An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases

Disasters pile up on the rubbing heel: Sporothrix globosa as secondary infection to Mycobacterium chelonae infection

Mycobacterium chelonae and Sporothrix globosa, both of which are opportunistic pathogens, have been proved to be possible multidrug resistant. However, are all recurring symptoms in chronic infections related to decreasing susceptibility? Here we report a case of sporotrichosis secondary to M. chelonae infection. In addition, we find that the blackish-red spots under the dermoscopic view can be employed as a signal for the early identification and regression of subcutaneous fungal infection.

The clinical features and prognostic factors of miliary tuberculosis in a high tuberculosis burden area

BACKGROUND

Miliary Tuberculosis (TB) remains an important infectious disease that threatens human health. The clinical characteristics and prognostic factors of miliary TB are summarized in this study.

METHODS

The clinical information of miliary TB patients between 2010 and 2022 was retrospectively analyzed. Patients with miliary TB were characterized and compared to adverse outcomes cases. Factors independently associated with adverse outcomes were determined via multivariate logistic regression analysis.

RESULTS

A total of 288 patients were analyzed, including 181 with adverse outcomes. The clinical manifestations are atypical. 88.54% Of them experienced systemic symptoms, whilst 69.79% manifested respiratory symptoms. 40.97% Presented with neurologic symptoms, while 35.07% reported gastrointestinal symptoms. The major comorbidities were pharmacological immunosuppression (21.53%), pneumoconiosis (15.28%), diabetes (10.76%), and pregnancy or postpartum (7.29%). Regarding microbiology, most patients were diagnosed via sputum or Bronchoalveolar Lavage Fluid (BALF), pleural effusion, ascites, cerebrospinal fluid, urine TB-DNA, and tuberculosis culture. Meanwhile, 2.43% of patients were diagnosed via cerebrospinal fluid NGS. Independent risk factors predictive of adverse outcomes were current smoking, leukocytosis, elevated alanine aminotransferase (ALT) levels, and the combination of lymphopenia with bone marrow tuberculosis or tuberculous lymphadenitis. The accuracy of the model was validated by an area under the ROC curve of 0.753 (95% IC 0.697-0.810).

CONCLUSIONS

The clinical manifestations of miliary TB are atypical, and early diagnosis is challenging. The major comorbidities in miliary TB patients were pharmacological immunosuppression, pneumoconiosis, diabetes, pregnancy, and postpartum. Regarding etiological detection, multi-site and multi-type specimens should be collected for a timely diagnosis. Cerebrospinal fluid mNGS test may be a viable choice in some cases. Finally, current smoking, leukocytosis, elevated ALT levels, and the combination of lymphopenia with bone marrow tuberculosis or tuberculous lymphadenitis were identified as independent risk factors for adverse outcomes.

Multidrug-resistant Mycobacterium abscessus infection in an anophthalmic socket treated with bedaquiline on a compassionate use basis: A case report

Purpose

To explore the management of a rare ophthalmic infection caused by a multi-resistant strain of Mycobacterium abscessus in the anophthalmic cavity of a patient with a history of multiple eye surgeries.

Observations

A 60-year-old woman with a history of multiple ocular complications, culminating in the enucleation of the eye and subsequent dermograft implant, developed a resistant infection in the anophthalmic cavity. The infection persisted despite various local interventions and broad-spectrum systemic antibiotic treatments. Resolution of the infection was only achieved after precise diagnosis and the implementation of intensive treatment, which included a specific combination of antibiotics and appropriate surgical debridement of the anophthalmic cavity.

Conclusions and importance

This case highlights the complexity in managing ophthalmic infections caused by non-tuberculous mycobacteria. It underscores the importance of a multidisciplinary and personalized treatment approach, as well as the need to develop specific guidelines for ophthalmic infections caused by rapidly growing mycobacteria.

Nontuberculous Mycobacteria Isolates in Respiratory Samples and Mycobacterial Pulmonary Disease in an Area of Northern Spain

Introduction

The epidemiology of nontuberculous mycobacteria (NTM) is not well known. In this study, we aimed to determine the incidence of NTM isolates and nontuberculous mycobacterial pulmonary disease (NTM-PD) in five closely located hospitals in an area of northern Spain and analyse differences between them.

Material and methods

Demographic, microbiological, clinical and radiological data were collected retrospectively from all patients with a NTM isolated from respiratory specimens at five hospitals between 2012 and 2019. Mycobacterium gordonae isolates were excluded. Once the data was collected, it was determined which patients met the NMT-PD criteria.

Results

594 patients were included in the study. The mean incidence rate of NTM isolates across all five hospitals in the period studied was 4.15 per 100,000 person-year, while the rate of NTM-PD was 1.2. The annual number of isolates showed an upward trend over this period, but the same did not occur in the number of cases of NTM-PD. The species most frequently isolated were Mycobacterium avium complex (MAC) and Mycobacterium xenopi and those most frequently causing disease were MAC and Mycobacterium kansassi. There were significant differences between the five centres.

Conclusions

Our results are in line with similar studies in Europe in terms of NTM isolation and NTM-PD incidence and species isolated; however, we do not see the upward trend in NTM-PD rates described elsewhere. The great variability in isolation and disease rates, as well as in species isolated in geographically close areas, underlines, in our opinion, the importance of local environmental factors.

Analysis of Clinical Isolation Characteristics of Nontuberculous Mycobacteria and Drug Sensitivity of Rapidly Growing Mycobacteria in the General Hospital of Guangzhou, China

Purpose

The clinical distribution characteristics of nontuberculous mycobacteria (NTM) in general hospital were explored to guide the clinical diagnosis and treatment of NTM infection.

Methods

Samples with positive mycobacterium culture in the First Affiliated Hospital of Guangzhou Medical University were collected and identified through PCR. Phenotypic drug sensitivity experiments were conducted on 44 Mycobacteroides abscessus isolated from clinical departments with broth microdilution method, and rrl, rrs and erm (41) genes associated with drug resistance were detected.

Results

From September 2020 to July 2023, 314 mycobacterium-positive isolates were separated from patients in the First Affiliated Hospital of Guangzhou Medical University, with 147 (46.8%) NTM isolates were included in our study. The samples were respiratory tract specimens mainly, with 64% bronchoalveolar lavage fluid. Of 144 cases identified, samples were from 133 patients (60 males and 73 females; gender ratio of 0.82:1). NTM was mainly isolated from the people aged 40 and above, especially females (χ2 = 10.688, P = 0.014). M. abscessus (61, 42.36%), M. intracellulare (35, 24.31%) were the two most NTMs in this hospital. Clinical strains of M. abscessus exhibited high resistance to antibiotics, except for cefoxitin (31.8%), linezolid (25.0%), amikacin (0%), and clarithromycin (18.2%). Among 8 strains of M. abscessus with clarithromycin acquired resistance, just 4 strains (50.0%) showed mutations (A2270G, A2271G) in rrl gene, but a new mutation (C2750T) was detected in 1 strain. Among 14 strains of M. abscessus with clarithromycin-induced resistance, 13 (93.0%) strains had T28 erm (41) gene and 1 (7.0%) strain had C28 erm (41) gene.

Conclusion

M. avium-intracellulare complex was gradually becoming predominant strain in Guangzhou area. The resistant situation of M. abscessus in general hospital had shown severe. Potential mutation in rrl gene associated with clarithromycin acquired resistance of M. abscessus were found, but drug-resistant mechanism remained unclear.

Source-to-tap investigation of the occurrence of nontuberculous mycobacteria in a full-scale chloraminated drinking water system

Nontuberculous mycobacteria (NTM) in drinking water are a significant public health concern. However, an incomplete understanding of the factors that influence the occurrence of NTM in drinking water limits our ability to characterize risk and prevent infection. This study sought to evaluate the influence of season and water treatment, distribution, and stagnation on NTM in drinking water. Samples were collected source-to-tap in a full-scale, chloraminated drinking water system approximately monthly from December 2019 to November 2020. NTM were characterized using culture-dependent (plate culture with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry [MALDI-TOF MS] isolate analysis) and culture-independent methods (quantitative PCR and genome-resolved metagenomics). Sampling locations included source waters, three locations within the treatment plant, and five buildings receiving water from the distribution system. Building plumbing samples consisted of first draw, 5-min flush, and full flush cold-water samples. As the study took place during the COVID-19 pandemic, the influence of reduced water usage in three of the five buildings was also investigated. The highest NTM densities source-to-tap were found in the summer first draw building water samples (107 gene copies/L), which also had the lowest monochloramine concentrations. Flushing was found to be effective for reducing NTM and restoring disinfectant residuals, though flush times necessary to improve water quality varied by building. Clinically relevant NTM species, including Mycobacterium avium, were recovered via plate culture, with increased occurrence observed in buildings with higher water age. Four of five NTM metagenome-assembled genomes were identified to the species level and matched identified isolates.IMPORTANCENTM infections are increasing in prevalence, difficult to treat, and associated with high morbidity and mortality rates. Our lack of understanding of the factors that influence NTM occurrence in drinking water limits our ability to prevent infections, accurately characterize risk, and focus remediation efforts. In this study, we comprehensively evaluated NTM in a full-scale drinking water system, showing that various steps in treatment and distribution influence NTM presence. Stagnant building water contained the highest NTM densities source-to-tap and was associated with low disinfectant residuals. We illustrated the differences in NTM detection and characterization obtained from culture-based and culture-independent methods, highlighting the complementarity between these approaches. We demonstrated that focusing NTM mitigation efforts in building plumbing systems, which have the highest NTM densities source-to-tap, has potential for immediate positive effects. We also identified steps during treatment that increase NTM levels, which provides beneficial information for utilities seeking to reduce NTM in finished water.

