional. CONCLUSIONS: These guidelines are not intended to impose a standard of care. They provide the basis for rational decisions in the diagnosis of tuberculosis in the context of the existing evidence. No guidelines can take into account all of the often compelling unique individual clinical circumstances.

Mycobacterium tuberculosis is recognised as the primary cause of human tuberculosis worldwide. However, substantial evidence suggests that the burden of Mycobacterium bovis, the cause of bovine tuberculosis, might be underestimated in human beings as the cause of zoonotic tuberculosis. In 2013, results from a systematic review and meta-analysis of global zoonotic tuberculosis showed that the same challenges and concerns expressed 15 years ago remain valid. These challenges faced by people with zoonotic tuberculosis might not be proportional to the scientific attention and resources allocated in recent years to other diseases. The burden of zoonotic tuberculosis in people needs important reassessment, especially in areas where bovine tuberculosis is endemic and where people live in conditions that favour direct contact with infected animals or animal products. As countries move towards detecting the 3 million tuberculosis cases estimated to be missed annually, and in view of WHO's end TB strategy endorsed by the health authorities of WHO Member States in 2014 to achieve a world free of tuberculosis by 2035, we call on all tuberculosis stakeholders to act to accurately diagnose and treat tuberculosis caused by M bovis in human beings.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

BACKGROUND: Using genotyping techniques that have differentiated Mycobacterium bovis from M. tuberculosis since 2005, we review the epidemiology of human TB caused by M. bovis in the United States and validate previous findings nationally. METHODS: All TB cases with a genotyped M. tuberculosis complex isolate reported during 2006-2013 in the United States were eligible for analysis. We used binomial regression to identify characteristics independently associated with M. bovis disease using adjusted prevalence ratios (aPRs) and corresponding 95% confidence intervals (95%CI). RESULTS: During 2006-2013, the annual percentages of TB cases attributable to M. bovis remained consistent nationally (range: 1.3-1.6%) among all TB cases (n=59,273). Compared with adults 25-44 years of age, infants 0-4 years (aPR 1.9, 95% CI 1.4-2.8) and children 5-14 years (aPR 4.0, 95% CI 3.1-5.3) had higher prevalences of M. bovis disease. Patients who were foreign-born (aPR 1.4, 95% CI 1.2-1.7), Hispanic (aPR 3.9, 95% CI 3.0-5.0), female (aPR 1.4, 95% CI 1.3-1.6),), and resided in U.S.-Mexico border counties (aPR 2.0, 95% CI 1.7-2.4) also had higher M. bovis prevalences. Exclusively extrapulmonary disease (aPR 3.7, 95% CI 3.3-4.2) or disease that was both pulmonary and extrapulmonary (aPR 2.4, 95% CI 2.1-2.9) were associated with a higher prevalence of M. bovis disease CONCLUSIONS: Children, foreign-born persons, Hispanics, and women are disproportionately affected by M. bovis, which was independently associated with extrapulmonary disease. Targeted prevention efforts aimed at Hispanic mothers and caregivers are warranted.

BACKGROUND: Reexamining the prevalence of persons infected with tuberculosis (TB) is important to determine trends over time. In 2011-2012 a TB component was included in the National Health and Nutrition Examination Survey (NHANES) to estimate the reservoir of persons infected with TB. METHODS: Civilian, noninstitutionalized U.S. population survey participants aged 6 years and older were interviewed regarding their TB history and eligibility for the tuberculin skin test (TST) and interferon gamma release assay (IGRA) blood test. Once eligibility was confirmed, both tests were conducted. Prevalence and numbers of TST positive (10 mm or greater), IGRA positive, and both TST and IGRA positive were calculated by adjusting for the complex survey design after applying corrections for item nonresponse and digit preference in TST induration measurements. To examine TST positivity over time, data from NHANES 1999-2000 were reanalyzed using the same statistical methods. The TST was performed using Tubersol, a commercially available purified protein derivative (PPD), rather than PPD-S, which was the antigen used in NHANES 1999-2000. Prior patient history of TB vaccination was not collected in this study nor were patients examined for the presence of a Bacillus of Calmette and Guerin (BCG) vaccine scar. RESULTS: For NHANES 2011-2012, TST and IGRA results were available for 6,128 (78.4%) and 7,107 (90.9%) eligible participants, respectively. There was no significant difference between the percentage of the U.S. population that was TST positive in 2011-2012 (4.7% [95% CI 3.4-6.3]; 13,276,000 persons) compared with 1999-2000 (4.3%; 3.5-5.3). In 2011-2012 the percentage that was IGRA positive was 5.0% (4.2-5.8) and double TST and IGRA positivity was 2.1% (1.5-2.8). The point estimate of IGRA positivity prevalence in foreign-born persons (15.9%; 13.5-18.7) was lower than for TST (20.5%; 16.1-25.8) in 2011-2012. The point estimate of IGRA positivity prevalence in U.S.-born persons (2.8%; 2.0-3.8) was higher than for TST (1.5%; 0.9-2.6). CONCLUSIONS: No statistically significant decline in the overall estimated prevalence of TST positivity was detected from 1999-2000 to 2011-2012. The prevalence of TB infection, whether measured by TST or IGRA, remains lower among persons born in the United States compared with foreign-born persons.

