Sputum culture reversion in longer treatments with bedaquiline, delamanid, and repurposed drugs for drug-resistant tuberculosis.

Sputum culture reversion after conversion is an indicator of tuberculosis (TB) treatment failure. We analyze data from the endTB multi-country prospective observational cohort (NCT03259269) to estimate the frequency (primary endpoint) among individuals receiving a longer (18-to-20 month) regimen for multidrug- or rifampicin-resistant (MDR/RR) TB who experienced culture conversion. We also conduct Cox proportional hazard regression analyses to identify factors associated with reversion, including comorbidities, previous treatment, cavitary disease at conversion, low body mass index (BMI) at conversion, time to conversion, and number of likely-effective drugs. Of 1,286 patients, 54 (4.2%) experienced reversion, a median of 173 days (97-306) after conversion. Cavitary disease, BMI < 18.5, hepatitis C, prior treatment with second-line drugs, and longer time to initial culture conversion were positively associated with reversion. Reversion was uncommon. Those with cavitary disease, low BMI, hepatitis C, prior treatment with second-line drugs, and in whom culture conversion is delayed may benefit from close monitoring following conversion.

Determinants of multidrug-resistant tuberculosis among adults undergoing treatment for tuberculosis in Tigray Region, Ethiopia: a case-control study.

BACKGROUND: Multidrug-resistant tuberculosis is a type of tuberculosis that is resistant to at least the first-line antituberculosis drugs namely, rifampicin and isoniazid. However, most of these studies were limited only to a single hospital. Therefore, this study aimed to identify the determinants of multidrug-resistant tuberculosis among adults undergoing treatment for tuberculosis in the Tigray region of Ethiopia. METHODS: Hospital-based unmatched case-control study was conducted from 1 April 2019 to 30 June 2019. A simple random sampling method was used to select the required sample size. Variables at a p value less than 0.25 in bivariate analysis were entered into a multivariable analysis to identify the determinant factors of multidrug-resistant tuberculosis. Finally, the level of significance was declared at p<0.05. RESULTS: Rural residence (adjusted OR (AOR) 2.54; 95% CI 1.34 to 4.83), HIV (AOR 4.5; 95% CI 1.4 to 14.2), relapse (AOR 3.86; 95% CI 1.98 to 7.5), return after lost follow-up (AOR 6.29; 95% CI 1.64 to 24.2), treatment failure (AOR 5.87; 95% CI 1.39 to 24.8) were among the determinants of multidrug-resistant tuberculosis. CONCLUSION: Rural residence, HIV, relapses, return after lost follow-up and treatment failure were the identified determinant factors of multidrug-resistance tuberculosis.

Population structure and spatial distribution of Mycobacterium tuberculosis in Ethiopia.

Ethiopia is one of the countries with a high tuberculosis (TB) burden, yet little is known about the spatial distribution of Mycobacterium tuberculosis (Mtb) lineages. This study identifies the spoligotyping of 1735 archived Mtb isolates from the National Drug Resistance Survey, collected between November 2011 and June 2013, to investigate Mtb population structure and spatial distribution. Spoligotype International Types (SITs) and lineages were retrieved from online databases. The distribution of lineages was evaluated using Fisher's exact test and logistic regression models. The Global Moran's Index and Getis-Ord Gi statistic were utilized to identify hotspot areas. Our results showed that spoligotypes could be interpreted and led to 4 lineages and 283 spoligotype patterns in 91% of the isolates, including 4% of those with multidrug/rifampicin resistance (MDR/RR) TB. The identified Mtb lineages were lineage 1 (1.8%), lineage 3 (25.9%), lineage 4 (70.6%) and lineage 7 (1.6%). The proportion of lineages 3 and 4 varied by regions, with lineage 3 being significantly greater than lineage 4 in reports from Gambella (AOR = 4.37, P < 0.001) and Tigray (AOR = 3.44, P = 0.001) and lineage 4 being significantly higher in Southern Nations Nationalities and Peoples Region (AOR = 1.97, P = 0.026) than lineage 3. Hotspots for lineage 1 were located in eastern Ethiopia, while a lineage 7 hotspot was identified in northern and western Ethiopia. The five prevalent spoligotypes, which were SIT149, SIT53, SIT25, SIT37 and SIT26 account for 42.8% of all isolates under investigation, while SIT149, SIT53 and SIT21 account for 52-57.8% of drug-resistant TB cases. TB and drug resistant TB are mainly caused by lineages 3 and 4, and significant proportions of the prevalent spoligotypes also influence drug-resistant TB and the total TB burden. Regional variations in lineages may result from both local and cross-border spread.

