Multidrug-resistant tuberculosis, People's Republic of China, 2007-2009

Transmission of multidrug-resistant tuberculosis in Jiangxi, China, and associated risk factors

In order to effectively combat the urgent threat of multidrug-resistant tuberculosis (MDR-TB), it is imperative to gain a comprehensive understanding of the drug-resistant profiles, transmission dynamics, and associated risk factors. Our study encompassed a population-based retrospective analysis with 130 MDR-TB patients from 2018 to 2021. The research methodology incorporated whole-genome sequencing, drug susceptibility testing , and logistic regression analysis to discern the risk factors of genomic clustering linked to recent transmission. The findings from phenotypic drug resistance assessments revealed notable resistance rates: ethambutol at 62.3% (81/130), streptomycin at 72.3% (94/130), levofloxacin at 51.5% (67/130), and moxifloxacin at 50.0% (65/130). Furthermore, among all patients, 38 individuals (29.23%, 38/130) were found to be part of 17 clusters, indicating instances of recent MDR-TB transmission. The genomic clustering patients were deeply investigated. Lineage 2.2.1 was established as the primary sub-lineage (86.15%, 112/130), followed by lineage 4 (9.23%, 12/130). Moreover, the logistic regression analysis underscored that unemployment, farming occupations, and prior TB treatment were identified as significant risk factors for recent transmission.

IMPORTANCE

The high prevalence of multidrug-resistant tuberculosis (MDR-TB) in Jiangxi Province highlights the importance of understanding the genetic background and drug resistance patterns of these strains. This knowledge is crucial for developing effective control methods. Furthermore, in light of the significance of preventing transmission among tuberculosis patients, whole-genome sequencing was utilized to investigate the recent transmission of MDR-TB and identify associated risk factors. The findings revealed that individuals in the farming sector, those who are unemployed, and patients with a history of tuberculosis treatment are at elevated risk. Consequently, targeted public interventions for these at-risk groups are imperative.

Prevalence and patterns of drug-resistant Mycobacterium tuberculosis in newly diagnosed patients in China: A systematic review and meta-analysis

BACKGROUND

Tuberculosis (TB), one of the deadliest infectious diseases globally, is increasingly exacerbated in China by the emergence of resistant Mycobacterium tuberculosis (MTB) strains. Drug-resistant TB, including mono-drug-resistant TB, multidrug-resistant TB (MDR-TB), and extensively drug-resistant TB (XDR-TB), presents significant public health challenges.

METHODS

We conducted a systematic literature review from January 2010 to February 2024 using databases such as PubMed, Embase, Web of Science, and Google Scholar. Our focus was on empirical data related to drug resistance patterns in newly diagnosed TB cases. Non-empirical studies were excluded through meticulous filtering. For the meta-analysis, we used Review Manager (RevMan) 5.2 and assessed evidence quality using the Newcastle-Ottawa Scale (NOS).

RESULTS

Our search strategy identified 40 studies that met the inclusion criteria, encompassing a total sample size of 87,667 participants. Among new TB cases, the estimated prevalence of MDR-TB in China was 6.9% (95% CI: 5.6-8.1%). Prevalence rates for mono-drug resistance to first-line anti-TB medications were as follows: isoniazid at 18.2% (95% CI: 16.4-20.6%), rifampicin at 10.5% (95% CI: 8.6-12.8%), and ethambutol at 5.7% (95% CI: 4.1-7.3%). The prevalence of streptomycin resistance, a former first-line anti-TB drug, was 17.1% (95% CI: 14.6-19.1%). The prevalence of other types of mono-drug resistance was 15.2% (95% CI: 13.9-17.3%), and for XDR-TB, it was 0.9% (95% CI: 0.6-1.4%).

CONCLUSIONS

The high prevalence of drug-resistant TB in China poses a significant public health challenge. There is an urgent need for targeted interventions and continued surveillance to combat the spread of drug-resistant TB.

Risk factors for multidrug-resistant tuberculosis: A worldwide systematic review and meta-analysis

Background

Since multidrug-resistant tuberculosis (MDR-TB) is a significant public health problem worldwide, identifying associated risk factors is critical for developing appropriate control strategies.

Methods

A systematic review and meta-analysis was conducted for identifying factors independently predicting MDR-TB. The random-effects model was used to determine pooled odds ratios (ORs) and respective 95% confidence intervals (CIs) for the related factors.

Results

Of the 2301 retrieved reports, 28 studies were analyzed, assessing 3152 MDR-TB and 52715 DS-TB cases. Totally 22 related factors were analyzed. The pooled ORs were 1.478 (95%CI 1.077–2.028) for positive sputum AFB smear, 1.716 (95%CI 1.149–2.564) for lung cavity, 6.078 (95%CI 2.903–12.725) for previous TB disease and 5.427 (95%CI 3.469–8.490) for a history of anti-TB therapy. All Z test p values were below 0.05, indicating these parameters were significantly associated with MDR-TB.

Conclusions

Positive sputum AFB smear, lung cavity, previously diagnosed TB and a history of anti-TB therapy are significant risk factors for MDR-TB, which are independent of the clinical setting worldwide. Increased attention should be paid to cases with such parameters to achieve more effective TB control and avoid MDR-TB through the development of a global policy.

