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Rationale: Observational studies suggest that high-dose isoniazid may be efficacious in treating multidrug-resistant tuberculosis. However, its activity against Mycobacterium tuberculosis (M.tb) with katG mutations (which typically confer high-level resistance) is not established. Objectives: To characterize the early bactericidal activity (EBA) of high-dose isoniazid in patients with tuberculosis caused by katG-mutated M.tb. Methods: A5312 was a phase IIA randomized, open-label trial. Participants with tuberculosis caused by katG-mutated M.tb were randomized to receive 15 or 20 mg/kg isoniazid daily for 7 days. Daily sputum samples were collected for quantitative culture. Intensive pharmacokinetic sampling was performed on Day 6. Data were pooled across all A5312 participants for analysis (drug-sensitive, inhA-mutated, and katG-mutated M.tb). EBA was determined using nonlinear mixed-effects modeling. Measurements and Main Results: Of 80 treated participants, 21 had katG-mutated M.tb. Isoniazid pharmacokinetics were best described by a two-compartment model with an effect of NAT2 acetylator phenotype on clearance. Model-derived maximum concentration and area under the concentration–time curve in the 15 and 20 mg/kg groups were 15.0 and 22.1 mg/L and 57.6 and 76.8 mg ⋅ h/L, respectively. Isoniazid bacterial kill was described using an effect compartment and a sigmoidal maximum efficacy relationship. Isoniazid potency against katG-mutated M.tb was approximately 10-fold lower than in inhA-mutated M.tb. The highest dose of 20 mg/kg did not demonstrate measurable EBA, except against a subset of slow NAT2 acetylators (who experienced the highest concentrations). There were no grade 3 or higher drug-related adverse events. Conclusions: This study found negligible bactericidal activity of high-dose isoniazid (15–20 mg/kg) in the majority of participants with tuberculosis caused by katG-mutated M.tb. Clinical trial registered with (NCT01936831). [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) continues to affect over 10 million people per year worldwide. Despite advances in diagnosis, smear microscopy insufficiently detects pulmonary disease, with test result reporting taking longer than a day. While urine assays to detect the lipopolysaccharide lipoarabinomannan (LAM), present in mycobacterial cell walls, can provide results within minutes, the currently available assay has low sensitivity and its application is limited to patients with HIV suspected of having TB. In this issue of the JCI, Broger and Nicol et al. investigated 3 rapid urine tests in 372 ambulatory HIV-negative individuals suspected of having TB in South Africa and Peru. FujiLAM emerged as a rapid test to confirm TB diagnosis in the HIVseronegative population. This study shows that FujiLAM has considerable potential to reshape the TB diagnostics landscape, making diagnosis and treatment in one office visit a reality for TB., Rapid tests for pulmonary TB Despite the World Health Organization's (WHO) designation of tuberculosis (TB) as a global health emergency nearly 30 years ago, a true point-of-care diagnostic test for [...]

Rationale: Pretomanid is a new nitroimidazole with proven treatment-shortening efficacy in drug-resistant tuberculosis. Pretomanid-rifamycin-pyrazinamide combinations are potent in mice but have not been tested clinically. Rifampicin, but not rifabutin, reduces pretomanid exposures.Objective: Evaluate the safety and efficacy of pretomanid-rifamycin-pyrazinamide containing regimens among participants with drug-sensitive pulmonary tuberculosis.Methods: Phase 2 twelve-week open-label randomized trial of isoniazid, pyrazinamide, plus (a) pretomanid and rifampicin (Arm 1); (b) pretomanid and rifabutin (Arm 2) or (c) rifampicin and ethambutol (standard of care, Arm 3). Safety labs and sputum cultures were collected at Weeks 1, 2, 3, 4, 6, 8, 10, 12. Time to culture conversion on liquid media was the primary outcome.Results: Among 157 participants, 125 (80%) had cavitary disease. Median time to liquid culture negativity in the modified intention to treat (mITT) population (n=150) was 41 (Arm 1), 28 (Arm 2), and 55 (Arm 3) days (p=0.01)(adjusted hazard ratios of 1.41 (0.93-2.12, p=0.10), Arm 1 vs. Arm 3) and 1.89 (1.24-2.87, p=0.003, Arm 2 vs. Arm 3)). Eight-week liquid culture conversion was 79%, 89%, and 69%, respectively. Grade >3 adverse events occurred in 3/56 (5%), 5/53 (9%), and 2/56 (4%) of participants. Six participants were withdrawn owing to elevated transaminases (5 in Arm 2, 1 in Arm 1).There were 3 serious adverse events (Arm 2) and no deaths.Conclusions: Pretomanid enhanced the microbiologic activity of rifamycin-pyrazinamide containing regimens. Efficacy and hepatic adverse events appeared highest with the pretomanid and rifabutin-containing regimen. Whether this is due to higher pretomanid concentrations merits exploration. Clinical trial registration available at www.Clinicaltrials: gov, ID: NCT02256696. [ABSTRACT FROM AUTHOR]

