What can we offer to 3 million MDRTB household contacts in 2016?

Contact investigation in multidrug-resistant tuberculosis: ethical challenges

Contact investigation is an evidence-based intervention of multidrug-resistant tuberculosis (MDR-TB) to protect public health by interrupting the chain of transmission. In pursuit of contact investigation, patients' MDR-TB status has to be disclosed to third parties (to the minimum necessary) for tracing the contacts. Nevertheless, disclosure to third parties often unintentionally leads the MDR-TB patients suffered from social discrimination and stigma. For this reason, patients are less inclined to reveal their MDR-TB status and becomes a significant issue in contact investigation. This issue certainly turns into a negative impact on the public interest. Tension between keeping MDR-TB status confidential and safeguarding public health arises in relation to this issue. Regarding MDR-TB management, patient compliance with treatment and contact investigation are equally important. Patients might fail to comply with anti-TB therapy and be reluctant to seek healthcare due to disclosure concerns. In order to have treatment adherence, MDRTB patients should not live through social discrimination and stigma arising from disclosure and TB team has a duty to support them as a mean of reciprocity. However, implementation of contact investigation as a public health policy can still be challenging even with promising reciprocal support to the patients because MDR-TB patients are living in different contexts and situations. There can be no straight forward settlement but an appropriate justification for each distinct context is needed to strike a balance between individual confidentiality and public interest.

Tuberculosis Diagnosis and Preventive Monotherapy Among Children and Adolescents Exposed to Rifampicin-Resistant Tuberculosis in the Household

Background

Children and adolescents with household exposure to multidrug- or rifampicin-resistant tuberculosis (MDR/RR-TB) are at high risk of developing TB disease. Tuberculosis preventive therapy (TPT) is recommended, but programmatic experience is limited, particularly for adolescents.

Methods

We conducted a prospective cohort study to describe MDR/RR-TB diagnosis and TPT provision for individuals aged <18 years with MDR/RR-TB exposure. Participants were assessed for TB either in homes or health facilities, with referral for chest x-ray or specimen collection at clinician discretion. The TPT regimens included levofloxacin, isoniazid, or delamanid monotherapy for 6 months, based on source patient drug-resistance profile.

Results

Between March 1, 2020 and July 31, 2021, 112 participants were enrolled; median age was 8.5 years, 57 (51%) were female, and 6 (5%) had human immunodeficiency virus. On screening, 11 (10%) were diagnosed with TB: 10 presumptive MDR/RR-TB and 1 drug-susceptible TB. Overall, 95 (94% of 101) participants started TPT: 79 with levofloxacin, 9 with isoniazid, and 7 with delamanid. Seventy-six (80%) completed TPT, 12 (13%) were lost to follow up, and 7 (7%) stopped TPT early due to adverse events. Potential adverse events were reported for 12 (13%) participants; none were serious. There were no further TB diagnoses (200 days median follow up).

Conclusions

Post-MDR/RR-TB exposure management for children and adolescents resulted in significant MDR/RR-TB detection and both high TPT initiation and completion. Tuberculosis preventive monotherapy was well tolerated and there were no further TB diagnoses after initial assessment. Key factors supporting these outcomes included use of pediatric formulations for young children, monotherapy, and community-based options for assessment and follow up.

Caregiver willingness to give TPT to children living with drug-resistant TB patients

BACKGROUND Pediatric household contacts (HHCs) of patients with multidrug-resistant TB (MDR-TB) are at high risk of infection and active disease. Evidence of caregiver willingness to give MDR-TB preventive therapy (TPT) to children is limited.METHODS This was a cross-sectional study of HHCs of patients with MDR-TB to assess caregiver willingness to give TPT to children aged <13 years.RESULTS Of 743 adult and adolescent HHCs, 299 reported caring for children aged <13 years of age. The median caregiver age was 35 years (IQR 27-48); 75% were women. Among caregivers, 89% were willing to give children MDR TPT. In unadjusted analyses, increased willingness was associated with TB-related knowledge (OR 5.1, 95% CI 2.3-11.3), belief that one can die of MDR-TB (OR 5.2, 95% CI 1.2-23.4), concern for MDR-TB transmission to child (OR 4.5, 95% CI 1.6-12.4), confidence in properly taking TPT (OR 4.5, 95% CI 1.6-12.6), comfort telling family about TPT (OR 5.5, 95% CI 2.1-14.3), and willingness to take TPT oneself (OR 35.1, 95% CI 11.0-112.8).CONCLUSIONS A high percentage of caregivers living with MDR- or rifampicin-resistant TB patients were willing to give children a hypothetical MDR TPT. These results provide important evidence for the potential uptake of effective MDR TPT when implemented.