Characterization of non-tuberculous mycobacterial pulmonary disease and pulmonary tuberculosis in patients with AFB smear-positive sputum: A retrospective comparative study

Background

Distinguishing nontuberculous mycobacteria pulmonary disease (NTM-PD) from pulmonary tuberculosis (PTB) is a challenge especially in patients with positive sputum smear of acid-fast bacilli (AFB). This study aimed to compare and identify the clinical characteristics between the two diseases among patients with positive sputum AFB.

Methods

From February 2017 through March 2021, patients with positive sputum AFB were reviewed in two hospitals of China. Among them, clinical data of NTM-PD and PTB patients was collected and compared.

Results

76 cases of NTM-PD and 92 cases of PTB were included in our study. When compared with PTB, NTM-PD patients were older (59.2 ± 11.4 vs 44.2 ± 19.5 years, P < 0.001) and manifested more hemoptysis and dyspnea (28.9 % vs 14.1 %, P < 0.05; 48.7 % vs 17.4 %, P < 0.001 respectively). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) for Xpert were 85.9 %, 96.1 %, 96.3 %, 84.9 %, respectively, compared to 94.2 %, 81.1 %, 83.1 %, 93.5 %, respectively for T-spot in diagnosing PTB. In radiological features, NTM-PD affected more lobes (4.53 ± 0.89 vs 3.61 ± 1.41, P < 0.001) and showed more consolidation (50 % vs 32.6 %, P < 0.05), destroyed lung (22.7 % vs 9.8 %, P < 0.05), honeycomb lung (26.7 % vs 6.5 %, P < 0.001) but less nodules (80.3 % vs 95.7 %, P < 0.05), tree-in-bud sign (49.3 % vs 87 %, P < 0.001), and satellite nodules (14.5 % vs 90.2 %, P < 0.001) than PTB. Age (odds ratio [OR], 1.043; 95 % confidence interval [CI], 1.018-1.069, P < 0.05), hemoptysis (OR, 3.552; 95%CI, 1.421-8.729, P < 0.05), and dyspnea (OR, 2.631; 95%CI, 1.151-6.016, P < 0.05) were independently correlated with NTM infection.

Conclusions

NTM-PD and PTB share similar clinical manifestations. Among them, advanced age, hemoptysis, and dyspnea are the independent predictors for NTM infection. Xpert is an efficiency analysis in discriminating between NTM-PD and PTB in patients with positive sputum AFB.

Current challenges in pulmonary nontuberculous mycobacterial infection: a case series with literature review

BACKGROUND

The prevalence of nontuberculous mycobacteria pulmonary disease (NTM-PD), particularly caused by Mycobacterium avium complex (MAC), is rising due to improved diagnostics, increased awareness, and more susceptible populations. NTM-PD significantly affects quality of life and imposes substantial economic costs. Understanding its clinical features, risk factors, and treatment challenges is vital for enhancing patient outcomes.

PATIENTS AND METHODS

A convenience sample from the University of Connecticut Health Center and Wayne State University involving patients with NTM-PD from 2021 to 2024 was studied retrospectively. Cases were selected to demonstrate typical diagnostic and treatment challenges, followed by a multidisciplinary roundtable discussion to examine patient-centered care strategies.

RESULTS

Analysis of six cases pinpointed chronic lung conditions and immunomodulatory therapy as key risk factors. Standard treatment, involving extensive multi-drug regimens, frequently results in poor adherence due to side effects and complex management requirements. The discussions underlined the importance of a customized, interdisciplinary approach to improve treatment effectiveness and patient quality of life.

CONCLUSIONS

NTM-PD is an escalating public health issue with notable clinical and economic consequences. Managing this disease effectively demands a comprehensive, patient-centered strategy that includes precise diagnosis, flexible treatment plans, and collaborative care.

Improved detection of mycobacteria in CF and tissue samples grown in mycobacteria growth indicator tube incubated at 30°C compared to conventional growth conditions of liquid and solid media

This study evaluates the growth of mycobacteria in samples from cystic fibrosis (CF) patients and tissue samples using the mycobacteria growth indicator tube (MGIT) incubated at 30°C in comparison to conventional MGIT cultures incubated at 37°C in a BACTEC MGIT 960 device and solid media incubated at 36°C and 30°C. A total of 1,549 samples were analyzed, of which 202 mycobacterial isolates were cultured from 197 positive specimens, including five mixed cultures. The highest detection rate was achieved from MGIT at 30°C, with 84.2% of mycobacterial isolates (170 of 202), which was significantly higher than any other culture condition (P < 0.0001 for any condition). MGIT at 37°C yielded 61.4% (124 of 202) of the recovered isolates, whereas Löwenstein Jensen (LJ) and Stonebrink at 36°C, and LJ and Stonebrink at 30°C retrieved 47.0% (95), 49.5% (100), 50.0% (101), and 53.0% (107) of the isolates, respectively. Of the 53 isolates that were grown exclusively under one culture condition, the highest number of isolates (36) was recovered from MGIT incubated at 30°C. MGIT at 37°C recovered eight of the 53 isolates, whereas LJ incubated at 30°C and Stonebrink incubated at 30°C and 36°C recovered five, three, and one isolate, respectively. No isolates were grown exclusively from LJ incubated at 36°C. In CF patients and tissue samples, MGIT cultivated at 30°C for 8 weeks increases the performance of mycobacterial culture.

IMPORTANCE

Our study shows that the addition of mycobacteria growth indicator tube (MGIT) liquid culture incubated at 30°C improves the detection of mycobacteria from CF and tissue samples. MGIT incubated at 30°C recovered significantly more mycobacterial isolates than MGIT incubated at 37°C and significantly more isolates than either Lowenstein Jensen or Stonebrink solid media incubated at either 36°C or 30°C. Of 202 mycobacterial isolates recovered from 1,549 specimens, 170 were recovered from MGIT incubated at 30°C, followed by MGIT incubated at 37°C with 124 isolates and solid media culture conditions that recovered between 95 and 107 mycobacterial isolates. All conventional culture conditions combined without MGIT incubated at 30°C recovered 166 isolates. MGIT incubated at 30°C recovered the highest number of isolates detected exclusively by a single culture condition and recovered mycobacterial isolates of highly relevant mycobacterial species, including Mycobacterium abscessus and Mycobacterium tuberculosis.

Increasing trends of non-tuberculous mycobacteria clinical isolates in Guangzhou, China

Non-tuberculous mycobacteria (NTM) are one of major public health concern. The current study aimed to find the prevalence trends of NTM in Guangzhou, China from January 2018 to December 2023. A total of 26,716 positive mycobacterial cultures were collected. Thirty-six specimens with incomplete personal information were excluded. The remaining 26,680 specimens were identified using a gene chip method. 16,709 isolates were Mycobacterium tuberculosis (MTB) (62.63 %), and 9,971 were NTM (37.37 %). 43.43 % (4,330/9,971) of NTM isolates were male, and 56.57 % (5,641/9,971) were female (χ2 = 24.36, P < 0.05), a male to female ratio of approximately 1:1.30. Infections in individuals with aged 40 years and above was higher (77.63 %) than below 40 years (22.37 %) (χ2 = 4.94, P = 0.026). The annual NTM isolation rates from 2018 to 2023 were 32.03 %, 34.00 %, 36.27 %, 38.58 %, 38.99 %, and 43.24 %, respectively, showing an increasing trend (χ2 for trend = 0.097, P < 0.05) (R = 0.097, P < 0.05). Out of 9,971 NTM isolates, 8,881 cases include only five common NTM species (MAC, M. abscessus/M. chelonae, M. kansasii, M. fortuitum, and M. gordonae). The overall NTM isolation rate was 37.37 %. The NTM isolation rate was significantly higher than the national average, showing an increasing trend over the last six years.

Significance of changes in cavity after treatment in Mycobacterium avium complex pulmonary disease

Cavities are characteristic radiological features related to increased mycobacterial burden and poor prognosis in Mycobacterium avium complex pulmonary disease (MAC-PD). However, cavity changes following treatment and their clinical implications remain unknown. We aimed to elucidate whether cavity obliteration or reduction in cavity size or wall thickness correlates with microbiological cure. In total, 136 adult patients with cavitary MAC-PD treated for ≥ 6 months between January 1st, 2009, and December 31st, 2021, in a tertiary referral centre in South Korea were enrolled. The cavity with the largest diameter at treatment initiation was tracked for size and thickness changes. Following median treatment of 20.0 months, 74 (54.4%) patients achieved microbiological cure. Cavity obliteration, achieved in 58 (42.6%) patients at treatment completion, was independently associated with microbiological cure. In patients with persistent cavities, size reduction of ≥ 10% was significantly associated with microbiological cure, whereas thickness reduction was not. Five-year mortality rates in patients with cavity obliteration, persistent but reduced cavity, and persistent cavity without shrinkage were 95.6%, 72.1%, and 65.3%, respectively (P < 0.001). In conclusion, cavity obliteration or shrinkage at treatment completion is associated with microbiological cure and reduced mortality in MAC-PD, suggesting that cavity changes could serve as a proxy indicator for treatment response.