Transmission of multidrug-resistant tuberculosis in Shimen community in Shanghai, China: a molecular epidemiology study

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) has become a major public health problem in China, with mounting evidence suggesting that recent transmission accounts for the majority of MDR-TB. Here we aimed to reveal the transmission pattern of an MDR-TB outbreak in the Jing'an District of Shanghai between 2010 and 2015.

METHODS

We used whole-genome sequencing (WGS) to conduct genomic clustering analysis along with field epidemiological investigation to determine the transmission pattern and drug resistance profile of a cluster with ten MDR-TB patients in combining field epidemiological investigation.

RESULTS

The ten MDR-TB patients with genotypically clustered Beijing lineage strains lived in a densely populated, old alley with direct or indirect contact history. The analysis of genomic data showed that the genetic distances of the ten strains (excluding drug-resistant mutations) were 0-20 single nucleotide polymorphisms (SNPs), with an average distance of 9 SNPs, suggesting that the ten MDR-TB patients were infected and developed the onset of illness by the recent transmission of M. tuberculosis. The genetic analysis confirmed definite epidemiological links between the clustered cases.

CONCLUSIONS

The integration of the genotyping tool in routine tuberculosis surveillance can play a substantial role in the detection of MDR-TB transmission events. The leverage of genomic analysis in combination with the epidemiological investigation could further elucidate transmission patterns. Whole-genome sequencing could be integrated into intensive case-finding strategies to identify missed cases of MDR-TB and strengthen efforts to interrupt transmission.

Diagnostic Performance of GeneChip for the Rapid Detection of Drug-Resistant Tuberculosis in Different Subgroups of Patients

Objective

Drug-resistant tuberculosis (DR-TB) is a growing problem worldwide. The rapid drug susceptibility test (DST) of DR-TB enables the timely administration of a chemotherapy regimen that effectively treats DR-TB. GeneChip has been reported as a novel molecular diagnostic tool for rapid diagnosis but has limited data on the performance of subgroup patients with DR-TB. This study aims to assess the diagnostic value of GeneChip in patients with different sexes, ages, treatment histories, treatment outcomes, and places of residence.

Methods

We recruited newly registered sputum smear-positive pulmonary TB patients from January 2011 to September 2020 in Lianyungang City, Jiangsu Province, China. We applied both GeneChip and DST to measure drug resistance to rifampin (RIF) and isoniazid (INH). The kappa value, sensitivity, specificity, and agreement rate (AR) were calculated. We also applied a Classification and Regression Tree to explore factors related to the performance of GeneChip.

Results

We observed that sex, age, treatment history, treatment outcomes, and drug resistance type were significantly associated with the performance of GeneChip. For RIF resistance, there was significant accordance in young patients (kappa: 0.79) and cases with the treatment failure outcome (kappa: 0.92). For multidrug resistance (MDR), there was significant accordance in young cases (kappa: 0.77). Compared with previously treated patients, the newly treated patients had a significantly higher AR in detecting RIF resistance (0.97 vs 0.92), INH resistance (0.95 vs 0.89), and MDR (0.98 vs 0.92). The overall sensitivity, specificity, AR and kappa value for the diagnosis of MDR-TB were 0.70 (95% CI: 0.63–0.70), 0.99 (95% CI: 0.98–0.99), 0.98 (95% CI: 0.97–0.98), and 0.72 (95% CI: 0.67–0.78), respectively.

Conclusion

We observed a high concordance between GeneChip and DST among TB patients with different characteristics, indicating that GeneChip can be a potential alternative tool for rapid MDR-TB detection.

Evidence for the Effect of Vaccination on Host-Pathogen Interactions in a Murine Model of Pulmonary Tuberculosis by Mycobacterium tuberculosis

The global control of Tuberculosis remains elusive, and Bacillus Calmette-Guérin (BCG) -the most widely used vaccine in history-has proven insufficient for reversing this epidemic. Several authors have suggested that the mass presence of vaccinated hosts might have affected the Mycobacterium tuberculosis (MTB) population structure, and this could in turn be reflected in a prevalence of strains with higher ability to circumvent BCG-induced immunity, such as the recent Beijing genotype. The effect of vaccination on vaccine-escape variants has been well-documented in several bacterial pathogens; however the effect of the interaction between MTB strains and vaccinated hosts has never been previously described. In this study we show for the first time the interaction between MTB Beijing-genotype strains and BCG-vaccinated hosts. Using a well-controlled murine model of progressive pulmonary tuberculosis, we vaccinated BALB/c mice with two different sub-strains of BCG (BCG-Phipps and BCG-Vietnam). Following vaccination, the mice were infected with either one of three selected MTB strains. Strains were selected based on lineage, and included two Beijing-family clinical isolates (strains 46 and 48) and a well-characterized laboratory strain (H37Rv). Two months after infection, mice were euthanized and the bacteria extracted from their lungs. We characterized the genomic composite of the bacteria before and after exposure to vaccinated hosts, and also characterized the local response to the bacteria by sequencing the lung transcriptome in animals during the infection. Results from this study show that the interaction within the lungs of the vaccinated hosts results in the selection of higher-virulence bacteria, specifically for the Beijing genotype strains 46 and 48. After exposure to the BCG-induced immune response, strains 46 and 48 acquire genomic mutations associated with several virulence factors. As a result, the bacteria collected from these vaccinated hosts have an increased ability for immune evasion, as shown in both the host transcriptome and the histopathology studies, and replicates far more efficiently compared to bacteria collected from unvaccinated hosts or to the original-stock strain. Further research is warranted to ascertain the pathways associated with the genomic alterations. However, our results highlight novel host-pathogen interactions induced by exposure of MTB to BCG vaccinated hosts.

