Low body mass index as a predictor of sputum culture conversion and treatment outcomes among patients receiving treatment for multidrug-resistant tuberculosis in Lesotho

BACKGROUND

A low body mass index (BMI) at the start of treatment for rifampicin- or multidrug-resistant tuberculosis (MDR/RR-TB) is associated with poor treatment outcomes and may contribute to delayed sputum culture conversion, thereby prolonging the period of potential transmission to others. Whether the relative importance of low BMI in predicting treatment outcomes differs by HIV status is unclear.

OBJECTIVES

We evaluated the association between low BMI and two dependent variables, sputum culture conversion and end-of-treatment outcome, among patients receiving treatment for MDR/RR-TB in Lesotho, a setting with a high prevalence of HIV infection.

METHODS

Secondary data from a prospective cohort of patients initiating a longer (18-20 months) treatment containing bedaquiline and/or delamanid under routine programmatic conditions in Lesotho were analysed. Risk ratios and differences were adjusted for potential confounders using multivariable logistic regression, and estimates were stratified by HIV status.

RESULTS

Of 264 patients, 105 and 250 were eligible for culture conversion and end-of-treatment analyses, respectively. Seventy-one per cent of patients (74/105) experienced culture conversion within six months, while 74% (184/250) experienced a favourable end-of-treatment outcome. Low BMI was associated with a lower frequency of culture conversion at six months among those who were not living with HIV (relative risk [RR]: 0.50 [95% CI: 0.21, 0.79]); this association was attenuated among those living with HIV (RR: 0.88 [95% CI: 0.68, 1.23]). A low BMI was moderately associated with a lower frequency of treatment success (RR = 0.89 [95% CI: 0.77, 1.03]), regardless of HIV status.

CONCLUSIONS

Low BMI was common and associated with the frequency of six-month culture conversion and end-of-treatment outcomes. The association with culture conversion was more pronounced among those not living with HIV. Addressing the myriad factors that drive low BMI in this setting could hasten culture conversion and improve end-of-treatment outcomes. This will require a multipronged approach focused on alleviating food insecurity and enabling prompt diagnosis and treatment of HIV and TB.

Genomic analysis of lineage-specific transmission of multidrug resistance tuberculosis in China

OBJECTIVES

We investigated the genetic diversities and lineage-specific transmission dynamics of multidrug-resistant tuberculosis (MDR-TB), with the goal of determining the potential factors driving the MDR epidemics in China.

METHODS

We curated a large nationwide Mycobacterium tuberculosis (M. tuberculosis) whole genome sequence data set, including 1313 MDR strains. We reconstructed the phylogeny and mapped the transmission networks of MDR-TB across China using Bayesian inference. To identify drug-resistance variants linked to enhanced transmissibility, we employed ordinary least-squares (OLS) regression analysis.

RESULT

The majority of MDR-TB strains in China belong to lineage 2.2.1. Transmission chain analysis has indicated that the repeated and frequent transmission of L2.2.1 plays a central role in the establishment of MDR epidemic in China, but no occurrence of a large predominant MDR outbreak was detected. Using OLS regression, the most common single nucleotide polymorphisms (SNPs) associated with resistance to isoniazid (katG_p.Ser315Thr and katG_p.Ser315Asn) and rifampicin (rpoB_p.Ser450Leu, rpoB_p.His445Tyr, rpoB_p.His445Arg, rpoB_p.His445Asp, and rpoB_p.His445Asn) were more likely to be found in L2 clustered strains. Several putative compensatory mutations in rpoA, rpoC, and katG were significantly associated with clustering. The eastern, central, and southern regions of China had a high level of connectivity for the migration of L2 MDR strains throughout the country. The skyline plot showed distinct population size expansion dynamics for MDR-TB lineages in China.

CONCLUSION

MDR-TB epidemic in China is predominantly driven by the spread of highly transmissible Beijing strains. A range of drug-resistance mutations of L2 MDR-TB strains displayed minimal fitness costs and may facilitate their transmission.

Transmission of fluoroquinolones resistance among multidrug-resistant tuberculosis in Shanghai, China: a retrospective population-based genomic epidemiology study

Fluoroquinolones (FQ) are essential for the treatment of multidrug-resistant tuberculosis (MDR-TB). The FQ resistance (FQ-R) rate in MDR-TB in China and its risk factors remain poorly understood. We conducted a retrospective, population-based genomic epidemiology study of MDR-TB patients in Shanghai, China, from 2009 to 2018. A genomic cluster was defined as strains with genetic distances ≤ 12 single nucleotide polymorphisms. The transmitted FQ-R was defined as the same FQ resistance-conferring mutations shared by ≥ 2 strains in a genomic cluster. We used multivariable logistic regression analysis to identify the risk factors for drug resistance. Among the total 850 MDR-TB patients included in the study, 72.8% (619/850) were male, the median age was 39 (interquartile range 28, 55) years, 52.7% (448/850) were migrants, and 34.5% (293/850) were previously treated patients. Most of the MDR-TB strains belong to the Beijing lineage (91.7%, 779/850). Overall, the genotypic resistance rate of FQ was 34.7% (295/850), and 47.1% (139/295) FQ-R patients were in genomic clusters, of which 98 (33.2%, 98/295) were presumed as transmitted FQ-R. Patients with treatment-naïve (aOR = 1.84; 95% CI: 1.09, 3.16), diagnosed in a district-level hospital (aOR = 2.69; 95% CI: 1.56, 4.75), and streptomycin resistance (aOR = 3.69; 95% CI: 1.65, 9.42) were significantly associated with the transmission of FQ-R. In summary, the prevalence of FQ-R among MDR-TB patients was high in Shanghai, and at least one-third were transmitted. Enforced interventions including surveillance of FQ drug susceptibility testing and screening among MDR-TB before initiation of treatment were urgently needed.

Genetic factors associated with acquired phenotypic drug resistance and its compensatory evolution during tuberculosis treatment

OBJECTIVES

We elucidated the factors, evolution, and compensation of antimicrobial resistance (AMR) in Mycobacterium tuberculosis (MTB) isolates under dual pressure from the intra-host environment and anti-tuberculosis (anti-TB) drugs.

METHODS

This retrospective case-control study included 337 patients with pulmonary tuberculosis from 15 clinics in Tianjin, China, with phenotypic drug susceptibility testing results available for at least two time points between January 1, 2009 and December 31, 2016. Patients in the case group exhibited acquired AMR to isoniazid (INH) or rifampicin (RIF), while those in the control group lacked acquired AMR. The whole-genome sequencing (WGS) was conducted on 149 serial longitudinal MTB isolates from 46 patients who acquired or reversed phenotypic INH/RIF-resistance during treatment. The genetic basis, associated factors, and intra-host evolution of acquired phenotypic INH/RIF-resistance were elucidated using a combined analysis.

