Alarming levels of drug-resistant tuberculosis in HIV-infected patients in metropolitan Mumbai, India

A systematic review and meta-analysis on the correlation between HIV infection and multidrug-resistance tuberculosis

Background

The emergence of multidrug-resistant tuberculosis (MDR-TB) in HIV-positive people poses a significant challenge to international efforts to eradicate tuberculosis (TB). Many studies found conflicting results when examining the correlation between HIV and MDR-TB. The purpose of the present investigation was to comprehensively review the literature on the association between HIV infection and MDR-TB in order to evaluate the impact of HIV on MDR-TB worldwide.

Methods

Utilizing the databases PubMed, Scopus, Google Scholar, and ScienceDirect, studies published between January 2000 and March 2023 that are eligible for meta-analysis were selected. Using the random-effects model, the aggregated odds ratio of the empirical relationship between HIV and MDR-TB was calculated, along with a confidence interval ranging from 0 to 95 %. Examining the asymmetry of the funnel plot and utilizing Egger's and Begg's test, the possibility of publication bias was investigated. The extent of heterogeneity was determined using the I2 statistics.

Results

Through a database search, we identified 1214 studies, from which we ultimately selected 15 studies involving 9667 patients. The odds ratio of 2.78 (95 % confidence interval: 1.07-7.20) between HIV/AIDS and MDR-TB indicates a significant positive correlation. Tau 2 = 3.46, chi 2 = 1440.46, df = 14, I2 = 99.0 %, z = 2.10, and p 0.05 indicate that there is substantial heterogeneity among pooled studies. Since I2 is 99 % (>50 %), a random effect model was employed. The percentage of multidrug-resistant HIV-positive patients across all included studies follows a normal distribution, as shown by a Box and whisker plot with a symmetric skewness and a mesokurtic tail and a scatter plot with a significant R2 value below 1 [R2 = 0.2476] showed the positive correlation between multidrug resistance and HIV infection.

Conclusion

HIV infection increases MDR-TB risk, and the preceding pooled analysis showed an increased risk trend. Thus, MDR-TB, especially in HIV-positive patients, requires early case detection, quality-assured bacteriology diagnosis, and an effective infection control program.

Global prevalence of drug-resistant tuberculosis: a systematic review and meta-analysis

BACKGROUND

Tuberculosis is a bacterial infectious disease, which affects different parts of a human body, mainly lungs and can lead to the patient's death. The aim of this study is to investigate the global prevalence of drug-resistant tuberculosis using a systematic review and meta-analysis.

METHODS

In this study, the PubMed, Scopus, Web of Science, Embase, ScienceDirect and Google Scholar repositories were systematically searched to find studies reporting the global prevalence of drug-resistant tuberculosis. The search did not entail a lower time limit, and articles published up until August 2022 were considered. Random effects model was used to perform the analysis. The heterogeneity of the studies was examined with the I² test. Data analysis was conducted within the Comprehensive Meta-Analysis software.

RESULTS

In the review of 148 studies with a sample size of 318,430 people, the I² index showed high heterogeneity (I² = 99.6), and accordingly random effects method was used to analyze the results. Publication bias was also examined using the Begg and Mazumdar correlation test which indicated the existence of publication bias in the studies (P = 0.008). According to our meta-analysis, the global pooled prevalence of multi-drug resistant TB is 11.6% (95% CI: 9.1-14.5%).

CONCLUSIONS

The global prevalence of drug-resistant tuberculosis was found to be very high, thus health authorities should consider ways to control and manage the disease to prevent a wider spread of tuberculosis and potentially subsequent deaths.

A systematic review and meta-analysis of active case finding for tuberculosis in India

Background

Active case finding (ACF) for tuberculosis (TB) is the cornerstone case-finding strategy in India's national TB policy. However, ACF strategies are highly diverse and pose implementation challenges in routine programming. We reviewed the literature to characterise ACF in India; assess the yield of ACF for different risk groups, screening locations, and screening criteria; and estimate losses to follow-up (LTFU) in screening and diagnosis.

Methods

We searched PubMed, EMBASE, Scopus, and the Cochrane library to identify studies with ACF for TB in India from November 2010 to December 2020. We calculated 1) weighted mean number needed to screen (NNS) stratified by risk group, screening location, and screening strategy; and 2) the proportion of screening and pre-diagnostic LTFU. We assessed risk of bias using the AXIS tool for cross-sectional studies.

Findings

Of 27,416 abstracts screened, we included 45 studies conducted in India. Most studies were from southern and western India and aimed to diagnose pulmonary TB at the primary health level in the public sector after screening. There was considerable heterogeneity in risk groups screened and ACF methodology across studies. Of the 17 risk groups identified, the lowest weighted mean NNS was seen in people with HIV (21, range 3-89, n=5), tribal populations (50, range 40-286, n=3), household contacts of people with TB (50, range 3-undefined, n=12), people with diabetes (65, range 21-undefined, n=3), and rural populations (131, range 23-737, n=5). ACF at facility-based screening (60, range 3-undefined, n=19) had lower weighted mean NNS than at other screening locations. Using the WHO symptom screen (135, 3-undefined, n=20) had lower weighted mean NNS than using criteria of abnormal chest x-ray or any symptom. Median screening and pre-diagnosis loss-to-follow-up was 6% (IQR 4.1%, 11.3%, range 0-32.5%, n=12) and 9.5% (IQR 2.4%, 34.4%, range 0-86.9%, n=27), respectively.

Interpretation

For ACF to be impactful in India, its design must be based on contextual understanding. The narrow evidence base available currently is insufficient for effectively targeting ACF programming in a large and diverse country. Achieving case-finding targets in India requires evidence-based ACF implementation.

Funding

WHO Global TB Programme.

A comparative analysis of molecular genotypes of Mycobacterium tuberculosis isolates from HIV-positive and HIV-negative patients

SETTING

Tuberculosis Research Laboratory, Division of Clinical Microbiology and Molecular Medicine, Department of Laboratory Medicine, All India Institute of Medical Sciences, and the National Institute of Tuberculosis and Respiratory Diseases (NITRD), both situated in New Delhi.

OBJECTIVES

We aimed to identify the distribution of various genotypes of M. tuberculosis among HIV-positive and HIV-negative patients suspected of having Tuberculosis, seen at the National Institute of Tuberculosis and Respiratory Diseases, New Delhi, which is a tertiary care dedicated TB hospital.

PATIENTS AND METHODS

Genotyping by Spoligotyping and 24 loci MIRU-VNTR was performed and analyzed using SITVITWEB and MIRU-VNTRplus. Drug susceptibility patterns were also analyzed.