Prevalence, drug resistance, and genotypic diversity of the RDRio subfamily of Mycobacterium tuberculosis in Ecuador: a retrospective analysis for years 2012-2016.

Introduction: A major sublineage within the Mycobacterium tuberculosis (MTB) LAM family characterized by a new in-frame fusion gene Rv3346c/55c was discovered in Rio de Janeiro (Brazil) in 2007, called RDRio, associated to drug resistance. The few studies about prevalence of MTB RDRio strains in Latin America reported values ranging from 3% in Chile to 69.8% in Venezuela, although no information is available for countries like Ecuador. Methods: A total of 814 MTB isolates from years 2012 to 2016 were screened by multiplex PCR for RDRio identification, followed by 24-loci MIRU-VNTR and spoligotyping. Results: A total number of 17 MTB RDRio strains were identified, representing an overall prevalence of 2.09% among MTB strains in Ecuador. While 10.9% of the MTB isolates included in the study were multidrug resistance (MDR), 29.4% (5/17) of the RDRio strains were MDR. Discussion: This is the first report of the prevalence of MTB RDRio in Ecuador, where a strong association with MDR was found, but also a very low prevalence compared to other countries in Latin America. It is important to improve molecular epidemiology tools as a part of MTB surveillance programs in Latin America to track the transmission of potentially dangerous MTB stains associated to MDR TB like MTB RDRio.

Drug-resistant Mycobacterium tuberculosis among Nepalese patients at a tuberculosis referral center.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB), characterized by isoniazid and rifampicin resistance, is caused by chromosomal mutations that restrict treatment options and complicate tuberculosis management. This study sought to investigate the prevalence of pre-extensively drug-resistant (pre-XDR) and extensively drug-resistant (XDR) tuberculosis, as well as mutation pattern, in Nepalese patients with MDR/rifampicin-resistant (RR)-TB strains. METHODS: A cross-sectional study was conducted on MDR/RR-TB patients at the German Nepal Tuberculosis Project from June 2017 to June 2018. The MTBDRsl line probe assay identified pre-XDR-TB and XDR-TB. Pre-XDR-TB included MDR/RR-TB with resistance to any fluoroquinolone (FLQ), while XDR-TB included MDR/RR-TB with resistance to any FLQ and at least one additional group A drug. Mutation status was determined by comparing bands on reaction zones [gyrA and gyrB for FLQ resistance, rrs for SILD resistance, and eis for low-level kanamycin resistance, according to the GenoType MTBDRsl VER 2.0, Hain Lifescience GmbH, Nehren, Germany definition of pre-XDR and XDR] to the evaluation sheet. SPSS version 17.0 was used for data analysis. RESULTS: Out of a total of 171 patients with MDR/RR-TB, 160 had (93.57%) had MTBC, of whom 57 (35.63%) had pre-XDR-TB and 10 (6.25%) had XDR-TB. Among the pre-XDR-TB strains, 56 (98.25%) were FLQ resistant, while 1 (1.75%) was SLID resistant. The most frequent mutations were found at codons MUT3C (57.14%, 32/56) and MUT1 (23.21%, 13/56) of the gyrA gene. One patient had SLID resistant genotype at the MUT1 codon of the rrs gene (100%, 1/1). XDR-TB mutation bands were mostly detected on MUT1 (30%, 3/10) of the gyrA and rrs, MUT3C (30%, 3/10) of the gyrA, and MUT1 (30%, 3/10) of the rrs. CONCLUSIONS: Pre-XDR-TB had a significantly higher likelihood than XDR-TB, with different specific mutation bands present in gyrA and rrs genes.

Effectiveness, cost, and safety of four regimens recommended by WHO for RR/MDR-TB treatment: a cohort study in Eastern China.