RESULTS

Anti-TB interruption duration of ≥30 days showed association with acquired phenotypic INH/RIF resistance (aOR = 2·2, 95% CI, 1·0-5·1) and new rpoB mutations (p = 0·024). The MTB evolution was 1·2 (95% CI, 1·02-1·38) single nucleotide polymorphisms per genome per year under dual pressure from the intra-host environment and anti-TB drugs. AMR-associated mutations occurred before phenotypic AMR appearance in cases with acquired phenotypic INH (10 of 16) and RIF (9 of 22) resistances.

DISCUSSION

Compensatory evolution may promote the fixation of INH/RIF-resistance mutations and affect phenotypic AMR. The TB treatment should be adjusted based on gene sequencing results, especially in persistent culture positivity during treatment, which highlights the clinical importance of WGS in identifying reinfection and AMR acquisition before phenotypic drug susceptibility testing.

SUBFOVEAL CHOROIDAL TUBERCULOMA IN A HEALTHY YOUNG WOMAN CAUSED BY MYCOBACTERIUM BOVIS

PURPOSE

To describe a case of a macular tuberculoma in a young and healthy woman after developing a tuberculous lymphadenitis caused by Mycobacterium bovis .

METHODS

Retrospective case report.

RESULTS

Tuberculous lymphadenitis caused by M. bovis was detected after biopsy and histological examination as well as polymerase chain reaction test testing of cervical lymph nodes in a 20-year-old patient. An interferon gamma was positive. Shortly starting antitubercular therapy, the patient developed visual deterioration caused by a single yellowish subretinal structure in the macula of the right eye. Optical coherence tomography showed a dome-shaped, hyperreflective, subfoveal choroidal lesion with subtle subretinal fluid. Antitubercular therapy with isoniazid, rifampicin, ethambutol, and pyrazinamide was performed, and the deescalation therapy with isoniazid and rifampicin was extended to 7 months. Further examinations showed regression of choroidal tuberculoma to a scar.

CONCLUSION

This is the first reported case of choroidal tuberculoma after tuberculous lymphadenitis caused by M. bovis .

Unlocking InhA: Novel approaches to inhibit Mycobacterium tuberculosis

Multidrug-resistant tuberculosis continues to pose a health security risk and remains a public health emergency. Antimicrobial resistance result from treatment regimens that are both insufficient and incomplete leading to the emergence of multidrug-resistant tuberculosis, extensively drug-resistant tuberculosis and totally drug-resistant tuberculosis. The impact of tuberculosis on the people suffering from HIV (Human immunodeficiency virus infection) have resulted in the increased research efforts in designing and discovery of novel antitubercular drugs that may result in decreasing treatment duration, minimising the need for multiple drug intake, minimising cytotoxicity and enhancing the mechanism of action of drug. While many drugs are available to treat tuberculosis, a precise and timely cure is still absent. Consequently, further investigation is needed to identify more recent molecular equivalents that have the potential to swiftly remove this disease. Isoniazid (INH), a treatment for tuberculosis (TB), targets the enzyme InhA (mycobacterium enoyl acyl carrier protein reductase), the Mycobacterium tuberculosis enoyl-acyl carrier protein (ACP) reductase, most common INH resistance is circumvented by InhA inhibitors that do not require KatG (catalase-peroxidase) activation, as a result, researchers are trying to work in the area of development of InhA inhibitors which could help in eradicating the era of tuberculosis from the world.

Multidrug-resistant tuberculosis: latest opinions on epidemiology, rapid diagnosis and management

PURPOSE OF REVIEW

This review addresses the escalating global challenge of multidrug-resistant tuberculosis (MDR-TB) in Sub-Saharan Africa, with a focus on its complex comorbidity with HIV/AIDS. Emphasizing the urgency of the issue, the review aims to shed light on the unique healthcare landscape shaped by the convergence of high prevalence rates and intersecting complexities with HIV/AIDS in the region.

RECENT FINDINGS

A notable increase in MDR-TB cases across Sub-Saharan Africa is attributed to challenges in timely diagnoses, treatment initiation, and patient treatment defaulting. The literature underscores the critical need for proactive measures to address diagnostic and treatment gaps associated with MDR-TB, particularly concerning its comorbidity with HIV/AIDS.

SUMMARY

To effectively manage MDR-TB and its co-morbidity with HIV/AIDS, proactive screening programs are imperative. The review highlights the necessity of active follow-up strategies to ensure treatment adherence and reduce default rates, offering evidence-based insights for improved disease management in the region.

Transmission of drug-resistant Mycobacterium tuberculosis isolates between Finnish- and foreign-born cases, 2014-2021: A molecular epidemiological study

BACKGROUND

Data on the molecular epidemiology and transmission of drug-resistant Mycobacterium tuberculosis (MTB) in low-incidence settings with immigration from high-incidence settings is limited.

METHOD

We included 115 drug-resistant (DR) MTB isolates with whole-genome sequencing data isolated in Finland between 2014 and 2021. Potential transmission clusters were identified using a threshold of 12 single-nucleotide polymorphisms (SNPs). Highly related clusters were identified using a threshold of 5 SNPs.

RESULT

Of the 115 DR MTB isolates, 31 (27.0%) isolates were from Finnish-born cases and 84 (73.0%) were from foreign-born cases. The proportion of multidrug-resistant (MDR) MTB isolates (30/84, 35.7%) from foreign-born cases was higher than that of MDR MTB isolates from Finnish-born cases (8/31, 25.8%). Lineage 2 (40/115, 34.8%) and lineage 4 (40/115, 34.8%) were the most prevalent lineages. A total of 25 (21.7%) isolates were classified into eight potential transmission clusters (≤12 SNPs). Furthermore, five highly related clusters (≤5 SNPs) were identified, including three DR MTB isolates from Finnish-born cases and 14 DR isolates from foreign-born cases.

CONCLUSION

The risk of DR MTB transmission between Finnish- and foreign-born persons is not negligible. Further research on clustering analysis in drug-susceptible MTB is worth to inform tuberculosis management and control in low-incidence settings with increasing immigration.

Tuberculosis treatment during the COVID-19 pandemic: actions offered and case profile

OBJECTIVE

To analyze the association between the provision of tuberculosis treatment actions and the sociodemographic and clinical characteristics of cases during the COVID-19 pandemic.

METHOD

Cross-sectional study conducted with data from secondary sources of 134 tuberculosis cases that underwent treatment in 2020 in the city of Pelotas, RS, Brazil. Data were analyzed using descriptive statistics, Chi-square test, and Fisher's exact test.