Challenges in the screening and treatment of latent multidrug-resistant tuberculosis infection

Individuals in close contact with multidrug-resistant tuberculosis (MDR-TB) patients are subject to an elevated risk of infection, and may develop latent MDR-TB infection. Numerous studies have described latent tuberculosis infection (LTBI) as a reservoir of new TB disease. The screening and treatment of latent MDR-TB infection are challenging. Hereby, we reviewed the epidemiology, current management and prevention approach of LTBI in MDR-TB close contacts, to provide additional information for future research direction and policy design formulation to reduce the LTBI reservoir.

Transmission of multidrug-resistant tuberculosis within family households by DTM-PCR and MIRU-VNTR genotyping

Background

Drug-resistant tuberculosis (TB) continues to be a public health threat. There are few studies on transmission and genotyping of MDR-TB family households in China. This study aimed to investigate transmission of multidrug-resistant tuberculosis (MDR-TB) within family households by deletion-targeted multiplex polymerase chain reaction (DTM-PCR), mycobacterial interspersed repetitive unit variable number tandem repeats (MIRU-VNTR) genotyping.

Methods

Among 993 MDR-TB patients registered from Wuhan Institute for Tuberculosis Control, drug resistance and the time interval between the index patients and secondary patients were analyzed in 49 MDR-TB patients from 23 families, in which 22 MDR-TB strains from 11 families who had matched strains were genotyped by DTM-PCR and standard 24-loci MIRU-VNTR genotyping method.

Results

The time interval between the index patients and the secondary patients ranged from half a month to 110 months. Thirteen secondary patients developed active MDR-TB within two years and accounted for 50% (13/26) of all secondary patients. Among eleven pairs of MDR-TB families, six pairs had identical genotypes, the cluster rate was 54.5% (12/22); three pairs had a single MIRU-VNTR locus variation. If a single MIRU-VNTR locus variation was tolerated in the cluster definition, the cluster rate raised to 81.8% (18/22).

Conclusions

The family households of MDR-TB patients are at risk for infection of MDR-TB. To reduce transmission, MDR-TB patients should be diagnosed earlier and promptly treated in an effective manner, meanwhile, the close family contacts should be screened for TB infection.

High rate of successful treatment outcomes among childhood rifampicin/multidrug-resistant tuberculosis in Pakistan: a multicentre retrospective observational analysis

Background

There was a complete lack of information about the treatment outcomes of rifampicin/multidrug resistant (RR/MDR) childhood TB patients (age ≤ 14 years) from Pakistan, an MDR-TB 5th high burden country. Therefore, this study evaluated the socio-demographic characteristics, drug resistance pattern, treatment outcomes and factors associated with unsuccessful outcomes among childhood RR/MDR-TB patients in Pakistan.

Methods

This was a multicentre retrospective record review of all microbiologically confirmed childhood RR/MDR-TB patients (age ≤ 14 years) enrolled for treatment at seven units of programmatic management of drug-resistant TB (PMDT) in Pakistan. The baseline and follow-up information of enrolled participants from treatment initiation until the end of treatment were retrieved from electronic nominal recording and reporting system. World Health Organization (WHO) defined criterion was used for deciding treatment outcomes. The outcomes of “cured” and “treatment completed” were collectively grouped as successful, whereas “death”, “treatment failure” and “lost to follow-up” were grouped together as unsuccessful outcomes. Multivariable binary logistic regression analysis was used to find factors associated with unsuccessful outcomes. A p-value < 0.05 reflected statistically significant findings.

Results

A total of 213 children RR/MDR-TB (84 RR and 129 MDR-TB) were included in the study. Majority of them were females (74%), belonged to the age group 10–14 years (82.2%) and suffered from pulmonary TB (85.9%). A notable proportion (37.1%) of patients had no history of previous TB treatment. Patients were resistant to a median of two drugs (interquartile range: 1–4) and 23% were resistant to any second line anti-TB drug. A total of 174 (81.7%) patients achieved successful treatment outcomes with 144 (67.6%) patients being cured and 30 (14.1%) declared treatment completed. Among the 39 (18.3%) patients with unsuccessful outcomes, 35 (16.4%) died and 4 (1.9%) experienced treatment failure. In multivariable analysis, the use of ethambutol had statistically significant negative association with unsuccessful outcomes (odds ratio = 0.36, p-value = 0.02).