BACKGROUND: To compare the effectiveness, cost, and safety of four regimens recommended by the World Health Organization (WHO) for rifampicin resistance/multidrug-resistance tuberculosis (RR/MDR-TB) Treatment in Eastern China. METHODS: We performed a cohort study among patients with RR/MDR between 2020 and 2022 in Jiangsu Province. The treatment success rate, cost, and drug adverse reaction rate were compared. RESULTS: Between 2020 and 2022, 253 RR/MDR-TB patients were enrolled in the study. 37 (14.62%), 76 (30.04%), 74 (29.25%), and 66 (26.09%) patients had the short-term regimens, the new long-term oral regimens, the new long-term injectable regimens, and the traditional long-term regimens, respectively. The treatment success rate was the highest among patients treated with the short-term regimen (75.68%) and was the lowest among patients treated with the traditional long-term regimens (60.61%). The estimated mean cost per favorable outcome was 142.61 thousand Chinese Yuan (CNY), and the short-term regimens showed the lowest cost in the four regimes (88.51 thousand CNY vs. 174.24 thousand CNY, 144.00 thousand CNY, and 134.98 thousand CNY). Incremental cost-effectiveness ratios of the short-term regimens, the new long-term oral regimen, and the new long-term injectable regimens were -3083.04, 6040.09, and 819.68 CNY compared to the traditional long-term regimens. CONCLUSIONS: For RR/MDR-TB patients in China who meet the criteria for short-term regimens, the short-term regimens were proven to be the most cost-effective of the four regimens recommended by WHO. For RR/MDR-TB patients in China who don't meet the criteria for short-term regimens, the new long-term injectable regimens are more cost-effective than the remaining two regimens.

This is the first study to evaluate the effectiveness, cost, and safety of four regimens recommended by the WHO for RR/MDR-TB treatment in China.For RR/MDR-TB patients in China who meet the criteria for the short-term regimens, the short-term regimens were proven to be the most cost-effective of the four regimens recommended by WHO.

Prevalence and genetic basis of Mycobacterium tuberculosis resistance to pretomanid in China.

BACKGROUND: Pretomanid is a key component of new regimens for the treatment of drug-resistant tuberculosis (TB) which are being rolled out globally. However, there is limited information on the prevalence of pre-existing resistance to the drug. METHODS: To investigate pretomanid resistance rates in China and its underlying genetic basis, as well as to generate additional minimum inhibitory concentration (MIC) data for epidemiological cutoff (ECOFF)/breakpoint setting, we performed MIC determinations in the Mycobacterial Growth Indicator Tube™ (MGIT) system, followed by WGS analysis, on 475 Mycobacterium tuberculosis (MTB) isolated from Chinese TB patients between 2013 and 2020. RESULTS: We observed a pretomanid MIC distribution with a 99% ECOFF equal to 0.5 mg/L. Of the 15 isolates with MIC values > 0.5 mg/L, one (MIC = 1 mg/L) was identified as MTB lineage 1 (L1), a genotype previously reported to be intrinsically less susceptible to pretomanid, two were borderline resistant (MIC = 2-4 mg/L) and the remaining 12 isolates were highly resistant (MIC ≥ 16 mg/L) to the drug. Five resistant isolates did not harbor mutations in the known pretomanid resistant genes. CONCLUSIONS: Our results further support a breakpoint of 0.5 mg/L for a non-L1 MTB population, which is characteristic of China. Further, our data point to an unexpected high (14/475, 3%) pre-existing pretomanid resistance rate in the country, as well as to the existence of yet-to-be-discovered pretomanid resistance genes.

A systematic review of economic evaluations of pharmacological treatments for active tuberculosis.

Objectives: The continuing spread of tuberculosis (TB) worldwide, especially drug-resistant TB, poses a major challenge to healthcare systems globally. Addressing this requires appraising the cost effectiveness of existing pharmacological interventions against TB to identify key drivers of cost effectiveness and value and guide pharmaceutical innovation and novel drug regimen development. Methods: Studies were identified from a search of six database: MEDLINE MEDLINE-In Process, MEDLINE Epub Ahead of Print, EMBASE, Cochrane Database of Systematic Reviews, and Econlit in July 2022. Two reviewers independently assessed all identified studies and reports using pre-defined inclusion/exclusion criteria. Study methodological quality was assessed, data were extracted in standard tables, and results were narratively synthesized. Results: Overall, 991 studies and 53 HTA reports were identified with 20 studies and 3 HTA reports meeting the inclusion criteria. Quality assessment of the 20 studies identified 4 with minor limitations, while the remainder were assessed as having potentially or very serious limitations. Sixteen studies conducted cost-utility analyses, 6 conducted cost-effectiveness analyses, and 2 conducted cost-comparison analyses with some studies performing multiple analyses. The majority (n = 16) were model-based. Eleven studies analyzed the cost-effectiveness of bedaquiline, 6 compared shorter to longer/standard duration regimens, 2 assessed ethambutol, and 1 assessed delamanid. Key drivers of cost effectiveness were drug costs, the number of TB cases, the portion of cases with sputum culture conversion, treatment delivery costs, and treatment efficacy. Common value elements considered included adverse events, drug resistance, and improving treatment adherence. Conclusion: Our results suggest that out of the pharmacological treatments assessed, bedaquiline is likely a cost-effective addition to existing treatment regimens/background treatment regimens, while ethambutol is not likely to be. Newer shorter regimens, even if more costly, seem to be more cost-effective compared to longer regimens. These results illustrate the limited number of novel cost-effective pharmacological interventions and highlight a need to develop new drugs/regimens against TB to overcome resistance, taking into account the key drivers of cost effectiveness and other value attributes identified from this review.