RESULTS

The least frequently offered actions in the period were: three or more control smear microscopies (12.7%), smear microscopy at the end of treatment (16.7%), chest X-ray at sixth month (48.5%) and sputum culture (49%). The number of medical and nursing consultations did not reach six in 52.9% and 83.3% of cases, respectively. The lower offer of treatment actions was associated with: retreatment (p<0.001); comorbidities (p=0.023); HIV infection (p<0.001); mental disorder (p=0.013); illicit substance use (p=0.018); normal chest X-ray (p=0.024); and special treatment regimen (p=0.009).

CONCLUSION

After the COVID-19 pandemic, it is essential to invest in cases follow-up, especially those undergoing retreatment, with comorbidities, drug use, normal chest X-ray results, and special treatment regimens.

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 .

[Application and optimization of CRISPRi to the biology of Mycobacterium tuberculosis]

Tuberculosis, caused by infection with Mycobacterium tuberculosis (MTB), remains a global public health challenge. Multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) strains make tuberculosis more difficult to control. New tools to study the biology of MTB can identify novel targets for drug discovery. Recently, the Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi) combined with next-generation sequencing has provided many novel insights into the physiology and genetics of MTB. This review summarizes the application and optimization of CRISPRi in MTB biology.

[Annual progress of immunotherapy for tuberculosis in 2023]

As a chronic infectious disease, tuberculosis (TB) is closely related to immune regulation and immune effect. Immunotherapy which can improve the curative effect of tuberculosis and control the spread of tuberculosis, is one of the important means for the comprehensive treatment of tuberculosis. From October 2022 to September 2023, research on the immunotherapy of tuberculosis at home and abroad continues to increase, providing new opportunities for the treatment of multidrug-resistant and extensively drug-resistant tuberculosis. Host-targeted therapy and therapeutic vaccines are new directions for research into TB adjuvant therapy.

Impact of Prior Tuberculosis Treatment With New/Companion Drugs on Clinical Outcomes in Patients Receiving Concomitant Bedaquiline and Delamanid for Multidrug- and Rifampicin-Resistant Tuberculosis

BACKGROUND

There are scarce data on the clinical outcomes of persons retreated with new/companion anti-tuberculosis (TB) drugs for multidrug- and rifampicin-resistant tuberculosis (MDR/RR-TB). We sought to evaluate the efficacy and safety of bedaquiline and delamanid containing regimens among patients with and without prior exposure to the new/companion drugs (bedaquiline, delamanid, linezolid, clofazimine, and fluoroquinolones).

METHODS

We conducted a retrospective cohort study among patients with pulmonary MDR/RR-TB in Georgia who received bedaquiline and delamanid combination as a part of a salvage regimen from November 2017 to December 2020 in a programmatic setting.

RESULTS

Among 106 persons with a median age of 39.5 years, 44 (41.5%) were previously treated with new/companion TB drugs. Patients with prior exposure to new/companion drugs had higher rates of baseline resistance compared to those without exposure to new/companion TB drugs (bedaquiline 15.2% vs 1.8%, linezolid 22.2% vs 16.7%). Sputum culture conversion rates among patients exposed and not exposed to new/companion drugs were 65.9% vs 98.0%, respectively (P < .001). Among patients with and without prior new/companion TB drug use, favorable outcome rates were 41.0% and 82.3%, respectively (P < .001). Treatment adherence in 32 (30.2%) patients was ≤80%. Five of 21 patients (23.8%) who had a baseline and repeat susceptibility test had acquired bedaquiline resistance. QTC/F prolongation (>500 ms) was rare (2.8%).

CONCLUSIONS

Prior exposure to new/companion TB drugs was associated with poor clinical outcomes and acquired drug resistance. Tailoring the TB regimen to each patient's drug susceptibility test results and burden of disease and enhancing adherence support may improve outcomes.

Application of the Hollow-Fiber Infection Model to Personalized Precision Dosing of Isoniazid in a Clinical Setting

BACKGROUND

The hollow-fiber infection model (HFIM) is a valuable tool for evaluating pharmacokinetics/pharmacodynamics relationships and determining the optimal antibiotic dose in monotherapy or combination therapy, but the application for personalized precision medicine in tuberculosis treatment remains limited. This study aimed to evaluate the efficacy of adjusted antibiotic doses for a tuberculosis patient using HFIM.

METHODS

Model-based Bayesian forecasting was utilized to assess the proposed reduction of the isoniazid dose from 300 mg daily to 150 mg daily in a patient with an ultra-slow-acetylation phenotype. The efficacy of the adjusted 150-mg dose was evaluated in a time-to-kill assay performed using the bacterial isolate Mycobacterium tuberculosis (Mtb) H37Ra in a HFIM that mimicked the individual pharmacokinetic profile of the patient.

RESULTS

The isoniazid concentration observed in the HFIM adequately reflected the target drug exposures simulated by the model. After 7 days of repeated dose administration, isoniazid killed 4 log10 Mtb CFU/mL in the treatment arm, while the control arm without isoniazid increased 1.6 log10 CFU/mL.

CONCLUSION

Our results provide an example of the utility of the HFIM for predicting the efficacy of specific recommended doses of anti-tuberculosis drugs in real clinical setting.

Development of a multiplex droplet digital PCR method for detection and monitoring of Mycobacterium tuberculosis and drug-resistant tuberculosis

BACKGROUND

The prevalence of multidrug-resistant tuberculosis (MDR-TB) among Korean tuberculosis patients is about 4.1%, which is higher than the OECD average of 2.6%. Inadequate drug use and poor patient compliance increase MDR-TB prevalence through selective pressure. Therefore, prompt detection of drug resistance in tuberculosis patients at the time of diagnosis and quantitative monitoring of these resistant strains during treatment are crucial.

METHODS

A multiplex droplet digital PCR (ddPCR) assay was developed and assessed using DNA material of nine Mycobacterium tuberculosis strains with known mutation status that were purchased from the Korean National Tuberculosis Association. We collected a total of 18 MDR-TB residual samples referred for PCR analysis. Total DNA was extracted from the samples and subjected to the quadruplex ddPCR assay. Their results were compared to those of known resistance phenotypes.

RESULTS

The analytical sensitivity and specificity of the multiplex ddPCR assay for detecting INH, RIF, EMB, FQ, and SM resistance-causing mutations ranged from 71.43 to 100% and 94.12-100%, respectively. Follow-up sample results showed that the quadruplex ddPCR assay was sensitive enough to detect IS6110 and other mutations even after onset of treatment.

CONCLUSIONS

We developed a sensitive and accurate multiplex ddPCR assay that can detect the presence of tuberculosis quantitatively and resistance-conveying mutations concurrently. This tool could aid clinicians in the diagnosis and treatment monitoring of tuberculosis.