Epidemiology of drug-resistant tuberculosis in Chongqing, China: A retrospective observational study from 2010 to 2017

China is one of the top 30 countries with high multidrug-resistant tuberculosis (MDR-TB) and rifampin-resistant tuberculosis (RR-TB) burden. Chongqing is a southwest city of China with a large rural population. A retrospective observational study has been performed based on routine tuberculosis (TB) surveillance data in Chongqing from 2010 to 2017. The MDR/RR-TB notification rate increased from 0.03 cases per 100,000 population in 2010 to 2.1 cases per 100,000 population in 2017. The extensively drug-resistant TB (XDR-TB) notification rate has increased to 0.09 cases per 100,000 population in 2017. There was a decreasing detection gap between the number of notified MDR/RR-TB cases and the estimate number of MDR/RR-TB cases in new TB cases. The treatment success rate of MDR/RR-TB was 59% (95% confidence interval [CI], 53%-65%) in this period. Despite the progress achieved, the prevalence of MDR/RR-TB was still high facing challenges including detection gaps in new TB cases, the regional disparity, and the high risk for MDR/RR-TB in elderly people and farmers. Sustained government financing and policy support should be guaranteed in the future.

Risk factors of multidrug-resistant tuberculosis in China: A meta-analysis

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) brings major challenges to the health care workers (HCWs). This study is to determine the risk factors for MDR-TB, latent tuberculosis infection (LTBI), and tuberculosis (TB) disease among HCWs in China.

METHODS

A meta-analysis was conducted to evaluate the risk factors for MDR-TB, LTBI, and TB disease among HCWs using a random-effects model, and the pooled odds ratios (ORs) with 95% confidence interval (CI) were used as effect indicators.

RESULTS

We identified 46 eligible studies and found eight factors were associated with MDR. The ORs with 95% CI are migrant population 1.96 (95% CI, 1.50-2.57), low family income 2.23 (95% CI, 1.74-2.85), retreatment 7.22 (95% CI, 5.63-9.26), anti-TB treatment history 5.65 (95% CI, 4.80-6.65), multiple episodes of treatment 3.28 (95% CI, 2.60-4.13), adverse reactions 3.48 (95% CI, 2.54-4.76), interrupted treatment 3.18 (95% CI, 2.60-3.89), and lung cavities 1.42 (95% CI, 1.14-1.77). Work duration as a HCW for 5 years and above increased the risk of LTBI and TB. HCWs aged 30 years and above were more susceptible to TB (OR = 1.70, 95% CI: 1.37-2.09).

CONCLUSION

The risk factors for MDR-TB in China are possibly migrant population, low family income, retreatment, anti-TB treatment history, adverse reactions, interrupted treatment, and lung cavities. Longer work duration and greater age are risk factors for LTBI and TB among HCWs.

Drug-resistance profiling and transmission dynamics of multidrug-resistant Mycobacterium tuberculosis in Saudi Arabia revealed by whole genome sequencing

Background

In Saudi Arabia, cross-border transmission of multidrug-resistant (MDR) Mycobacterium tuberculosis complex (MTBC) strains might be particularly fostered by high immigration rates. Herein, we aimed to elucidate the transmission dynamics of MDR-MTBC strains and reveal a detailed prediction of all resistance-conferring mutations for the first- and second-line drugs.

Methods

We investigated all MDR-MTBC strains collected between 2015 and 2017 from provincial mycobacteria referral laboratories and compared demographic and clinical parameters to a cohort of non-MDR-TB patients using a whole genome sequencing approach. Clusters were defined based on a maximum strain-to-strain genetic distance of five single-nucleotide polymorphisms (SNPs) as surrogate marker for recent transmission, and then investigated molecular drug-resistance markers (37 genes).

Results

Forty-eight (67.6%) MDR-MTBC strains were grouped in 14 different clusters, ranging in size from two to six strains; 22.5% (16/71) of all MDR-MTBC isolates were predicted to be fully resistant to all five first-line drugs, and five strains (7.0%) exhibited fluoroquinolone resistance. Moreover, we revealed the presence of 12 compensatory mutations as well as 26 non-synonymous SNPs in the rpoC gene and non-hotspot region in rpoB, respectively.

Conclusion

Optimized TB molecular surveillance, diagnosis, and patient management are urgently needed to contain MDR-MTBC transmission and prevent the development of additional drug resistance.

Risk factors of multidrug-resistant tuberculosis: A global systematic review and meta-analysis

OBJECTIVES

Since the risk of multidrug-resistant tuberculosis (MDR-TB) may depend on the setting, we aimed to determine the associations of risk factors of MDR-TB across different regions.

METHODS

A systematic review and meta-analysis was performed with Pubmed and Embase databases. Information was retrieved on 37 pre-defined risk factors of MDR-TB. We estimated overall Mantel-Haenszel odds ratio as a measure of the association.

RESULTS

Factors of previous TB disease and treatment are the most important risk factors associated with MDR-TB. There was also a trend towards increased risk of MDR-TB for patients 40 years and older, unemployed, lacking health insurance, smear positive, with non-completion and failure of TB treatment, showing adverse drug reaction, non-adherent, HIV positive, with COPD and with M. Tuberculosis Beijing infection. Effect modification by geographical area was identified for several risk factors such as male gender, married patients, urban domicile, homelessness and history of imprisonment.

