Non-tuberculosis Mycobacteria Infection Research Articles

Particulate matter deposition and its impact on tuberculosis severity: A cross-sectional study in Taipei

The objective of this study was to examine the association between the lung lobe-deposited dose of inhaled fine particulate matter (PM2.5) and chest X-ray abnormalities in different lung lobes of pulmonary tuberculosis (TB), multidrug-resistant tuberculosis (MDR-TB), and non-tuberculosis mycobacteria infections (NTM). A cross-sectional study was conducted between 2014 and 2022, comprising 1073 patients who were recruited from chest department clinic in a tertial refer hospital in Taipei City, Taiwan. Ambient 1-, 7-, and 30-day PM2.5 exposure and the deposition of PM2.5 in different lung lobes were estimated in each subject. The β coefficient for PM2.5 and deposited PM2.5 in lungs with the outcome variables (pulmonary TB, MDR-TB, and NTM infection) was derived through regression analysis and adjusted for age, gender, BMI, smoking status, and family income. We observed that a 1 μg/m3 increase in ambient PM2.5 was associated with an increase of MDR-TB infections of 0.004 times (95%CI: 0.001–0.007). A 1 μg/m3 increase in 1-day and 7-day PM2.5 deposition in left upper lobe and left lower lobe was associated with an increase in chest X-ray abnormalities of 9.19 % and 1.18 % (95%CI: 0.87–17.51 and 95%CI: 0.08–2.28), and 4.52 % and 5.20 % (95%CI: 0.66–8.38 and 95%CI: 0.51–9.89) in left lung of TB patients, respectively. A 1 μg/m3 increase in 30-day PM2.5 deposition in alveolar region was associated with an increase in percent abnormality of 2.50 % (95%CI: 0.65–4.35) in left upper lobe and 3.33 % (95%CI: 0.65–6.01) in right middle lobe, while in total lung was 0.63 % (95%CI: 0.01–1.27) in right upper lobe and 0.37 % (95%CI, 0.06–0.81) in right lung of MDR-TB patients. Inhaled PM2.5 deposition in lungs was associated with an exacerbation of the radiographic severity of pulmonary TB, particularly in pulmonary MDR-TB patients in upper and middle lobes. Particulate air pollution may potentially exacerbate the radiographic severity and treatment resistance in individuals with pulmonary TB.

Nitric oxide-releasing prodrug for the treatment of complex Mycobacterium abscessus infections.

Non-tuberculosis mycobacteria (NTM) can cause severe respiratory infection in patients with underlying pulmonary conditions, and these infections are extremely difficult to treat. In this report, we evaluate a nitric oxide (NO)-releasing prodrug [methyl tris diazeniumdiolate (MD3)] against a panel of NTM clinical isolates and as a treatment for acute and chronic NTM infections in vivo. Its efficacy in inhibiting growth or killing mycobacteria was explored in vitro alongside evaluation of the impact to primary human airway epithelial tissue. Airway epithelial tissues remained viable after exposure at concentrations of MD3 needed to kill mycobacteria, with no inherent toxic effect from drug scaffold after NO liberation. Resistance studies conducted via serial passage with representative Mycobacterium abscessus isolates demonstrated no resistance to MD3. When administered directly into the lung via intra-tracheal administration in mice, MD3 demonstrated significant reduction in M. abscessus bacterial load in both acute and chronic models of M. abscessus lung infection. In summary, MD3 is a promising treatment for complex NTM pulmonary infection, specifically those caused by M. abscessus, and warrants further exploration as a therapeutic.

Risk adjustment model for tuberculosis compared to non-tuberculosis mycobacterium or latent tuberculosis infection: Center for Personalized Precision Medicine of Tuberculosis (cPMTb) cohort database

BackgroundThe Center for Personalized Precision Medicine of Tuberculosis (cPMTb) was constructed to develop personalized pharmacotherapeutic systems for tuberculosis (TB). This study aimed to introduce the cPMTb cohort and compare the distinct characteristics of patients with TB, non-tuberculosis mycobacterium (NTM) infection, or latent TB infection (LTBI). We also determined the prevalence and specific traits of polymorphisms in N-acetyltransferase-2 (NAT2) and solute carrier organic anion transporter family member 1B1 (SLCO1B1) phenotypes using this prospective multinational cohort.MethodsUntil August 2021, 964, 167, and 95 patients with TB, NTM infection, and LTBI, respectively, were included. Clinical, laboratory, and radiographic data were collected. NAT2 and SLCO1B1 phenotypes were classified by genomic DNA analysis.ResultsPatients with TB were older, had lower body mass index (BMI), higher diabetes rate, and higher male proportion than patients with LTBI. Patients with NTM infection were older, had lower BMI, lower diabetes rate, higher previous TB history, and higher female proportion than patients with TB. Patients with TB had the lowest albumin levels, and the prevalence of the rapid, intermediate, and slow/ultra-slow acetylator phenotypes were 39.2%, 48.1%, and 12.7%, respectively. The prevalence of rapid, intermediate, and slow/ultra-slow acetylator phenotypes were 42.0%, 44.6%, and 13.3% for NTM infection, and 42.5%, 48.3%, and 9.1% for LTBI, respectively, which did not differ significantly from TB. The prevalence of the normal, intermediate, and lower transporter SLCO1B1 phenotypes in TB, NTM, and LTBI did not differ significantly; 74.9%, 22.7%, and 2.4% in TB; 72.0%, 26.1%, and 1.9% in NTM; and 80.7%, 19.3%, and 0% in LTBI, respectively.ConclusionsUnderstanding disease characteristics and identifying pharmacokinetic traits are fundamental steps in optimizing treatment. Further longitudinal data are required for personalized precision medicine.Trial registrationThis study registered ClinicalTrials.gov NO. NCT05280886.