The recent rapid expansion of multidrug resistant Ural lineage Mycobacterium tuberculosis in Moldova

The projected trajectory of multidrug resistant tuberculosis (MDR-TB) epidemics depends on the reproductive fitness of circulating strains of MDR M. tuberculosis (Mtb). Previous efforts to characterize the fitness of MDR Mtb have found that Mtb strains of the Beijing sublineage (Lineage 2.2.1) may be more prone to develop resistance and retain fitness in the presence of resistance-conferring mutations than other lineages. Using Mtb genome sequences from all culture-positive cases collected over two years in Moldova, we estimate the fitness of Ural (Lineage 4.2) and Beijing strains, the two lineages in which MDR is concentrated in the country. We estimate that the fitness of MDR Ural strains substantially exceeds that of other susceptible and MDR strains, and we identify several mutations specific to these MDR Ural strains. Our findings suggest that MDR Ural Mtb has been transmitting efficiently in Moldova and poses a substantial risk of spreading further in the region.

Novel strategies based on natural products and synthetic derivatives to overcome resistance in Mycobacterium tuberculosis

One of the biggest health challenges of today's world is the emergence of antimicrobial resistance (AMR), which renders conventional therapeutics insufficient and urgently demands the generation of novel antimicrobial strategies. Mycobacterium tuberculosis (M. tuberculosis), the pathogen causing tuberculosis (TB), is among the most successful bacteria producing drug-resistant infections. The versatility of M. tuberculosis allows it to evade traditional anti-TB agents through various acquired and intrinsic mechanisms, rendering TB among the leading causes of infectious disease-related mortality. In this context, researchers worldwide focused on establishing novel approaches to address drug resistance in M. tuberculosis, developing diverse alternative treatments with varying effectiveness and in different testing phases. Overviewing the current progress, this paper aims to briefly present the mechanisms involved in M. tuberculosis drug-resistance, further reviewing in more detail the under-development antibiotics, nanotechnological approaches, and natural therapeutic solutions that promise to overcome current treatment limitations.

Case Report: Clinical and Pathological Findings of Tuberculous Gumma: A Case Report and Literature Review

Tuberculous gumma (TG) is a rare type of cutaneous tuberculosis thought to occur as a result of the hematogenous spread of Mycobacterium tuberculosis, which is more common in immunosuppressed individuals. An 8-year-old boy presented with a 2-month history of multiple indolent enlarging ulcerated nodules on his left upper extremity. He had a past medical history of bacille Calmette-Guerin vaccine induced lupus vulgaris. Skin biopsy of the nodules showed granulomas and neutrophil-dominated purulent inflammation. Ziehl-Neelsen staining was negative, and the cultures were positive for M. tuberculosis. Furthermore, the M. tuberculosis complex was identified using metagenomic next-generation sequencing. Standard antitubercular therapy was started at full doses, and the skin lesions had significantly improved 3 months later. Here we review the literature since 2000 and describe the clinical and pathological features of TG.

Bactericidal and sterilizing activity of novel regimens combining bedaquiline or TBAJ-587 with GSK2556286 and TBA-7371 in a mouse model of tuberculosis

The combination of bedaquiline, pretomanid, and linezolid (BPaL) has become a preferred regimen for treating multidrug- and extensively drug-resistant tuberculosis (TB). However, treatment-limiting toxicities of linezolid and reports of emerging bedaquiline and pretomanid resistance necessitate efforts to develop new short-course oral regimens. We recently found that the addition of GSK2556286 increases the bactericidal and sterilizing activity of BPa-containing regimens in a well-established BALB/c mouse model of tuberculosis. Here, we used this model to evaluate the potential of new regimens combining bedaquiline or the more potent diarylquinoline TBAJ-587 with GSK2556286 and the DprE1 inhibitor TBA-7371, all of which are currently in early-phase clinical trials. We found the combination of bedaquiline, GSK2556286, and TBA-7371 to be more active than the first-line regimen and nearly as effective as BPaL in terms of bactericidal and sterilizing activity. In addition, we found that GSK2556286 and TBA-7371 were as effective as pretomanid and the novel oxazolidinone TBI-223 when either drug pair was combined with TBAJ-587 and that the addition of GSK2556286 increased the bactericidal activity of the TBAJ-587, pretomanid, and TBI-223 combination. We conclude that GSK2556286 and TBA-7371 have the potential to replace pretomanid, an oxazolidinone, or both components, in combination with bedaquiline or TBAJ-587.

Cardiac Tuberculosis: A Case Series from Ethiopia, Italy, and Uganda and a Literature Review

Extrapulmonary tuberculosis (TB) is estimated to account for up to 20% of active cases of TB disease, but its prevalence is difficult to ascertain because of the difficulty of diagnosis. Involvement of the heart is uncommon, with constrictive pericarditis being the most common cardiac manifestation. Diagnostic research for cardiac disease is frequently lacking, resulting in a high mortality rate. In addition to direct cardiac involvement, instances of cardiac events during antitubercular therapy are described. This case series describes five cases of TB affecting the heart (cardiac TB) from Italy and high-burden, low-income countries (Ethiopia and Uganda), including a case of Loeffler syndrome manifesting as myocarditis in a patient receiving antitubercular therapy. Our study emphasizes how cardiac TB, rare but important in high-burden areas, is a leading cause of pericardial effusion or pericarditis. Timely diagnosis and a comprehensive approach, including imaging and microbiological tools, are crucial. Implementing high-sensitivity methods and investigating alternative samples, such as detection of tuberculosis lipoarabinomannan or use of the GeneXpert assay with stool, is recommended in TB control programs.

Ethambutol and meropenem/clavulanate synergy promotes enhanced extracellular and intracellular killing of Mycobacterium tuberculosis

Increasing evidence supports the repositioning of beta-lactams for tuberculosis (TB) therapy, but further research on their interaction with conventional anti-TB agents is still warranted. Moreover, the complex cell envelope of Mycobacterium tuberculosis (Mtb) may pose an additional obstacle to beta-lactam diffusion. In this context, we aimed to identify synergies between beta-lactams and anti-TB drugs ethambutol (EMB) and isoniazid (INH) by assessing antimicrobial effects, intracellular activity, and immune responses. Checkerboard assays with H37Rv and eight clinical isolates, including four drug-resistant strains, exposed that only treatments containing EMB and beta-lactams achieved synergistic effects. Meanwhile, the standard EMB and INH association failed to produce any synergy. In Mtb-infected THP-1 macrophages, combinations of EMB with increasing meropenem (MEM) concentrations consistently displayed superior killing activities over the individual antibiotics. Flow cytometry with BODIPY FL vancomycin, which binds directly to the peptidoglycan (PG), confirmed an increased exposure of this layer after co-treatment. This was reinforced by the high IL-1β secretion levels found in infected macrophages after incubation with MEM concentrations above 5 mg/L, indicating an exposure of the host innate response sensors to pathogen-associated molecular patterns in the PG. Our findings show that the proposed impaired access of beta-lactams to periplasmic transpeptidases is counteracted by concomitant administration with EMB. The efficiency of this combination may be attributed to the synchronized inhibition of arabinogalactan and PG synthesis, two key cell wall components. Given that beta-lactams exhibit a time-dependent bactericidal activity, a more effective pathogen recognition and killing prompted by this association may be highly beneficial to optimize TB regimens containing carbapenems.IMPORTANCEAddressing drug-resistant tuberculosis with existing therapies is challenging and the treatment success rate is lower when compared to drug-susceptible infection. This study demonstrates that pairing beta-lactams with ethambutol (EMB) significantly improves their efficacy against Mycobacterium tuberculosis (Mtb). The presence of EMB enhances beta-lactam access through the cell wall, which may translate into a prolonged contact between the drug and its targets at a concentration that effectively kills the pathogen. Importantly, we showed that the effects of the EMB and meropenem (MEM)/clavulanate combination were maintained intracellularly. These results are of high significance considering that the time above the minimum inhibitory concentration is the main determinant of beta-lactam efficacy. Moreover, a correlation was established between incubation with higher MEM concentrations during macrophage infection and increased IL-1β secretion. This finding unveils a previously overlooked aspect of carbapenem repurposing against tuberculosis, as certain Mtb strains suppress the secretion of this key pro-inflammatory cytokine to evade host surveillance.