RESULTS

A total of 503 subjects who were PTB/EPTB suspected were recruited and 287 were culture positive. Among them, 276 had growth of Mycobacterium tuberculosis (MTB) and in 11 patients non-tuberculous mycobacteria (NTM) were grown. The isolation rate of NTM was predominantly from HIV positive [10 of 130 (7.6%)] patients. Of the total isolates of MTB, 156 (56.5%) were from HIV negative patients and 120 (43.5%) were from HIV positive patients. All 276 M. tuberculosis isolates were genotyped and tested for drug susceptibility patterns. The CAS genotype was most predominant [153 (55.4%)], followed by Beijing lineage [44 (15.9%)], East African India [25 (9.1%)] and others [54 (19.6%)]. Beijing genotype was significantly more common in HIV positive patients (22.5%) than in HIV negative patients (10.9%). In MIRU-VNTR analysis, clustering was found to be more frequent in CAS strains irrespective of HIV status. In the HIV positive group, spoligotyping could differentiate various genotypes in 90% of isolates and MIRU-VNTR analysis in 84.2% of isolates. The clustering of various MTB strains was more associated with drug resistance.

CONCLUSION

The Beijing lineage was predominant in HIV-TB coinfected cases, even though the Central Asian Strain (CAS) was overall more predominant in the region.

Evaluation of role of interferon gamma release assays in the diagnosis of latent tuberculosis in human immunodeficiency virus-infected patients

Introduction:

Tuberculosis (TB) is the most common opportunistic infection in human immunodeficiency virus (HIV)-infected individuals. The risk of eventually developing active TB from latent TB infection (LTBI) is about 10% per year in HIV-positive patients in contrast to 10% lifetime risk in HIV-negative patients. Until recently, the tuberculin skin test (TST) was the only tool available for diagnosing LTBI. Interferon-gamma release assays (IGRAs) were recently developed and address many of the limitations of TST test, especially in immunocompromised state.

Aims and Objectives:

(1) To determine the prevalence of latent, active pulmonary, and multidrug-resistant (MDR)-TB among HIV-positive patients in and around Aligarh region; (2) sensitivity and specificity of TST and IGRAs for diagnosis of LTBI in HIV positive patients; and (3) to assess drug resistance and mutational patterns of the clinical isolates of MDR-TB in HIV-TB co-infection.

Materials and Methods:

A cross-sectional study was done on all the patients attended the ICTC centre, JNMC, AMU Aligarh, seropositive for HIV, i.e. 469 (sample size) for the study period of 2 years from October 2015 to October 2017. All 469 HIV-positive patients were screened for latent and active pulmonary TB. Diagnosis of TB (active and latent) was made using clinical, radiological, and microbiological tests. TST and IGRA testing along with CD4 cell counts were also determined. Line probe assay was also done to assess drug resistance and mutational patterns of MDR-TB in HIV patients.

Results:

In our study, prevalence of HIV infection was 5.04%. Sixty-seven (14.28%) patients were as active TB (HIV-TB co-infection), out of which only one patient (1.49%) was confirmed as MDR-TB, 117 (24.94%) were diagnosed as LTBI. It was also evaluated that IGRA has more sensitivity (75%) and specificity (76%) than TST with sensitivity of 71.7% and specificity 66%.

Conclusion:

As there is no gold standard test for latent TB, longitudinal follow-up is needed to interpret discordant test results. There is a need to interpret negative QFT results with caution and to test for latent TB at higher CD4 counts, if possible. Interferon gamma assays can become better tool for diagnosis of especially for latent TB. However, more research study required for establish their relevance, especially in immunocompromised states.

Acceptability of the Medication Event Reminder Monitor for Promoting Adherence to Multidrug-Resistant Tuberculosis Therapy in Two Indian Cities: Qualitative Study of Patients and Health Care Providers

Background

Patients with multidrug-resistant tuberculosis (MDR-TB) face challenges adhering to medications, given that treatment is prolonged and has a high rate of adverse effects. The Medication Event Reminder Monitor (MERM) is a digital pillbox that provides pill-taking reminders and facilitates the remote monitoring of medication adherence.

Objective

This study aims to assess the MERM’s acceptability to patients and health care providers (HCPs) during pilot implementation in India’s public sector MDR-TB program.

Methods

From October 2017 to September 2018, we conducted qualitative interviews with patients who were undergoing MDR-TB therapy and were being monitored with the MERM and HCPs in the government program in Chennai and Mumbai. Interview transcripts were independently coded by 2 researchers and analyzed to identify the emergent themes. We organized findings by using the Unified Theory of Acceptance and Use of Technology (UTAUT), which outlines 4 constructs that predict technology acceptance—performance expectancy, effort expectancy, social influence, and facilitating conditions.

Results

We interviewed 65 patients with MDR-TB and 10 HCPs. In patient interviews, greater acceptance of the MERM was related to perceptions that the audible and visual reminders improved medication adherence and that remote monitoring reduced the frequency of clinic visits (performance expectancy), that the device’s organization and labeling of medications made it easier to take them correctly (effort expectancy), that the device facilitated positive family involvement in the patient’s care (social influences), and that remote monitoring made patients feel more cared for by the health system (facilitating conditions). Lower patient acceptance was related to problems with the durability of the MERM’s cardboard construction and difficulties with portability and storage because of its large size (effort expectancy), concerns regarding stigma and the disclosure of patients’ MDR-TB diagnoses (social influences), and the incorrect understanding of the MERM because of suboptimal counseling (facilitating conditions). In their interviews, HCPs reported that MERM implementation resulted in fewer in-person interactions with patients and thus allowed HCPs to dedicate more time to other tasks, which improved job satisfaction.

Conclusions

Several features of the MERM support its acceptability among patients with MDR-TB and HCPs, and some barriers to patient use could be addressed by improving the design of the device. However, some barriers, such as disease-related stigma, are more difficult to modify and may limit use of the MERM among some patients with MDR-TB. Further research is needed to assess the accuracy of MERM for measuring adherence, its effectiveness for improving treatment outcomes, and patients’ sustained use of the device in larger scale implementation.

Association of the Clinico-Demographic and Laboratory Profile with Treatment Outcomes in Patients with Drug-Resistant Pulmonary Tuberculosis

Background:

Drug-resistant tuberculosis (DR-TB) is a significant public health problem, especially in the developing and underdeveloped countries; its treatment is relatively expensive, of longer duration, and associated with more adverse effects.

Objective:

The objective of this study was to report the treatment outcomes in patients with DR-TB and determine if a few selected clinico-demographic parameters and baseline laboratory values, done as part of the pre-treatment evaluation, have any impact on sputum culture conversion and outcomes. The aim was to identify the potential factors associated with unfavourable outcomes prior to starting the treatment.

Methods:

A retrospective analysis of data of patients diagnosed with DR-TB admitted at our centre from January 2015 to May 2016 was done. Of the 114 patients included, culture reports were available in 85 and 72 patients at the end of the third and sixth month, respectively. The clinicodemographic and laboratory parameters were compared with the sputum culture report at the end of the third and sixth month and final treatment outcomes.