CONCLUSIONS

Assessment of risk factors of MDR-TB should be conducted regionally to develop the most effective strategy for MDR-TB control. Across all regions, factors associated with previous TB disease and treatment are essential risk factors, indicating the appropriateness of diagnosis, treatment and monitoring are an important requirements.

Trends and characteristics of drug-resistant tuberculosis in rural Shandong, China

OBJECTIVES

The aim of this study was to describe the secular trends in drug-resistant tuberculosis (DR-TB) and to identify unique characteristics of multidrug-resistant tuberculosis (MDR-TB) in rural China.

METHODS

A retrospective study was conducted using TB data collected from 36 TB prevention and control institutions serving rural populations in Shandong Province, China, for the period 2006-2015.

RESULTS

Approximately 8.3% of patients suffered from MDR-TB, among whom 70% were newly treated patients; this rate increased by 1.3% annually during the 10-year study period. An increase in the percentage of overall first-line drug resistance against isoniazid, rifampicin, ethambutol, and streptomycin was confirmed (p<0.05). The percentage of MDR-TB in new and previously treated cases increased at yearly rates of 9.9% and 11.1%, respectively. MDR-TB patients were more likely to be female (odds ratio (OR) 1.58, 95% confidence interval (CI) 1.32-1.89), smokers (OR 1.75, 95% CI 1.47-2.07), to have had recent TB contact (OR 1.58, 95% CI 1.04-2.42), or to have been retreated (OR 2.89, 95% CI 2.46-3.41).

CONCLUSIONS

Increasing MDR-TB and rates of primary MDR-TB characterize DR-TB cases in rural China. Persistent efforts need to be made among MDR-TB patients in future TB control strategies.

Transmission is a Noticeable Cause of Resistance Among Treated Tuberculosis Patients in Shanghai, China

It is generally believed that drug resistance among treated tuberculosis (TB) patients is as a result of acquired drug resistance due to inappropriate treatment. Previous studies have shown that primary drug resistance caused by transmission also plays a role among treated cases. Differentiating the two types of drug resistance will help in developing appropriate strategies for control of drug resistant tuberculosis. In this study, we tested the hypothesis that drug resistance among treated TB patients is mainly caused by primary resistance rather than acquired resistance. Defining resistance profiles by molecular drug susceptibility test, we used Unit Variable Number Tandem Repeats (VNTR) to genotype and Whole Genome Sequencing (WGS) to confirm the accordance of the first and last Mycobacterium tuberculosis isolates from treated pulmonary TB patients in Shanghai from 2009–2015. Among 81 patients with increasing drug resistance, out of 390 patients enrolled, paired isolates from 59.3% (48/81) had different VNTR patterns indicating primary drug resistance. Our results have demonstrated that primary resistance due to exogenous reinfection is the major cause of drug resistance among treated TB patients in Shanghai; thus, strategies aimed at preventing and interrupting transmission are urgently needed to effectively reduce the epidemic of drug resistant tuberculosis.

Drug Resistance in Newly Presenting and Previously Treated Tuberculosis Patients in Guangxi Province, People's Republic of China

Drug-resistant Mycobacterium tuberculosis strains are a major threat to the control of tuberculosis (TB), but the prevalence of drug-resistant TB is still unknown in the southern ethnic region of China. A cluster-randomized sampling method was used to include the study population. Isolates were tested for resistance to 6 antituberculosis drugs, and genotyped to identify Beijing strains. Overall, 11.3% (139/1229) of new cases and 33.0% (126/382) of retreated cases had drug-resistant tuberculosis. Multiple previous TB treatment episodes and multiple treatment interruptions were risk factors for both drug-resistant and multidrug-resistant TB among retreated cases. A total of 53.2% of the patients were infected with a Beijing strain of M tuberculosis. Infection with a Beijing strain was significantly associated with drug resistance among new cases (odds ratio, 1.44; 95% CI, 1.01-2.07). Novel strategies to rapid diagnosis and effective treatment are urgently needed to prevent the development of drug resistance.

Financial barriers and coping strategies: a qualitative study of accessing multidrug-resistant tuberculosis and tuberculosis care in Yunnan, China

BACKGROUND

Tuberculosis (TB) and multidrug-resistance tuberculosis (MDR-TB) pose serious challenges to global health, particularly in China, which has the second highest case burden in the world. Disparities in access to care for the poorest, rural TB patients may be exacerbated for MDR-TB patients, although this has not been investigated widely. We examine whether certain patient groups experience different barriers to accessing TB services, whether there are added challenges for patients with MDR-TB, and how patients and health providers cope in Yunnan, a mountainous province in China with a largely rural population and high TB burden.

METHODS

Using a qualitative study design, we conducted five focus group discussions and 47 in-depth interviews with purposively sampled TB and MDR-TB patients and healthcare providers in Mandarin, between August 2014 and May 2015. Field-notes and interview transcripts were analysed via a combination of open and thematic coding.

RESULTS

Patients and healthcare providers consistently cited financial constraints as the most common barriers to accessing care. Rural residents, farmers and ethnic minorities were the most vulnerable to these barriers, and patients with MDR-TB reported a higher financial burden owing to the centralisation and longer duration of treatment. Support in the form of free or subsidised treatment and medical insurance, was deemed essential but inadequate for alleviating financial barriers to patients. Most patients coped by selling their assets or borrowing money from family members, which often strained relationships. Notably, some healthcare providers themselves reported making financial and other contributions to assist patients, but recognised these practices as unsustainable.