Patterns and profiles of drug resistance-conferring mutations in Mycobacterium tuberculosis genotypes isolated from tuberculosis-suspected attendees of spiritual holy water sites in Northwest Ethiopia.

Purpose: This study examined the patterns and frequency of genetic changes responsible for resistance to first-line (rifampicin and isoniazid), fluoroquinolones, and second-line injectable drugs in drug-resistant Mycobacterium tuberculosis (MTB) isolated from culture-positive pulmonary tuberculosis (PTB) symptomatic attendees of spiritual holy water sites (HWSs) in the Amhara region. Patients and methods: From June 2019 to March 2020, a cross-sectional study was carried out. A total of 122 culture-positive MTB isolates from PTB-suspected attendees of HWSs in the Amhara region were evaluated for their drug resistance profiles, and characterized gene mutations conferring resistance to rifampicin (RIF), isoniazid (INH), fluoroquinolones (FLQs), and second-line injectable drugs (SLIDs) using GenoType®MTBDRplus VER2.0 and GenoType®MTBDRsl VER2.0. Drug-resistant MTB isolates were Spoligotyped following the manufacturer's protocol. Results: Genetic changes (mutations) responsible for resistance to RIF, INH, and FLQs were identified in 15/122 (12.3%), 20/122 (16.4%), and 5/20 (25%) of MTB isolates, respectively. In RIF-resistant, rpoB/Ser531Lue (n = 12, 80%) was most frequent followed by His526Tyr (6.7%). Amongst INH-resistant isolates, katG/Ser315Thr1 (n = 19, 95%) was the most frequent. Of 15 MDR-TB, the majority (n = 12, 80%) isolates had mutations at both rpoB/Ser531Leu and katG/Ser315Thr1. All 20 INH and/or RIF-resistant isolates were tested with the MTBDRsl VER 2.0, yielding 5 FLQs-resistant isolates with gene mutations at rpoB/Ser531Lue, katG/Ser315Thr1, and gyrA/Asp94Ala genes. Of 20 Spoligotyped drug-resistant MTB isolates, the majority (n = 11, 55%) and 6 (30%) were SIT149/T3-ETH and SIT21/CAS1-Kili sublineages, respectively; and they were any INH-resistant (mono-hetero/multi-). Of 15 RIF-resistant (RR/MDR-TB) isolates, 7 were SIT149/T3-ETH, while 6 were SIT21/CAS1-Kili sublineages. FLQ resistance was detected in four SIT21/CAS1-Kili lineages. Conclusion: In the current study, the most common gene mutations responsible for resistance to INH, RIF, and FLQs were identified. SIT149/T3-ETH and SIT21/CAS1-Kili constitute the majority of drug-resistant TB (DR-TB) isolates. To further understand the complete spectrum of genetic changes/mutations and related genotypes, a sequencing technology is warranted.

Transmission characteristics in Tuberculosis by WGS: nationwide cross-sectional surveillance in China.