Results:

Favorable outcome (cured) was seen in 33.3% (38/114) patients. Female gender was associated with delayed sputum culture conversion at three months (P = 0.020). A positive culture at the end of the sixth month was significantly associated with unfavourable outcomes (P = 0.002). A low body mass index (BMI) (15.86 [IQR, 14.10-18.11]) and a higher platelet count (358 × 109/L [IQR, 282-4.85]) at the initiation of treatment were independently and significantly associated with unfavorable outcomes.

Conclusion:

Patients with a low BMI and high platelet count are more likely to have unfavourable treatment outcomes. Identifying patients with these risk factors during the pre-treatment phase, more intensive follow-up during the treatment course could be advocated.

Drug-Resistant Tuberculosis and HIV Infection: Current Perspectives

Drug-resistant tuberculosis (DR-TB), including multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB), is considered a potential obstacle for elimination of TB globally. HIV coinfection with M/XDR-TB further complicates the scenario, and is a potential threat with challenging management. Reports have shown poor outcomes and alarmingly high mortality rates among people living with HIV (PLHIV) coinfected with M/XDR-TB. This coinfection is also responsible for all forms of M/XDR-TB epidemics or outbreaks. Better outcomes with reductions in mortality have been reported with concomitant treatment containing antiretroviral drugs for the HIV component and antitubercular drugs for the DR-TB component. Early and rapid diagnosis with genotypic tests, prompt treatment with appropriate regimens based on drug-susceptibility testing, preference for shorter regimens fortified with newer drugs, a patient-centric approach, and strong infection-control measures are all essential components in the management of M/XDR-TB in people living with HIV.

Whole-genome sequencing-based epidemiological analysis of anti-tuberculosis drug resistance genes in Japan in 2007: Application of the Genome Research for Asian Tuberculosis (GReAT) database

We investigated the lineages of Mycobacterium tuberculosis (Mtb) isolates from the RYOKEN study in Japan in 2007 and the usefulness of genotypic drug susceptibility testing (DST) using the Genome Research for Asian Tuberculosis (GReAT) database. In total, 667 isolates were classified into lineage 1 (4.6%), lineage 2 (0.8%), lineage 2/Beijing (72.1%), lineage 3 (0.5%), and lineage 4 (22.0%). The nationality, gender, and age groups associated with the isolates assigned to lineage 1 were significantly different from those associated with other lineages. In particular, isolates of lineage 1.2.1 (EAI2) formed sub-clusters and included a 2,316-bp deletion in the genome. The proportion of the isolates resistant to at least one anti-tuberculosis (TB) drug was 10.8%, as determined by either the genotypic or phenotypic method of DST. However, the sensitivities to isoniazid, streptomycin, and ethambutol determined by the genotypic method were low. Thus, unidentified mutations in the genome responsible for drug resistance were explored, revealing previously unreported mutations in the katG, gid, and embB genes. This is the first nationwide report of whole-genome analysis of TB in Japan.

Analysis of drug resistance mutations in pulmonary Mycobacterium tuberculosis isolates in the Southern coastal region of Andhra Pradesh, India

Purpose and objectives

Detection of drug resistance plays a crucial role in tuberculosis (TB) treatment and prevention of Mycobacterium tuberculosis (MTB) transmission. The aim of this study was to determine the levels and patterns of resistance of MTB isolates to two key anti-TB drugs (rifampicin, RIF and isoniazid, INH) and the type of mutations in drug resistance genes (rpoB, katG and inhA) of the isolates at the southern coastal region of Andhra Pradesh, India, using commercially available GenoType MTBDRplus assay under the Revised National TB Control Program.

Methods

GenoType MTBDRplus assay was performed on 2859 sputum smear-positive samples and the mutations in the genes responsible for resistance (rpoB, katG and inhA) were analyzed.

Results

Among the line probe assay (LPA) valid isolates (2894), 1990 (68.76%) were drug susceptible, 437 (15.13%) were INH monoresistant, 104 (3.59%) were RIF monoresistant, and 363 (12.54%) were multidrug resistant. Codon 531 of rpoB gene and codon 315 of katG gene were found to have the highest mutation frequency for RIF resistance (270/467; 57.81%) and INH resistance (501/800; 62.62%), respectively. The RIF resistant rpoB mutations observed in the samples were S531 L (57.81%), H526Y (8.56%), D516 V (6.42%), and H526D (6.20%). Mutations in inhA promoter were found in 24.75% INH resistant isolates with C15 T being the most common (85.85%). The turnaround times of the LPA test were from 48 to72 h.

Conclusion

The frequency of mutations in MTB in the coastal region of Andhra Pradesh, India, is similar to that in retreatment cases from most settings, with close to 80% in rpoB codon 516, 526, and 531, and over 80% in codons katG 315 and/or inhA promoter. The increase in INH monoresistance underlines the need for greater enforcement of national TB control programs.

Multidrug-resistant tuberculosis (MDR-TB) and multidrug-resistant HIV (MDR-HIV) syndemic: challenges in resource limited setting

Tuberculosis (TB) is common among persons living with HIV. This public health concern is aggravated by infection with multidrug-resistant organisms and adverse effects of polypharmacy. There are few published cases of multidrug-resistant tuberculosis (MDR-TB) in multidrug-resistant HIV (MDR-HIV) infected patients. We report a case of a 29-year-old Filipino man with HIV on zidovudine (AZT)-containing antiretroviral therapy (ART) but was eventually shifted to tenofovir due to anaemia. He presented with left flank tenderness, which was found to be due to an MDR-TB psoas abscess, and for which second-line anti-TB treatment was started. HIV genotyping showed MDR-HIV infection susceptible only to AZT, protease inhibitors and integrase inhibitors. Subsequently, he developed neck abscess that grew Mycobacterium avium complex and was treated with ethambutol and azithromycin. ART regimen was revised to AZT plus lamivudine and lopinavir/ritonavir. Erythropoietin was administered for recurrent AZT-induced anaemia. Both abscesses resolved and no recurrence of anaemia was noted.

Elucidation of drug resistance mutations in Mycobacterium tuberculosis isolates from North India by whole-genome sequencing

OBJECTIVES

Rapid diagnosis of drug-resistant tuberculosis (TB) is required for better patient management and treatment outcomes. Whole-genome sequencing (WGS) can be used to detect single nucleotide polymorphisms (SNPs) and deletions/insertions that are responsible for mostMycobacterium tuberculosis drug resistance. WGS is being performed at scale in high-income countries, but there are limited reports of its use in India.

METHODS

In this study, 33 clinicalM. tuberculosis isolates from the Mycobacterial Repository in Chandigarh underwent WGS. Phenotypic drug susceptibility testing was performed according to World Health Organization (WHO) recommendations. Four isolates were excluded from the analysis due to culture contamination or mislabelling during the study.