Sub-MIC levels of bedaquiline and clofazimine can select Mycobacterium tuberculosis mutants with increased MIC

Multidrug-resistant tuberculosis (MDR-TB) patients not cured at the time of stopping treatment are exposed to Minimum Inhibitory Concentration (MIC) and sub-MIC levels for many months after discontinuing bedaquiline (BDQ) or clofazimine (CFZ) treatment. In vitro cultures treated with BDQ and CFZ sub-MIC concentrations clearly showed enrichment in the Rv0678 mutant population, demonstrating that pre-existing Rv0678 mutants can be selected by sub-MIC concentrations of BDQ and CFZ if not protected by an alternative MDR-TB treatment.

Genetic mechanisms of co-emergence of INH-resistant Mycobacterium tuberculosis strains during the standard course of antituberculosis therapy

The incidence of isoniazid (INH) resistant Mycobacterium tuberculosis is increasing globally. This study aimed to identify the molecular mechanisms behind the development of INH resistance in M. tuberculosis strains collected from the same patients during the standard course of treatment. Three M. tuberculosis strains were collected from a patient before and during antituberculosis (anti-TB) therapy. The strains were characterized using phenotypic drug susceptibility tests, Mycobacterial Interspersed Repeated Unit-Variable-Number Tandem Repeats (MIRU-VNTR), and whole-genome sequencing (WGS) to identify mutations associated with INH resistance. To validate the role of the novel mutations in INH resistance, the mutated katG genes were electroporated into a KatG-deleted M. tuberculosis strain (GA03). Three-dimensional structures of mutated KatG were modeled to predict their impact on INH binding. The pre-treatment strain was susceptible to INH. However, two INH-resistant strains were isolated from the patient after anti-TB therapy. MIRU-VNTR and WGS revealed that the three strains were clonally identical. A missense mutation (P232L) and a nonsense mutation (Q461Stop) were identified in the katG of the two post-treatment strains, respectively. Transformation experiments showed that katG of the pre-treatment strain restored INH susceptibility in GA03, whereas the mutated katG genes from the post-treatment strains rendered negative catalase activity and INH resistance. The protein model indicated that P232L reduced INH-KatG binding affinity while Q461Stop truncated gene transcription. Our results showed that the two katG mutations, P232L and Q461Stop, accounted for the co-emergence of INH-resistant clones during anti-TB therapy. The inclusion of these mutations in the design of molecular assays could increase the diagnostic performance.IMPORTANCEThe evolution of drug-resistant strains of Mycobacterium tuberculosis within the lung lesions of a patient has a detrimental impact on treatment outcomes. This is particularly concerning for isoniazid (INH), which is the most potent first-line antimycobacterial drug. However, the precise genetic factors responsible for drug resistance in patients have not been fully elucidated, with approximately 15% of INH-resistant strains harboring unknown genetic factors. This raises concerns about the emergence of drug-resistant clones within patients, further contributing to the global epidemic of resistance. In this study, we revealed the presence of two novel katG mutations, which emerged independently due to the stress exerted by antituberculosis (anti-TB) treatment on a parental strain. Importantly, we experimentally demonstrated the functional significance of both mutations in conferring resistance to INH. Overall, this research sheds light on the genetic mechanisms underlying the evolution of INH resistance within patients and provides valuable insights for improving diagnostic performance by targeting specific mutations.

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.

Tuberculosis treatment outcomes and associated factors among tuberculosis patients treated at healthcare facilities of Motta Town, Northwest Ethiopia: a five-year retrospective study

Tuberculosis (TB) remains a significant public health concern, particularly in low-resource settings. The treatment outcome is a crucial indicator of the effectiveness of TB treatment programs. Assessing the current treatment outcome and its associated factors is essential for improving patient care and reducing the spread of TB. Therefore, this study aimed to assess TB treatment outcomes and their associated factors among TB patients who received treatment at public healthcare facilities in Motta Town, Northwest Ethiopia. A facility-based retrospective cross-sectional study design was employed in two TB treatment centers in Motta town from January 2017 to December 2021. The study participants were all patients diagnosed with TB who received treatment. A p-value of 0.05 with a 95% confidence interval (CI) was used to determine statistical significance. A total of 362 TB patients were included in the study. The overall treatment success rate was 88.4% (95% CI 85.1, 91.7). Male gender (AOR = 2.40, 95% CI 1.16, 4.98), normal nutritional status (AOR = 3.11, 95% CI 1.33, 7.25), HIV negative status (AOR = 3.35, 95% CI 1.31, 8.60), and non-presumptive drug resistance to TB (AOR = 3.72, 95% CI 1.74, 7.98) were significantly associated with successful TB treatment outcomes (p < 0.05). In the current study, nine out of ten study participants had successful TB treatment outcome rates. Male gender, normal nutritional status, non-presumed drug resistance to TB, and HIV-negative status were significantly associated with successful TB treatment outcomes. By taking risk factors associated with poor treatment outcomes like those found in this study into account, patient management and treatment can be optimized. Sufficient TB control measures for populations are imperative and could significantly reduce the nation's total TB burden.

Incidence of tuberculosis disease in individuals diagnosed with tuberculosis infection after screening: A population-based cohort study in South Korea

OBJECTIVES

Limited evidence exists regarding the impact of adherence to diverse tuberculosis (TB) preventive therapy (TPT) regimens on TB risk in individuals with TB infections (TBIs). This study aimed to examine the association between adherence to three TPT regimens and TB incidence.