Clinical characteristics of pulmonary Mycobacterium avium complex disease in patients with interstitial lung disease

OBJECTIVE

Mycobacterium avium complex pulmonary disease (MAC-PD) is occasionally complicated by interstitial lung disease (ILD) in clinical practice, but clinical studies are limited. This study aims to elucidate the clinical and imaging characteristics of MAC-PD in patients with ILD.

METHODS

We retrospectively analyzed imaging and clinical data from medical records of 54 consecutive ILD patients diagnosed with MAC-PD from 2011 to 2021 at our institution. We compared the imaging and clinical data of these patients with 2218 ILD patients diagnosed at our institution.

RESULTS

The mean age of the patients was 74 years, with 25 males and 29 females, and a mean body mass index (BMI) of 20.0 kg/m2. Compared to all ILD patients, ILD-associated MAC-PD had older ages, lower BMI. The most common underlying ILD diagnosis was unclassifiable interstitial pneumonia. MAC-PD imaging classification was nodular-bronchiectatic (NB) type in 17 patients, fibro-cavitary (FC) type in 15 patients, and unclassifiable (UC) type in 22 patients. Many UC types were difficult to diagnose due to the absence of clear findings indicative of MAC infection. Chronic pulmonary aspergillosis complication was 24.1 %. The mean survival of ILD-associated MAC-PD was 55.6 months, shorter than that of regular MAC-PD. The UC type had a shorter survival than the NB type, similar to the FC type.

CONCLUSION

MAC-PD associated with ILD frequently complicates chronic pulmonary aspergillosis and has a poor prognosis. The most common imaging type, UC type, particularly has a shorter survival. Careful management is essential for MAC-PD associated with ILD.

Fatal disseminated Mycobacterium avium infection with bone marrow infiltration and hemophagocytic syndrome

Disseminated non-tuberculous mycobacterial (NTM) infection can affect patients with underlying immunosuppressive conditions. Despite being rare, delay in diagnosis can lead to life-threatening uncontrolled immune response and hemophagocytic syndrome (HPS). We report a case of a 63-year-old female with suspected autoimmune disease, in whom HPS was diagnosed according to HLH-2004 criteria and H-score. Mycobacterium avium (M. avium) was isolated from blood culture, bronchoalveolar lavage (BAL) and bone marrow biopsy. In immunosuppressed patients, early clinical suspicion and prompt microbiological diagnosis of mycobacterial infection together with drug susceptibility tests (DST)-based treatment, as well as HPS, are pivotal to increase the likelihood of treatment success.

Distinctive clinical features of radiological pleuroparenchymal fibroelastosis with nontuberculous mycobacterial pulmonary disease: A multicenter retrospective cohort study

OBJECTIVES

To compare the characteristics and prognosis of patients with nontuberculous mycobacterial (NTM) pulmonary disease (PD) with pleuroparenchymal fibroelastosis (PPFE) with those of patients with nodular/bronchiectatic (NB) and fibrocavitary (FC) NTM-PD.

METHODS

This multicenter, retrospective, observational study enrolled 32 patients with NTM-PPFE (median age: 70.5 years, 15 females) from six institutions in Japan from January 2003 to December 2018. Their clinical characteristics, and response to therapy were compared with age- and sex-matched cohorts of patients with non-cavitary NB and cavitary NB/FC NTM-PD.

RESULTS

Patients with NTM-PPFE had a lower body mass index and a higher standard NTM-PD therapy initiation rate than patients with other NTM-PD types. Sputum culture conversion rates were comparable between groups; however, patients with NTM-PPFE had a higher incidence of treatment-related adverse events, including optic neuropathy associated with high-dose ethambutol therapy, lower percent predicted forced vital capacity values, higher serum Krebs von den Lungen 6 (KL-6) levels, and poorer treatment outcomes than the other groups. Cox regression revealed that NTM-PPFE was an independent risk factor for death/pneumothorax (adjusted hazard ratio: 35.3, 95% confidence interval: 3.90-4692).

CONCLUSIONS

NTM-PPFE is a unique NTM-PD phenotype with a poorer prognosis than the NB and FC phenotypes.

Nontuberculous mycobacterial pulmonary disease presenting as bronchiolitis pattern on CT without cavity or bronchiectasis

BACKGROUND

This study aimed to investigate the radiological changes in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) having bronchiolitis patterns on computed tomography (CT).

METHODS

We retrospectively reviewed the final diagnosis and radiologic changes of patients suspected of having NTM-PD without cavity or bronchiectasis on CT image, between January 1, 2005 and March 31, 2021. NTM-PD was diagnosed based on the American Thoracic Society and Infectious Diseases Society of America criteria. The initial and final CT findings (bronchiectasis, cellular bronchiolitis, cavity formation, nodules, and consolidation) were compared between patients diagnosed with and without NTM-PD.

RESULTS

This study included 96 patients and 515 CT images. The median CT follow-up duration was 1510.5 (interquartile range: 862.2-3005) days. NTM-PD was recognized in 43 patients. The clinical variables were not significantly different between patients with and without NTM-PD, except for underlying chronic airway disease (P < 0.001). Nodule and consolidation were more frequently observed on the initial CT scans of patients with NTM-PD compared with those without (P < 0.05). On the final follow-up CT scan, bronchiectasis (P < 0.001), cavity (P < 0.05), nodule (P < 0.05), and consolidation (P < 0.05) were more frequently observed in patients with NTM-PD. Among the 43 patients with NTM-PD, 30 showed a radiological progression on CT, with bronchiectasis (n = 22) being the most common finding. The incidence of bronchiectasis increased over time.

CONCLUSION

The bronchiolitis pattern on CT images of patients with NTM-PD showed frequent radiological progression during the follow-up period.

Rapid lateral flow test for Mycobacterium tuberculosis complex and non-tuberculous mycobacteria differentiation

The diagnosis of mycobacterial infections, including both the Mycobacterium tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM), poses a significant global medical challenge. This study proposes a novel approach using immunochromatographic (IC) strip tests for the simultaneous detection of MTBC and NTM. Traditional methods for identifying mycobacteria, such as culture techniques, are hindered by delays in distinguishing between MTBC and NTM, which can affect patient care and disease control. Molecular methods, while sensitive, are resource-intensive and unable to differentiate between live and dead bacteria. In this research, we developed unique monoclonal antibodies (mAbs) against Ag85B, a mycobacterial secretory protein, and successfully implemented IC strip tests named 8B and 9B. These strips demonstrated high concordance rates with conventional methods for detecting MTBC, with positivity rates of 93.9% and 85.9%, respectively. For NTM detection, the IC strip tests achieved a 63.2% detection rate compared to culture methods, considering variations in growth rates among different NTM species. Furthermore, this study highlights a significant finding regarding the potential of MPT64 and Ag85B proteins as markers for MTBC detection. In conclusion, our breakthrough method enables rapid and accurate detection of both MTBC and NTM bacteria within the BACTEC MGIT system. This approach represents a valuable tool in clinical settings for distinguishing between MTBC and NTM infections, thereby enhancing the management and control of mycobacterial diseases. KEY POINTS: • Panel of mAbs for differentiating MTB versus NTM • IC strips for diagnosing MTBC and NTM after the BACTEC MGIT • Combined detection of MTP64 and Ag85B enhances diagnostic accuracy.

Immunopathology of lung transplantation: from infection to rejection and vice versa

Lung transplantation offers a lifesaving option for patients with end-stage lung disease, but it is marred by a high risk of post-transplant infections, particularly involving multidrug-resistant bacteria, Cytomegalovirus, and fungal pathogens. This elevated infection rate, the highest among solid organ transplants, poses a significant challenge for clinicians, particularly within the first year post-transplantation, where infections are the leading cause of mortality. The direct exposure of lung allografts to the external environment exacerbates this vulnerability leading to constant immune stimulation and consequently to an elevated risk of triggering alloimmune responses to the lung allograft. The necessity of prolonged immunosuppression to prevent allograft rejection further complicates patient management by increasing susceptibility to infections and neoplasms, and complicating the differentiation between rejection and infection, which require diametrically opposed management strategies. This review explores the intricate balance between preventing allograft rejection and managing the heightened infection risk in lung transplant recipients.

Clinical practice guideline for the prevention and management of peritoneal dialysis associated infections in children: 2024 update

Infection-related complications remain the most significant cause for morbidity and technique failure in infants, children and adolescents who receive maintenance peritoneal dialysis (PD). The 2024 update of the Clinical Practice Guideline for the Prevention and Management of Peritoneal Dialysis Associated Infection in Children builds upon previous such guidelines published in 2000 and 2012 and provides comprehensive treatment guidance as recommended by an international group of pediatric PD experts based upon a review of published literature and pediatric PD registry data. The workgroup prioritized updating key clinical issues contained in the 2012 guidelines, in addition to addressing additional questions developed using the PICO format. A variety of new guideline statements, highlighted by those pertaining to antibiotic therapy of peritonitis as a result of the evolution of antibiotic susceptibilities, antibiotic stewardship and clinical registry data, as well as new clinical benchmarks, are included. Recommendations for future research designed to fill important knowledge gaps are also provided.

