Clofazimine susceptibility testing of Mycobacterium avium complex and Mycobacterium abscessus: a meta-analysis study

Drugs for treating infections caused by non-tubercular mycobacteria: a narrative review from the study group on mycobacteria of the Italian Society of Infectious Diseases and Tropical Medicine

BACKGROUND

Non-tuberculous mycobacteria (NTM) are generally free-living organism, widely distributed in the environment, with sporadic potential to infect. In recent years, there has been a significant increase in the global incidence of NTM-related disease, spanning across all continents and an increased mortality after the diagnosis has been reported. The decisions on whether to treat or not and which drugs to use are complex and require a multidisciplinary approach as well as patients' involvement in the decision process.

METHODS AND RESULTS

This review aims at describing the drugs used for treating NTM-associated diseases emphasizing the efficacy, tolerability, optimization strategies as well as possible drugs that might be used in case of intolerance or resistance. We also reviewed data on newer compounds highlighting the lack of randomised clinical trials for many drugs but also encouraging preliminary data for others. We also focused on non-pharmacological interventions that need to be adopted during care of individuals with NTM-associated diseases CONCLUSIONS: Despite insufficient efficacy and poor tolerability this review emphasizes the improvement in patients' care and the needs for future studies in the field of anti-NTM treatments.

Prevalence of resistance to macrolides and aminoglycosides in Mycobacterium avium, M. abscessus, and M. chelonae identified in the Laboratorio Nacional de Referencia of Colombia from 2018 to 2022

Introduction

The Mycobacterium chelonae species and the M. avium and M. abscessus complexes are emerging pathogens that cause mycobacteriosis. Treatment depends on the species and subspecies identified. The drugs of choice are macrolides and aminoglycosides. However, due to the resistance identified to these drugs, determining the microbe’s sensitivity profile will allow clinicians to improve the understanding of the prognosis and evolution of these pathologies.

Objective

To describe the macrolide and aminoglycoside susceptibility profile of cultures identified by Colombia’s Laboratorio Nacional de Referencia de Mycobacteria from 2018 to 2022, as Mycobacterium avium complex, M. abscessus complex, and M. chelonae. Materials and methods. This descriptive study exposes the susceptibility profile to macrolides and aminoglycosides of cultures identified as M. avium complex, M. abscessus complex, and M. chelonae using the GenoType® NTM-DR method.

Materials and methods

This descriptive study exposes the susceptibility profile to macrolides and aminoglycosides of cultures identified as M. avium complex, M. abscessus complex, and M. chelonae using the GenoType® NTM-DR method.

Results

We identified 159 (47.3 %) cultures as M. avium complex, of which 154 (96.9 %) were sensitive to macrolides, and 5 (3.1 %) were resistant; all were sensitive to aminoglycosides. From the 125 (37.2 %) cultures identified as M. abscessus complex, 68 (54.4 %) were sensitive to macrolides, 57 (45.6 %) were resistant to aminoglycosides, and just one (0.8 %) showed resistance to aminoglycosides. The 52 cultures (15.5 %) identified as M. chelonae were sensitive to macrolides and aminoglycosides.

Conclusions

The three studied species of mycobacteria have the least resistance to Amikacin. Subspecies identification and their susceptibility profiles allow the establishment of appropriate treatment schemes, especially against M. abscessus.

Management of M. abscessus subsp. abscessus early-onset prosthetic joint infection: Case report and literature review

Nontuberculous mycobacteria are a rare but still emerging cause of difficult-to-treat prosthetic joint infection. To our knowledge only 17 cases of M. abscessus complex prosthetic joint infection are reported in literature, of which only 1 is by M. abscessus subps. abscessus. No guidelines are available for this clinical scenario. We describe a 68-years-old female patient with an early-onset M. abscessus subsp. abscessus prosthetic joint infection, successfully treated with a tailored medical-surgical strategy, and present an overview of cases currently available in the literature to assist physicians in the management of these uncommon infections.

Regulation of cancer stem cells and immunotherapy of glioblastoma (Review)

Glioblastoma (GB) is one of the most adverse diagnoses in oncology. Complex current treatment results in a median survival of 15 months. Resistance to treatment is associated with the presence of cancer stem cells (CSCs). The present review aimed to analyze the mechanisms of CSC plasticity, showing the particular role of β-catenin in regulating vital functions of CSCs, and to describe the molecular mechanisms of Wnt-independent increase of β-catenin levels, which is influenced by the local microenvironment of CSCs. The present review also analyzed the reasons for the low effectiveness of using medication in the regulation of CSCs, and proposed the development of immunotherapy scenarios with tumor cell vaccines, containing heterogenous cancer cells able of producing a multidirectional antineoplastic immune response. Additionally, the possibility of managing lymphopenia by transplanting hematopoietic stem cells from a healthy sibling and using clofazimine or other repurposed drugs that reduce β-catenin concentration in CSCs was discussed in the present study.

Efficacy of clofazimine-containing regimens for treatment of Mycobacterium avium complex-pulmonary disease in patients unsuitable for standard treatment regimen

OBJECTIVES

Patients with Mycobacterium avium complex-pulmonary disease (MAC-PD) can exhibit contraindications in applying the recommended treatment regimens by the guidelines. Clofazimine (CFZ) is considered a promising drug for MAC-PD treatment and is frequently included in alternative regimens; however, its efficacy remains unclear.

METHODS

MAC-PD patients, unsuitable for standard regimens, were enrolled continuously in a prospective study at Beijing Chest Hospital. The treatment response of the CFZ-containing regimen was monitored.