China, with the third largest share of global tuberculosis cases, faces a substantial challenge in its healthcare system as a result of the high burden of multidrug-resistant and rifampicin-resistant tuberculosis (MDR/RR-TB). This study employs a genomic epidemiological approach to assess recent tuberculosis transmissions between individuals, identifying potential risk factors and discerning the role of transmitted resistant isolates in the emergence of drug-resistant tuberculosis in China. We conducted a population-based retrospective study on 5052 Mycobacterium tuberculosis (MTB) isolates from 70 surveillance sites using whole genome sequencing (WGS). Minimum spanning tree analysis identified resistance mutations, while epidemiological data analysis pinpointed transmission risk factors. Of the 5052 isolates, 23% (1160) formed 452 genomic clusters, with 85.6% (387) of the transmissions occurring within the same counties. Individuals with younger age, larger family size, new cases, smear positive, and MDR/RR were at higher odds for recent transmission, while higher education (university and above) and occupation as a non-physical workers emerged as protective factors. At least 61.4% (251/409) of MDR/RR-TB were likely a result of recent transmission of MDR/RR isolates, with previous treatment (crude OR = 2.77), smear-positive (cOR = 2.07) and larger family population (cOR = 1.13) established as risk factors. Our findings highlight that local transmission remains the predominant form of TB transmission in China. Correspondingly, drug-resistant tuberculosis is primarily driven by the transmission of resistant tuberculosis isolates. Targeted interventions for high-risk populations to interrupt transmission within the country will likely provide an opportunity to reduce the prevalence of both tuberculosis and drug-resistant tuberculosis.

Prevalence and risk factors of anxiety and depression in patients with multi-drug/rifampicin-resistant tuberculosis.

Background: Mental health disorders in patients with multi-drug or rifampicin-resistant tuberculosis (MDR/RR-TB) receive consistent attention. Anxiety and depression can manifest and may impact disease progression in patients with MDR/RR-TB. Given the heightened stressors resulting from the COVID-19 pandemic, this scenario is even more concerning. Objective: To evaluate the prevalence of and risk factors associated with anxiety and depression among patients with MDR/RR-TB in southern China. Methods: A facility-based cross-sectional study was undertaken at Guangzhou Chest Hospital in southern China, encompassing a cohort of 219 patients undergoing outpatient and inpatient treatment for MDR/RR-TB. Anxiety and depressive symptoms were assessed using the 7-Item Generalized Anxiety Disorder (GAD-7) scale and Patient Health Questionnaire-9 (PHQ-9). The ramifications of anxiety and depression were examined using univariate and multivariate logistic regression analyses, with odds ratios (ORs) and age- and sex-adjusted ORs (AORs) employed to quantify their influence. All data underwent statistical analysis using SPSS 25.0, with statistical significance established at P < 0.05. Results: Two hundred and nineteen individuals with MDR/RR-TB were included in the study. The prevalence of anxiety and depression was 57.53% (n = 126) and 65.75% (n = 144), respectively, with 33.3% (n = 73) of the participants experiencing both conditions simultaneously. Multivariate logistic regression analysis revealed that an age of 20-40 years [anxiety AOR = 3.021, 95% confidence interval (CI): 1.240-7.360; depression AOR = 3.538, 95% CI: 1.219-10.268], disease stigma (anxiety AOR = 10.613, 95% CI: 2.966-37.975; depression AOR = 4.514, 95% CI: 2.051-10.108) and poor physical health (anxiety AOR = 7.636, 95% CI: 2.938-19.844; depression AOR = 6.190, 95% CI: 2.468-15.529) were significant risk factors for moderate levels of anxiety and depression. Conclusions: We found that individuals with MDR/RR-TB had an elevated risk of anxiety and depression. To decrease the likelihood of unfavorable treatment outcomes, it is imperative to carefully monitor the psychological wellbeing of patients with MDR/RR-TB and promptly address any detrimental psychiatric conditions.

Trends and risk factors for drug-resistant tuberculosis among children in Sichuan, China: A 10-year retrospective analysis, 2013-2022.