RESULTS

Among the remaining 29 isolates, 21 (72.4%) were multidrug-resistant TB (MDR-TB) and 1 (3.4%) was extensively-drug resistant TB (XDR-TB). The most common mutations observed for isoniazid, rifampicin, ofloxacin and kanamycin resistance werekatG(S315T), rpoB(S450L), gyrA(A90V) and rrs(A1401G), respectively. The isolates mainly belonged to lineages 2 and 3, with most MDR-TB among lineage 2 isolates.

CONCLUSION

WGS ofM. tuberculosis isolates allows the detection of drug resistance to all drugs in a single test and also provides insight into the evolution and drug-resistant TB.

High prevalence of multi drug resistant tuberculosis in people living with HIV in Western India

BACKGROUND

Most studies assessing drug resistant tuberculosis (DRTB) in human immunodeficiency virus (HIV) co-infected patients in India have used conventional culture- based systems to diagnose DRTB that have a longer turnaround time leading to risk of amplification of resistance to an empirical regimen. We determined the prevalence of DRTB amongst people living with HIV (PLHIV) using the line probe assay and determined risk factors associated with the presence of multi drug resistant tuberculosis (MDRTB).

METHODS

A Cross-sectional study was undertaken at Poona Hospital and Research Center (PHRC) and the Institute of Infectious Diseases, two tertiary level private care centers in Pune, India. Consenting PLHIV with confirmed Pulmonary TB (PTB) and/or extra-pulmonary TB (EPTB) diagnosed based on detection of Mycobacterium TB by line probe assay (Geno Type MTBDRplus version 2) on clinical specimens were included. Those with documented past history of DRTB were excluded. Resistance against anti-TB drugs was determined by the same assay. The prevalence of any form of drug resistant TB (DRTB), MDRTB, Rifampicin resistant TB (RRTB) and Isoniazid (INH) mono-resistant TB were determined as the proportion of these amongst all included PLHIV-TB. A multivariate analysis was conducted to determine risk factors that were statistically associated with MDRTB, DRTB, RRTB and INH mono-resistant TB.

RESULTS

Two hundred PLHIV were recruited. The prevalence (95% CI) of MDRTB, INH mono- resistance and RR resistance was 12.5% (7.9-17.1%), 9% (6.9-11.2%) and 2.5% (1.4-3.6%), respectively. The prevalence (95% CI) of MDRTB among new and relapsed patients was 8.8% (6.5-11.1%) and 23.1% (17.2-28.9%), respectively. Tuberculosis relapse was the only factor significantly associated with MDRTB, DRTB and INH mono-resistant TB.

CONCLUSION

We document a high prevalence of drug resistance to anti-TB drugs including MDRTB among PLHIV in our setting using Geno Type MTBDRplus directly on clinical specimens. This validates the WHO recommendation of performing routine rapid molecular resistance testing prior to initiating anti-TB treatment among all PLHIV with presumptive TB. Using rapid molecular testing especially Geno Type MTBDRplus (that detects resistance to INH and Rifampicin simultaneously) reduces the turn-around time helping in optimizing treatment.

Multidrug-resistant tuberculosis outbreak associated with poor treatment adherence and delayed treatment: Arua District, Uganda, 2013-2017

BACKGROUND

In August 2017, the Uganda Ministry of Health was notified of increased cases of multidrug-resistant tuberculosis (MDR-TB) in Arua District, Uganda during 2017. We investigated to identify the scope of the increase and risk factors for infection, evaluate health facilities' capacity to manage MDR-TB, and recommend evidence-based control measures.

METHODS

We defined an MDR-TB case-patient as a TB patient attending Arua Regional Referral Hospital (ARRH) during 2013-2017 with a sputum sample yielding Mycobacterium tuberculosis resistant to at least rifampicin and isoniazid, confirmed by an approved drug susceptibility test. We reviewed clinical records from ARRH and compared the number of MDR-TB cases during January-August 2017 with the same months in 2013-2016. To identify risk factors specific for MDR-TB among cases with secondary infection, we conducted a case-control study using persons with drug-susceptible TB matched by sub-county of residence as controls. We observed infection prevention and control practices in health facilities and community, and assessed health facilities' capacity to manage TB.

RESULTS

We identified 33 patients with MDR-TB, of whom 30 were secondary TB infection cases. The number of cases during January-August 2017 was 10, compared with 3-4 cases in January-August from 2013 to 2016 (p = 0.02). Men were more affected than women (6.5 vs 1.6/100,000, p < 0.01), as were cases ≥18 years old compared to those < 18 years (8.7 vs 0.21/100,000, p < 0.01). In the case-control study, poor adherence to first-line anti-TB treatment (aOR = 9.2, 95% CI: 2.3-37) and initiating treatment > 15 months from symptom onset (aOR = 11, 95% CI: 1.5-87) were associated with MDR-TB. All ten facilities assessed reported stockouts of TB commodities. All 15 ambulatory MDR-TB patients we observed were not wearing masks given to them to minimize community infection. The MDR-TB ward at ARRH capacity was 4 patients but there were 11 patients.

CONCLUSION

The number of cases during January-August in 2017 was significantly higher than during the same months in 2013-2016. Poor adherence to TB drugs and delayed treatment initiation were associated with MDR-TB infection. We recommended strengthening directly-observed treatment strategy, increasing access to treatment services, and increasing the number of beds in the MDR-TB ward at ARRH.

Modelling the impact of effective private provider engagement on tuberculosis control in urban India

In India, the country with the world’s largest burden of tuberculosis (TB), most patients first seek care in the private healthcare sector, which is fragmented and unregulated. Ongoing initiatives are demonstrating effective approaches for engaging with this sector, and form a central part of India’s recent National Strategic Plan: here we aimed to address their potential impact on TB transmission in urban settings, when taken to scale. We developed a mathematical model of TB transmission dynamics, calibrated to urban populations in Mumbai and Patna, two major cities in India where pilot interventions are currently ongoing. We found that, when taken to sufficient scale to capture 75% of patient-provider interactions, the intervention could reduce incidence by upto 21.3% (95% Bayesian credible interval (CrI) 13.0–32.5%) and 15.8% (95% CrI 7.8–28.2%) in Mumbai and Patna respectively, between 2018 and 2025. There is a stronger impact on TB mortality, with a reduction of up to 38.1% (95% CrI 20.0–55.1%) in the example of Mumbai. The incidence impact of this intervention alone may be limited by the amount of transmission that has already occurred by the time a patient first presents for care: model estimates suggest an initial patient delay of 4–5 months before first seeking care, followed by a diagnostic delay of 1–2 months before ultimately initiating TB treatment. Our results suggest that the transmission impact of such interventions could be maximised by additional measures to encourage early uptake of TB services.