Latent tuberculosis infection (LTBI) is characterised by the presence of immune responses to previously acquired Mycobacterium tuberculosis infection without clinical evidence of active tuberculosis (TB). Here we report evidence-based guidelines from the World Health Organization for a public health approach to the management of LTBI in high risk individuals in countries with high or middle upper income and TB incidence of <100 per 100 000 per year. The guidelines strongly recommend systematic testing and treatment of LTBI in people living with HIV, adult and child contacts of pulmonary TB cases, patients initiating anti-tumour necrosis factor treatment, patients receiving dialysis, patients preparing for organ or haematological transplantation, and patients with silicosis. In prisoners, healthcare workers, immigrants from high TB burden countries, homeless persons and illicit drug users, systematic testing and treatment of LTBI is conditionally recommended, according to TB epidemiology and resource availability. Either commercial interferon-gamma release assays or Mantoux tuberculin skin testing could be used to test for LTBI. Chest radiography should be performed before LTBI treatment to rule out active TB disease. Recommended treatment regimens for LTBI include: 6 or 9 month isoniazid; 12 week rifapentine plus isoniazid; 3-4 month isoniazid plus rifampicin; or 3-4 month rifampicin alone.

This paper describes an action framework for countries with low tuberculosis (TB) incidence (<100 TB cases per million population) that are striving for TB elimination. The framework sets out priority interventions required for these countries to progress first towards "pre-elimination" (<10 cases per million) and eventually the elimination of TB as a public health problem (less than one case per million). TB epidemiology in most low-incidence countries is characterised by a low rate of transmission in the general population, occasional outbreaks, a majority of TB cases generated from progression of latent TB infection (LTBI) rather than local transmission, concentration to certain vulnerable and hard-to-reach risk groups, and challenges posed by cross-border migration. Common health system challenges are that political commitment, funding, clinical expertise and general awareness of TB diminishes as TB incidence falls. The framework presents a tailored response to these challenges, grouped into eight priority action areas: 1) ensure political commitment, funding and stewardship for planning and essential services; 2) address the most vulnerable and hard-to-reach groups; 3) address special needs of migrants and cross-border issues; 4) undertake screening for active TB and LTBI in TB contacts and selected high-risk groups, and provide appropriate treatment; 5) optimise the prevention and care of drug-resistant TB; 6) ensure continued surveillance, programme monitoring and evaluation and case-based data management; 7) invest in research and new tools; and 8) support global TB prevention, care and control. The overall approach needs to be multisectorial, focusing on equitable access to high-quality diagnosis and care, and on addressing the social determinants of TB. Because of increasing globalisation and population mobility, the response needs to have both national and global dimensions.

