Second Nationwide Tuberculosis Outbreak Caused by Bone Allografts Containing Live Cells - United States, 2023.

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.

Guidelines for the Treatment of Latent Tuberculosis Infection: Recommendations from the National Tuberculosis Controllers Association and CDC, 2020.

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.

Update of Recommendations for Use of Once-Weekly Isoniazid-Rifapentine Regimen to Treat Latent Mycobacterium tuberculosis Infection.

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.

Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children.

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.

Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children.

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.

Comparison of Sputum-Culture Conversion for Mycobacterium bovis and M. tuberculosis.

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.

Human Tuberculosis Caused by Mycobacterium bovis in the United States, 2006-2013.

BACKGROUND: Using genotyping techniques that have differentiated Mycobacterium bovis from Mycobacterium tuberculosis since 2005, we review the epidemiology of human tuberculosis caused by M. bovis in the United States and validate previous findings nationally. METHODS: All tuberculosis 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 (CIs). RESULTS: During 2006-2013, the annual percentages of tuberculosis cases attributable to M. bovis remained consistent nationally (range, 1.3%-1.6%) among all tuberculosis cases (N = 59 273). Compared with adults 25-44 years of age, infants aged 0-4 years (aPR, 1.9 [95% CI, 1.4-2.8]) and children aged 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 US-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 females are disproportionately affected by M. bovis, which was independently associated with extrapulmonary disease. Targeted prevention efforts aimed at Hispanic mothers and caregivers are warranted.

Management of latent Mycobacterium tuberculosis infection: WHO guidelines for low tuberculosis burden countries.

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.

Towards tuberculosis elimination: an action framework for low-incidence countries.

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.

Nationwide tuberculosis outbreak in the USA linked to a bone graft product: an outbreak report.

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.

Bridging implementation, knowledge, and ambition gaps to eliminate tuberculosis in the United States and globally.

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.

Unexpected decline in tuberculosis cases coincident with economic recession - United States, 2009.

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.

Treatment of latent tuberculosis infection: An update.

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.

Epidemiology of extrapulmonary tuberculosis in the United States, 1993-2006.

BACKGROUND: Almost one-fifth of United States tuberculosis cases are extrapulmonary; unexplained slower annual case count decreases have occurred in extrapulmonary tuberculosis (EPTB), compared with annual case count decreases in pulmonary tuberculosis (PTB) cases. We describe the epidemiology of EPTB by means of US national tuberculosis surveillance data. METHODS: US tuberculosis cases reported from 1993 to 2006 were classified as either EPTB or PTB. EPTB encompassed lymphatic, pleural, bone and/or joint, genitourinary, meningeal, peritoneal, and unclassified EPTB cases. We excluded cases with concurrent extrapulmonary-pulmonary tuberculosis and cases of disseminated (miliary) tuberculosis. Demographic characteristics, drug susceptibility test results, and risk factors, including human immunodeficiency virus (HIV) status, were compared for EPTB and PTB cases. RESULTS: Among 253,299 cases, 73.6% were PTB and 18.7% were EPTB, including lymphatic (40.4%), pleural (19.8%), bone and/or joint (11.3%), genitourinary (6.5%), meningeal (5.4%), peritoneal (4.9%), and unclassified EPTB (11.8%) cases. Compared with PTB, EPTB was associated with female sex (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.7-1.8) and foreign birth (OR, 1.5; CI, 1.5-1.6), almost equally associated with HIV status (OR, 1.1; CI, 1.1-1.1), and negatively associated with multidrug resistance (OR, 0.6; CI, 0.5-0.6) and several tuberculosis risk factors, especially homelessness (OR, 0.3; CI, 0.3-0.3) and excess alcohol use (OR, 0.3; CI, 0.3-0.3). Slower annual decreases in EPTB case counts, compared with annual decreases in PTB case counts, from 1993 through 2006 have caused EPTB to increase from 15.7% of tuberculosis cases in 1993 to 21.0% in 2006. CONCLUSIONS: EPTB epidemiology and risk factors differ from those of PTB, and the proportion of EPTB has increased from 1993 through 2006. Further study is needed to identify causes of the proportional increase in EPTB.

Nontuberculous mycobacteria infections and anti-tumor necrosis factor-alpha therapy.