Patients at risk of nontuberculous mycobacterial pulmonary disease who need testing evaluated using a modified Delphi process by European experts

Background

Identifying patients at risk of nontuberculous mycobacterial pulmonary disease (NTM-PD) is challenging. Delays in NTM-PD identification and management are associated with declining lung function and increased morbidity and mortality.

Study design and methods

European NTM-PD experts (n=12) participated in a three-round modified Delphi process to score symptoms and comorbidities potentially associated with NTM-PD as reasons to test for nontuberculous mycobacteria.

Results

Experts reached a consensus on the symptoms and comorbidities that should and should not prompt testing for nontuberculous mycobacteria. Requirements for testing were scored as high (mean ≥7), medium (mean ≥4-<7) or low (mean <4). Nontuberculous mycobacteria testing should be undertaken when multiple suggestive symptoms are present simultaneously in all patients except those with cancer (7.3-8.8), or when radiology is indicative of NTM-PD (≥8.9). Symptoms of persistent sputum production, recurrent respiratory infection and haemoptysis should prompt testing for nontuberculous mycobacteria, particularly in those with underlying respiratory diseases. Symptomatic patients with bronchiectasis or previous tuberculosis/NTM-PD or those being prescribed or undergoing long-term macrolide therapy for a respiratory condition should also be tested. Testing is not warranted in patients without an underlying respiratory disorder or in those without a history of respiratory disorders unless presenting with multiple symptoms.

Conclusions

Assessing patients' risk of NTM-PD is challenging. This Delphi consensus process provides insight into symptoms and clinical characteristics that should prompt NTM-PD assessment. Timely testing and diagnosis would enable initiation of appropriate management.

Incidence and clinical significance of non-tuberculous mycobacteria among migrants in Denmark: A nationwide register-based cohort study from 1991 through 2021

BACKGROUND

There is limited knowledge about non-tuberculous mycobacteria (NTM) infections in migrants. We aimed to assess the incidence and clinical significance of NTM among migrants in Denmark.

METHOD

Nationwide register-based cohort study of migrants with a positive NTM culture in Denmark from 1991 through 2021, stratified by patient demographics, disease localisation, species, and clinical significance.

RESULTS

433 migrants had a positive NTM culture, resulting in an overall incidence rate (IR) of 3.7 (95%CI 3.3-4.0) per 100,000 migrants. Overall NTM IRs for definite disease were 1.0 (95%CI 0.9-1.2), possible disease 1.0 (95%CI 0.8-1.2), and isolation 1.7 (95%CI 1.4-1.9) per 100,000 migrants. Migrants had considerably higher age- and sex-adjusted NTM IRs of positive cultures (incidence rate ratio [IRR] = 2.1, 95%CI 1.9-2.3, p < 0.001), possible disease (IRR = 2.4, 95%CI 2.0-3.0, p < 0.001), and isolation (IRR = 4.6, 95%CI 3.9-5.4, p < 0.001) compared to Danish-born, but not of definite disease (IRR = 1.1, 95%CI 0.9-1.3, p = 0.562). IRs of migrants with positive NTM cultures did not increase over time (-0.8 %/year, p = 0.133).

CONCLUSIONS

Migrants have a higher, but stable, burden of NTM compared with Danish-born. The higher rates likely reflect that more specimens are examined for Mycobacterium tuberculosis. Microbiologically classified definite NTM disease is not substantially more common among migrants.

Metagenomic next-generation sequencing assistance in identifying Mycobacterium iranicum pulmonary infection: A case report

Nontuberculous mycobacteria (NTM) are important opportunistic pathogens in humans, mostly affecting the lungs, and potentially causing progressive disease in individuals with underlying diseases. The prevalence of NTM infections is increasing worldwide. However, Mycobacterium iranicum (M. iranicum) infections are less common. Here we report a 65-year-old female who developed pneumonia caused by Mycobacterium iranicum, which was detected in bronchoalveolar lavage fluid (BALF) through metagenomic next-generation sequencing (mNGS). The patient was treated with moxifloxacin, doxycycline, and sulfamethoxazole/trimethoprim. Symptoms were relieved and lung abnormalities were shown to be partially absorbed on the follow-up chest computed tomography (CT) scans. As we know, this is the first case of Mycobacterium iranicum pulmonary infection identified by mNGS in BALF.

Disseminated Mycobacterium avium Complex Infection Following CD3/CD20 Bispecific Antibody Therapy in a Patient With Follicular Lymphoma

Infections remain a major concern following bispecific antibody therapy but are not well described in pivotal trials. We present the first well-documented case of a classic but rare opportunistic infection, disseminated Mycobacterium avium complex, in a patient receiving bispecific antibody therapy.

Rates and Risk Factors of Progression in Patients With Nontuberculous Mycobacterial Pulmonary Disease: Secondary Analysis of a Prospective Cohort Study

BACKGROUND

The clinical course of nontuberculous mycobacterial pulmonary disease (NTM-PD) is varied, and a watchful waiting management strategy is appropriate for a subset of patients. Understanding disease progression and risk factors for progression is essential for deciding on an appropriate follow-up strategy.

RESEARCH QUESTION

What is the rate of NTM-PD progression, and what are the predictors of progression?

STUDY DESIGN AND METHODS

Patients with NTM-PD who were enrolled in a prospective observational cohort study between July 1, 2011, and December 31, 2022, were included in this analysis. Clinical, bacterial, laboratory, and radiographic data were collected at enrollment and then regularly during follow-up. NTM-PD progression was defined as either the initiation of treatment or the clinician's intention to treat. The rate of progression was calculated and the predictors for progression were analyzed.

RESULTS

Of the 477 patients enrolled, NTM-PD progressed in 192 patients over a median follow-up of 5.4 years. The incidence of NTM-PD progression was 11.0 cases per 100 person-years (95% CI, 9.5-12.7 cases per 100 person-years). The proportion of patients experiencing disease progression was 21.4% at 1 year, 33.8% at 3 years, and 43.3% at 5 years. The final multivariable analysis model identified female sex (adjusted hazard ratio [aHR], 1.69; 95% CI, 1.19-2.39), elevated erythrocyte sedimentation rate (aHR, 1.79; 95% CI, 1.31-2.43), FEV1 % predicted (aHR, 0.89; 95% CI, 0.82-0.96), and the presence of a cavity (aHR, 2.78; 95% CI, 2.03-3.80) as predictors of progression.

INTERPRETATION

About one-half of patients with NTM-PD experienced progression during an observation period of > 5 years. Patients with risk factors for progression should be observed closely.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01616745; URL: www.

CLINICALTRIALS

gov.

Qualitative Interviews Exploring Adverse Event Mitigation Strategies in Adults Receiving Amikacin Liposome Inhalation Suspension

INTRODUCTION

This study aimed to gain insight from patients with refractory Mycobacterium avium complex lung disease (MAC-LD) into strategies used to manage adverse events (AEs) associated with amikacin liposome inhalation suspension (ALIS).

METHODS

We conducted semi-structured interviews with US patients with refractory MAC-LD prescribed ALIS in a real-world setting. Interview transcripts were analyzed and coded to identify patterns in participants' descriptions of their ALIS treatment experiences, including AEs and their disruptiveness, and AE mitigation strategies, including participants' ratings of strategies' effectiveness. Concept saturation was also assessed.

RESULTS

Twenty participants (mean age 48.7 years; 80% women; mean ALIS duration 5.45 months) were interviewed. At the time of the interview, 15 participants (75%) had received ALIS for > 1 month and 13 (65%) were currently receiving ALIS. Participants described 44 unique AE mitigation strategies, which can be categorized into three groups: prepare for treatment; prevent increased emergence of AEs; and persist on treatment by mitigating AEs. Common strategies (reported by ≥ 50% of participants) included use of educational materials from the patient support program, localized management of throat irritation, and symptom management to reduce fatigue. Evidence of concept saturation was observed: no new strategies were identified in the last five interviews, which suggests the sample was robust enough to identify all mitigation strategies likely to be used by the broader patient population.

CONCLUSIONS

This real-world study identified a diverse set of potential AE mitigation strategies intended to help individual patients prepare for ALIS treatment, prevent the increased emergence of certain AEs, and mitigate the impact of AEs on treatment persistence. Developing a comprehensive accounting of the types of mitigation strategies in use among patients in real-world settings can inform future investigation of the effectiveness of such strategies, and support evidence-based recommendations for treatment management.

Clinical Significance, Species Distribution, and Temporal Trends of Nontuberculous Mycobacteria, Denmark, 1991-2022

Nontuberculous mycobacteria (NTM) are emerging as notable causative agents of opportunistic infections. To examine clinical significance, species distribution, and temporal trends of NTM in Denmark, we performed a nationwide register-based study of all unique persons with NTM isolated in the country during 1991-2022. We categorized patients as having definite disease, possible disease, or isolation by using a previously validated method. The incidence of pulmonary NTM increased throughout the study period, in contrast to earlier findings. Mycobacterium malmoense, M. kansasii, M. szulgai, and M. avium complex were the most clinically significant species based on microbiologic findings; M. avium dominated in incidence. This study shows the need for surveillance for an emerging infection that is not notifiable in most countries, provides evidence to support clinical decision-making, and highlights the importance of not considering NTM as a single entity.