Multidrug-resistant tuberculosis (MDR TB) is caused by Mycobacterium tuberculosis that is resistant to at least isoniazid and rifampin, the two most effective of the four first-line TB drugs (the other two drugs being ethambutol and pyrazinamide). MDR TB includes the subcategory of extensively drug-resistant TB (XDR TB), which is MDR TB with additional resistance to any fluoroquinolone and to at least one of three injectable anti-TB drugs (i.e., kanamycin, capreomycin, or amikacin). MDR TB is difficult to cure, requiring 18-24 months of treatment after sputum culture conversion with a regimen that consists of four to six medications with toxic side effects, and carries a mortality risk greater than that of drug-susceptible TB. Bedaquiline fumarate (Sirturo or bedaquiline) is an oral diarylquinoline. On December 28, 2012, on the basis of data from two Phase IIb trials (i.e., well-controlled trials to evaluate the efficacy and safety of drugs in patients with a disease or condition to be treated, diagnosed, or prevented), the Food and Drug Administration (FDA) approved use of bedaquiline under the provisions of the accelerated approval regulations for "serious or life-threatening illnesses" (21CFR314.500) (Cox EM. FDA accelerated approval letter to Janssen Research and Development. Available at http://www.accessdata.fda.gov/drugsatfda_docs/appletter/2012/204384Orig1s000ltr.pdf). This report provides provisional CDC guidelines for FDA-approved and unapproved, or off-label, uses of bedaquiline in certain populations, such as children, pregnant women, or persons with extrapulmonary MDR TB who were not included in the clinical trials for the drug. CDC's Division of TB Elimination developed these guidelines on the basis of expert opinion informed by data from systematic reviews and literature searches. This approach is different from the statutory standards that FDA uses when approving drugs and drug labeling. These guidelines are intended for health-care professionals who might use bedaquiline for the treatment of MDR TB for indicated and off-label uses. Aspects of these guidelines are not identical to current FDA-approved labeling for bedaquiline. Bedaquiline should be used with clinical expert consultation as part of combination therapy (minimum four-drug treatment regimen) and administered by direct observation to adults aged ≥18 years with a diagnosis of pulmonary MDR TB (Food and Drug Administration. SIRTURO [bedaquiline] tablets label. Available at http://www.accessdata.fda.gov/drugsatfda_docs/label/2012/204384s000lbl.pdf). Use of the drug also can be considered for individual patients in other categories (e.g., persons with extrapulmonary TB, children, pregnant women, or persons with HIV or other comorbid conditions) when treatment options are limited. However, further study is required before routine use of bedaquiline can be recommended in these populations. A registry for persons treated with bedaquiline is being implemented by Janssen Therapeutics to track patient outcomes, adverse reactions, laboratory testing results (e.g., diagnosis, drug susceptibility, and development of drug resistance), use of concomitant medications, and presence of other comorbid conditions. Suspected adverse reactions (i.e., any adverse event for which there is a reasonable possibility that the drug caused the adverse event) and serious adverse events (i.e., any adverse event that results in an outcome such as death, hospitalization, permanent disability, or a life-threatening situation) should be reported to Janssen Therapeutics at telephone 1-800-526-7736, to FDA at telephone 1-800-332-1088 or at http://www.fda.gov/medwatch, and to CDC's Emergency Operations Center at telephone 1-770-488-7100.

Effective Diagnosis and Treatment of Latent Tuberculosis infection (LTBI) to prevent progression to tuberculosis (TB) disease is one of the priority strategies for control, prevention, and eventual elimination of TB in the United States. Recent mathematical TB transmission modeling has shown that substantial improvements in addressing LTBI will be needed to eliminate TB before the 22nd century.1 Effective management of LTBI has been hampered by limitations of both treatment regimens and diagnostic tools. The advent of medication regimens with much shorter durations (eg, 12 weekly doses of isoniazid and rifapentine) than the current standard of 9 months of isoniazid is likely to lead to higher rates of treatment completion. Efforts have also been directed at finding a replacement for the tuberculin skin test (TST), which despite its many limitations has been the mainstay of LTBI diagnosis. | Beginning in the 1990s, interferon-γ–release assays (IG-RAs) were developed to diagnose LTBI. Currently, 2 US Food and Drug Administration-approved IGRAs are commercially available, QuantiFERON TB Gold In-Tube (Cellestis/Qiagen) and T-SPOT.TB (Oxford Immunotec). These blood tests detect ex vivo interferon-γ production by peripheral blood mononuclear cells exposed to peptides designed to simulate Mycobacterium tuberculosis antigens. Interferon-γ–release assays offer several practical and theoretical advantages over TST. Interferon-γ–release assays require only 1 patient visit as opposed to 2 for TST (1 visit for placement and 1 visit for reading 48-72 hours later). Interferon-γ–release assays use an objective measurement of interferon-7 production as opposed to human measurement of induration for TST. Also, IGRAs use peptides simulating specific M tuberculosis antigens (early secretory antigenic target 6 [ESAT-6], culture filtrate protein 10 [CFP-10], TB7.7), whereas TST uses purified protein derivative. Purified protein derivative contains numerous M tuberculosis antigens that cross-react with bacille Calmette-Guérin (BCG) and many nontuberculous mycobacteria. ESAT-6, CFP-10, and TB7.7 are found in very few nontuberculous mycobacteria and not found in BCG.