New modalities of Pre-exposure Prophylaxis (PrEP) such as long-acting injectable PrEP (LAI-PrEP) promise increased prevention of HIV transmission; however, similar biomedical interventions have not been met with universal adoption by healthcare providers or populations most affected by HIV. This qualitative study explores healthcare provider considerations for the rollout of LAI-PrEP. Eleven key-informant in-depth interviews were conducted with clinicians who prescribe daily oral PrEP. Participants reviewed a currently proposed LAI regimen and were asked to reflect on its implications for their clinical practice. Interviews were transcribed verbatim and thematically coded, with results organized using the Consolidated Framework for Implementation Research (CFIR). All participants expressed interest in prescribing LAI-PrEP and anticipated that at least some patients would be interested. Participants identified characteristics of the intervention, inner intervention setting, and outer intervention setting that will be influential in bringing LAI-PrEP to scale. Clinicians in the South have unique insights into the challenges of and opportunities for successful rollout of future PrEP regimens. Bringing these insights into a CFIR framework highlights the nuances surrounding LAI-PrEP, including structural concerns such as cost barriers and access to in-person healthcare services. It is critical to address these challenges to ensure successful implementation of new PrEP formulations. [ABSTRACT FROM AUTHOR]

Background There is currently no single treatment that mitigates all harms caused by severe acute respiratory syndrome coronavirus 2 infection. Tocilizumab, an interleukin-6 antagonist, may have a role as an adjunctive immune-modulating therapy. Methods This was an observational retrospective study of hospitalized adult patients with confirmed coronavirus disease 2019 (COVID-19). The intervention group comprised patients who received tocilizumab; the comparator arm was drawn from patients who did not receive tocilizumab. The primary outcome was all-cause mortality censored at 28 days; secondary outcomes were all-cause mortality at discharge, time to clinical improvement, and rates of secondary infections. Marginal structural Cox models via inverse probability treatment weights were applied to estimate the effect of tocilizumab. A time-dependent propensity score–matching method was used to generate a 1:1 match for tocilizumab recipients; infectious diseases experts then manually reviewed these matched charts to identify secondary infections. Results This analysis included 90 tocilizumab recipients and 1669 controls. Under the marginal structural Cox model, tocilizumab was associated with a 62% reduced hazard of death (adjusted hazard ratio [aHR], 0.38; 95% CI, 0.21 to 0.70) and no change in time to clinical improvement (aHR, 1.13; 95% CI, 0.68 to 1.87). The 1:1 matched data set also showed a lower mortality rate (27.8% vs 34.4%) and reduced hazards of death (aHR, 0.47; 95% CI, 0.25 to 0.88). Elevated inflammatory markers were associated with reduced hazards of death among tocilizumab recipients compared with controls. Secondary infection rates were similar between the 2 groups. Conclusions Tocilizumab may provide benefit in a subgroup of patients hospitalized with COVID-19 who have elevated biomarkers of hyperinflammation, without increasing the risk of secondary infection. [ABSTRACT FROM AUTHOR]

Treatment outcomes for Mycobacteroides abscessus ( Mab , also known as Mycobacterium abscessus ) disease are still unsatisfactory, mainly due to issues with drug toxicity, tolerability, and efficacy. Treating Mab disease is challenging due to its high baseline antibiotic resistance, initial requirement for intravenous therapy, and poor medication tolerance. Omadacycline, a new tetracycline, is active against Mab . Since any new antibiotic effective against Mab is expected to be used in combination with other antibiotics, we evaluated the efficacy of two triple-drug combinations comprising omadacycline, omadacycline + amikacin + imipenem, and omadacycline + clofazimine + linezolid against two contemporary Mab clinical isolates in a mouse model of Mab lung disease. Antibiotic administration was initiated 1-week post-infection and was given daily, with Mab burden in the lungs at treatment completion serving as the endpoint. Omadacycline alone moderately reduced Mab levels and maintained better health in mice compared to untreated ones, which typically suffered from the infection. The omadacycline + clofazimine + linezolid combination showed immediate bactericidal activity and enhanced efficacy over 6 weeks, particularly against the more resistant strain (M9507). However, the clofazimine + linezolid combination lacked early bactericidal activity. When combined with amikacin and imipenem, omadacycline did not improve the regimen's effectiveness over 4 weeks of treatment. Our study showed that omadacycline + clofazimine + linezolid exhibited significant bactericidal activity over an extended treatment duration. However, adding omadacycline to amikacin and imipenem did not improve regimen effectiveness against the evaluated clinical isolates within 4 weeks. Further research in Mab disease patients is needed to determine the most effective omadacycline-containing regimen.IMPORTANCE Mycobacteroides abscessus is a common environmental bacterium that causes infections in people with compromised lung function, including those with bronchiectasis, cystic fibrosis, chronic obstructive pulmonary disease, and weakened immune systems, especially among older individuals. Treating M. abscessus disease is challenging due to the limited effectiveness and toxicity of current antibiotics, which often require prolonged use. Omadacycline, a new antibiotic, shows promise against M. abscessus . Using a mouse model that mimics M. abscessus disease in humans, we studied the effectiveness of including omadacycline with recommended antibiotics. Adding omadacycline to clofazimine and linezolid significantly improved treatment outcomes, rapidly clearing the bacteria from the lungs and maintaining effectiveness throughout. This oral combination is convenient for patients. However, adding omadacycline to amikacin and imipenem did not improve treatment effectiveness within 4 weeks. Further study with M. abscessus patients is necessary to optimize omadacycline-based treatment strategies for this disease., Competing Interests: Daniel H. Deck and Alisa W. Serio are employees of Paratek Pharmaceuticals, Inc. All authors vouch for the integrity, completeness, and accuracy of the data and analyses and assume responsibility for the fidelity of the study.