Clinical characteristics and antimicrobial susceptibility profiles of Mycobacterium abscessus and Mycobacterium massiliense pulmonary infection

OBJECTIVES

Mycobacterium abscessus complex (MABC) is the most common rapidly growing Mycobacterium species in structural pulmonary diseases and can be life-threatening. This study aimed to assess the clinical characteristics and drug-susceptibility statuses of different M. abscessus (MAB) subspecies in the Zhejiang Province.

METHODS

DNA sequencing was used to differentiate clinical MABC subspecies isolates. The Clinical and Laboratory Standards Institute guidelines were used to determine in vitro susceptibility of imipenem-relebactam (IMP-REL), omadacycline, and other conventional antibiotics. Patient clinical characteristics were collected and analysed.

RESULTS

In total, 139 M. abscessus, 39 Mycobacterium massiliense, and 1 Mycobacterium bolletii isolates were collected, accounting for 77.7%, 21.8%, and 0.5% of the MABC isolates, respectively. Patients with M. abscessus pulmonary disease (M.ab-PD) had higher proportions of older adults, tuberculosis history, chronic pulmonary disease, and malignancy than those with M. massiliense pulmonary disease (M.ma-PD). Patients with M.ab-PD had higher rates of bilateral middle- and lower-lobe involvement than patients with M.ma-PD. Both subspecies showed high resistance rates to doxycycline and moxifloxacin, and clarithromycin-induced resistance was more common in M.ab than in M.ma. IMP-REL resulted in a twofold reduction in the minimum inhibitory concentration (MIC) value compared with imipenem alone among MAB; furthermore, the MIC was lower in M.ab than in M.ma. Omadacycline and tigecycline had comparable in vitro susceptibility, and the MIC showed no statistically significant difference between M.ab and M.ma.

CONCLUSIONS

M.ab is the most prevalent MABC subspecies in the Zhejiang Province. Patients with M.ab-PD have complex underlying diseases and broader lobar lesions. IMP-REL and omadacycline are promising antibiotics for MABC infection treatment.

Fishy story: paradoxical reaction associated with Mycobacterium marinum

Paradoxical reactions occur when an infection has acute worsening in response to antibiotic therapy. Here, we describe a patient with chronic cutaneous ulcerative lymphangitis that acutely worsened following initiation of antibiotic therapy. The infection was caused by Mycobacterium marinum, a species which has not previously been associated with paradoxical reaction in immunocompetent persons. In this case report, we describe our patient's diagnosis and management, review the management of Mycobacterium marinum infection, and discuss paradoxical reactions in mycobacterial disease.

MALDI-TOF mass spectrometry from nucleic acid: development and evaluation of a novel platform for identification of mycobacteria and detection of genetic markers of resistance

Complete identification methods are critical for evaluating nontuberculous mycobacteria (NTM). Here, we describe a novel diagnostic method for identification of eight NTM, Mycobacterium tuberculosis complex, and three drug resistance markers using PCR/matrix-assisted, laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) from cultured organisms. With this technology, a multiplex end-point PCR is performed for targets of interest. Detection probes that are extended in the presence of a target are added. The extended probes have greater molecular weight and can be detected by MALDI-TOF MS. An AFB Primary Panel was designed to differentiate Mycobacterium avium; Mycobacterium intracellulare subsp. chimaera; Mycobacterium avium complex (other); Mycobacterium abscessus subsp. abscessus, bolletii, and massiliense; Mycobacterium kansasii, and M. tuberculosis complex. This design should cover 90% (3,483/3,691) of mycobacteria seen onsite. A development set of unblinded isolates (n = 217) was used to develop PCR primers, detection probes, and probe barcodes. It demonstrated 99.1% (215/217) agreement with reference methods. An evaluation set using blinded isolates (n = 320) showed an overall sensitivity of 94.3% (range by target: 90.0-100%). Overall specificity from negative media, non-target mycobacteria, and bacteria was 99.1% (108/109; range by target: 94.4-100%). Three drug resistance markers erm (41), rrl, and rrs demonstrated 100%, 91%, and 100% sensitivity, respectively, and >99% specificity. Limit of detection per target ranged from 2.2 × 103 to 9.9 × 106 CFU/mL. The AFB Primary Panel allows for mycobacterial speciation, subspeciation, and resistance mutation detection, which is essential for diagnosis, appropriate therapy, identifying outbreaks, and managing treatment-refractory disease. It can perform with high-throughput and high specificity and sensitivity from isolates.IMPORTANCEEven closely related mycobacteria can have unique treatment patterns, but differentiating these organisms is a challenge. Here, we tested an innovative platform that combines two commonly used technologies and creates something new: matrix-assisted, laser-desorption ionization time-of flight mass spectrometry was performed on PCR amplicons instead of on proteins. This created a robust system with the advantages of PCR (high discriminatory power, high throughput, detection of resistance) with the advantages of mass spectrometry (more targets, lower operational cost) in order to identify closely related mycobacterial organisms.

Efflux pumps and membrane permeability contribute to intrinsic antibiotic resistance in Mycobacterium abscessus

Mycobacterium abscessus is a pulmonary pathogen that exhibits intrinsic resistance to antibiotics, but the factors driving this resistance are incompletely understood. Insufficient intracellular drug accumulation could explain broad-spectrum resistance, but whether antibiotics fail to accumulate in M. abscessus and the mechanisms required for drug exclusion remain poorly understood. We measured antibiotic accumulation in M. abscessus using mass spectrometry and found a wide range of drug accumulation across clinically relevant antibiotics. Of these compounds, linezolid accumulates the least, suggesting that inadequate uptake impacts its efficacy. We utilized transposon mutagenesis screening to identify genes that cause linezolid resistance and found multiple transporters that promote membrane permeability or efflux, including an uncharacterized, M. abscessus-specific protein that effluxes linezolid and several chemically related antibiotics. This demonstrates that membrane permeability and drug efflux are critical mechanisms of antibiotic resistance in M. abscessus and suggests that targeting membrane transporters could potentiate the efficacy of certain antibiotics.

Mycobacterium marseillense bloodstream infection combined with skin fungal infection: a case report and literature review

BACKGROUND

Non-tuberculous mycobacteria (NTM) are present widely in the natural environment and can invade the human body through the respiratory tract, gastrointestinal tract, and skin. Immunocompromised patients are particularly prone to infection, which primarily affects multiple organs, including the lungs, lymph nodes, and skin. However, cases of NTM bloodstream infections are rare. Here, we report a rare case of Mycobacterium marseillense bloodstream infection with concurrent skin fungal infection in a patient after kidney transplantation. Related literature was reviewed to enhance the understanding of this rare condition.

CASE PRESENTATION

A 58-year-old male with a history of long-term steroid and immunosuppressant use after kidney transplantation presented with limb swelling that worsened over the past two months. Physical examination revealed redness and swelling of the skin in all four limbs, with a non-healing wound on the lower left limb. Skin tissue analysis by metagenomic next-generation sequencing (mNGS) and fungal culture indicated infection with Trichophyton rubrum. Blood culture results suggested infection with Mycobacterium marseillense. After receiving anti-NTM treatment, the patient's symptoms significantly improved, and he is currently undergoing treatment.

CONCLUSION

Mycobacterium marseillense is a NTM. Gram staining suffered from misdetection, and the acid-fast staining result was positive. This bacterium was identified by mass spectrometry and mNGS analyses. Antimicrobial susceptibility tests for NTM were performed using the broth microdilution method. The results of the susceptibility test showed that Mycobacterium marseillense was sensitive to clarithromycin, an intermediary between moxifloxacin and linezolid. Bacterial clearance requires a combination of drugs and an adequate course of treatment. NTM bloodstream infections are relatively rare, and early identification and proactive intervention are key to their successful management.

Supporting Patients with Nontuberculous Mycobacterial Pulmonary Disease: Ensuring Best Practice in UK Healthcare Settings

Nontuberculous mycobacterial pulmonary disease (NTM-PD) results from opportunistic lung infections by mycobacteria other than Mycobacterium tuberculosis or Mycobacterium leprae species. Similar to many other countries, the incidence of NTM-PD in the United Kingdom (UK) is on the rise for reasons that are yet to be determined. Despite guidelines established by the American Thoracic Society (ATS), the Infectious Diseases Society of America, and the British Thoracic Society, NTM-PD diagnosis and management remain a significant clinical challenge. In this review article, we comprehensively discuss key challenges in NTM-PD diagnosis and management, focusing on the UK healthcare setting. We also propose countermeasures to overcome these challenges and improve the detection and treatment of patients with NTM-PD.

Emerging and alternative strategies for the treatment of nontuberculous mycobacterial infections

INTRODUCTION

Nontuberculous mycobacteria (NTM) infections have emerged as a significant clinical challenge due to their intrinsic multidrug resistance and the limited efficacy of existing treatments. These infections are becoming increasingly prevalent, with a need for new and effective therapeutic strategies.