METHODS

This population-based retrospective cohort study used South Korean national health insurance data to identify individuals who were newly diagnosed with TBI between 2015 and 2020. TB incidence was compared among the different TPT regimens used. Treatment adherence was evaluated using the medication possession ratio (MPR).

RESULTS

The study involved 220,483 individuals with TBI, with half undergoing TPT. Over a mean 3.17-year follow-up, 2,430 cases of active TB were observed. TPT was associated with a 14% reduction in TB incidence risk in the entire study population with varying levels of TB risk. Non-adherence (MPR <80%) rates were 36% for 9 months of treatment with isoniazid, 22% for 4 months of treatment with rifampicin, and 18% for 3 months of treatment with isoniazid and rifampicin. Non-adherence to TPT did not lead to a decrease in the risk of TB incidence, whereas adherence to TPT (MPR ≥80%) reduced the risk of TB incidence by up to 72%.

CONCLUSIONS

This study reveals increased adherence with shorter TPT regimens in a national TBI cohort, emphasizing the pivotal role of medication adherence in preventing TB.

Correlation between serum isoniazid concentration and therapeutic response in patients of pulmonary tuberculosis in Central India: A prospective observational study

BACKGROUND

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis is one of the top ten causes of death worldwide. Isoniazid (INH) is an important component of anti-tuberculosis therapy (ATT). Low isoniazid levels can serve as a risk factor for the development of treatment failure, relapse of disease and acquired secondary resistance. Hence, serum level of isoniazid becomes a critical factor in determining the treatment outcome of patients on ATT. This study aimed to evaluate the correlation between serum isoniazid concentration and therapeutic response in patients of pulmonary tuberculosis in Central India.

METHODS

This was a prospective single cohort observational study conducted at a tertiary care hospital. Therapeutic response in newly diagnosed patients of pulmonary TB was determined based the microbiological, clinical and radiological parameters. Serum INH levels were estimated based on a spectrophotometric method using nano-spectrophotometer.

RESULTS

In this study, patients had a significant improvement in treatment outcome as evident by a significant decrease in the TB score I at end of IP (p = 0.001) and a significant decline in the Timika score at end of CP (p = 0.001). Although all patients converted to sputum negative at end of CP, 20% remained positive at end of IP. Lower INH levels were seen in 13.3% of the study population. Higher INH levels were observed in sputum converters, patients with low TB score I and low Timika score, although no statistically significant difference was noted (p > 0.05).

CONCLUSION

In this study, we could not find any statistically significant association between serum INH levels and therapeutic outcome of the patients. Further studies on a larger population could provide better understanding about the prevalence of low serum isoniazid levels among the Indian population and establish its relationship with therapeutic outcome. Also, the usage of a comparatively less expensive spectrophotometric method of analysis makes this feasible in almost every district hospital without the need of high-performance liquid chromatography which is costlier and needs more expertise.

Evaluation of clinical profiles, imaging findings and antituberculosis treatment outcome in granulomatous mastitis: An Indian scenario

BACKGROUND

The management of choice for granulomatous mastitis (GM) has yet to be determined but few studies have demonstrated that anti-tubercular treatment (ATT) could be an effective alternative therapeutic option. Hence, the objective of the current study is to determine the clinical feature, radiological imaging findings, and histopathological examination results exhibited by GM and tuberculosis (TB)-proven GM as well as to evaluate the ATT clinical outcome in GM patients.

METHODS

The study was performed on 68 GM patients who were referred to the department of pulmonology by the breast clinic (from January 2018 to August 2021). Study populations were categorized into two groups GM and TB-proven GM patients and all were prescribed with standard ATT regimen and were continuously followed up. SPSS version 25 was employed for statistical assessment.

RESULTS

Our study showed that 6 patients from GM and 4 patients from the TB-proven GM group got relapsed. For patients who displayed partial remission, ATT treatment was started after assessing the side effects potential. 14.6% (n = 6) and 7.4% (n = 2) patients who initially demonstrated partial remission were also completely cured. ATT treatment curable rate was determined to be 90% (n = 37) and 81.5% (n = 22) for GM and TB-proven GM patients correspondingly. Therefore, the current study demonstrated nil significant differences between groups.

CONCLUSION

The current study warrants that ATT therapy could be an effective and better treatment of choice for GM patients irrespective of their clinical condition.

Decentralising DOT for drug-susceptible TB from the health facilities to the community level in Togo

In Togo, the COVID-19 pandemic paved the way for decentralising directly observed treatment (DOT) to the community level through the evaluation of two innovative community-based DOT approaches-a community health worker-based (CHW-DOT) and family-based (FB-DOT). METHODS We conducted an observational prospective study from April 2021 to January 2022. Sputum conversion at Month 2 and favourable treatment outcomes at Month 6 were assessed and compared between the two groups. Sociodemographic and clinical factors related to these outcomes were identified. RESULTS A total of 182 TB patients were enrolled. The CHW-DOT group had significantly increased odds of sputum conversion (aOR 2.95, 95% CI 1.09-7.98) and lower odds of unsuccessful treatment outcomes (aOR 0.37, 95% CI 0.13-1.1). Non-smokers had 4.85 higher odds of converting than smokers (aOR 4.85, 95% CI 1.76-13.42) and lower odds of an unsuccessful treatment than smokers (aOR 0.11, 95% CI 0.04-0.32). CONCLUSION CHW-DOT is associated with higher sputum smear conversion rates and a more favourable treatment outcome. The use of tobacco, significantly associated with outcomes, also suggests that a smoking cessation component may be a valuable adjunct to a CHW-DOT approach during TB treatment..

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.

The Effect of Immunoglobulin G on the Humoral Immunity in Patients with Tuberculosis/HIV Coinfection

Previously, an increase in clinical effectiveness of the antituberculosis treatment (ATT) and antiretroviral therapy (ART) in case of additional immunoglobulin G (IgG) administration in patients with multidrug-resistant tuberculosis (MDR-TB)/HIV coinfection was reported. The aim of this study was to investigate the impact of IgG administration in addition to the standard second-line ATT and ART on the humoral immunity status in patients with MDR-TB/HIV coinfection immune deficiency. The study involved 52 patients living with HIV with MDR-TB coinfection and CD4+ lymphocyte cell count below 50 cells/μCL. Patients in the control group and intervention group received the second-line ATT and ART; in addition, patients in the intervention group received IgG intravenously. The humoral immunity status was evaluated by measurement of IgA, IgE, IgG, and IgM in plasma. The standard ATT and ART resulted in a two-step change in humoral immunity: IgM, IgG, IgA, and IgE levels gradually increased to a maximal level at the 5-month mark and started to gradually decrease after the 8-month mark. Addition of IgG to the standard therapy resulted in a steeper decrease in the immunoglobulin level in serum, especially IgG, compared with standard therapy alone, allowing for an earlier initiation of ART in patients in the intervention group.