To investigate the status of the drug-resistant tuberculosis (DR-TB) among children in Sichuan, and to find out the risk factors and high-risk population related to drug resistance among children. The clinical data of tuberculosis patients ≤14 years old with culture-confirmed tuberculosis hospitalized in Chengdu Public Health Clinical Center from January 2013 through December 2022 were collected. Clinical data such as gender, age, ethnicity, history of anti-TB treatment, history of exposure to tuberculosis, nutritional status, and specific drug resistance of the children were collected and recorded. The drug resistance of children in different age groups (0-4 years old, 5-9 years old, 10-14 years old) and different periods (2013-2017 and 2018-2022) were grouped and compared. Logistic regression analysis was to analyze analysis of risk factors of drug resistance in children. A total of 438 children with culture-confirmed tuberculosis were screened. Among them, 26.19% (11/42) were 0 to 4 years old, 33.33% (22/66) were 5 to 9 years old, and 36.67% (121/330) were 10 to 14 years old among the resistant children. There was no statistically significant difference in the resistance rate among the 3 groups (P = .385). The proportions of DR-TB, monoresistant tuberculosis, polydrug-resistant tuberculosis were decreased during 2019 to 2022 compared with 2013 to 2017 (P < .0001). The resistance rates of drug resistant, monoresistant, polydrug-resistant, isoniazid-resistant, and rifampicin resistant during 2018 to 2022 were decreased compared with those from 2013 to 2017 (P < .05), but the multi-drug resistance rate was not decreased (P = .131, without statistical difference). The results of logistic regression analysis showed that male gender OR = 1.566 (95% CI 1.035-2.369), a history of antituberculosis therapy OR = 4.049 (95% CI 1.442-11.367), and pulmonary and extrapulmonary tuberculosis OR = 7.335 (95% CI 1.401-38.392) were risk factors for the development of drug resistance; but fever OR = 0.581 (95% CI 0.355-0.950) was Protective factor. The total drug resistance rate of children in Sichuan showed a downward trend, but the rate of multi-drug-resistant tuberculosis was still at a high level, and the form of drug resistance was still severe. Absence of fever, male, retreatment, and pulmonary concurrent with extrapulmonary tuberculosis are risk factors for DR-TB in children.

A robust computational quest: Discovering potential hits to improve the treatment of pyrazinamide-resistant Mycobacterium tuberculosis.

The rise of pyrazinamide (PZA)-resistant strains of Mycobacterium tuberculosis (MTB) poses a major challenge to conventional tuberculosis (TB) treatments. PZA, a cornerstone of TB therapy, must be activated by the mycobacterial enzyme pyrazinamidase (PZase) to convert its active form, pyrazinoic acid, which targets the ribosomal protein S1. Resistance, often associated with mutations in the RpsA protein, complicates treatment and highlights a critical gap in the understanding of structural dynamics and mechanisms of resistance, particularly in the context of the G97D mutation. This study utilizes a novel integration of computational techniques, including multiscale biomolecular and molecular dynamics simulations, physicochemical and medicinal chemistry predictions, quantum computations and virtual screening from the ZINC and Chembridge databases, to elucidate the resistance mechanism and identify lead compounds that have the potential to improve treatment outcomes for PZA-resistant MTB, namely ZINC15913786, ZINC20735155, Chem10269711, Chem10279789 and Chem10295790. These computational methods offer a cost-effective, rapid alternative to traditional drug trials by bypassing the need for organic subjects while providing highly accurate insight into the binding sites and efficacy of new drug candidates. The need for rapid and appropriate drug development emphasizes the need for robust computational analysis to justify further validation through in vitro and in vivo experiments.

Synchronization of Mycobacterium life cycle: A possible novel mechanism of antimycobacterial drug resistance evolution and its manipulation.

Mycobacterium Tuberculosis (Mtb) causing Tuberculosis (TB) is a widespread disease infecting millions of people worldwide. Additionally, emergence of drug resistant tuberculosis is a major challenge and concern in high TB burden countries. Most of the drug resistance in mycobacteria is attributed to developing acquired resistance due to spontaneous mutations or intrinsic resistance mechanisms. In this review, we emphasize on the role of bacterial cell cycle synchronization as one of the intrinsic mechanisms used by the bacteria to cope with stress response and perhaps involved in evolution of its drug resistance. The importance of cell cycle synchronization and its function in drug resistance in cancer cells, malarial and viral pathogens is well understood, but its role in bacterial pathogens has yet to be established. From the extensive literature survey, we could collect information regarding how mycobacteria use synchronization to overcome the stress response. Additionally, it has been observed that most of the microbial pathogens including mycobacteria are responsive to drugs predominantly in their logarithmic phase, while they show resistance to antibiotics when they are in the lag or stationary phase. Therefore, we speculate that Mtb might use this novel strategy wherein they regulate their cell cycle upon antibiotic pressure such that they either enter in their low metabolic phase i.e., either the lag or stationary phase to overcome the antibiotic pressure and function as persister cells. Thus, we propose that manipulating the mycobacterial drug resistance could be possible by fine-tuning its cell cycle.