Few eligible for the newly recommended short course MDR-TB regimen at a large Mumbai private clinic

BACKGROUND

India has the world's highest tuberculosis burden, and Mumbai is particularly affected by multidrug resistant tuberculosis (MDR-TB). WHO recommends short, intensive treatment ("Short Course") for previously untreated pulmonary MDR-TB patients but does not require universal drug susceptibility testing (DST) before Short Course. DST would likely screen out many MDR-TB patients in places like Mumbai with significant drug resistance.

METHODS

MDR-TB patients at a private clinic were recruited for a prospective observational cohort. Short Course eligibility was evaluated by clinical criteria and DST results. Eligibility by DST was classified as rifampin monoresistance (as tested by Xpert MTB/RIF), rifampin, fluoroquinolones, and 2nd-line injectable drugs resistance (as tested by line probe assays) and resistance to other drugs.

RESULTS

Of 559 participants with MDR-TB, 33% met clinical eligibility for Short Course. DST for rifampin, fluoroquinolones, and 2nd-line injectable drugs excluded 74.7% of participants. Complete phenotypic DST excluded 96.6% of participants. Prior treatment with either 1st or 2nd-line drugs did not significantly affect eligibility.

CONCLUSIONS

In a global MDR-TB hotspot, < 5% of participants with MDR-TB were appropriate for Short Course by clinical characteristics and DST results. Rapid molecular testing would not sufficiently identify drug resistance in this population. Eligibility rates were not significantly reduced by prior TB treatment.

Risk factors for multidrug-resistant tuberculosis among tuberculosis patients in Serbia: a case-control study

BACKGROUND

Multidrug resistant (MDR) tuberculosis (TB) represents TB which is simultaneous resistant to at least rifampicin (R) and isoniazid (H). Identifying inadequate therapy as the main cause of this form of the disease and explaining the factors leading to its occurrence, numerous social determinants that affect the risk of developing resistance are highlighted. The objectives of the study was to identify independent factors of MDR-TB among tuberculosis patients.

METHODS

Case-control study was conducted from 1st September 2009 to 1st June 2014 in 31 healthcare institutions in Serbia where MDR-TB and TB patients were treated. TB patients infected with MDR- M. tuberculosis and non MDR- M. tuberculosis strain were considered as cases and controls, respectively. Cases and controls were matched by the date of hospitalization. The data was collected using structured questionnaire with face to face interview. Bivariate and multivariable logistic regression analysis (MLRA) were used to identify determinants associated with MDR-TB.

RESULTS

A total of 124 respondents, 31 cases and 93 controls were participated in the study. MLRA identified six significant independent risk factors for the occurrence of MDR-TB as follows: monthly income of the family (Odds ratio (OR) = 3.71; 95% Confidence Interval (CI) = 1.22-11.28), defaulting from treatment (OR = 3.33; 95% CI = 1.14-9.09), stigma associated with TB (OR = 2.97; 95% CI = 1.18-7.45), subjective feeling of sadness (OR = 4.05; 95% CI = 1.69-9.70), use of sedatives (OR = 2.79; 95% CI = 1.02-7.65) and chronic obstructive pulmonary disease (OR = 4.51; 95% CI = 1.07-18.96).

CONCLUSION

In order to reduce burden of drug resistance, strategies of controlling MDR-TB in Serbia should emphasize multi-sectorial actions, addressing health care and social needs of TB patients.

Extensively drug-resistant tuberculosis in India: Current evidence on diagnosis & management

Emergence of extensively drug-resistant tuberculosis (XDR-TB) has significantly threatened to jeopardize global efforts to control TB, especially in HIV endemic regions. XDR-TB is mainly an iatrogenically created issue, and understanding the epidemiological and risk factors associated with it is of paramount importance in curbing this menace. Emergence of this deadly phenomenon can be prevented by prompt diagnosis and effective treatment with second-line drugs in rifampicin-resistant TB (RR-TB) as well as multidrug-resistant TB (MDR-TB) patients. Optimal treatment of RR-TB, MDR-TB and XDR-TB cases alone will not suffice to reduce the global burden. The TB control programmes need to prioritize on policies focusing on the effective as well as rational use of first-line drugs in every newly diagnosed drug susceptible TB patients so as to prevent the emergence of drug resistance.

Association of Immune Factors with Drug-Resistant Tuberculosis: A Case-Control Study

Background

Presently, studies of factors associated with drug-resistant tuberculosis (TB) focus on patients’ socio-demographic characteristics and living habits, to the exclusion of biochemical indicators, especially immune factors. This study was carried out to determine whether immune factors are associated with drug-resistant TB.

Material/Methods

A total of 227 drug-resistant pulmonary TB patients and 225 drug-susceptible pulmonary TB patients were enrolled in this study. Information on socio-demographic characteristics and biochemical indicators were obtained through their clinical records. Non-conditional logistic regression was used to analyze the association of these indicators with drug-resistant TB.

Results

There were significant differences in re-treatment, marital status, alanine aminotransferase (ALT), blood uric acid (BUA), carcino-embryonic antigen (CEA), T-spot, and CD3 and CD4 counts between the 2 groups. In multivariable analysis, re-treatment [Odds Ratio (OR)=5.290, 95% Confidence Interval [CI]=2.652–10.551); CD3 (OR=1.034, 95% CI=1.001–1.068); CD4 (OR=1.035, 95% CI =1.001–1.070) and IgM (OR=1.845, 95% CI=1.153–2.952) were associated with drug-resistant TB.

Conclusions

These results suggest the need for greater attention to re-treatment cases and immune function when treating drug-resistant TB.

Current and developing therapies for the treatment of multi drug resistant tuberculosis (MDR-TB) in India

INTRODUCTION

India accounts for 25% of the global burden of MDR-TB. In 2016, the India's Revised National TB Control Programme reported a success rate of 46% among 19,298 MDR-TB patients treated under the programme. This suboptimal treatment outcome warrants an urgent need for newer drugs and newer regimens in the treatment of MDR-TB. India requires new shorter, cheap, safe and effective anti-TB regimen to treat MDR-TB. Areas covered: We used different search strategies to obtain relevant literature from PubMed, on Indian experiences of developing therapies for the treatment of MDR-TB. Further information from the Central TB Division Government of India on programmatic management of resistant TB was collected. Expert opinion: In 2016 WHO recommended a shorter MDR-TB regimen of 9-12 months (4-6 Km-Mfx-Pto-Cfz-Z-Hhigh-dose-E /5 Mfx-Cfz-Z-E) may be used instead of longer regimens. Currently, conducting trials involving newer drugs such as bedaquiline, have been proposed. The regimen will be of a shorter duration containing isoniazid, prothionamide, bedaquiline, levofloxacin, ciprofloxacin, ethambutol and pyrazinamide (STREAM regimen). To successfully treat MDR-TB one requires new classes of antibiotic and newer diagnostic tests. This represents an enormous financial and technical challenge to the programme managers and policy makers.