Non-Mycobacteria Tuberculosis in Africa: A Literature Review.

Non-tuberculous mycobacteria (NTM) have been reported to cause pulmonary and extrapulmonary infections. These NTMs are often misdiagnosed as MTB due to their similar clinical presentations to tuberculosis, leading to inappropriate treatment and increased morbidity and mortality rates. This literature review aims to provide an overview of the prevalence, clinical manifestations, diagnosis, and management of NTM infections in Africa. A systematic search was performed using various electronic databases including PubMed, Scopus, and Web of Science. The search was limited to studies published in the English language from 2000 to 2021. The following keywords were used: "non-tuberculous mycobacteria", "NTM", "Africa", and "prevalence". Studies that focused solely on the Mycobacterium tuberculosis complex or those that did not report prevalence rates were excluded. Data extraction was performed on eligible studies. Overall, a total of 32 studies met the inclusion criteria and were included in this review. In our literature review, we identified a total of 32 studies that reported non-tuberculosis mycobacteria (NTM) in Africa. The majority of these studies were conducted in South Africa, followed by Ethiopia and Nigeria. The most commonly isolated NTM species were Mycobacterium avium complex (MAC), Mycobacterium fortuitum, and Mycobacterium abscessus. Many of the studies reported a high prevalence of NTM infections among HIV-positive individuals. Other risk factors for NTM infection included advanced age, chronic lung disease, and previous tuberculosis infection. In conclusion, this literature review highlights the significant burden of non-tuberculosis mycobacteria infections in Africa. The prevalence of these infections is high, and they are often misdiagnosed due to their similarity to tuberculosis. The lack of awareness and diagnostic tools for non-tuberculosis mycobacteria infections in Africa is a major concern that needs to be addressed urgently. It is crucial to improve laboratory capacity and develop appropriate diagnostic algorithms for these infections.

Treatment of non-tuberculosis mycobacteria skin infections.

Non-tuberculosis mycobacteria (NTM) skin infections have become increasingly prevalent in recent years, presenting a unique challenge in clinical management. This review explored the complexities of NTM infections localized to the superficial tissues and provided valuable insights into the optimal therapeutic strategies. The antibiotic selection should base on NTM species and their susceptibility profiles. It is recommended to adopt a comprehensive approach that considers the unique characteristics of superficial tissues to improve treatment effectiveness and reduce the incidence of adverse reactions, infection recurrence, and treatment failure. Infection control measures, patient education, and close monitoring should complement the treatment strategies to achieve favorable outcomes in managing NTM skin infections. Further efforts are warranted to elucidate factors and mechanisms contributing to treatment resistance and relapse. Future research should focus on exploring novel treatment options, innovative drug development/delivery platforms, and precise methodologies for determining therapeutic duration. Longitudinal studies are also needed to assess the long-term safety profiles of the integrated approaches.

Nontuberculous mycobacteria isolation from sputum specimens: A retrospective analysis of 1061 cases.

In recent years, with the development of laboratory methods, the frequency of nontuberculosis mycobacteria (NTM) infections has increased. The primary aim of this study was to evaluate the clinical significance of therapeutic drug monitoring (TDM) growths in respiratory samples, and the secondary aim was to evaluate the treatment regimens and treatment outcomes of treatment for TDM disease. This study was a retrospective cohort study. Persons with NTM growth in respiratory samples admitted to the reference hospital between 2009 and 2020 were included in this study. Samples detected as NTM by the immunochromatographic rapid diagnostic test, those requested by the clinicians, species were determined by the hsp65PCRREA method. The subjects were classified into 3 groups: patients with NTM infection who received treatment (135, 12.7%), those followed up without treatment (690, 65.1%), and a last group of patients with Mycobacterium tuberculosis (TB) complex strains were isolated and received TB treatment (236, 22.2%). Initiating NTM treatment was decided in accordance with the American Thoracic Society recommendations. The mean ± standard deviation age of patients was 53.8 ± 16.5 years, and 749 (70.6%) were male. In total, 278 (26.2%) out of 1061 cases had identified, and the most frequent species were MAC (81; Mycobacterium avium: 39, Mycobacterium intracellulare: 39, and MAC: 3), Mycobacterium abscessus (67), Mycobacterium kansasii (48), Mycobacterium fortuitum (23), Mycobacterium chelonae (12), Mycobacterium gordonae (11), and Mycobacterium szulgai (11). In the NTM treatment group, 116 (85.9%) of 135 patients had multiple culture positivity. Previous TB treatment history had 51 (37.8%) of 135 patients, respiratory comorbidities were evident in 37 (27.4%) of 135 patients. Thorax computed tomography imaging in 84 patients revealed nodule 38 (45.2%), consolidation 46 (54.8%), cavity 52 (61.9%), and bronchiectasis 27 (32.1%). Treatment results in the NTM treatment group were as follows: ongoing treatment 14 (10.4%), cure 64 (47.4%), default 33 (24.4%), exitus 19 (14.1%), recurrence 3 (2.2%), and refractory disease 2 (1.5%). This is a large case series evaluating the clinical significance of NTM growths and NTM treatment in Turkey. The clinical significance of NTM growth in respiratory samples is low. Treatment success rates of NTM patients who are treated are low. Treatment defaults and mortality rates are high. New drugs and new regimens are needed.