AREAS COVERED

This review addresses several key aspects of NTM infections: i) pathogenesis and epidemiology; ii) the limitations and challenges of current treatment options; iii) emerging and alternative therapeutic strategies; iv) advanced drug delivery systems such as nanoparticles and efflux pump inhibitors; v) innovative antibacterial alternatives like antimicrobial peptides, bacteriophage therapy, and phytochemicals; and vi) other potential treatment modalities such as inhaled nitric oxide, small molecules, surgical debridement, phototherapy, and immunomodulatory therapy.

EXPERT OPINION

Personalized medicine, advanced drug delivery systems, and alternative therapies hold promise for the future of NTM treatment. Early and accurate identification of NTM species, enabled by improved diagnostic methods, is critical for tailoring treatment regimens. Emerging therapies show promise against drug-resistant NTM strains, but overcoming barriers like clinical trials, regulatory hurdles, and high production costs is crucial. Continued research and innovation are essential to improve treatment efficacy and patient outcomes.

Chemical optimization and derivatization of micrococcin p2 to target multiple bacterial infections: new antibiotics from thiopeptides

Antimicrobial resistance poses a significant threat to humanity, and the development of new antibiotics is urgently needed. Our research has focused on thiopeptide antibiotics such as micrococcin P2 (MP2) and derivatives thereof as new anti-infective agents. Thiopeptides are sulfur-rich, structurally complex substances that exhibit potent activity against Gram-positive pathogens and Mycobacteria species, including clinically resistant strains. The clinical development of thiopeptides has been hampered by the lack of efficient synthetic platforms to conduct detailed structure-activity relationship studies of these natural products. The present contribution touches upon efficient synthetic routes to MP2 that laid the groundwork for clinical translation. The medicinal chemistry campaign on MP2 has been guided by computational molecular dynamic simulations and parallel investigations to improve drug-like properties, such as enhancing the aqueous solubility and optimizing antibacterial activity. Such endeavors have enabled identification of promising lead compounds, AJ-037 and AJ-206, against Mycobacterium avium complex (MAC). Extensive in vitro studies revealed that these compounds exert potent activity against MAC species, a subspecies of non-tuberculous mycobacteria (NTM) that proliferate inside macrophages. Two additional pre-clinical candidates have been identified: AJ-024, for the treatment of Clostridioides difficile infections, and AJ-147, for methicillin-resistant Staphylococcus aureus impetigo. Both compounds compare quite favorably with current first-line treatments. In particular, the ability of AJ-147 to downregulate pro-inflammatory cytokines adds a valuable dimension to its clinical use. In light of above, these new thiopeptide derivatives are well-poised for further clinical development.

Single-cell transcriptomics of blood identified IFIT1+ neutrophil subcluster expansion in NTM-PD patients

OBJECTIVE

Non-tuberculous mycobacterial pulmonary disease (NTM-PD) is caused by an imbalance between pathogens and impaired host immune responses. Mycobacterium avium complex (MAC) and Mycobacterium abscessus (MAB) are the two major pathogens that cause NTM-PD. In this study, we sought to dissect the transcriptomes of peripheral blood immune cells at the single-cell resolution in NTM-PD patients and explore potential clinical markers for NTM-PD diagnosis and treatment.

METHODS

Peripheral blood samples were collected from six NTM-PD patients, including three MAB-PD patients, three MAC-PD patients, and two healthy controls. We employed single-cell RNA sequencing (scRNA-seq) to define the transcriptomic landscape at a single-cell resolution. A comprehensive scRNA-seq analysis was performed, and flow cytometry was conducted to validate the results of scRNA-seq.

RESULTS

A total of 27,898 cells were analyzed. Nine T-cells, six mononuclear phagocytes (MPs), and four neutrophil subclusters were defined. During NTM infection, naïve T-cells were reduced, and effector T-cells increased. High cytotoxic activities were shown in T-cells of NTM-PD patients. The proportion of inflammatory and activated MPs subclusters was enriched in NTM-PD patients. Among neutrophil subclusters, an IFIT1+ neutrophil subcluster was expanded in NTM-PD compared to healthy controls. This suggests that IFIT1+ neutrophil subcluster might play an important role in host defense against NTM. Functional enrichment analysis of this subcluster suggested that it is related to interferon response. Cell-cell interaction analysis revealed enhanced CXCL8-CXCR1/2 interactions between the IFIT1+ neutrophil subcluster and NK cells, NKT cells, classical mononuclear phagocytes subcluster 1 (classical Mo1), classical mononuclear phagocytes subcluster 2 (classical Mo2) in NTM-PD patients compared to healthy controls.

CONCLUSIONS

Our data revealed disease-specific immune cell subclusters and provided potential new targets of NTM-PD. Specific expansion of IFIT1+ neutrophil subclusters and the CXCL8-CXCR1/2 axis may be involved in the pathogenesis of NTM-PD. These insights may have implications for the diagnosis and treatment of NTM-PD.

Forecasting climate-associated non-tuberculous mycobacteria (NTM) infections in the UK using international surveillance data and machine learning

Nontuberculous mycobacteria (NTM) cause skin and lung infections, have high mortality rates, and are resistant to a range of antibiotics and water treatment methods. As NTM reside in environmental reservoirs, they are sensitive to environmental conditions. The suitability of their environmental reservoirs can increase as a result of climate change, subsequently increasing environmental exposure and infection rates. NTM infections are not generally notifiable, including in the UK, but sustained increases have been observed in regions that report NTM infection rates. To assess the burden of NTM infections in the UK under projected climate change, we examined the relationship between climate variables and available NTM surveillance data internationally. Statistically significant increases were found in regions where NTM infections are notifiable, which were positively associated with increased precipitation and temperatures. A random forest regressor was trained using supervised learning from international NTM surveillance data and linked climate variables. The random forest model was applied to UK climate projections, projecting a 6.2% increase in NTM infection rates over the next 10 years, with notable regional variation. Our random forest model predicts that the forecasted impacts of climate change in the UK, including increasing temperatures and frequency of heavy rainfall, will lead to increases in NTM infection rates. Robust surveillance in the future is necessary to increase data available to train models, increasing our predictive power in forecasting climate-associated NTM trends. Our results highlight a novel aspect of how climate change will impact health outcomes in the UK.

Ceftriaxone Efficacy for Mycobacterium avium Complex Lung Disease in the Hollow Fiber and Translation to Sustained Sputum Culture Conversion in Patients

BACKGROUND

Only 35.6%-50.8% of patients with Mycobacterium avium complex (MAC) pulmonary disease achieve sustained sputum culture conversion (SSCC) on treatment with the azithromycin-ethambutol-rifabutin standard of care (SOC). We tested the efficacy of ceftriaxone, a β-lactam with a lung-to-serum penetration ratio of 12.18-fold.

METHODS

We mimicked lung concentration-time profiles of 7 ceftriaxone once-daily doses for 28 days in the hollow fiber system model of intracellular MAC (HFS-MAC). Monte Carlo experiments were used for dose selection. We also compared once-daily ceftriaxone monotherapy to 3-drug SOC against 5 MAC clinical isolates in HFS-MAC using γ (kill) slopes, and translated to SSCC rates.

RESULTS

Ceftriaxone killed 1.02-3.82 log10 colony-forming units (CFU)/mL, at optimal dose of 2 g once-daily. Ceftriaxone killed all 5 strains below day 0 versus 2 of 5 for SOC. The median γ (95% confidence interval [CI]) was 0.49 (.47-.52) log10 CFU/mL/day for ceftriaxone and 0.38 (.34-.43) log10 CFU/mL/day for SOC. In patients, the SOC was predicted to achieve SSCC rates (CI) of 39.3% (36%-42%) at 6 months. The SOC SSCC was 50% at 8.18 (3.64-27.66) months versus 3.58 (2.20-7.23) months for ceftriaxone, shortening time to SSCC 2.35-fold.

CONCLUSIONS

Ceftriaxone is a promising agent for creation of short-course chemotherapy.

PARK2 as a susceptibility factor for nontuberculous mycobacterial pulmonary disease

BACKGROUND

The genetic signatures associated with the susceptibility to nontuberculous mycobacterial pulmonary disease (NTM-PD) are still unknown. In this study, we performed RNA sequencing to explore gene expression profiles and represent characteristic factor in NTM-PD.

METHODS

Peripheral blood samples were collected from patients with NTM-PD and healthy individuals (controls). Differentially expressed genes (DEGs) were identified by RNA sequencing and subjected to functional enrichment and immune cell deconvolution analyses.

RESULTS

We enrolled 48 participants, including 26 patients with NTM-PD (median age, 58.0 years; 84.6% female), and 22 healthy controls (median age, 58.5 years; 90.9% female). We identified 21 upregulated and 44 downregulated DEGs in the NTM-PD group compared to those in the control group. NTM infection did not have a significant impact on gene expression in the NTM-PD group compared to the control group, and there were no differences in the proportion of immune cells. However, through gene ontology (GO), gene set enrichment analysis (GSEA), and protein-protein interaction (PPI) analysis, we discovered that PARK2 is a key factor associated with NTM-PD. The PARK2 gene, which is linked to the ubiquitination pathway, was downregulated in the NTM-PD group (fold change, - 1.314, P = 0.047). The expression levels of PARK2 remained unaltered after favorable treatment outcomes, suggesting that the gene is associated with host susceptibility rather than with the outcomes of infection or inflammation. The area under the receiver operating characteristic curve for the PARK2 gene diagnosing NTM-PD was 0.813 (95% confidence interval, 0.694-0.932).