Conclusions

In this study, the WHO target of successful treatment outcomes (≥ 75%) among childhood RR/MDR-TB patients was achieved. The notable proportion of patients with no history of previous TB treatment (37.1%) and the disproportionately high number of female patients (74%) respectively stress for infection control measures and provision of early and high quality care for female drug susceptible TB patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06935-6.

Effectiveness of Shorter Treatment Regimen in Multidrug-Resistant Tuberculosis Patients in Pakistan: A Multicenter Retrospective Record Review

In Pakistan, the treatment of multidrug-resistant tuberculosis (MDR-TB) with a shorter treatment regimen (STR), that is, 4-6 months of amikacin, moxifloxacin (Mfx), ethionamide, clofazimine (Cfz), pyrazinamide (Z), ethambutol (E), and high-dose isoniazid, followed by 5 months of Mfx, Cfz, Z, and E, was initiated in 2018. However, there is a lack of information about its effectiveness in Pakistani healthcare settings. Therefore, this retrospective record review of MDR-TB patients treated with STR at eight treatment sites in Pakistan aimed to fill this gap. Data were analyzed using SPSS 23. Multivariate binary logistic regression (MVBLR) analysis was conducted to find factors associated with death and treatment failure, and lost to follow-up (LTFU). A P-value < 0.05 was considered statistically significant. Of 912 MDR-TB patients enrolled at the study sites, only 313 (34.3%) eligible patients were treated with STR and included in the current study. Of them, a total of 250 (79.9%) were cured, 12 (3.8%) completed treated, 31 (9.9%) died, 16 (5.1%) were LTFU, and four (1.3%) were declared as treatment failures. The overall treatment success rate was 83.7%. In MVBLR analysis, patients' age of 41-60 (odds ratio [OR] = 4.9, P-value = 0.020) and > 60 years (OR = 3.6, P-value = 0.035), being underweight (OR = 2.7, P-value = 0.042), and previous TB treatment (OR = 0.4, P-value = 0.042) had statistically significant association with death and treatment failure, whereas patients' age of > 60 years (OR = 5.4, P-value = 0.040) and previous TB treatment (OR = 0.2, P-value = 0.008) had statistically significant association with LTFU. The treatment success rate of STR was encouraging. However, to further improve the treatment outcomes, special attention should be paid to the patients with identified risk factors.

An e-registry for household contacts exposed to multidrug resistant TB in Mongolia

BACKGROUND

The WHO recommends that individuals exposed to persons with multidrug resistant tuberculosis (MDRTB) should be screened for active TB and followed up for 2 years to detect and treat secondary cases early. Resource prioritisation means this is rarely undertaken and where it is performed it's usually using a paper-based record, without collation of data. Electronic data collection into a web-based registry offers the opportunity for simplified and systematic TB contact surveillance with automatic synthesis of data at local, regional and national level. This pilot study was designed to explore the feasibility of usage of a novel e-registry tool and explore obstacles and facilitating factors to implementation.

METHODS

In parallel with their paper records, seven dispensaries in Ulaanbaatar, Mongolia collected standardized data electronically using Open Data Kit (ODK). Patients with MDRTB and their contacts were recruited during a single clinic visit. Staff and patients were interviewed to gain insights into acceptability and to identify areas for improvement.

RESULTS

Seventy household contacts of 32 MDR-TB index patients were recruited. 7/70 contacts (10%) traced had active TB at the time they were recruited to the e-registry. Paper registry satisfaction was low; 88% of staff preferred the e-registry as it was perceived as faster and more secure. Patients and their contacts were generally supportive of the e-registry; however, a significant minority 10/42 (24%) of index cases who were invited, declined to participate in the e-registry, with data security cited as their top concern.

CONCLUSION

E-registries are a promising tool for MDRTB contact tracing, but their acceptability amongst patients should not be taken for granted.