BACKGROUND: Since 1953, through the cooperation of state and local health departments, the U.S. Centers for Disease Control and Prevention (CDC) has collected information on incident cases of tuberculosis (TB) disease in the United States. In 2009, TB case rates declined -11.4%, compared to an average annual -3.8% decline since 2000. The unexpectedly large decline raised concerns that TB cases may have gone unreported. To address the unexpected decline, we examined trends from multiple sources on TB treatment initiation, medication sales, and laboratory and genotyping data on culture-positive TB. METHODS: We analyzed 142,174 incident TB cases reported to the U. S. National Tuberculosis Surveillance System (NTSS) during January 1, 2000-December 31, 2009; TB control program data from 59 public health reporting areas; self-reported data from 50 CDC-funded public health laboratories; monthly electronic prescription claims for new TB therapy prescriptions; and complete genotyping results available for NTSS cases. Accounting for prior trends using regression and time-series analyses, we calculated the deviation between observed and expected TB cases in 2009 according to patient and clinical characteristics, and assessed at what point in time the deviation occurred. RESULTS: The overall deviation in TB cases in 2009 was -7.9%, with -994 fewer cases reported than expected (P <.001). We ruled out evidence of surveillance underreporting since declines were seen in states that used new software for case reporting in 2009 as well as states that did not, and we found no cases unreported to CDC in our examination of over 5400 individual line-listed reports in 11 areas. TB cases decreased substantially among both foreign-born and U.S.-born persons. The unexpected decline began in late 2008 or early 2009, and may have begun to reverse in late 2009. The decline was greater in terms of case counts among foreign-born than U.S.-born persons; among the foreign-born, the declines were greatest in terms of percentage deviation from expected among persons who had been in the United States less than 2 years. Among U.S.-born persons, the declines in percentage deviation from expected were greatest among homeless persons and substance users. Independent information systems (NTSS, TB prescription claims, and public health laboratories) reported similar patterns of declines. Genotyping data did not suggest sudden decreases in recent transmission. CONCLUSIONS: Our assessments show that the decline in reported TB was not an artifact of changes in surveillance methods; rather, similar declines were found through multiple data sources. While the steady decline of TB cases before 2009 suggests ongoing improvement in TB control, we were not able to identify any substantial change in TB control activities or TB transmission that would account for the abrupt decline in 2009. It is possible that other multiple causes coincident with economic recession in the United States, including decreased immigration and delayed access to medical care, could be related to TB declines. Our findings underscore important needs in addressing health disparities as we move towards TB elimination in the United States.

BACKGROUND: Mycobacterium tuberculosis (Mtb) infection may cause overt disease or remain latent. Interferon gamma release assays (IGRAs) detect Mtb infection, both latent infection and infection manifesting as overt disease, by measuring whole-blood interferon gamma (IFN-gamma) responses to Mtb antigens such as early secreted antigenic target-6 (ESAT-6), culture filtrate protein 10 (CFP-10), and TB7.7. Due to a lack of adequate diagnostic standards for confirming latent Mtb infection, IGRA sensitivity for detecting Mtb infection has been estimated using patients with culture-confirmed tuberculosis (CCTB) for whom recovery of Mtb confirms the infection. In this study, cytokines in addition to IFN-gamma were assessed for potential to provide robust measures of Mtb infection. METHODS: Cytokine responses to ESAT-6, CFP-10, TB7.7, or combinations of these Mtb antigens, for patients with CCTB were compared with responses for subjects at low risk for Mtb infection (controls). Three different multiplexed immunoassays were used to measure concentrations of 9 to 20 different cytokines. Responses were calculated by subtracting background cytokine concentrations from cytokine concentrations in plasma from blood stimulated with Mtb antigens. RESULTS: Two assays demonstrated that ESAT-6, CFP-10, ESAT-6+CFP-10, and ESAT-6+CFP-10+TB7.7 stimulated the release of significantly greater amounts of IFN-gamma, IL-2, IL-8, MCP-1 and MIP-1beta for CCTB patients than for controls. Responses to combination antigens were, or tended to be, greater than responses to individual antigens. A third assay, using whole blood stimulation with ESAT-6+CFP-10+TB7.7, revealed significantly greater IFN-gamma, IL-2, IL-6, IL-8, IP-10, MCP-1, MIP-1beta, and TNF-alpha responses among patients compared with controls. One CCTB patient with a falsely negative IFN-gamma response had elevated responses with other cytokines. CONCLUSIONS: Multiple cytokines are released when whole blood from patients with CCTB is stimulated with Mtb antigens. Measurement of multiple cytokine responses may improve diagnostic sensitivity for Mtb infection compared with assessment of IFN-gamma alone.

