Relations entre la BPCO et les infections à mycobactéries non tuberculeuses

Long-term case-fatality rate of nontuberculous mycobacterial disease in people living with HIV

Background

Few data are available regarding the long-term case-fatality rate (CFR) among people living with HIV (PLWH) with nontuberculous mycobacteria (NTM) disease. The aim of this study is to analyze the long-term CFR in patients with NTM disease and to identify risk factors for their death.

Methods

A retrospective cohort study of 379 cases of microbiologically confirmed NTM disease in PLWH was conducted from January 1, 2012, to December 31, 2020, in Shanghai, China. We used Kaplan–Meier survival analysis and the log-rank test to compare the long-term CFR in patients with disseminated NTM (DNTM) and localized NTM disease. Univariate Cox proportional hazards regression analysis and a stepwise Cox proportional hazards regression model were used to estimate the predictors of long-term CFR.

Results

The cohort was followed up for a median of 26 months. The total CFR was 15.7% by one year and increased to 22.6% at 5 years after the diagnosis of NTM disease. The 5-year CFR of PLWH with DNTM was significantly higher than that of PLWH with localized NTM (26.7% vs 19.6% for DNTM and localized NTM disease, respectively). Older age [hazard ratio (HR) = 1.04, 95% confidence interval (CI): 1.02–1.06, P < 0.001], comorbidity (HR = 2.05, 95% CI: 1.21–3.49, P < 0.01), DNTM (HR = 2.08, 95% CI: 1.17–3.68, P < 0.05), and HIV viral load (HR = 1.32, 95% CI: 1.12–1.55, P < 0.001) were all independent risk factors for long-term CFR. In the subgroup analysis, time to culture positivity was negatively correlated with CFR in patients with DNTM (HR = 0.90, 95% CI: 0.82–0.98, P < 0.05).

Conclusions

NTM was associated with a high long-term CFR in PLWH. Further approaches to prevent NTM disease in PLWH are urgently needed.

Graphical Abstract

Exploring Potential COPD Immunosuppression Pathways Causing Increased Susceptibility for MAC Infections among COPD Patients

Although there has been a drastic decline in the cases of Tuberculosis in the United States, the prevalence of infections caused by Mycobacterium avium Complex (MAC) has steadily increased in the past decades. Mycobacterium avium (M. avium) is one of the most abundant microorganisms in the MAC species. The mycobacterium genus is divided into two major groups: tuberculosis causing mycobacteria and non-tuberculous mycobacteria. MAC is most prominent among the non-tuberculous mycobacteria. MAC is an opportunistic pathogen that is present in soil, water, and droplets in the air. MAC infections can result in respiratory disease and can disseminate in affected patients. MAC infections are especially prevalent in patients with preexisting respiratory conditions such as Chronic Obstructive Pulmonary Disease (COPD). COPD is one of the most common lung conditions in the world with the primary cause being smoking in developed countries. COPD involves chronic inflammation of lung tissue resulting in increased susceptibility to infection. There is a lack of research regarding the pathophysiology that leads COPD patients to be susceptible to MAC infection. Our review paper therefore aims to investigate how the pathogenicity of MAC bacteria and immune decline seen in COPD patients leads to a greater susceptibility to MAC infection among COPD patients.

[Emerging bacteria in cystic fibrosis and non-cystic fibrosis bronchiectasis from a microbiologist's perspective]

INTRODUCTION

Common major pathogens like Pseudomonas aeruginosa are identified in the airways of patients with cystic fibrosis (CF) and non-CF bronchiectasis. However, other opportunistic bacterial pathogens like Achromobacter xylosoxidans complex, Stenotrophomonas maltophilia and non-tuberculous mycobacteria are currently emerging in CF and are also reported in non-CF bronchiectasis.

BACKGROUND

The emergence of opportunistic bacterial pathogens has been recognized in CF through annual national reports of sputum microbiology data. Despite common factors driving the emergence of bacteria identified in CF and non-CF bronchiectasis patients, bronchiectasis registries have been created more recently and no longitudinal analysis of recorded microbiological data is currently available in the literature, thereby preventing the recognition of emerging bacteria in patients with non-CF bronchiectasis.

OUTLOOK

A longitudinal follow-up of microbiological data is still needed in non-CF bronchiectasis to identify emerging opportunistic bacterial pathogens. Homogeneity in practice of sputum microbiological examination is also required to allow comparative analysis of data in CF and non-CF bronchiectasis.

CONCLUSION

Bacterial pathogens recognized as emerging in CF have to be more carefully monitored in non-CF bronchiectasis in view of their association with deterioration of the lung disease.

Pulmonary non-tuberculous mycobacterial infections: current state and future management

Currently, there is a trend of increasing incidence in pulmonary non-tuberculous mycobacterial infections (PNTM) together with a decrease in tuberculosis (TB) incidence, particularly in developed countries. The prevalence of PNTM in underdeveloped and developing countries remains unclear as there is still a lack of detection methods that could clearly diagnose PNTM applicable in these low-resource settings. Since non-tuberculous mycobacteria (NTM) are environmental pathogens, the vicinity favouring host-pathogen interactions is known as important predisposing factor for PNTM. The ongoing changes in world population, as well as socio-political and economic factors, are linked to the rise in the incidence of PNTM. Development is an important factor for the improvement of population well-being, but it has also been linked, in general, to detrimental environmental consequences, including the rise of emergent (usually neglected) infectious diseases, such as PNTM. The rise of neglected PNTM infections requires the expansion of the current efforts on the development of diagnostics, therapies and vaccines for mycobacterial diseases, which at present, are mainly focused on TB. This review discuss the current situation of PNTM and its predisposing factors, as well as the efforts and challenges for their control.

[Bronchiectasis imaging]

Bronchiectasis are defined as an irreversible focal or diffuse dilatation of the bronchi and can be associated with significant morbidity. The prevalence is currently increasing, probably due to an increased use of thoracic computed tomography (CT). Indeed, the diagnosis relies on imaging and chest CT is the gold standard technique. The main diagnosis criterion is an increased bronchial diameter as compared to that of the companion artery. However, false positives are possible when the artery diameter is decreased, which is called pseudo-bronchiectasis. Other features such as the lack of bronchial tapering, and visibility of bronchi within 1cm of the pleural surface are also diagnostic criteria, and other CT features of bronchial disease are commonly seen. Thoracic imaging also allows severity assessment and long-term monitoring of structural abnormalities. The distribution pattern and the presence of associated findings on chest CT help identifying specific causes of bronchiectasis. Lung MRI and ultra-low dose CT and are promising imaging modalities that may play a role in the future. The objectives of this review are to describe imaging features for the diagnosis and severity assessment of bronchiectasis, to review findings suggesting the cause of bronchiectasis, and to present the new developments in bronchiectasis imaging.