Treatment as prevention and other interventions to reduce transmission of multidrug-resistant tuberculosis

Drug-resistant tuberculosis (DR-TB) represents a major programmatic challenge at the national and global levels. Only ∼30% of patients with multidrug-resistant TB (MDR-TB) were diagnosed, and ∼25% were initiated on treatment for MDR-TB in 2016. Increasing evidence now points towards primary transmission of DR-TB, rather than inadequate treatment, as the main driver of the DR-TB epidemic. The cornerstone of DR-TB transmission prevention should be earlier diagnosis and prompt initiation of effective treatment for all patients with DR-TB. Despite the extensive scale-up of Xpert^® MTB/RIF testing, major implementation barriers continue to limit its impact. Although there is longstanding evidence in support of the rapid impact of treatment on patient infectiousness, delays in the initiation of effective DR-TB treatment persist, resulting in ongoing transmission. However, it is also imperative to address the burden of latent drug-resistant tuberculous infection because it is estimated that many DR-TB patients will become infectious before seeking care and encounter various diagnostic delays before treatment. Addressing latent DR-TB primarily consists of identifying, treating and following the contacts of patients with MDR-TB, typically through household contact evaluation. Adjunctive measures, such as improved ventilation and use of germicidal ultraviolet technology can further reduce TB transmission in high-risk congregate settings. Although many gaps remain in our biological understanding of TB transmission, implementation barriers to early diagnosis and rapid initiation of effective DR-TB treatment can and must be overcome if we are to impact DR-TB incidence in the short and long term.

Willingness to Take Multidrug-resistant Tuberculosis (MDR-TB) Preventive Therapy Among Adult and Adolescent Household Contacts of MDR-TB Index Cases: An International Multisite Cross-sectional Study

BACKGROUND

Household contacts (HHCs) of individuals with multidrug-resistant tuberculosis (MDR-TB) are at high risk of infection and subsequent disease. There is limited evidence on the willingness of MDR-TB HHCs to take MDR-TB preventive therapy (MDR TPT) to decrease their risk of TB disease.

METHODS

In this cross-sectional study of HHCs of MDR-TB and rifampicin-resistant tuberculosis (RR-TB) index cases from 16 clinical research sites in 8 countries, enrollees were interviewed to assess willingness to take a hypothetical, newly developed MDR TPT if offered. To identify factors associated with willingness to take MDR TPT, a marginal logistic model was fitted using generalized estimating equations to account for household-level clustering.

RESULTS

From 278 MDR-TB/RR-TB index case households, 743 HHCs were enrolled; the median age of HHCs was 33 (interquartile range, 22-49) years, and 62% were women. HHC willingness to take hypothetical MDR TPT was high (79%) and remained high even with the potential for mild side effects (70%). Increased willingness was significantly associated with current employment or schooling (adjusted odds ratio [aOR], 1.83 [95% confidence interval {CI}, 1.07-3.13]), appropriate TB-related knowledge (aOR, 2.22 [95% CI, 1.23-3.99]), confidence in taking MDR TPT (aOR, 7.16 [95% CI, 3.33-15.42]), and being comfortable telling others about taking MDR TPT (aOR, 2.29 [95% CI, 1.29-4.06]).

CONCLUSIONS

The high percentage of HHCs of MDR-TB/RR-TB index cases willing to take hypothetical MDR TPT provides important evidence for the potential uptake of effective MDR TPT when implemented. Identified HHC-level variables associated with willingness may inform education and counseling efforts to increase HHC confidence in and uptake of MDR TPT.

Outcomes of Community-Based Systematic Screening of Household Contacts of Patients with Multidrug-Resistant Tuberculosis in Myanmar

Screening of household contacts of patients with multidrug-resistant tuberculosis (MDR-TB) is a crucial active TB case-finding intervention. Before 2016, this intervention had not been implemented in Myanmar, a country with a high MDR-TB burden. In 2016, a community-based screening of household contacts of MDR-TB patients using a systematic TB-screening algorithm (symptom screening and chest radiography followed by sputum smear microscopy and Xpert-MTB/RIF assays) was implemented in 33 townships in Myanmar. We assessed the implementation of this intervention, how well the screening algorithm was followed, and the yield of active TB. Data collected between April 2016 and March 2017 were analyzed using logistic and log-binomial regression. Of 620 household contacts of 210 MDR-TB patients enrolled for screening, 620 (100%) underwent TB symptom screening and 505 (81%) underwent chest radiography. Of 240 (39%) symptomatic household contacts, 71 (30%) were not further screened according to the algorithm. Children aged <15 years were less likely to follow the algorithm. Twenty-four contacts were diagnosed with active TB, including two rifampicin- resistant cases (yield of active TB = 3.9%, 95% CI: 2.3%-6.5%). The highest yield was found among children aged <5 years (10.0%, 95% CI: 3.6%-24.7%). Household contact screening should be strengthened, continued, and scaled up for all MDR-TB patients in Myanmar.