CONCLUSIONS

Financial constraints were identified by TB and MDR-TB patients and health care professionals as the most pervasive barrier to care. Barriers appeared to be magnified for ethnic minorities and patients coming from rural areas, especially those with MDR-TB. To reduce financial barriers and improve treatment outcomes, there is a need for further research into the total costs of seeking and accessing TB and MDR-TB care. This will enable better assessment and targeting of appropriate financial support for identified vulnerable groups and geographic development of relevant services.

Methodological and Clinical Aspects of the Molecular Epidemiology of Mycobacterium tuberculosis and Other Mycobacteria

Molecular typing has revolutionized epidemiological studies of infectious diseases, including those of a mycobacterial etiology. With the advent of fingerprinting techniques, many traditional concepts regarding transmission, infectivity, or pathogenicity of mycobacterial bacilli have been revisited, and their conventional interpretations have been challenged. Since the mid-1990s, when the first typing methods were introduced, a plethora of other modalities have been proposed. So-called molecular epidemiology has become an essential subdiscipline of modern mycobacteriology. It serves as a resource for understanding the key issues in the epidemiology of tuberculosis and other mycobacterial diseases. Among these issues are disclosing sources of infection, quantifying recent transmission, identifying transmission links, discerning reinfection from relapse, tracking the geographic distribution and clonal expansion of specific strains, and exploring the genetic mechanisms underlying specific phenotypic traits, including virulence, organ tropism, transmissibility, or drug resistance. Since genotyping continues to unravel the biology of mycobacteria, it offers enormous promise in the fight against and prevention of the diseases caused by these pathogens. In this review, molecular typing methods for Mycobacterium tuberculosis and nontuberculous mycobacteria elaborated over the last 2 decades are summarized. The relevance of these methods to the epidemiological investigation, diagnosis, evolution, and control of mycobacterial diseases is discussed.

The production and sales of anti-tuberculosis drugs in China

Background

Tuberculosis (TB) is a major infectious disease globally. Adequate and proper use of anti-TB drugs is essential for TB control. This study aims to study China’s production capacity and sales situation of anti-TB drugs, and to further discuss the potential for China to contribute to global TB control.

Methods

The production data of anti-TB drugs in China from 2011 to 2013 and the sales data from 2010 to 2014 were extracted from Ministry of Industry and Information Technology database of China and IMS Health database, respectively. The number of drugs was standardized to the molecular level of the key components before calculating. All data were described and analyzed by Microsoft Excel.

Results

First-line drugs were the majority in both sales (89.5 %) and production (92.3 %) of anti-TB drugs in China. The production of rifampicin held the majority share in active pharmaceutical ingredients (APIs) and finished products, whilst ethambutol and pyrazinamide were the top two sales in finished products. Fixed-dose combinations only held small percentages in total production and sales weight, though a slight increase was observed. The production and sales of streptomycin showed a tendency of decrease after 2012. The trends and proportion of different anti-TB drugs were similar in production and sales, however, the production weight was much larger than that of sales, especially for rifampicin and isoniazid.

Conclusions

First-line drugs were the predominant medicine produced and used in China. While the low production and sales of the second-line TB drugs and FDCs rose concerns for the treatment of multiple drug resistant TB. The redundant production amount, as well as the prompt influence of national policy on drug production and sales, indicated the potential for China to better contribute to global TB control.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-016-0184-z) contains supplementary material, which is available to authorized users.

Diabetes Reduces the Rate of Sputum Culture Conversion in Patients With Newly Diagnosed Multidrug-Resistant Tuberculosis

Background.  Diabetes is a risk factor for active tuberculosis (TB), but little is known about the relationship between diabetes and multidrug-resistant (MDR) TB. We aimed to assess risk factors for primary MDR TB, including diabetes, and determine whether diabetes reduced the rate of sputum culture conversion among patients with MDR TB. Methods.  From 2011 to 2014, we conducted a cohort study at the National Center for Tuberculosis and Lung Diseases in Tbilisi, Georgia. Adult (≥35 years) patients with primary TB were eligible. Multidrug-resistant TB was defined as resistance to at least rifampicin and isoniazid. Patients with capillary glycosylated hemoglobin (HbA1c) ≥ 6.5% or previous diagnosis were defined to have diabetes. Polytomous regression was used to estimate the association of patient characteristics with drug resistance. Cox regression was used to compare rates of sputum culture conversion in patients with and without diabetes. Results.  Among 318 patients with TB, 268 had drug-susceptibility test (DST) results. Among patients with DST results, 19.4% (52 of 268) had primary MDR TB and 13.4% (36 of 268) had diabetes. In multivariable analyses, diabetes (adjusted odds ratio [aOR], 2.51; 95% confidence interval [CI], 1.00-6.31) and lower socioeconomic status (aOR, 3.51; 95% CI, 1.56-8.20) were associated with primary MDR TB. Among patients with primary MDR TB, 44 (84.6%) converted sputum cultures to negative. The rate of sputum culture conversion was lower among patients with diabetes (adjusted hazard ratio [aHR], 0.34; 95% CI, .13-.87) and among smokers (aHR, 0.16; 95% CI, .04-.61). Conclusions.  We found diabetes was associated with an increased risk of primary MDR TB; both diabetes and smoking were associated with a longer time to sputum culture conversion.