Patients receiving anti-tumor necrosis factor-alpha (anti-TNF-alpha) therapy are at increased risk for tuberculosis and other granulomatous diseases, but little is known about illness caused by nontuberculous mycobacteria (NTM) in this setting. We reviewed the US Food and Drug Administration MedWatch database for reports of NTM disease in patients receiving anti-TNF-alpha therapy. Of 239 reports collected, 105 (44%) met NTM disease criteria. Median age was 62 years; the majority of patients (66, 65%) were female, and most (73, 70%) had rheumatoid arthritis. NTM infections were associated with infliximab (n = 73), etanercept (n = 25), and adalimumab (n = 7); most patients were taking prednisone (n = 68, 65%) or methotrexate (n = 58, 55%) concurrently. Mycobacteria avium (n = 52, 50%) was most commonly implicated, and 9 patients (9%) had died at the time their infections were reported. A high rate of extrapulmonary manifestations (n = 46, 44%) was also reported.

Extensively drug-resistant tuberculosis.

PURPOSE OF REVIEW: To describe the origin, epidemiology, diagnosis, treatment, prevention, and control of extensively drug-resistant tuberculosis (XDR TB). RECENT FINDINGS: XDR TB is defined as the occurrence of TB in persons whose Mycobacterium tuberculosis isolates are resistant to isoniazid and rifampin and to any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin). As of June 2008, XDR TB has been found in 49 countries including the United States. It generally takes several weeks to detect XDR TB using conventional culture-based methods, although some progress is being made in developing rapid molecular tests. Treatment for XDR TB is difficult, usually requiring at least 18-24 months of four to six second-line anti-TB drugs. Treatment success rates are generally 30-50%, with very poor outcomes in HIV-infected patients. Management of contacts to infectious XDR TB patients is complicated by the lack of a proven effective treatment for XDR latent tuberculosis infection. SUMMARY: XDR TB is an emerging global health threat. The disease is difficult and expensive to diagnose and treat, and outcomes are frequently poor. New rapid diagnostic tests and new classes of anti-TB drugs are needed to successfully combat this global problem.

Epidemiology of Tuberculosis in the United States.

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.

Human tuberculosis due to Mycobacterium bovis in the United States, 1995-2005.

BACKGROUND: Understanding the epidemiology of human Mycobacterium bovis tuberculosis (TB) in the United States is imperative; this disease can be foodborne or airborne, and current US control strategies are focused on TB due to Mycobacterium tuberculosis and airborne transmission. The National TB Genotyping Service's work has allowed systematic identification of M. tuberculosis-complex isolates and enabled the first US-wide study of M. bovis TB. METHODS: Results of spacer oligonucleotide and mycobacterial interspersed repetitive units typing were linked to corresponding national surveillance data for TB cases reported for the period 2004-2005 and select cases for the period 1995-2003. We also used National TB Genotyping Service data to evaluate the traditional antituberculous drug resistance-based case definition of M. bovis TB. RESULTS: Isolates from 165 (1.4%) of 11,860 linked cases were identified as M. bovis. Patients who were not born in the United States, Hispanic patients, patients <15 years of age, patients reported to be HIV infected, and patients with extrapulmonary disease each had increased adjusted odds of having M. bovis versus M. tuberculosis TB. Most US-born, Hispanic patients with TB due to M. bovis (29 [90.6%] of 32) had extrapulmonary disease, and their overall median age was 9.5 years. The National TB Genotyping Service's data indicated that the pyrazinamide-based case definition's sensitivity was 82.5% (95% confidence interval; 75.3%-87.9%) and that data identified 14 errors in pyrazinamide-susceptibility testing or reporting. CONCLUSIONS: The prevalence of extrapulmonary disease in the young, US-born Hispanic population suggests recent transmission of M. bovis, possibly related to foodborne exposure. Because of its significantly different epidemiologic profile, compared with that of M. tuberculosis TB, we recommend routine surveillance of M. bovis TB. Routine surveillance and an improved understanding of M. bovis TB transmission dynamics would help direct the development of additional control measures.

Prospective comparison of the tuberculin skin test and 2 whole-blood interferon-gamma release assays in persons with suspected tuberculosis.