Global burden of latent multidrug-resistant tuberculosis: trends and estimates based on mathematical modelling

BACKGROUND

To end the global tuberculosis epidemic, latent tuberculosis infection needs to be addressed. All standard treatments for latent tuberculosis contain drugs to which multidrug-resistant (MDR) Mycobacterium tuberculosis is resistant. We aimed to estimate the global burden of multidrug-resistant latent tuberculosis infection to inform tuberculosis elimination policy.

METHODS

By fitting a flexible statistical model to tuberculosis drug resistance surveillance and survey data collated by WHO, we estimated national trends in the proportion of new tuberculosis cases that were caused by MDR strains. We used these data as a proxy for the proportion of new infections caused by MDR M tuberculosis and multiplied trends in annual risk of infection from previous estimates of the burden of latent tuberculosis to generate trends in the annual risk of infection with MDR M tuberculosis. These estimates were used in a cohort model to estimate changes in the global and national prevalence of latent infection with MDR M tuberculosis. We also estimated recent infection levels (ie, in 2013 and 2014) and made predictions for the future burden of MDR tuberculosis in 2035 and 2050.

FINDINGS

19·1 million (95% uncertainty interval [UI] 16·4 million-21·7 million) people were latently infected with MDR tuberculosis in 2014-a global prevalence of 0·3% (95% UI 0·2-0·3). MDR strains accounted for 1·2% (95% UI 1·0-1·4) of the total latent tuberculosis burden overall, but for 2·9% (95% UI 2·6-3·1) of the burden among children younger than 15 years (risk ratio for those younger than 15 years vs those aged 15 years or older 2·65 [95% UI 2·11-3·25]). Recent latent infection with MDR M tuberculosis meant that 1·9 million (95% UI 1·7 million-2·3 million) people globally were at high risk of active MDR tuberculosis in 2015.

INTERPRETATION

We estimate that three in every 1000 people globally carry latent MDR tuberculosis infection, and prevalence is around ten times higher among those younger than 15 years. If current trends continue, the proportion of latent tuberculosis caused by MDR strains will increase, which will pose serious challenges for management of latent tuberculosis-a cornerstone of tuberculosis elimination strategies.

FUNDING

UK Medical Research Council, Bill & Melinda Gates Foundation, and European Research Council.

The burden of multidrug-resistant tuberculosis in children

BACKGROUND

Childhood tuberculosis (TB) has historically been neglected, although in recent years there has been increased focus on this problem. In particular, there have been two efforts to estimate the burden of pediatric multidrug-resistant TB (MDR-TB).

METHODS

We review current estimates of the global incidence of pediatric MDR-TB disease. We then combine pediatric MDR-TB treatment data from the World Health Organization and recently published case fatality ratio estimates for children with TB to produce mortality estimates for children with MDR-TB. Finally, we combine treatment data and estimates of household size and disease risk to estimate how many children could be treated for probable or confirmed MDR-TB by carrying out household contact investigations around adult MDR-TB patients.

RESULTS

Between 25 000 and 32 000 children develop MDR-TB disease annually, accounting for around 3% of all pediatric TB cases. Only 3-4% of these children are likely to receive MDR-TB treatment. We estimate that around 21% of children who develop MDR-TB disease will die. Carrying out household contact investigations around adult MDR-TB patients could find an estimated 12 times as many pediatric MDR-TB cases as are currently being identified.

DISCUSSION

The diagnosis and treatment of children with MDR-TB needs to be prioritized by TB programs.

New drugs and perspectives for new anti-tuberculosis regimens

Tuberculosis (TB) is the ninth cause of global death, more than any other infectious disease. With growing drug resistance the epidemic remains and will require significant attention and investment for the elimination of this disease to occur. With susceptible TB treatment not changing over the last four decades and the advent of drug resistance, new drugs and regimens are required. Recently, through greater collaboration and research networks some progress with significant advances has taken place, not withstanding the comparatively low amount of resources invested. Of late the availability of the new drugs bedaquiline, delamanid and repurposed drugs linezolid, clofazimine and carbapenems are being used more frequently in drug-resistant TB regimens. The WHO shorter multidrug-resistant tuberculosis regimen promises to reach more patients and treat them more quickly and more cheaply. With this new enthusiasm and hope we this review gives an update on the new drugs and perspectives for the treatment of drug-susceptible and drug-resistant tuberculosis.