Access to and affordability of healthcare for TB patients in China: issues and challenges

This paper introduces the background, aim and objectives of the project entitled "China-the Gates Foundation Collaboration on TB Control in China" that has been underway for many years. It also summarizes the key findings of the nine papers included in this special issue, which used data from the baseline survey of Phase II of the project. Data were collected from the survey of TB and MDR-TB patients, from designated hospitals, health insurance agencies and the routine health information systems, as well as key informant interviews and focus group discussions with relevant key stakeholders. Key issues discussed in this series of papers include the uses of TB services and anti-TB medicines and their determining factors related to socio-economic and health systems development; expenditures on TB care and the financial burden incurred on TB patients; and the impact of health insurance schemes implemented in China on financial protection.

Drug-resistant tuberculosis control in China: progress and challenges

BACKGROUND

China has the second highest caseload of multidrug-resistant tuberculosis (MDR-TB) in the world. In 2009, the Chinese government agreed to draw up a plan for MDR-TB prevention and control in the context of a comprehensive health system reform launched in the same year.

DISCUSSION

China is facing high prevalence rates of drug-resistant TB and MDR-TB. MDR-TB disproportionally affects the poor rural population and the highest rates are in less developed regions largely due to interrupted and/or inappropriate TB treatment. Most households with an affected member suffer a heavy financial burden because of a combination of treatment and other related costs. The influential Global Fund programme for MDR-TB control in China provides technical and financial support for MDR-TB diagnosis and treatment. However, this programme has a fixed timeline and cannot provide a long term solution. In 2009, the Bill and Melinda Gates Foundation, in cooperation with the National Health and Family Planning Commission of China, started to develop innovative approaches to TB/MDR-TB management and case-based payment mechanisms for treatment, alongside increased health insurance benefits for patients, in order to contain medical costs and reduce financial barriers to treatment. Although these efforts appear to be in the right direction, they may not be sufficient unless (a) domestic sources are mobilized to raise funding for TB/MDR-TB prevention and control and (b) appropriate incentives are given to both health facilities and their care providers. Along with the on-going Chinese health system reform, sustained government financing and social health protection schemes will be critical to ensure universal access to appropriate TB treatment in order to reduce risk of developing MDR-TB and systematic MDR-TB treatment and management.

Health system delay in treatment of multidrug resistant tuberculosis patients in Bangladesh

Background

Bangladesh is one of the 27 high burden countries for multidrug resistant tuberculosis listed by the World Health Organization. Delay in multidrug resistant tuberculosis treatment may allow progression of the disease and affect the attempts to curb transmission of drug resistant tuberculosis. The main objective of this study was to investigate the health system delay in multidrug resistant tuberculosis treatment in Bangladesh and to explore the factors related to the delay.

Methods

Information related to the delay was collected as part of a previously conducted case–control study. The current study restricts analysis to patients with multidrug resistant tuberculosis who were diagnosed using rapid diagnostic methods (Xpert MTB/RIF or the line probe assay). Information was collected by face-to-face interviews and through record reviews from all three Government hospitals providing multidrug resistant tuberculosis services, from September 2012 to April 2013. Multivariable regression analysis was performed using Bootstrap variance estimators. Definitions were as follows: Provider delay: time between visiting a provider for first consultation on MDR-TB related symptom to visiting a designated diagnostic centre for testing; Diagnostic delay: time from date of diagnostic sample provided to date of result; Treatment initiation delay: time between the date of diagnosis and date of treatment initiation; Health system delay: time between visiting a provider to start of treatment. Health system delay was derived by adding provider delay, diagnostic delay and treatment initiation delay.

Results

The 207 multidrug resistant tuberculosis patients experienced a health system delay of median 7.1 weeks. The health system delay consists of provider delay (median 4 weeks), diagnostic delay (median 5 days) and treatment initiation delay (median 10 days). Health system delay (Coefficient: 37.7; 95 %; CI 15.0–60.4; p 0.003) was associated with the visit to private practitioners for first consultation.

Conclusions

Diagnosis time for multidrug resistant tuberculosis was fast using the rapid tests. However, some degree of delay was present in treatment initiation, after diagnosis. The most effective way to reduce health system delay would be through strategies such as engaging private practitioners in multidrug resistant tuberculosis control.

Risk Factors for Multidrug-Resistant Tuberculosis among Patients with Pulmonary Tuberculosis at the Central Chest Institute of Thailand

There are limited data available on the risk factors for multidrug-resistant tuberculosis (MDR-TB). Therefore, we here conducted a retrospective matched case-control study among adults with pulmonary TB who received treatment at the Central Chest Institute of Thailand (CCIT) between January 2007 and December 2013, in order to determine the risk factors associated with MDR-TB among patients with pulmonary TB. We identified 145 patients with pulmonary MDR-TB (cases) and 145 patients with drug-sensitive pulmonary TB (controls). Multivariate analysis identified the independent risk factors for MDR-TB as follows: (1) ≥ 2 episodes of prior pulmonary TB (odds ratio [OR] 39.72, 95% confidence interval (95% CI) 7.86-200.66), (2) duration of illness > 60 days (OR 3.08, 95% CI 1.52-6.22), (3) sputum acid fast bacilli smear 3+ (OR 13.09, 95% CI 4.64-36.91), (4) presence of lung cavities (OR 3.82, 95% CI 1.89-7.73), and (5) presence of pleural effusion (OR 2.75, 95% CI 1.06-7.16). Prior pulmonary TB management with a non-category I regimen (P = 0.012) and having treatment failure or default as treatment outcomes (P = 0.036) were observed in a higher proportion among patients with MDR-TB. Particular characteristics of lung cavities, including the maximum diameter ≥ 30 mm (P < 0.001), the number of cavities ≥ 3 (P = 0.001), bilateral involvement (P < 0.001), and ≥ 2 lung zones involved (P = 0.001) were more commonly observed in patients with MDR-TB. In conclusion, these clinical factors and chest radiographic findings associated with MDR-TB among patients with pulmonary TB may help physicians to provide proper management of cases for prevention of the development and spread of MDR-TB in future.