Prevalence of mutations in genes associated with rifampicin and isoniazid resistance in Mycobacterium tuberculosis clinical isolates

Purpose: To analyze prevalence of mutations in genes associated with rifampicin and isoniazid resistance in Mycobacterium tuberculosis clinical isolates from patients with possible MDR TB of Puducherry, South India and to explore the association of specific mutations conferring rifampicin (RIF) resistance. Methods: We performed a commercial Genotype MDBDRplus V.2.0 assay for the rapid detection of rifampicin and isoniazid resistance directly on sputum specimens of patients with possible MDR TB. Results: Totally 558 multidrug resistant, 293 RIF mono resistant and 923 INH mono resistant tuberculosis were detected from the 12,786 patients with possible MDR TB samples. The 50.5% mutations were observed in the region of S531L in MDR TB patients and 55.6% in rifampicin monoresistant cases. In total isoniazid monoresistant, 68.0% mutations were detected in katG gene, which is more prevalent in comparison to inhA gene 32.0%. There were about 57.9% and 32.2% MDR TB cases diagnosed in the age group of > 15 to ≤ 45 years and > 45 to ≤ 60 years respectively. Conclusions: The rate of occurrences of mutations were found widely in the Rifampicin Resistant Determination Region (81 bp) of rpoB gene and the hypervariable region 530-533 codons of rpoB gene is alarming in the specification. The higher frequency of mutation in codons of rpoB (S531L) and katG (S315T) gene help to design simple, new and less expensive molecular techniques to use in peripheral laboratories.

Re-inventing adherence: toward a patient-centered model of care for drug-resistant tuberculosis and HIV

BACKGROUND

Despite renewed focus on molecular tuberculosis (TB) diagnostics and new antimycobacterial agents, treatment outcomes for patients co-infected with drug-resistant TB and human immunodeficiency virus (HIV) remain dismal, in part due to lack of focus on medication adherence as part of a patient-centered continuum of care.

OBJECTIVE

To review current barriers to drug-resistant TB-HIV treatment and propose an alternative model to conventional approaches to treatment support.

DISCUSSION

Current national TB control programs rely heavily on directly observed therapy (DOT) as the centerpiece of treatment delivery and adherence support. Medication adherence and care for drug-resistant TB-HIV could be improved by fully implementing team-based patient-centered care, empowering patients through counseling and support, maintaining a rights-based approach while acknowledging the responsibility of health care systems in providing comprehensive care, and prioritizing critical research gaps.

CONCLUSION

It is time to re-invent our understanding of adherence in drug-resistant TB and HIV by focusing attention on the complex clinical, behavioral, social, and structural needs of affected patients and communities.

Expected effects of adopting a 9 month regimen for multidrug-resistant tuberculosis: a population modelling analysis

Background

In May, 2016, WHO endorsed a 9 month regimen for multidrug-resistant tuberculosis that is cheaper and potentially more effective than the conventional, longer (20–24 month) therapy. We aimed to investigate the population-level implications of scaling up this new regimen.

Methods

In this population modelling analysis, we developed a dynamic transmission model to simulate the introduction of this short-course regimen as an instantaneous switch in 2016. We projected the corresponding percentage reduction in the incidence of multidrug-resistant tuberculosis by 2024 compared with continued use of longer therapy. In the primary analysis in a representative southeast Asian setting, we assumed that the short-course regimen would double treatment access (through savings in resources or capacity) and achieve long-term efficacy at levels seen in preliminary cohort studies. We then did extensive sensitivity analyses to explore a range of alternative scenarios.

Findings

Under the optimistic assumptions in the primary analysis, the incidence of multidrug-resistant tuberculosis in 2024 would be 3·3 (95% uncertainty range 2·2–5·6) per 100 000 population with the short-course regimen and 4·3 (2·9–7·6) per 100 000 population with continued use of longer therapy—ie, the short-course regimen could reduce incidence by 23% (10–38). Incidence would be reduced by 14% (4–28) if the new regimen affected only treatment effectiveness and by 11% (3–24) if it affected only treatment availability. Under more pessimistic assumptions, the short-course regimen would have minimal effect and even potential for harm—eg, when 30% of patients are ineligible for the new regimen because of second-line drug resistance, we projected a change in incidence of −2% (−20 to +28). The new regimen's effect was greater in settings with more ongoing transmission of multidrug-resistant tuberculosis, but results were otherwise similar across settings with different levels of tuberculosis incidence and prevalence of multidrug resistance.

Interpretation

The short-course regimen has potential to substantially lessen the multidrug-resistant tuberculosis epidemic, but this effect depends on its long-term efficacy, its ability to expand treatment access, and the role of second-line drug resistance.

Funding

US National Institutes of Health and Bill & Melinda Gates Foundation.

Recent developments in genomics, bioinformatics and drug discovery to combat emerging drug-resistant tuberculosis

Emergence of drug-resistant tuberculosis (DR-TB) is a big challenge in TB control. The delay in diagnosis of DR-TB leads to its increased transmission, and therefore prevalence. Recent developments in genomics have enabled whole genome sequencing (WGS) of Mycobacterium tuberculosis (M. tuberculosis) from 3-day-old liquid culture and directly from uncultured sputa, while new bioinformatics tools facilitate to determine DR mutations rapidly from the resulting sequences. The present drug discovery and development pipeline is filled with candidate drugs which have shown efficacy against DR-TB. Furthermore, some of the FDA-approved drugs are being evaluated for repurposing, and this approach appears promising as several drugs are reported to enhance efficacy of the standard TB drugs, reduce drug tolerance, or modulate the host immune response to control the growth of intracellular M. tuberculosis. Recent developments in genomics and bioinformatics along with new drug discovery collectively have the potential to result in synergistic impact leading to the development of a rapid protocol to determine the drug resistance profile of the infecting strain so as to provide personalized medicine. Hence, in this review, we discuss recent developments in WGS, bioinformatics and drug discovery to perceive how they would transform the management of tuberculosis in a timely manner.

Sequence Analysis of Fluoroquinolone Resistance-Associated Genes gyrA and gyrB in Clinical Mycobacterium tuberculosis Isolates from Patients Suspected of Having Multidrug-Resistant Tuberculosis in New Delhi, India

Fluoroquinolones (FQs) are broad-spectrum antibiotics recommended for the treatment of multidrug-resistant tuberculosis (MDR-TB) patients. FQ resistance, caused by mutations in the gyrA and gyrB genes of Mycobacterium tuberculosis, is increasingly reported worldwide; however, information on mutations occurring in strains from the Indian subcontinent is scarce. Hence, in this study, we aimed to characterize mutations in the gyrA and gyrB genes of acid-fast bacillus (AFB) smear-positive sediments or of M. tuberculosis isolates from AFB smear-negative samples from patients in India suspected of having MDR-TB. A total of 152 samples from patients suspected of having MDR-TB were included in the study. One hundred forty-six strains detected in these samples were characterized by sequencing of the gyrA and gyrB genes. The extracted DNA was subjected to successive amplifications using a nested PCR protocol, followed by sequencing. A total of 27 mutations were observed in the gyrA genes of 25 strains, while no mutations were observed in the gyrB genes. The most common mutations occurred at amino acid position 94 (13/27 [48.1%]); of these, the D94G mutation was the most prevalent. The gyrA mutations were significantly associated with patients with rifampin (RIF)-resistant TB. Heterozygosity was seen in 4/27 (14.8%) mutations, suggesting the occurrence of mixed populations with different antimicrobial susceptibilities. A high rate of FQ-resistant mutations (17.1%) was obtained among the isolates of TB patients suspected of having MDR-TB. These observations emphasize the need for accurate and rapid molecular tests for the detection of FQ-resistant mutations at the time of MDR-TB diagnosis.