A systematic efficacy analysis of tuberculosis treatment with BPaL-containing regimens using a multiscale modeling approach

Tuberculosis (TB) is a life-threatening infectious disease. The standard treatment is up to 90% effective; however, it requires the administration of four antibiotics (isoniazid, rifampicin, pyrazinamide, and ethambutol [HRZE]) over long time periods. This harsh treatment process causes adherence issues for patients because of the long treatment times and a myriad of adverse effects. Therefore, the World Health Organization has focused goals of shortening standard treatment regimens for TB in their End TB Strategy efforts, which aim to reduce TB-related deaths by 95% by 2035. For this purpose, many novel and promising combination antibiotics are being explored that have recently been discovered, such as the bedaquiline, pretomanid, and linezolid (BPaL) regimen. As a result, testing the number of possible combinations with all possible novel regimens is beyond the limit of experimental resources. In this study, we present a unique framework that uses a primate granuloma modeling approach to screen many combination regimens that are currently under clinical and experimental exploration and assesses their efficacies to inform future studies. We tested well-studied regimens such as HRZE and BPaL to evaluate the validity and accuracy of our framework. We also simulated additional promising combination regimens that have not been sufficiently studied clinically or experimentally, and we provide a pipeline for regimen ranking based on their efficacies in granulomas. Furthermore, we showed a correlation between simulation rankings and new marmoset data rankings, providing evidence for the credibility of our framework. This framework can be adapted to any TB regimen and can rank any number of single or combination regimens.

Status of HIV and comorbidities in refugees with HIV from Ukraine

PURPOSE

To describe the clinical characteristics of refugees with HIV from Ukraine that seek continuation of medical care in Germany.

METHODS

Fourty-six refugees with HIV that had left Ukraine between 24 February and 30 December 2022 were examined. Information on patients' history was obtained using a standardized questionnaire for clinical care. Interviews were conducted in Russian during their first clinical presentation.

RESULTS

Fourty-six persons (41 females and 5 males) were included and their mean age was 39.6 (±8.4) years. The mean time since HIV diagnosis was 8.0 (median, IQR 7.15) years and 70.3% of participants currently received tenfofovir-DF, lamividine and dolutegravir. Most refugees had an undetectable HIV viral load and their current mean CD4 T cell count was 702 (SD ± 289) per μL. Serology revealed previous hepatitis B infection in 50.4% without evidence for replication, with undetectable anti-hepatitis B surface antigen in the remaining refugees. Antibodies against hepatitis C were present in 23 refugees (50%), but only 10 patients had been diagnosed with hepatitis C previously. Five refugees had undergone successful antiviral treatment for hepatitis C. Detectable HCV-RNA was evident in nine patients (19.6%). Sixteen (38.6%) refugees had a positive tuberculosis (TB) interferon gamma release assay, and four were on TB treatment for previously diagnosed infection. One had been diagnosed with multidrug-resistant (MDR) TB, two with pre-extensively drug-resistant (pre-XDR) TB and two with XDR TB and were treated with combinations of second-line and novel agents according to WHO guidelines.

CONCLUSIONS

Based on this preliminary analysis of a not fully representative cohort, refugees with HIV from Ukraine were young, mostly healthy females highly adherent to antiretroviral therapy. The rate of transmittable co-infections urges early diagnostic evaluation and treatment.

Estimation of country-specific tuberculosis resistance antibiograms using pathogen genomics and machine learning

BACKGROUND

Global tuberculosis (TB) drug resistance (DR) surveillance focuses on rifampicin. We examined the potential of public and surveillance Mycobacterium tuberculosis (Mtb) whole-genome sequencing (WGS) data, to generate expanded country-level resistance prevalence estimates (antibiograms) using in silico resistance prediction.

METHODS

We curated and quality-controlled Mtb WGS data. We used a validated random forest model to predict phenotypic resistance to 12 drugs and bias-corrected for model performance, outbreak sampling and rifampicin resistance oversampling. Validation leveraged a national DR survey conducted in South Africa.

RESULTS

Mtb isolates from 29 countries (n=19 149) met sequence quality criteria. Global marginal genotypic resistance among mono-resistant TB estimates overlapped with the South African DR survey, except for isoniazid, ethionamide and second-line injectables, which were underestimated (n=3134). Among multidrug resistant (MDR) TB (n=268), estimates overlapped for the fluoroquinolones but overestimated other drugs. Globally pooled mono-resistance to isoniazid was 10.9% (95% CI: 10.2-11.7%, n=14 012). Mono-levofloxacin resistance rates were highest in South Asia (Pakistan 3.4% (0.1-11%), n=111 and India 2.8% (0.08-9.4%), n=114). Given the recent interest in drugs enhancing ethionamide activity and their expected activity against isolates with resistance discordance between isoniazid and ethionamide, we measured this rate and found it to be high at 74.4% (IQR: 64.5-79.7%) of isoniazid-resistant isolates predicted to be ethionamide susceptible. The global susceptibility rate to pyrazinamide and levofloxacin among MDR was 15.1% (95% CI: 10.2-19.9%, n=3964).

CONCLUSIONS

This is the first attempt at global Mtb antibiogram estimation. DR prevalence in Mtb can be reliably estimated using public WGS and phenotypic resistance prediction for key antibiotics, but public WGS data demonstrates oversampling of isolates with higher resistance levels than MDR. Nevertheless, our results raise concerns about the empiric use of short-course fluoroquinolone regimens for drug-susceptible TB in South Asia and indicate underutilisation of ethionamide in MDR treatment.

Multidrug-resistant tuberculosis

Tuberculosis (TB) remains the foremost cause of death by an infectious disease globally. Multidrug-resistant or rifampicin-resistant TB (MDR/RR-TB; resistance to rifampicin and isoniazid, or rifampicin alone) is a burgeoning public health challenge in several parts of the world, and especially Eastern Europe, Russia, Asia and sub-Saharan Africa. Pre-extensively drug-resistant TB (pre-XDR-TB) refers to MDR/RR-TB that is also resistant to a fluoroquinolone, and extensively drug-resistant TB (XDR-TB) isolates are additionally resistant to other key drugs such as bedaquiline and/or linezolid. Collectively, these subgroups are referred to as drug-resistant TB (DR-TB). All forms of DR-TB can be as transmissible as rifampicin-susceptible TB; however, it is more difficult to diagnose, is associated with higher mortality and morbidity, and higher rates of post-TB lung damage. The various forms of DR-TB often consume >50% of national TB budgets despite comprising <5-10% of the total TB case-load. The past decade has seen a dramatic change in the DR-TB treatment landscape with the introduction of new diagnostics and therapeutic agents. However, there is limited guidance on understanding and managing various aspects of this complex entity, including the pathogenesis, transmission, diagnosis, management and prevention of MDR-TB and XDR-TB, especially at the primary care physician level.