Transmission of Mycobacterium tuberculosis in China: a population-based molecular epidemiologic study

BACKGROUND

Understanding the transmission of Mycobacterium tuberculosis is essential for the development of efficient tuberculosis control strategies. China has the second-largest tuberculosis burden in the world. Recent transmission and infection with M. tuberculosis, particularly drug-resistant strains, may account for many new tuberculosis cases.

METHODS

We performed a population-based molecular epidemiologic study of pulmonary tuberculosis in China during 1 July 2009 to 30 June 2012. We defined clusters as cases with identical variable number tandem repeat genotype patterns and identified the risk factors associated with clustering, by logistic regression. Relative transmission rates were estimated by the sputum smear status and drug susceptibility status of tuberculosis patients.

RESULTS

Among 2274 culture-positive tuberculosis patients with genotyped isolates, there were 705 (31.0%) tuberculosis patients in 287 clusters. Multidrug-resistant (MDR) tuberculosis (adjusted odds ratio [aOR], 1.86; 95% confidence interval [CI], 1.25-2.63) and infection with a Beijing family strain (aOR, 1.56; 95% CI, 1.23-2.96) were associated with clustering. Eighty-four of 280 (30.0%) clusters had a putative source case that was sputum smear negative, and 30.6% of their secondary cases were attributed to transmission by sputum smear-negative patients. The relative transmission rate for sputum smear negative compared with sputum smear-positive patients was 0.89 (95% CI, .68-1.10), and was 1.51 (95% CI, 1.00-2.24) for MDR tuberculosis vs drug-susceptible tuberculosis.

CONCLUSIONS

Recent transmission of M. tuberculosis, including MDR strains, contributes substantially to tuberculosis disease in China. Sputum smear-negative cases were responsible for at least 30% of the secondary cases. Interventions to reduce the transmission of M. tuberculosis should be implemented in China.

Diagnostic value of GeneChip for detection of resistant Mycobacterium tuberculosis in patients with differing treatment histories

The increasing burden of drug-resistant tuberculosis (TB) poses an escalating threat to national TB control programs. To assist appropriate treatment for TB patients, accurate and rapid detection of drug resistance is critical. The GeneChip test is a novel molecular tool for the diagnosis of TB drug resistance. Performance-related data on GeneChip are limited, and evaluation in new and previously treated TB cases has never been performed. We evaluated the diagnostic performance of GeneChip in detecting resistance to rifampin (RMP) and isoniazid (INH) and in detecting multidrug-resistant tuberculosis (MDR-TB) in comparison with standard drug susceptibility testing (DST) and compared the results in a group of previously treated and newly detected TB patients in an urban area in southeastern China. One thousand one hundred seventy-three (83.8%) new cases and 227 (16.2%) previously treated cases were collected between January 2011 and September 2013. The GeneChip showed a specificity of 97.8% and a sensitivity of 94.8% for detection of RMP resistance and 97.3% and 70.9%, respectively, for INH resistance in new cases. For previously treated cases, the overall sensitivity, specificity, and agreement rate are 94.6%, 91.3%, and 92.1%, respectively, for detection of RMP resistance and 69.7%, 95.4%, and 86.8%, respectively, for INH resistance. The sensitivity and specificity of MDR-TB were 81.8% and 99.0% in new cases and 77.8% and 93.4% in previously treated cases, respectively. The GeneChip system provides a simple, rapid, reliable, and accurate clinical assay for the detection of TB drug resistance, and it is a potentially important diagnostic tool in a high-prevalence area.

Are we doing enough to stem the tide of acquired MDR-TB in countries with high TB burden? Results of a mixed method study in Chongqing, China

Multi-drug resistant tuberculosis (MDR-TB) represents a threat to health and development in countries with high TB burden. China’s MDR-TB prevalence rate of 6.8% is the highest in the world. Interventions to remove barriers against effective TB control, and prevention of MDR-TB are urgently needed in the country. This paper reports a cross-sectional questionnaire survey of 513 pulmonary TB (PTB) patients, and qualitative interviews of 10 healthcare workers (HCWs), and 15 PTB patients. The objective was to assess barriers against effective control of PTB and prevention of MDR-TB by elucidating the perspectives of patients and healthcare providers. Results showed that more than half of the patients experienced patient delay of over 12.5 days. A similar proportion also experienced detection delay of over 30 days, and delay in initiating treatment of over 31 days. Consulting a non-TB health facility ≥3 times before seeking care at TB dispensary was a risk factor for both detection delay [AOR (95% CI): 1.89(1.07, 3.34) and delay in initiating treatment[AOR (95% CI): 1.88 (1.06, 3.36). Results revealed poor implementation of Directly Observed Therapy (DOT), whereby treatment of 34.3% patients was never monitored by HCWs. Only 31.8% patients had ever accessed TB health education before their TB diagnosis. Qualitative data consistently disclosed long patient delay, and indicated that patient’s poor TB knowledge and socioeconomic barriers were primary reasons for patient delay. Seeking care and being treated at a non-TB hospital was an important reason for detection delay. Patient’s long work hours and low income increased risk for treatment non-adherence. Evidence-based measures to improve TB health seeking behavior, reduce patient and detection delays, improve the quality of DOT, address financial and system barriers, and increase access to TB health promotion are urgently needed to address the burgeoning prevalence of MDR-TB in China.