In a recent article in this Journal, Holland et al. correlate TB incidence in the United States since 1952 with time, immigration, and HIV in the late 1980s and early 1990s.1 The authors also correlate proportional decreases in TB incidence in 2008–2009 with increases in unemployment in 2009–2010 in a separate linear regression in which lagged unemployment explains about 10% of state variance in TB incidence (R2 = 0.10). Given the disparities in TB incidence trends comparing US-born versus foreign-born persons in the United States,2 these models may be enhanced by considering origin of birth as an explanatory or stratification variable. | Provisional national surveillance data as of 26 February 2011 show a continued decline in TB case counts, to 11 181 cases in 2010 compared with 11 531 cases in 2009.3 In provisional data, the proportion of all TB patients with cavitary disease was 26% in 2009 and 25% in 2010, while 2% of patients were dead at diagnosis in both years. Despite the aberrant decline in 2009, these data suggest no increase in the number or severity of cases in 2010. As the 2010 case count data are finalized, we continue to investigate and be vigilant for any resurgence in TB. To date, none has been observed.

Treatment of latent tuberculosis infection (LTBI) is an important tuberculosis prevention and control strategy, especially in high-resource countries. The effectiveness of LTBI treatment, which usually consists of isoniazid (also known as isonicotinylhydrazine (INH)) for 6–9 months, is limited by poor patient adherence because of long treatment duration and adverse effects. The most common serious adverse effect of INH is hepatotoxicity, which increases with age and can be fatal.1 A meta-analysis of six studies found that the pooled rate of INH-associated hepatotoxicity was 0.6%.2

We reflect on remarkable accomplishments in global tuberculosis (TB) control and identify persistent obstacles to the successful elimination of TB from the United States and globally. One hundred and twenty nine years after Koch's discovery of the etiologic agent of TB, this health scourge continues to account for 9.4 million cases and 1.7 million deaths annually worldwide. Implementation of the Directly Observed Treatment Short-course strategy from 1995 through 2009 has saved 6 million lives. TB control is increasingly being achieved in countries with high-income economies, yet TB continues to plague persons living in countries with low-income and lower-middle-income economies. To accelerate progress against the global effects of disease caused by TB and achieve its elimination, we must bridge 3 key gaps in implementation, knowledge, and ambition.

In 2005, CDC published guidelines for using the QuantiFERON-TB Gold test (QFT-G) (Cellestis Limited, Carnegie, Victoria, Australia) (CDC. Guidelines for using the QuantiFERON-TB Gold test for detecting Mycobacterium tuberculosis infection, United States. MMWR;54[No. RR-15]:49-55). Subsequently, two new interferon gamma (IFN- gamma) release assays (IGRAs) were approved by the Food and Drug Administration (FDA) as aids in diagnosing M. tuberculosis infection, both latent infection and infection manifesting as active tuberculosis. These tests are the QuantiFERON-TB Gold In-Tube test (QFT-GIT) (Cellestis Limited, Carnegie, Victoria, Australia) and the T-SPOT.TB test (T-Spot) (Oxford Immunotec Limited, Abingdon, United Kingdom). The antigens, methods, and interpretation criteria for these assays differ from those for IGRAs approved previously by FDA. For assistance in developing recommendations related to IGRA use, CDC convened a group of experts to review the scientific evidence and provide opinions regarding use of IGRAs. Data submitted to FDA, published reports, and expert opinion related to IGRAs were used in preparing these guidelines. Results of studies examining sensitivity, specificity, and agreement for IGRAs and TST vary with respect to which test is better. Although data on the accuracy of IGRAs and their ability to predict subsequent active tuberculosis are limited, to date, no major deficiencies have been reported in studies involving various populations. This report provides guidance to U.S. public health officials, health-care providers, and laboratory workers for use of FDA-approved IGRAs in the diagnosis of M. tuberculosis infection in adults and children. In brief, TSTs and IGRAs (QFT-G, QFT-GIT, and T-Spot) may be used as aids in diagnosing M. tuberculosis infection. They may be used for surveillance purposes and to identify persons likely to benefit from treatment. Multiple additional recommendations are provided that address quality control, test selection, and medical management after testing. Although substantial progress has been made in documenting the utility of IGRAs, additional research is needed that focuses on the value and limitations of IGRAs in situations of importance to medical care or tuberculosis control. Specific areas needing additional research are listed.