The importance of heteroresistance and efflux pumps in bedaquiline-resistant Mycobacterium tuberculosis isolates from Iran.

BACKGROUND: Tuberculosis (TB) continues to pose a threat to communities worldwide and remains a significant public health issue in several countries. We assessed the role of heteroresistance and efflux pumps in bedaquiline (BDQ)-resistant Mycobacterium tuberculosis isolates. METHODS: Nineteen clinical isolates were included in the study, of which fifteen isolates were classified as MDR or XDR, while four isolates were fully susceptible. To evaluate BDQ heteroresistance, the Microplate Alamar Blue Assay (MABA) method was employed. For screening mixed infections, MIRU-VNTR was performed on clinical isolates. Mutations in the atpE and Rv0678 genes were determined based on next-generation sequencing data. Additionally, real-time PCR was applied to assess the expression of efflux pump genes in the absence and presence of verapamil (VP). RESULTS: All 15 drug-resistant isolates displayed resistance to BDQ. Among the 19 total isolates, 21.05% (4/19) exhibited a heteroresistance pattern to BDQ. None of the isolates carried a mutation of the atpE and Rv0678 genes associated with BDQ resistance. Regarding the MIRU-VNTR analysis, most isolates (94.73%) showed the Beijing genotype. Fifteen (78.9%) isolates showed a significant reduction in BDQ MIC after VP treatment. The efflux pump genes of Rv0676c, Rv1258c, Rv1410c, Rv1634, Rv1819, Rv2459, Rv2846, and Rv3065 were overexpressed in the presence of BDQ. CONCLUSIONS: Our results clearly demonstrated the crucial role of heteroresistance and efflux pumps in BDQ resistance. Additionally, we established a direct link between the Rv0676c gene and BDQ resistance. The inclusion of VP significantly reduced the MIC of BDQ in both drug-susceptible and drug-resistant clinical isolates.

GenoMycAnalyzer: a web-based tool for species and drug resistance prediction for Mycobacterium genomes.

BACKGROUND: Drug-resistant tuberculosis (TB) is a major threat to global public health. Whole-genome sequencing (WGS) is a useful tool for species identification and drug resistance prediction, and many clinical laboratories are transitioning to WGS as a routine diagnostic tool. However, user-friendly and high-confidence automated bioinformatics tools are needed to rapidly identify M. tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM), detect drug resistance, and further guide treatment options. RESULTS: We developed GenoMycAnalyzer, a web-based software that integrates functions for identifying MTBC and NTM species, lineage and spoligotype prediction, variant calling, annotation, drug-resistance determination, and data visualization. The accuracy of GenoMycAnalyzer for genotypic drug susceptibility testing (gDST) was evaluated using 5,473 MTBC isolates that underwent phenotypic DST (pDST). The GenoMycAnalyzer database was built to predict the gDST for 15 antituberculosis drugs using the World Health Organization mutational catalogue. Compared to pDST, the sensitivity of drug susceptibilities by the GenoMycAnalyzer for first-line drugs ranged from 95.9% for rifampicin (95% CI 94.8-96.7%) to 79.6% for pyrazinamide (95% CI 76.9-82.2%), whereas those for second-line drugs ranged from 98.2% for levofloxacin (95% CI 90.1-100.0%) to 74.9% for capreomycin (95% CI 69.3-80.0%). Notably, the integration of large deletions of the four resistance-conferring genes increased gDST sensitivity. The specificity of drug susceptibilities by the GenoMycAnalyzer ranged from 98.7% for amikacin (95% CI 97.8-99.3%) to 79.5% for ethionamide (95% CI 76.4-82.3%). The incorporated Kraken2 software identified 1,284 mycobacterial species with an accuracy of 98.8%. GenoMycAnalyzer also perfectly predicted lineages for 1,935 MTBC and spoligotypes for 54 MTBC. CONCLUSIONS: GenoMycAnalyzer offers both web-based and graphical user interfaces, which can help biologists with limited access to high-performance computing systems or limited bioinformatics skills. By streamlining the interpretation of WGS data, the GenoMycAnalyzer has the potential to significantly impact TB management and contribute to global efforts to combat this infectious disease. GenoMycAnalyzer is available at http://www.mycochase.org .