Treatment of Latent Tuberculosis Infection

There are approximately 56 million people who harbor Mycobacterium tuberculosis that may progress to active tuberculosis (TB) at some point in their lives. Modeling studies suggest that if only 8% of these individuals with latent TB infection (LTBI) were treated annually, overall global incidence would be 14-fold lower by 2050 compared to incidence in 2013, even in the absence of additional TB control measures. This highlights the importance of identifying and treating latently infected individuals, and that this intervention must be scaled up to achieve the goals of the Global End TB Strategy. The efficacy of LTBI treatment is well established, and the most commonly used regimen is 9 months of daily self-administered isoniazid. However, its use has been hindered by limited provider awareness of the benefits, concern about potential side effects such as hepatotoxicity, and low rates of treatment completion. There is increasing evidence that shorter rifamycin-based regimens are as effective, better tolerated, and more likely to be completed compared to isoniazid. Such regimens include four months of daily self-administered rifampin monotherapy, three months of once weekly directly observed isoniazid-rifapentine, and three months of daily self-administered isoniazid-rifampin. The success of LTBI treatment to prevent additional TB disease relies upon choosing an appropriate regimen individualized to the patient, monitoring for potential adverse clinical events, and utilizing strategies to promote adherence. Safer, more cost-effective, and more easily completed regimens are needed and should be combined with interventions to better identify, engage, and retain high-risk individuals across the cascade from diagnosis through treatment completion of LTBI.

The challenge of the new tuberculosis drugs

Tuberculosis (TB) continues to cause more deaths worldwide than any other single infectious disease. Even though tuberculosis appears to be decreasing in incidence globally for some time, the proportion of drug resistance is increasing, contributing to greater complexity, morbidity and mortality as well as cost. Since the advent of rifampicin in the 1960s, and the implementation of standard quadruple anti-tuberculosis regimen in the late 1970s, no new drugs have been changed the first line regimen. This regimen is effective however it is pill burden, and duration has not received investment and innovation. Drug-resistant regimens are long and frequently poorly tolerated due to significant toxicity. This review is an update on what is new in the treatment of drug-susceptible and drug-resistant tuberculosis, new TB drugs currently being used and studied in clinical trials are also mentioned. Fortunately, there have been many significant advances in this field in recent years. The horizon is changing with the new WHO shorter multidrug-resistant tuberculosis regimens and with the increasing availability of new or repurposed drugs like bedaquiline, delamanid, clofazimine and linezolid. These drugs pose new challenges relating to their rational use to prevent selection of resistant strains of Mycobacterium tuberculosis even before a new regimen has been studied. The availability of these new drugs is offering hope and new possibilities for saving patients who had few or no treatment options. Their use and combination into effective regimens need to be studied; trials are in progress. It is hoped that soon we will be able to treat sensitive and drug-resistant cases with a universal regimen, this would revolutionise treatment and take us another step closer towards elimination.

Impact of the GeneXpert MTB/RIF Technology on Tuberculosis Control

Molecular technology revolutionized the diagnosis of tuberculosis (TB) with a paradigm shift to faster, more sensitive, clinically relevant patient care. The most recent molecular leader is the GeneXpert MTB/RIF assay (Xpert) (Cepheid, Sunnyvale, CA), which was endorsed by the World Health Organization with unprecedented speed in December 2010 as the initial diagnostic for detection of HIV-associated TB and for where high rates of drug resistance are suspected. South Africa elected to take an aggressive smear replacement approach to facilitate earlier diagnosis and treatment through the decision to implement the Xpert assay nationally in March 2011, against the backdrop of approximately 6.3 million HIV-infected individuals, one of highest global TB and HIV coinfection rates, no available implementation models, uncertainties around field performance and program costs, and lack of guidance on how to operationalize the assay into existing complex clinical algorithms. South Africa's national implementation was conducted as a phased, forecasted, and managed approach (March 2011 to September 2013), through political will and both treasury-funded and donor-funded support. Today there are 314 GeneXperts across 207 microscopy centers; over 8 million assays have been conducted, and South Africa accounts for over half the global test cartridge usage. As with any implementation of new technology, challenges were encountered, both predicted and unexpected. This chapter discusses the challenges and consequences of such large-scale implementation efforts, the opportunities for new innovations, and the need to strengthen health systems, as well as the impact of the Xpert assay on rifampin-sensitive and multidrug-resistant TB patient care that translated into global TB control as we move toward the sustainable development goals.