Factors contributing to the high prevalence of multidrug-resistant tuberculosis among previously treated patients: a case-control study from China

SETTING

Multidrug-resistant tuberculosis (MDR-TB) has emerged as a serious global public health problem. In China, the risk factors for MDR-TB have not been systematically evaluated.

OBJECTIVE

To identify risk factors associated with MDR-TB among previously treated patients in China.

DESIGN

A case-control study was carried out. Cases were selected from previously treated MDR-TB patients who were resistant to both isoniazid and rifampin, and controls were selected from previously treated TB patients who were sensitive to isoniazid and rifampin (non-MDR-TB). Information was collected from the registration database and a structured questionnaire.

RESULTS

A total of 61 cases and 50 controls were recruited. A multivariate analysis showed that the family annual per-capita income ≤7,000 Yuan (odds ratio [OR]=3.238; 95% confidence interval [CI]: 1.270-8.252), no history of fixed dose combinations (FDCs) in anti-TB treatment (OR=4.027; 95% CI: 1.457-11.129), and adverse reactions in the course of TB treatment (OR=3.568; 95% CI: 1.402-9.085) were independent predictors of MDR-TB. Moreover, among the TB patients who had adverse reactions, quitting the treatment was shown as a risk factor for MDR-TB (p=0.009).

CONCLUSION

In the control of MDR-TB among previously treated patients, lower socioeconomic groups, the expanding use of FDCs, and improving adherence to treatment by implementing Directly Observed Therapy Short Course-Plus (DOTS-Plus), strictly should become a priority that requires strong commitment and collaboration among health organizations.

Genotyping and clinical characteristics of multidrug and extensively drug-resistant tuberculosis in a tertiary care tuberculosis hospital in China

Background

There is a lack of information on the clinical characteristics of multidrug-resistant (MDR) tuberculosis (TB) and extensively drug-resistant (XDR) TB in the Jiangxi Province of China; furthermore, data have not been reported on the utility of mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) analyses in genotyping Mycobacterium tuberculosis strains isolated from this region. The aim of this study was to analyse the clinical features of patients with MDR and XDR TB from Jiangxi Province and to evaluate the discriminatory power of the 15-loci MIRU-VNTR method.

Methods

A retrospective study was conducted on patients diagnosed with MDR and XDR TB at the Jiangxi Chest Hospital from July 2010 to June 2011. The RD105 deletion-targeted multiplex PCR (DTM-PCR) and the 15-loci MIRU-VNTR method were used to determine the genetic background of the identified MDR and XDR M. tuberculosis clinical isolates.

Results

Of 804 M. tuberculosis clinical isolates, 159 (159/804, 19.8%) of the isolates were identified as MDR with first-line drug susceptibility testing. Of the 123 available MDR isolates, 13 (13/123, 10.6%) were XDR. The RD105 deletion-targeted multiplex PCR method identified 85 (85/110, 77.3%) MDR and 12 (12/13, 92.3%) XDR isolates as the Beijing genotype. MIRU-VNTR cluster analysis demonstrated that 101 MDR and 13 XDR strains had unique genotype patterns; the remaining 9 MDR strains were in 4 clusters, namely 1 cluster with 3 strains and 3 clusters with 2 strains, resulting in a low clustering rate (4.06%). The Hunter-Gaston discriminatory index (HGDI) of the 15-loci MIRU-VNTR method was as high as 0.992. In addition, clinical surveys showed that 87 (87/110, 79.1%) MDR TB patients and 10 (10/13, 76.9%) XDR TB patients had been previously treated. Diabetes mellitus was the most common comorbidity in both MDR TB (16/110, 14.5%) and XDR TB (2/13, 15.4%) patients.

Conclusions

Based on our preliminary data, the MDR and XDR M. tuberculosis clinical isolates identified at the Jiangxi Chest Hospital were genetically diverse and clustered at a low frequency. The 15-loci MIRU-VNTR method showed high discriminatory power and may be used as a first-line genotyping tool in investigating the molecular epidemiology of M. tuberculosis in Jiangxi, China. Decisive measures are urgently needed to effectively prevent and manage MDR and XDR tuberculosis in this province.

Multidrug-resistant Tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) threatens to become the dominant form of tuberculosis in many parts of the world because of decades of inappropriate treatment on a global scale. Infection with MDR-TB is associated with poor outcomes because of delays in treatment and the need for complex, toxic, and long medication regimens. Most cases are undetected because of technological and economic barriers to diagnosing tuberculosis and the availability of assays to test for drug resistance. Experience in treating MDR-TB is scarce. Tuberculosis was once curable, but could become a potentially untreatable infectious disease unless efforts are made to control it.