Cost-consequence analysis of ambulatory clinic- and home-based multidrug-resistant tuberculosis management models in Eswatini.

BACKGROUND: We compared the cost-consequence of a home-based multidrug-resistant tuberculosis (MDR-TB) model of care, based on task-shifting of directly observed therapy (DOT) and MDR-TB injection administration to lay health workers, to a routine clinic-based strategy within an established national TB programme in Eswatini. METHODS: Data on costs and effects of the two ambulatory models of MDR-TB care was collected using documentary data and interviews in the Lubombo and Shiselweni regions of Eswatini. Health system, patient and caregiver costs were assessed in 2014 in US$ using standard methods. Cost-consequence was calculated as the cost per patient successfully treated. RESULTS: In the clinic-based and home-based models of care, respectively, a total of 96 and 106 MDR-TB patients were enrolled in 2014, with treatment success rates of 67.8% and 82.1%. Health system costs per patient treated were slightly lower in the home-based strategy (US$19 598) compared to the clinic-based model (US$20 007). The largest costs in both models were for inpatient care, administration of DOT and injectable treatment, and drugs. Costs incurred by patients and caregivers were considerably higher in the clinic-based model of care due to the higher direct travel costs to the nearest clinic to receive DOT and injections daily. In total, MDR patients in the clinic-based strategy incurred average costs of US$670 compared to US$275 for MDR-TB patients in the home-based model. MDR-TB patients in the home-based programme, where DOT and injections was provided in their homes, only incurred out-of-pocket travel expenses for monthly outpatient treatment monitoring visits averaging US$100. The cost per successfully treated patient was US$31 106 and US$24 157 in the clinic-based and home-based models of care, respectively. The analysis showed that, in addition to the health benefits, direct and indirect costs for patients and their caregivers were lower in the home-based care model. CONCLUSION: The home-based strategy used less resources and generated substantial health and economic benefits, particularly for patients and their caregivers, and decision makers can consider this approach as an alternative to expand and optimise MDR-TB control in resource-limited settings. Further research to understand the appropriate mix of treatment support components that are most important for optimal clinical and public health outcomes in the ambulatory home-based model of MDR-TB care is necessary.

The clinical profile and outcomes of drug resistant tuberculosis in Central Province of Zambia.

BACKGROUND: The emergence of Drug Resistant Tuberculosis (DR-TB) is one of the main public health and economic problems facing the world today. DR-TB affects mostly those in economically productive years and prevents them from being part of the workforce needed for economic growth. The aim of this study was to determine the Clinical Profile and Outcomes of DR-TB in Central Province of Zambia. METHODS: This was a retrospective cross sectional study that involved a review of records of patients with confirmed DR-TB who were managed at Kabwe Central Hospital's Multi-Drug Resistant TB (MDR-TB) Ward from the year 2017 to 2021. 183 patients were managed during this period and all were recruited in the study. Data was collected from DR-TB registers and patient files and then entered in SPSS version 22 where all statistical analyses were performed. RESULTS: The study revealed that the prevalence of DR-TB among registered TB patients in Central Province was 1.4%. Majority of those affected were adults between the ages of 26 and 45 years (63.9%). The study also found that more than half of the patients were from Kabwe District (60.7%). Other districts with significant number of cases included Kapiri Mposhi 19 (10.4%), Chibombo 12 (6.6%), Chisamba 10 (5.5%), Mumbwa 7 (3.8%) and Mkushi 7 (3.8%). Furthermore, the analysis established that most of the patients had RR-TB (89.6%). 9.3% had MDR-TB, 0.5% had IR-TB and 0.5% had XDR-TB. RR-TB was present in 93.8% of new cases and 88.9% of relapse cases. MDR-TB was present in 6.2% of new cases and 10% of relapse cases. With regard to outcomes of DR-TB, the investigation revealed that 16.9% of the patients had been declared cured, 45.9% had completed treatment, 6% were lost to follow up and 21.3% had died. Risk factors for mortality on multivariate analysis included age 36-45 years (adjusted odds ratio [aOR] 0.253, 95% CI [0.70-0.908] p = 0.035) and male gender (aOR 0.261, 95% CI [0.107-0.638] p = 0.003). CONCLUSION: The research has shown beyond doubt that the burden of DR-TB in Central Province is high. The study recommends putting measures in place that will help improve surveillance, early detection, early initiation of treatment and proper follow up of patients.