Multidrug-resistant Mycobacterium tuberculosis transmission in Shandong, China

Multidrug-resistant tuberculosis (MDR-TB) has imposed a significant economic and health burden worldwide, notably in China. Using whole genome sequence, we sought to understand the mutation and transmission of MDR-TB in Shandong. A retrospective study of patients diagnosed with pulmonary tuberculosis in Shandong from 2009 to 2018 was conducted. To explore transmission patterns, we performed whole genome sequencing on MDR-TB isolates, identified genomic clusters, and assessed the drug resistance of TB isolates. Our study analyzed 167 isolates of MDR-TB, finding that 100 were clustered. The predominant lineage among MDR-TB isolates was lineage 2, specifically with a notable 88.6% belonging to lineage 2.2.1. Lineage 4 constituted a smaller proportion, accounting for 4.2% of the isolates. We discovered that Shandong has a significant clustering percentage for MDR-TB, with Jining having the highest percentage among all Shandong cities. The clustering percentages of MDR-TB, pre-extensively drug-resistant tuberculosis, and extensively drug-resistant tuberculosis were 59.9%, 66.0%, and 71.4%, respectively, and the clustering percentages increased with the expansion of the anti-TB spectrum. Isolates from genomic clusters 1 and 3 belonged to lineage 2.2.1 and showed signs of cross-regional transmission. The distribution of rrs A1401G and katG S315T mutations in lineage 2.2.1 and 2.2.2 strains differed significantly (P < .05). MDR-TB isolates with rpoB I480V, embA-12C > T, and rrs A1401G mutations showed a higher likelihood of clustering (P < .05). Our findings indicate a significant problem of local transmission of MDR-TB in Shandong, China. Beijing lineage isolates and some drug-resistant mutations account for the MDR-TB transmission in Shandong.

IL-10 and TGF-β1 may weaken the efficacy of preoperative anti-tuberculosis therapy in older patients with spinal tuberculosis

Spinal tuberculosis is a common extrapulmonary type that is often secondary to pulmonary or systemic infections. Mycobacterium tuberculosis infection often leads to the balance of immune control and bacterial persistence. In this study, 64 patients were enrolled and the clinicopathological and immunological characteristics of different age groups were analyzed. Anatomically, spinal tuberculosis in each group mostly occurred in the thoracic and lumbar vertebrae. Imaging before preoperative anti-tuberculosis therapy showed that the proportion of abscesses in the older group was significantly lower than that in the younger and middle-aged groups. However, pathological examination of surgical specimens showed that the proportion of abscesses in the older group was significantly higher than that in the other groups, and there was no difference in the granulomatous inflammation, caseous necrosis, inflammatory necrosis, acute inflammation, exudation, granulation tissue formation, and fibrous tissue hyperplasia. B cell number was significantly lower in the middle-aged and older groups compared to the younger group, while the number of T cells, CD4+ T cells, CD8+ T cells, macrophages, lymphocytes, plasma cells, and NK cells did not differ. Meaningfully, we found that the proportion of IL-10 high expression and TGF-β1 positive in the older group was significantly higher than that in the younger group. TNF-α, CD66b, IFN-γ, and IL-6 expressions were not different among the three groups. In conclusion, there are some differences in imaging, pathological, and immune features of spinal tuberculosis in different age groups. The high expression of IL-10 and TGF-β1 in older patients may weaken their anti-tuberculosis immunity and treatment effectiveness.

US Guidelines Fall Short on Short-Course Tuberculosis-Preventive Therapy

The provision of tuberculosis-preventive therapy (TPT) to vulnerable populations is critical for global control. Shorter-course TPT regimens are highly effective and improve completion rates. Despite incorporation of 1 month of rifapentine and isoniazid into global guidelines, current US TPT guidelines do not include this as a recommended regimen, but should.

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.

[Cryotherapy combined with local spraying of isoniazid for the treatment of nasopharyngeal tuberculosis: a case report]

Nasopharyngeal tuberculosis refers to the tuberculosis in the nasopharynx, which is mainly treated with systemic chemotherapy with anti-tuberculosis drugs. Here, we reported a case of nasopharyngeal tuberculosis treated by cryosurgery combined with local spraying of isoniazid on the basis of systemic chemotherapy with anti-tuberculosis drugs. By reviewing the case data and relevant literature, we understood the clinical manifestations, diagnosis and differential diagnosis of the disease, improved everyone's understanding of the disease, and proposed a new method of cryosurgery combined with local spraying of isoniazid for the treatment of nasopharyngeal tuberculosis for clinical discussion.

Mid-level managers' perspectives on implementing isoniazid preventive therapy for people living with HIV in Ugandan health districts: a qualitative study

BACKGROUND

Isoniazid preventive therapy (IPT) works to prevent tuberculosis (TB) among people living with HIV (PLHIV), but uptake remains low in Sub-Saharan Africa. In this analysis, we sought to identify barriers mid-level managers face in scaling IPT in Uganda and the mechanisms by which the SEARCH-IPT trial intervention influenced their abilities to increase IPT uptake.

METHODS

The SEARCH-IPT study was a cluster randomized trial conducted from 2017-2021. The SEARCH-IPT intervention created collaborative groups of district health managers, facilitated by local HIV and TB experts, and provided leadership and management training over 3-years to increase IPT uptake in Uganda. In this qualitative study we analyzed transcripts of annual Focus Group Discussions and Key Informant Interviews, from a subset of SEARCH-IPT participants from intervention and control groups, and participant observation field notes. We conducted the analysis using inductive and deductive coding (with a priori codes and those derived from analysis) and a framework approach for data synthesis.

RESULTS

When discussing factors that enabled positive outcomes, intervention managers described feeling ownership over interventions, supported by the leadership and management training they received in the SEARCH-IPT study, and the importance of collaboration between districts facilitated by the intervention. In contrast, when discussing factors that impeded their ability to make changes, intervention and control managers described external funders setting agendas, lack of collaboration in meetings that operated with more of a 'top-down' approach, inadequate supplies and staffing, and lack of motivation among frontline providers. Intervention group managers mentioned redistribution of available stock within districts as well as between districts, reflecting efforts of the SEARCH-IPT intervention to promote between-district collaboration, whereas control group managers mentioned redistribution within their districts to maximize the use of available IPT stock.

CONCLUSIONS

In Uganda, mid-level managers' perceptions of barriers to scaling IPT included limited power to set agendas and control over funding, inadequate resources, lack of motivation of frontline providers, and lack of political prioritization. We found that the SEARCH-IPT intervention supported managers to design and implement strategies to improve IPT uptake and collaborate between districts. This may have contributed to the overall intervention effect in increasing the uptake of IPT among PLHIV compared to standard practice.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03315962 , Registered 20 October 2017.