BACKGROUND: Interferon-gamma release assays (IGRAs) are attractive alternatives to the tuberculin skin test (TST) for detecting Mycobacterium tuberculosis infection. However, the inability to definitively confirm the presence of most M. tuberculosis infections hampers assessment of IGRA accuracy. Although IGRAs are primarily indicated for the detection of latent tuberculosis infection, we sought to determine the sensitivity of the TST and 2 whole-blood IGRAs (QuantiFERON-TB assay [QFT] and QuantiFERON-TB Gold assay [QFT-G]) in situations in which infection is confirmed by recovery of M. tuberculosis by culture. METHODS: We conducted a prospective, multicenter, cross-sectional comparison study in which 148 persons suspected to have tuberculosis were tested simultaneously with the TST, QFT, and QFT-G. RESULTS: M. tuberculosis was cultured from samples from 69 (47%) of 148 persons suspected to have tuberculosis; the TST induration was > or = 5 mm for 51 (73.9%) of the 69 subjects (95% confidence interval [CI], 62.5%-82.8%). The QFT indicated tuberculosis infection for 48 (69.6%) of the 69 subjects (95% CI, 57.9%-79.2%) and was indeterminate for 7 (10.1%). The QFT-G yielded positive results for 46 (66.7%) of the 69 subjects (95% CI, 54.9%-76.7%) and indeterminate results for 9 subjects (13.0%). If subjects with indeterminate QFT-G results were excluded, 46 (76.7%) of 60 subjects (95% CI, 64.6%-85.6%) had positive TST results, and the same number of subjects had positive QFT-G results. HIV infection was associated with false-negative TST results but not with false-negative QFT-G results. CONCLUSIONS: The TST, QFT, and QFT-G have similar sensitivity in persons with culture-confirmed infection. As with the TST, negative QFT and QFT-G results should not be used to exclude the diagnosis of tuberculosis in persons with suggestive signs or symptoms.

Detection of Mycobacterium tuberculosis infection in United States Navy recruits using the tuberculin skin test or whole-blood interferon-gamma release assays.

BACKGROUND: Military personnel are at risk for acquiring Mycobacterium tuberculosis infection because of activities in close quarters and in regions with a high prevalence of tuberculosis (TB). Accurate tests are needed to avoid unnecessary treatment because of false-positive results and to avoid TB because of false-negative results and failure to diagnose and treat M. tuberculosis infection. We sought to estimate the specificity of the tuberculin skin test (TST) and 2 whole-blood interferon-gamma release assays (QuantiFERON-TB assay [QFT] and QuantiFERON-TB Gold assay [QFT-G]) and to identify factors associated with test discordance. METHODS: A cross-sectional comparison study was performed in which 856 US Navy recruits were tested for M. tuberculosis infection using the TST, QFT, and QFT-G. RESULTS: Among the study subjects, 5.1% of TSTs resulted in an induration > or = 10 mm, and 2.9% of TSTs resulted in an induration > or = 15 mm. Eleven percent of QFT results and 0.6% of QFT-G results were positive. Assuming recruits at low risk for M. tuberculosis exposure were not infected, estimates of TST specificity were 99.1% (95% confidence interval [CI], 98.3%-99.9%) when a 15-mm cutoff value was used and 98.4% (95% CI, 97.3%-99.4%) when a 10-mm cutoff value was used. The estimated QFT specificity was 92.3% (95% CI, 90.0%-94.5%), and the estimated QFT-G specificity was 99.8% (95% CI, 99.5%-100%). Recruits who were born in countries with a high prevalence of TB were 26-40 times more likely to have discordant results involving a positive TST result and a negative QFT-G result than were recruits born in countries with a low prevalence of TB. Nineteen (50%) of 38 recruits with this type of discordant results had a TST induration > or = 15 mm. CONCLUSIONS: The QFT-G and TST are more specific than the QFT. No statistically significant difference in specificity between the QFT-G and TST was found using a 15-mm induration cutoff value. The discordant results observed among recruits with increased risk of M. tuberculosis infection may have been because of lower TST specificity or lower QFT-G sensitivity. Negative QFT-G results for recruits born in countries where TB is highly prevalent and whose TST induration was > or = 15 mm suggest that the QFT-G may be less sensitive than the TST. Additional studies are needed to determine the risk of TB when TST and QFT-G results are discordant.