Etiological study of lymphadenopathy in HIV-infected patients in a tertiary care hospital

INTRODUCTION

Human immunodeficiency virus (HIV) infection has become a global pandemic. Persistent generalized lymphadenopathy (PGL) is very common manifestation of HIV infection. Moreover, different opportunistic infections such as tuberculosis (TB) and malignancies may present with lymphadenopathy. Mycobacterium avium complex (MAC) infection is most common with cluster of differentiation (CD)4+ count ≤50 cells/μL. Fine-needle aspiration cytology (FNAC) offers a simple and effective modality for obtaining a representative sample of the material from lymph nodes, permitting cytological evaluation and other investigations.

AIMS AND OBJECTIVES

The aim of this study is to find out the different etiologies of lymphadenopathy in HIV-infected patients and to establish a possible correlation with CD4+ count.

MATERIALS AND METHODS

A total of 100 HIV-infected patients having significant (>1 cm) extrainguinal lymphadenopathy were studied in 1 year at the Department of Pathology by FNAC and the stains used were Leishman-Giemsa, Ziehl-Neelsen (ZN), Papanicoloau, and Gram stains. For tubercular culture, Löwenstein-Jensen (LJ) medium was used. CD4+count was done by flow cytometer.

RESULT

The present study revealed four types of cytomorphological variants in lymphadenopathy cases by FNAC, which include: Reactive hyperplasia and caseation necrosis; caseation necrosis and ill-formed granuloma; well-formed granuloma without any necrosis; and non-Hodgkin lymphoma (NHL). The highest acid-fast bacilli (AFB) positivity was among the patients showing caseation necrosis. Tubercular culture in LJ media turned out as a more sensitive method for diagnosis than routine ZN staining. The 2 cases that showed well-formed epithelioid granuloma without any necrosis turned out to be histoplasmosis and cryptococcosis, respectively. In this study, we found 2 cases of NHL. The study also revealed that caseation necrosis and AFB positivity along with opportunistic infections increases with decreased CD4+ count.

Infection Control for Drug-Resistant Tuberculosis: Early Diagnosis and Treatment Is the Key

Multidrug-resistant (MDR) tuberculosis, "Ebola with wings," is a significant threat to tuberculosis control efforts. Previous prevailing views that resistance was mainly acquired through poor treatment led to decades of focus on drug-sensitive rather than drug-resistant (DR) tuberculosis, driven by the World Health Organization's directly observed therapy, short course strategy. The paradigm has shifted toward recognition that most DR tuberculosis is transmitted and that there is a need for increased efforts to control DR tuberculosis. Yet most people with DR tuberculosis are untested and untreated, driving transmission in the community and in health systems in high-burden settings. The risk of nosocomial transmission is high for patients and staff alike. Lowering transmission risk for MDR tuberculosis requires a combination approach centered on rapid identification of active tuberculosis disease and tuberculosis drug resistance, followed by rapid initiation of appropriate treatment and adherence support, complemented by universal tuberculosis infection control measures in healthcare facilities. It also requires a second paradigm shift, from the classic infection control hierarchy to a novel, decentralized approach across the continuum from early diagnosis and treatment to community awareness and support. A massive scale-up of rapid diagnosis and treatment is necessary to control the MDR tuberculosis epidemic. This will not be possible without intense efforts toward the implementation of decentralized, ambulatory models of care. Increasing political will and resources need to be accompanied by a paradigm shift. Instead of focusing on diagnosed cases, recognition that transmission is driven largely by undiagnosed, untreated cases, both in the community and in healthcare settings, is necessary. This article discusses this comprehensive approach, strategies available, and associated challenges.

Antimicrobial Resistance in Mycobacterium tuberculosis: The Odd One Out

Antimicrobial resistance (AMR) threats are typically represented by bacteria capable of extensive horizontal gene transfer (HGT). One clear exception is Mycobacterium tuberculosis (Mtb). It is an obligate human pathogen with limited genetic diversity and a low mutation rate which lacks any evidence for HGT. Such features should, in principle, reduce its ability to rapidly evolve AMR. We identify key features in its biology and epidemiology that allow it to overcome its low adaptive potential. We focus in particular on its innate resistance to drugs, its unusual life cycle, including an often extensive latent phase, and its ability to shelter from exposure to antimicrobial drugs within cavities it induces in the lungs.

Durations and Delays in Care Seeking, Diagnosis and Treatment Initiation in Uncomplicated Pulmonary Tuberculosis Patients in Mumbai, India

Background

Timely diagnosis and treatment initiation are critical to reduce the chain of transmission of Tuberculosis (TB) in places like Mumbai, where almost 60% of the inhabitants reside in overcrowded slums. This study documents the pathway from the onset of symptoms suggestive of TB to initiation of TB treatment and examines factors responsible for delay among uncomplicated pulmonary TB patients in Mumbai.

Methods

A population-based retrospective survey was conducted in the slums of 15 high TB burden administrative wards to identify 153 self-reported TB patients. Subsequently in-depth interviews of 76 consenting patients that fit the inclusion criteria were undertaken using an open-ended interview schedule. Mean total, first care seeking, diagnosis and treatment initiation duration and delays were computed for new and retreatment patients. Patients showing defined delays were divided into outliers and non-outliers for all three delays using the median values.

Results

The mean duration for the total pathway was 65 days with 29% of patients being outliers. Importantly the mean duration of first care seeking was similar in new (24 days) and retreatment patients (25 days). Diagnostic duration contributed to 55% of the total pathway largely in new patients. Treatment initiation was noted to be the least among the three durations with mean duration in retreatment patients twice that of new patients. Significantly more female patients experienced diagnostic delay. Major shift of patients from the private to public sector and non-allopaths to allopaths was observed, particularly for treatment initiation.

Conclusion

Achieving positive behavioural changes in providers (especially non-allopaths) and patients needs to be considered in TB control strategies. Specific attention is required in counselling of TB patients so that timely care seeking is effected at the time of relapse. Prioritizing improvement of environmental health in vulnerable locations and provision of point of care diagnostics would be singularly effective in curbing pathway delays.