CONCLUSION

We identified the genetic signatures associated with NTM-PD in a cohort of Korean patients. The PARK2 gene presents as a potential susceptibility factor in NTM-PD .

Immunologic features of nontuberculous mycobacterial pulmonary disease based on spatially resolved whole transcriptomics

BACKGROUND

The immunologic features of nontuberculous mycobacterial pulmonary disease (NTM-PD) are largely unclear. This study investigated the immunologic features of NTM-PD using digital spatial profiling techniques.

METHODS

Lung tissues obtained from six patients with NTM-PD between January 1, 2006, and December 31, 2020, at Seoul National University Hospital were subjected to RNA sequencing. Cores from the peribronchial areas were stained with CD3, CD68, and DNASyto13, and gene expression at the whole-transcriptome level was quantified using PCR amplification and Illumina sequencing. Lung tissues from six patients with bronchiectasis collected during the same period were used as controls. The RNA sequencing results were validated using immunohistochemistry (IHC) in another cohort (30 patients with NTM-PD and 15 patients with bronchiectasis).

RESULTS

NTM-PD exhibited distinct gene expression patterns in T cells and macrophages. Gene set enrichment analysis revealed that pathways related to antigen presentation and processing were upregulated in NTM-PD, particularly in macrophages. Macrophages were more prevalent and the expression of genes associated with the M1 phenotype (CD40 and CD80) was significantly elevated. Although macrophages were activated in the NTM-PD group T cell activity was unaltered. Notably, expression of the costimulatory molecule CD28 was decreased in NTM-PD. IHC analysis showed that T cells expressing Foxp3 or TIM-3, which facilitate the regulatory functions of T cells, were increased.

CONCLUSIONS

NTM-PD exhibits distinct immunologic signatures characterized by the activation of macrophages without T cell activation.

Swollen Necrotic Lymphadenitis Infected with Mycobacterium Paracondontium in an AIDS Patient: a Case Report and Literature Review

Background

Non-tuberculous mycobacteria (NTM) are a group of mycobacteria that are commonly found in the environment and can cause disease in humans. The symptoms of NTM infection can be similar to those of tuberculosis, making diagnosis challenging. The morbidity associated with NTM is increasing, and clinical management can be challenging.

Case Description

This report details the case of a 32-year-old male who was found to have multiple enlarged and partially necrotic lymph nodes in the neck, axilla, mediastinum, and retroperitoneum. The causative agent was rapidly identified as Mycobacterium paracondontium through pathogen-targeted sequencing (tNGS). After two weeks of treatment with azithromycin, moxifloxacin, rifabutin, and amikacin, the patient's uncomfortable symptoms had resolved, and he is currently undergoing further review.

Conclusion

It is imperative that clinicians remain vigilant for the presence of NTM, particularly those that are rare, given their pervasiveness in the environment. Prompt diagnosis is of paramount importance, and molecular identification techniques represent a crucial tool in this regard. In vitro drug sensitivity testing should be conducted whenever feasible to guarantee the administration of an efficacious treatment regimen.

Prospective Analysis of urINe LAM to Eliminate NTM Sputum Screening (PAINLESS) study: Rationale and trial design for testing urine lipoarabinomannan as a marker of NTM lung infection in cystic fibrosis

Background

Routine screening for nontuberculous mycobacterial (NTM) lung disease is dependent on sputum cultures. This is particularly challenging in the cystic fibrosis (CF) population due to reduced sputum production and low culture sensitivity. Biomarkers of infection that do not rely on sputum may lead to earlier diagnosis, but validation trials require a unique prospective design.

Purpose

The rationale of this trial is to investigate the utility of urine lipoarabinomannan (LAM) as a test to identify people with CF with a new positive NTM culture. We hypothesize that urine LAM is a sensitive, non-invasive screening test with a high negative predictive value to identify individuals with a relatively low risk of having positive NTM sputum culture.

Study design

This is a prospective, single-center, non-randomized observational study in adults with CF, 3 years of negative NTM cultures, and no known history of NTM positive cultures. Patients are followed for two year-long observational periods with the primary endpoint being a positive NTM sputum culture within a year of a positive urine LAM result and a secondary endpoint of a positive NTM sputum culture within 3 years of a positive urine LAM result. Study implementation includes remote consent and sample collection to accommodate changes from the COVID-19 pandemic.

Conclusions

This report describes the study design of an observational study aimed at using a urine biomarker to assist in the diagnosis of NTM lung infection in pwCF. If successful, urine LAM could be used as an adjunct to traditional sputum cultures for routine NTM screening.

The Drug Susceptibility of Non-Tuberculous Mycobacteria (NTM) in a Referral Hospital in Rome from 2018 to 2023

Background: The treatment of non-tuberculous mycobacterial (NTM) infections is challenging because of the difficulty in obtaining phenotypic (pDST) and/or molecular (mDST) drug susceptibility testing and the need of a multi-drug regimen. Objectives: The objective was to describe the in vitro susceptibility patterns of various NTM species through an analysis of susceptibility results obtained on isolates collected between 2018 and 2023. Methods: Species identification and mutations in rrs or rrl genes (mDST) were identified by a line probe assay, while the pDST was performed by broth microdilution and interpreted according to CLSI criteria. Results: We analysed 337 isolates of NTM belonging to 15 species/subspecies. The Mycobacterium avium complex (MAC) was the most common (62%); other species identified included M. gordonae (11%), M. kansasii (5%), the M. abscessus complex (8%), M. chelonae (6%), and M. fortuitum (2%). The results of pDST (claritromycin and amikacin) and mDST (rrl and rrs genes) on 66 NTM strains showed that while wild-type rrl and rrs occurred in 86.3% and 94% strains, respectively, the pDST showed 88% sensitivity for clarithromycin and 57.5% for amikacin. The main incongruity was observed for macrolides. Conclusions: Most NTM are likely to be susceptible to macrolides and aminoglycosides. The molecular identification of resistant genotypes is accurate and strongly recommended for optimal patient management.

Long-term successfull management of recurrent episodes of nontuberculous mycobacterial infection in an apparently healthy Chinese woman

BACKGROUND

Disseminated non-tuberculous mycobacteria (dNTM) infections are mostly reported among individuals with an underlying congenital or acquired immunodeficiency or receiving immunosuppressive treatment, but are rarely documented in otherwise healthy subjects.

CASE PRESENTATION

We describe a case of recurrent disseminated mycobacterial infection in an apparently immunocompetent Chinese woman. Mycobacterium szulgai and Mycobacterium avium-complex were identified in distinct episodes. Long-term antimycobacterial therapy was administered given the occurrence of recurrent events when off-treatment. Successful management over more than 10 years and immunologic data are reported.

CONCLUSIONS

This case-report highlights that dNTM should be suspected also among apparently immunocompetent hosts and that thorough assessment of underling immune-impairments is helpful to define patients' management. Long-term antimycobacterial therapy and close monitoring is required to grant successful outcomes in case of recurrent dNTM infections.

Postprandial hypoglycemia caused by the combination of clarithromycin and rifampicin in a patient with nontuberculous mycobacterial pulmonary disease

Most cases of nontuberculous mycobacterial pulmonary disease (NTM-PD) have a progressive clinical course, and initiation of treatment is recommended rather than watchful waiting. The NTM-PD medications are frequently associated with adverse reactions, occasionally serious. Optimization of the methods for monitoring and managing adverse events in NTM-PD treatment is thus an important medical issue. Here we report a first case of postprandial hypoglycemia caused by the combination of clarithromycin (CAM) and rifampicin (RFP) in a patient with NTM-PD. A 73-year-old Japanese woman with NTM-PD was hospitalized for treatment with a combination of oral CAM, RFP, and ethambutol. She took the first doses of antibiotics before breakfast, and 3 h later went into a hypoglycemic state. Postprandial hypoglycemia occurred with high reproducibility and was accompanied by relative insulin excess. Continuous glucose monitoring with or without food and in combination with various patterns of medication revealed that the combination of CAM and RFP specifically induced postprandial hypoglycemia. Shifting the timing of administration of the CAM and RFP combination from morning to before sleep corrected the hypoglycemia and enabled continuation of the antimicrobial treatment. In conclusion, our report suggests the importance of introducing NTM-PD medication under inpatient management in order to closely monitor and early detect postprandial hypoglycemia and other serious adverse events.

Efficacy and treatment outcome of infected patients with pulmonary Mycobacterium kansasii: A systematic review

Background

Mycobacterium kansasii (M. kansasii) is a non-tuberculosis bacterium with a highly prevalent that is transferred by aerosols from water and soil resources to the respiratory system. M. kansasii is one of the main species responsible for NTM pulmonary disease.