Human tuberculosis (TB) caused by Mycobacterium bovis appears to be rare in most of the region of the Americas, although some localities have reported an unusually high prevalence of M. bovis among human TB cases (e.g., San Diego, CA, USA; parts of Mexico). As surveillance data are lacking in many countries, there is substantial uncertainty regarding actual incidence. M. bovis is most often not identified, as the diagnosis of TB is made by smear microscopy alone or using egg-containing culture media lacking pyruvate. Where human M. bovis cases have been studied in the region, they appear to be associated with ingestion of unpasteurized dairy products, or with airborne acquired infection in animal keepers and meat industry workers from countries where bovine TB remains a problem. Human-to-human transmission of M. bovis does occur, but appears to account for a very small proportion of cases. Efforts to eradicate M. bovis in humans in the Americas should therefore be directed at eradicating the disease in cattle, increasing pasteurization of dairy products and providing education about the dangers of consuming unpasteurized dairy products.

TUBERCULOSIS caused by Mycobacterium bovis | has been reported to cause disease in humans in widespread regions of the world. However, with few exceptions, the literature indicates that M. bovis accounts | for 1% or less of tuberculosis cases in humans.1–3 | Moreover, human-to-human transmission is rare and | is probably responsible for only a very small percentage of the cases.4 | The global picture of human tuberculosis caused | by M. bovis is, however, largely incomplete. Furthermore, it may be misleading to draw global conclusions | from the published literature on human M. bovis disease, which is mainly focused on high-income, lowtuberculosis burden countries.5,6 While reports indicate that M. bovis, including multidrug-resistant | M. bovis, has been isolated from some human immunodefi ciency virus (HIV) infected patients, the scope of | the problem has not been investigated in countries | where HIV infection is widespread.6,7 These countries | also tend to have large burdens of human tuberculosis. In addition, some may have substantial problems | with bovine tuberculosis and conditions that facilitate cattle-to-human transmission.8 For example, in | sub-Saharan Africa, where human tuberculosis and | HIV incidence are high and where no country has been | able to eradicate or effectively control bovine tuberculosis, half or more of the population may have direct contact with cattle, compared with less than 5% in | the United States.9 Routine or periodic surveillance of | M. bovis in cattle or humans in these high-tuberculosis | burden, high-HIV prevalence, low-resource settings | is not performed, and accurate information on the incidence of human M. bovis disease is not available

Tuberculosis (TB) is a pulmonary and systemic disease caused by Mycobacterium tuberculosis complex species. TB is spread from person to person by airborne transmission. Several factors determine the probability of transmission, including the infectiousness of the source patient and the nature of the environment where exposure occurs. This initial infection (primary TB) rapidly progresses to disease in some persons (especially children and immunocompromised persons), but resolves spontaneously in most individuals. This condition in which the organism lies dormant is known as latent TB infection (LTBI). In the United States, the diagnosis of LTBI is made with either the tuberculin skin test or an interferon-gamma release assay. LTBI is treated with isoniazid (INH; usually for 9 months) to prevent progression to TB disease. Up to 5% of immunocompetent persons will progress to TB disease at some time in the future, even decades after infection, if they are not treated for LTBI. Pulmonary TB disease is diagnosed using a combination of chest radiography and microscopic examination, culture and nucleic acid amplification testing of sputum. Treatment of drug-susceptible TB consists of at least 6 months of an INH and rifampin-containing regimen (with ethambutol and pyrazinamide for the first 2 months). In the United States, drug-resistant TB is relatively rare (approximately 1% of all patients), and is treated with an 18-24 month individualized regimen based on drug susceptibility test results.