Drug resistance characteristics and cluster analysis of M. tuberculosis in Chinese patients with multiple episodes of anti-tuberculosis treatment

Background

Tuberculosis (TB) patients with multiple episodes of anti-TB treatment represent an important source of TB transmission, as well as a serious threat to the control of drug resistant TB, due to the high risk of multidrug and extensively drug resistance (MDR/XDR) and elongating infectiousness of this patient group. In this study we analyzed the possible risk of development and transmission of MDR and XDR in TB patients with multiple episodes of previous treatment history.

Methods

The study subjects were pulmonary TB patients who had at least two episodes of previous anti-TB treatment. A total of 166 eligible patients were identified from 10 counties/districts distributed in east, west, north, south and central China. Drug susceptibility test (DST) was performed by proportion method on LJ-media for the 1st line anti-TB drugs and a line probe assay was used to detect mutations related to resistance of the key 2nd-line drugs. Genotyping of M. tuberculosis (Mtb) was performed with MIRU-VNTR and Spoligotyping.

Results

Resistances to 1st-line drugs was observed in 122 (73.5 %) of the 166 Mtb isolates with 97 (58.4 %) being MDR-TB. Mutations relevant to 2nd-line drug resistance was seen in 63 isolates, including 35 MDR-TB isolates (30 pre-XDR, 5 XDR-TB). The Spoligotyping revealed 83.1 % Mtb isolates belonged to the Beijing family. The MIRU-VNTR based genotyping revealed 32 (19.3 %) of patients were infected with more than one strain. The number of previous TB treatment episode was found being significantly associated with the risk of MDR-TB and XDR-TB. Among the remaining 134 patients infected with a single Mtb strain, MIRU-VNTR revealed a high homogeneity of strain especially within Beijing family despite the polymorphic variations along with geographic locations.

Conclusions

The high genetic relatedness and risk of MDR-TB and subsequent pre-XDR and XDR-TB among repeatedly treated patients suggest the establishment of M/XDR Mtb in this specific patient population. It highlights the urgent needs of providing DST of both 1st- and 2nd-line drugs before and during the medication in China’s MDR-TB control program. Furthermore, the possibility of infection with multiple strains should also be considered to be associated with the drug resistance, which calls for the modification of treatment regimen.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1331-z) contains supplementary material, which is available to authorized users.

Data for action: collection and use of local data to end tuberculosis

Accelerating progress in the fight against tuberculosis will require a drastic shift from a strategy focused on control to one focused on elimination. Successful disease elimination campaigns are characterised by locally tailored responses that are informed by appropriate data. To develop such a response to tuberculosis, we suggest a three-step process that includes improved collection and use of existing programmatic data, collection of additional data (eg, geographic information, drug resistance, and risk factors) to inform tailored responses, and targeted collection of novel data (eg, sequencing data, targeted surveys, and contact investigations) to improve understanding of tuberculosis transmission dynamics. Development of a locally targeted response for tuberculosis will require substantial investment to reconfigure existing systems, coupled with additional empirical data to evaluate the effectiveness of specific approaches. Without adoption of an elimination strategy that uses local data to target hotspots of transmission, ambitious targets to end tuberculosis will almost certainly remain unmet.

Burden of transmitted multidrug resistance in epidemics of tuberculosis: a transmission modelling analysis

Background

Multidrug-resistant tuberculosis (MDR-TB) can be acquired through de novo mutation during TB treatment or through transmission from other individuals with active MDR-TB. Understanding the balance between these two mechanisms is essential when allocating resources for MDR-TB.

Methods

We constructed a dynamic transmission model of an MDR-TB epidemic, allowing for both treatment-related acquisition and person-to-person transmission of resistance. We used national TB notification data to inform Bayesian estimates of the fraction of each country’s 2013 MDR-TB incidence that resulted from MDR transmission rather than treatment-related MDR acquisition.

Findings

Global estimates of 3·5% MDR-TB prevalence among new TB notifications and 20·5% among retreatment notifications translate into an estimate that resistance transmission rather than acquisition accounts for a median 96% (95% UR: 68–100%) of all incident MDR-TB, and 61% (16–95%) of incident MDR-TB in previously-treated individuals. The estimated percentage of MDR-TB resulting from transmission varied substantially with different countries’ notification data; for example, we estimated this percentage at 48% (30–75%) of MDR-TB in Bangladesh, versus 99% (91–100%) in Uzbekistan. Estimates were most sensitive to estimates of the transmissibility of MDR strains, the probability of acquiring MDR during tuberculosis treatment, and the responsiveness of MDR TB to first-line treatment.

Interpretation

Notifications of MDR prevalence from most high-burden settings are most consistent with the vast majority of incident MDR-TB resulting from transmission rather than new treatment-related acquisition of resistance. Merely improving the treatment of drug-susceptible TB is unlikely to greatly reduce future MDR-TB incidence. Improved diagnosis and treatment of MDR-TB – including new tests and drug regimens – should be highly prioritized.

Resistance patterns among multidrug-resistant tuberculosis patients in greater metropolitan Mumbai: trends over time

Background

While the high burden of multidrug-resistant tuberculosis (MDR-TB) itself is a matter of great concern, the emergence and rise of advanced forms of drug-resistance such as extensively drug-resistant TB (XDR-TB) and extremely drug-resistant TB (XXDR-TB) is more troubling. The aim of this study was to investigate the trends over time of patterns of drug resistance in a sample of MDR-TB patients in greater metropolitan Mumbai, India.

Methods

This was a retrospective, observational study of drug susceptibility testing (DST) results among MDR-TB patients from eight health care facilities in greater Mumbai between 2005 and 2013. We classified resistance patterns into four categories: MDR-TB, pre-XDR-TB, XDR-TB and XXDR-TB.

Results

A total of 340 MDR-TB patients were included in the study. Pre-XDR-TB was the most common form of drug-resistant TB observed overall in this Mumbai population at 56.8% compared to 29.4% for MDR-TB. The proportion of patients with MDR-TB was 39.4% in the period 2005–2007 and 27.8% in 2011–2013, while the proportion of those with XDR-TB and XXDR-TB was changed from 6.1% and 0% respectively to 10.6% and 5.6% during the same time period. During the same periods, the proportions of patients with ofloxacin, moxifloxacin and ethionamide resistance significantly increased from 57.6% to 75.3%, from 60.0% to 69.5% and from 24.2% to 52.5% respectively (p<0.05).

Discussion

The observed trends in TB drug-resistance patterns in Mumbai highlight the need for individualized drug regimens, designed on the basis of DST results involving first- and second-line anti-TB drugs and treatment history of the patient. A drug-resistant TB case-finding strategy based on molecular techniques that identify only rifampicin resistance will lead to initiation of suboptimal treatment regimens for a significant number of patients, which may in turn contribute to amplification of resistance and transmission of strains with increasingly advanced resistance within the community.