Methods

Web of Science, Scopus, and PubMed databases were systematically explored. Relevant articles from 1971 to November 2023 were reviewed. "The inclusion criteria" included patients with M. kansasii infection, treatment follow-up, and treatment outcomes. "The exclusion criteria" were clinical samples from animals, environmental samples, and other laboratory investigations.

Results

40 studies, including 1201 patients, were obtained through database search. Using the therapeutic regimens used in different studies, the therapy course for patients with M. kansasii infection ranged from 1 week to 118 months. In this study, the antibiotics prescribed in different treatment regimens for M. kansasii pulmonary infection were as follows: Rifampin, Ethambutol, Isoniazid, Clarithromycin, Streptomycin, and Pyrazinamide. Antibiotic combinations of three or four medicines, including rifampin, ethambutol, and isoniazid with or without streptomycin or pyrazinamide had the most therapeutic effect.

Conclusion

The initial treatment involves rifampin, ethambutol, isoniazid, and pyridoxine, per the guidelines from the American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA). Understanding the treatment plan and its outcomes is crucial for managing and determining the most effective therapy approach.

Clinical spectrum and relevance of Mycobacterium malmoense: Systematic review and meta-analysis of 859 patients

INTRODUCTION

The clinical relevance of Mycobacterium malmoense isolation from pulmonary specimens has been considered high compared with other non-tuberculous mycobacteria. In this study, we aimed to analyse all published clinical data of patients with M. malmoense isolation to investigate the clinical spectrum, relevance, and outcomes of infections with this uncommon mycobacterium.

METHODS

A systematic review of PubMed, Web of Science, Embase, and Scopus was performed to identify all clinical data about M. malmoense. Random effects meta-analyses of proportions were calculated for clinical relevance, treatment success, and mortality, as well as for other clinical characteristics. A logistic regression analysis, investigating predictors of mortality, as well as Kaplan-Meier survival analyses, were performed.

RESULTS

One hundred and eighty eight patients with individual data from 112 articles and 671 patients with pooled data from 12 articles were included in the meta-analyses. Of patients with individual data, pulmonary infection was the most common manifestation (n = 106/188, 56.4%). One third (n = 61/188, 32.4%) suffered from isolated extra-pulmonary and 21/188 (11.2%) from disseminated disease. In 288 patients with pooled data and pulmonary affection, clinical relevance was high with 68% (95% CI 44-85%) of patients fulfilling criteria for clinical disease. Macrolide and rifamycin-containing regimens were associated with improved survival (adjusted OR 0.12, 95% CI 0.03-0.42, p = 0.002, and 0.23, 95% CI 0.04-0.86, p = 0.03, for lethal events, respectively).

CONCLUSION

In this study, we provide a detailed clinical description of M. malmoense infections. The pathogen is of high clinical relevance for the individual patient with more than 2 out of 3 patients having relevant disease and >40% of manifestations being extra-pulmonary or disseminated. Macrolide and rifamycin-containing regimens are associated with improved survival.

Successful management of surgical site infection caused by Mycobacterium mageritense in a breast cancer patient

Mycobacterium mageritense (M. mageritense), a nontuberculous mycobacterium, is classified as a rapidly growing mycobacterium, class IV in the Runyon Classification. This bacterium is found in soil, water, and other habitats. Infections caused by M. mageritense are relatively rare and no treatment protocol has been established. Herein, we report a case of skin and soft tissue infection caused by M. mageritense. A 49-year-old woman underwent surgery for right breast cancer. Four months after surgery, a surgical site infection was found, and M. mageritense was identified in the wound culture using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Based on the sensitivity results, the patient was treated with levofloxacin and doxycycline for 4 months. In addition to antimicrobial agents, aggressive surgical interventions led to a favorable course of treatment. In conclusion, successful treatment of skin and soft tissue infections with M. mageritense requires surgical intervention whenever possible, aggressive susceptibility testing, and appropriate antimicrobial therapy.

Evaluation of treatment response with serial CT in patients with non-tuberculous mycobacterial pulmonary disease

OBJECTIVES

In patients with non-tuberculous mycobacterial pulmonary disease (NTM-PD), the response to treatment is evaluated based on microbiological, clinical, and radiological data. However, little is known about the dynamics of CT findings. The aim of this study was to evaluate CT changes in NTM-PD in order to define radiological criteria for treatment success.

METHODS

Retrospective multicenter study (Hannover, Heidelberg, Gauting). Sixty patients with NTM-PD and at least two consecutive CT scans were included. Scoring for NTM-PD was performed by evaluating variables of bronchiectasis, mucus plugging, bronchiolitis, cavities, nodules, and consolidations on an ordinal scale from 0 to 3. Differences between baseline and follow-up were calculated, and patients with/without cultural conversion were compared using the Mann-Whitney U-test. For paired comparison of the two consecutive CT scans the Wilcoxon test was used.

RESULTS

Comparing patients with and without culture conversion, there were significant differences in temporal changes of bronchiectasis (p < 0.001), cavities (p = 0.006), bronchiolitis (p < 0.001), consolidations (p = 0.004), and total score (p < 0.001). Nodules showed no significant differences between groups (p = 0.060). The Wilcoxon test showed significant differences between both CTs in patients with a microbiological cure for the total score (p < 0.001), cavities (p = 0.005), bronchiolitis (p < 0.001), and consolidations (p = 0.021) with a decrease after microbiological cure, whereas bronchiectasis (p = 0.102) and nodules (p = 0.18) stayed stable. In the case of persistently positive cultures, there was an increase in the total score (p = 0.010) which was attributable to progressive bronchiectasis (p < 0.001).

CONCLUSION

Cavities, consolidations, and bronchiolitis are useful to assess treatment response, whereas bronchiectasis and nodules may remain stable despite successful treatment.

CLINICAL RELEVANCE STATEMENT

Cavities, consolidations, and bronchiolitis can assess treatment response whereas bronchiectasis and nodules may remain stable despite successful treatment. In persistently positive cultures, bronchiectasis showed an increase over time indicating that NTM-PD is a progressive chronic disease.

KEY POINTS

Little is known about CT changes in nontuberculous mycobacteria pulmonary disease (NTM-PD) and criteria to evaluate treatment response. In the case of culture conversion, cavities and bronchiolitis decreased whereas bronchiectasis and nodules remained stable. Cavities and bronchiolitis can evaluate treatment response in NTM, but bronchiectasis and nodules may persist despite successful treatment.

Real-World Patients' Diagnosis-to-Treatment Journey with Nontuberculous Mycobacterial Pulmonary Disease: A Cross-Sectional Survey

INTRODUCTION

The incidence and prevalence of nontuberculous mycobacterial pulmonary disease (NTM-PD) are increasing globally. Approximately 80% of NTM-PD cases in Japan and five countries within Europe (Eur5; France, Germany, Italy, Spain, and the UK) are caused by Mycobacterium avium complex (MAC). This study describes the clinical decision-making process associated with the management of patients with NTM-PD in Japan and the Eur5.

METHODS

We analyzed data from a survey conducted between July 2013 and October 2013 among physicians treating patients with NTM-PD in clinical practice to compare the healthcare settings, clinical presentation, and patient management in Japan and the Eur5.

RESULTS

Overall, 619 physicians (Japan, 173; Eur5, 446) participated in the survey. Most patients in Japan (85%) and the Eur5 (79%) were diagnosed with MAC-PD. Patients were managed generally in hospital-based outpatient clinics (117/173, 68%) in Japan and research/teaching hospitals affiliated with medical schools (140/446, 31%) in the Eur5. The most common reason for delaying treatment was the patient's symptoms not being considered serious enough for treatment (55/128, 43%) in Japan and awaiting results of antimicrobial susceptibility testing (44/151, 29%) in the Eur5. Culture negativity was less commonly achieved after treatment in patients in Japan versus those in the Eur5 (31% [73/238] vs. 70% [300/426], p < 0.0001). In treatment phases that were either completed or discontinued, the primary goal was symptomatic improvement, followed by achieving culture conversion, in both Japan and the Eur5. Overall, 19% (16/85) of physicians in Japan and 43% (220/511) in the Eur5 were "entirely satisfied" with their patients' treatment outcomes.

CONCLUSIONS

Similarities and differences exist in the healthcare settings, clinical presentation, and management of patients with NTM-PD in Japan and the Eur5. Insufficient consideration of culture status by physicians, delayed treatment initiation, and symptom-based cessation emphasize the need for educational efforts on the guideline-based strategies.

Nontuberculosis mycobacteria (NTM) infections in patients with leukemia: a single center case series

Patients with leukemia experience profound immunosuppression both from their underlying disease as well as chemotherapeutic treatment. Little is known about the prevalence and clinical presentation of nontuberculous mycobacteria (NTM) in this patient population. We identified six cases of NTM infection from 29,743 leukemia patients who had acid-fast bacilli (AFB) cultures. Four cases had bloodstream infections and five had disseminated disease, including one who presented with an unusual case of diffuse cellulitis/myositis. All patients were lymphopenic at time of diagnosis, and two patients ultimately died from their NTM infection. NTM infections are a rare, but potentially life-threatening infection in patients with leukemia. Sending AFB cultures early is important to direct appropriate antimicrobial therapy and allow for future leukemia-directed therapy.