Tuberculosis (TB) is a significant disease for both humans and animals. Susceptibility to Mycobacterium tuberculosis is relatively high in humans, other primates and guinea pigs. Cattle, rabbits and cats are susceptible to M. bovis and are quite resistant to M. tuberculosis. Wild hoofed stock is generally susceptible to M. bovis, but few reports are available on the isolation of M. tuberculosis. Swine and dogs are susceptible to both M. bovis and M. tuberculosis. M. bovis accounts for only a small percentage of the reported cases of TB in humans; however, it is a pathogen of significant economic importance in wild and domestic animals around the globe, especially in countries where little information is available on the incidence of M. bovis infection in humans. Unlike transmission of M. bovis from cattle to humans, the role of human-to-human airborne transmission in the spread of M. bovis has been somewhat controversial. Investigations are needed to elucidate the relative importance of M. bovis on TB incidence in humans, especially in developing countries. Efforts should be concentrated in countries where human immunodeficiency virus (HIV) infection is widespread, as HIV-infected individuals are more susceptible to mycobacterial disease. Eradication of M. bovis in cattle and pasteurisation of dairy products are the cornerstones of the prevention of human disease.

Fluoroquinolone antibiotics are relatively new drugs in anti-tuberculosis (TB) treatment, with the potential to become the first new class of drugs to be recommended for routine treatment since rifamycins in the 1960s. Later generation fluoroquinolones, including levofloxacin, gatifloxacin, and moxifloxacin have been found to be safe and well-tolerated in observational studies and phase 2 clinical trials, except for a risk of severe dysglycemias with gatifloxacin. These drugs currently are used as second-line agents in treatment of TB cases with drug resistance and drug intolerance, and empirically in treatment of infected contacts of patients with multi-drug resistant TB. Widespread use of fluoroquinolones for treatment of community acquired pneumonia and other bacterial infections is leading to the emergence and spread of strains of Mycobacterium tuberculosis that are fluoroquinolone-resistant, putting at risk the potential effectiveness of these drugs against TB. Clinical trials are under way to determine whether fluoroquinolone-based treatment regimens can shorten the duration of TB therapy. The ultimate contributions of fluoroquinolones to TB control remain to be determined. copyright the author(s), publisher and licensee Libertas Academica Ltd.

Isoniazid (INH) has been the mainstay of treatment of latent tuberculosis infection for almost 50 years. The currently recommended preferred regimen is 9 months daily self-administered INH (9H); this has efficacy of more than 90% if completed properly. Unfortunately, INH is associated with serious adverse events, including hepatotoxicity. Although risk factors for this complication are well established, allowing for better selection of candidates for therapy, this complication still occurs, and is occasionally fatal. Hence close follow up of patients is necessary, increasing the cost and complexity of treatment. This problem, plus the lengthy duration, results in poor acceptance by patients and providers, and poor adherence by patients. As a result, many preventable cases of tuberculosis continue to occur, and the public health impact of latent tuberculosis infection treatment is suboptimal. These problems have spurred interest in finding shorter, safer and cheaper alternative regimens, with similar efficacy. Of the many regimens that have been examined, 2 months of rifampin and pyrazinamide has excellent efficacy-in experimental studies in mice and randomized trials, largely in HIV-infected persons. However, while the safety of 2 months of rifampin and pyrazinamide appears acceptable in HIV-infected persons and children, in non-HIV-infected adults this regimen is associated with an unacceptably high rate of severe liver toxicity. Three to four months of INH and rifampin has had equivalent effectiveness as 6 months INH in several randomized trials. However, completion of therapy and toxicity has been the same as with INH-possibly because two drugs are taken rather than one. The fourth commonly studied regimen is 4 months rifampin. This has been found to have significantly better completion than 9H, with significantly less toxicity, especially hepatotoxicity. However, only one trial has evaluated efficacy and effectiveness of mono-rifampin therapy. In this trial, 3 months rifampin had somewhat better efficacy than either 3 months of isoniazid and rifampin (3HR) or 6 months isoniazid. Two large scale trials are ongoing; one is comparing efficacy and effectiveness of 9H with 4 months rifampin (both daily and self-administered), while the second, which is nearing completion, compares daily self-administered 9H with 3 months directly observed once weekly INH combined with rifapentine. The results of these two trials will likely shape future recommendations substantially.