RESULTS

Fifty patients were enrolled in the initial treatment, and 25 patients had a history of anti-TB treatment. Nodular bronchiectasis was observed in 34 patients, while 8 patients exhibited fibrocavitary changes. Additionally, eight patients displayed a combination of both patterns. In a multivariate analysis, MAC-PD patients with CFZ MIC < 0.25 mg/L were significantly associated with culture conversion [OR 8.415, 95% CI (1.983-35.705); P = 0.004]. Among patients who had previous TB treatment history, patients with CFZ MIC < 0.25 mg/L had a higher chance of acquiring culture conversion outcomes [(OR 7.737, 95% CI 1.032-57.989); P = 0.046]. In contrast, among patients with no previous TB treatment history, the RIF-containing regimen had a higher chance of acquiring culture conversion outcomes [(OR 11.038, 95%CI 1.008-120.888); P = 0.049].

CONCLUSION

MAC-PD patients unsuitable for standard regimens could benefit from a CFZ-containing regimen, especially for patients with previous TB treatment history and baseline CFZ MIC values lower than 0.25 mg/L.

Secondary spontaneous pneumothorax in a patient with resistant Mycobacterium abscessus infection and systemic sclerosis-associated interstitial lung disease: A case report

Mycobacterium abscessus subsp. abscessus (MABA) is refractory and sometimes fatal especially in an immunocompromised patient. Also, MABA-associated pneumothorax is an extremely rare complication. We report a case of MABA pulmonary infection complicated pneumothorax treated successfully. A 69-year-old Japanese female with immunosuppressed systemic sclerosis-associated interstitial lung disease experienced left-sided secondary spontaneous pneumothorax. MABA was detected in the pleural effusion and blood culture. Microbial sensitivity test showed the MABA was sensitive to only amikacin, sitafloxacin, and clofazimine. Combination therapy with these antibiotics including azithromycin achieved remission within three weeks. In the treatment of MABA infection, compliance with microbial sensitivity test is crucial.

Clofazimine Inhalation Suspension Demonstrates Promising Toxicokinetics in Canines for Treating Pulmonary Nontuberculous Mycobacteria Infection

Pulmonary nontuberculous mycobacteria (NTM) infection is recognized as a major global health concern due to its rising prevalence worldwide. As an opportunistic pathogen with increasing antibiotics resistance, prolonged systemic dosing with multiple antibiotics remains the primary treatment paradigm. These prolonged treatments, administered predominantly by oral or parenteral routes, often lead to systemic toxicity. A novel inhaled formulation of clofazimine may finally resolve issues of toxicity, thereby providing for improved NTM therapy. Clofazimine inhalation suspension was evaluated in canines to determine toxicity over 28 days of once-a-day dosing. The good laboratory practice (GLP) repeat dosing study evaluated low, mid, and high dosing (2.72 mg/kg and 2.95 mg/kg; 5.45 mg/kg and 5.91 mg/kg; and 10.87 mg/kg and 10.07 mg/kg, average male versus female dosing) of nebulized clofazimine over 30, 60, and 120 min using a jet nebulizer. Toxicokinetic analyses were performed on study days 29, 56, and 84. All three dose levels showed significant residual drug in lung tissue, demonstrating impressive lung loading and long lung residence. Drug concentrations in the lung remained well above the average NTM MIC at all time points, with measurable clofazimine levels at 28 and 56 days postdosing. In contrast, plasma levels of clofazimine were consistently measurable only through 14 days postdosing, with measurements below the limit of quantitation at 56 days postdosing. Clofazimine inhalation suspension may provide an effective therapy for the treatment of NTM infections through direct delivery of antibiotic to the lungs, overcoming the systemic toxicity seen in oral clofazimine treatment for NTM.

Evaluation of comprehensive benefits of sponge cities using meta-analysis in different geographical environments in China

With the rapid progress in urbanization, frequent urban waterlogging and non-point source pollution are threatening the living and health of human beings. Sponge city construction has become an effective means to curb urban waterlogging. Although related studies have explored the comprehensive benefits of sponge cities, few studies have been conducted on the effects of different geographical environments on runoff control and suspended solid (SS) removal. Based on 76 cities with sponge cities in China, this study used the meta-analysis method to evaluate the relationships of climate, terrain, underlying surface conditions, and construction area with the increase in the total annual runoff control rate and SS removal rate. The results reveal that the runoff control benefit can be significantly improved by sponge cities under the combined conditions of average annual precipitation of approximately 1000 mm, high fractional vegetation cover, sufficient soil fertility, a terrain slope i of ≤2%, and a permeability coefficient of strata of 100-200 m/d, especially in northern China, where the weight representing the quantity of comprehensive benefits was calculated to be 25.5%. In addition, the study results assist in reforming unfavorable geographical environments in the construction of sponge city, thus providing more effective solutions for tackling SS pollution. The most significant benefits of SS removal were obtained in north central China, where the weight was 21.4%. This study comprehensively investigated the effects of geographical environmental factors on the comprehensive benefits of sponge city reflected by the improvement in the total annual runoff control rate and the SS removal rate. The results will provide guidance for the planning and design of global sponge cities and effectively optimize the practice, scale, and location of existing construction based on specific geographical environments.

In Vitro Bedaquiline and Clofazimine Susceptibility Testing in Mycobacterium abscessus

Bedaquiline and clofazimine are increasingly used to treat infections with Mycobacterium abscessus. We determined distributions of MICs by broth microdilution for bedaquiline and clofazimine for 61 M. abscessus clinical isolates using different media and incubation times. We show that incubation time and growth media critically influence the MIC. Our data will aid in defining future clinical breakpoints for in vitro susceptibility testing for bedaquiline and clofazimine in M. abscessus.