2185. Pulmonary Non-Tuberculosis Mycobacteria (NTM) Infections in Adult Patients at a Tertiary Care Hospital in Saudi Arabia

Abstract Background Burden of Non-tuberculous Mycobacteria (NTM) disease is increasing in both developed and developing countries. Local data is needed to guide our understanding of the epidemiology and outcome of NTM management in our population. The main objectives of the study are to describe management of patients with NTM infection and determine treatment outcomes in adult patients. Also, to explore the epidemiology of mycobacterial species associated with pulmonary NTM. Methods A 10-year (2010-2020), retrospective cohort study was conducted at a tertiary care hospital in Saudi Arabia. All patients with positive NTM culture were screened. Adult patients (≥ 18 years old) diagnosed with pulmonary NTM disease and received treatment for ≥ two months were included. Clinical data was collected from the patient’s chart using standardised form. The primary end points were overall cure rate (clinical, microbiological, and radiological cure), recurrence, relapse, and re-infection rate. The secondary end points were mortality and hospital admission rate for NTM infection. The Chi-square test was used to compare parameters. Univariate then multivariable logistic regression were used to model the effect of the outcome. Screening of patients with positive Non-tuberculous Mycobacteria culture for eligibility Results Forty-five patients met the study inclusion criteria. 60% were male with a median age of 53. The most common comorbidities were malignancy and bronchiectasis. NTM species were Mycobacterium simiae (35%), Mycobacterium avium Complex (27%), and Mycobacterium abscessus (18%). Overall cure rate was 95%, with 85%, 85% and 74% of microbiological, clinical, and radiological rate achieved, respectively. Greater number of patients were treated before the recent pulmonary NTM guideline. Regimens were based on general treatment for NTM infection with clarithromycin, ethambutol, and rifampicin utilized the most. 69% of regimens were adjusted after speciation. The median duration of treatment was 36 weeks. Relapse, recurrence and reinfection rate was 20%, 9%, and 2%, respectively. NTM related hospital admission rate was 34%. Baseline characteristics of Patients with Pulmonary Non-tuberculous Mycobacteria (n=45) Primary and secondary outcomes Clinical Presentation, diagnosis and treatment of Patients with pulmonary Non-tuberculous Mycobacteria (n=45) This table is showing the clinical course of all patients included in the study with subgroup analysis per each specie of Non-tuberculous Mycobacteria Conclusion Pulmonary NTM disease in our patients was mainly due to three species in 80%. High overall cure rate and low recurrence rate were achieved. The findings of this study will serve as a guide for the management of pulmonary NTM disease in Saudi population. Disclosures All Authors: No reported disclosures.

Evaluation of Mycobacterium tuberculosis specific antigen-stimulated CD27−CD38+IFN-γ+CD4+ T cells for discrimination of active tuberculosis

BackgroundActive tuberculosis (ATB) originates from primary Mycobacterium tuberculosis (MTB) infection or reactivation of latent tuberculosis. Besides bacteriological examination, MTB-reactive immunocytes detection can be an alternative testing for discrimination of active tuberculosis. The purpose of this study is to investigate the accuracy of peripheral blood CD27−CD38+IFN-γ+CD4+T cells in ATB diagnosis.MethodsThis prospective diagnostic accuracy study was conducted at Shanghai Pulmonary Hospital between January 2019 and December 2021. Patients with ATB, non-tuberculosis mycobacterium infection (NTM), latent tuberculosis infection (LTBI), other respiratory diseases (OD), and healthy individuals (HC) were enrolled. The accuracy of CD27−CD38+IFN-γ+CD4+/CD4+ and other phenotypic markers for ATB diagnosis was assessed.ResultsA total of 376 patients (237 ATB, 38 LTBI, 8 NTM, 50 OD, and 43 HC) were enrolled. The ratios of CD4+IFN-γ+CD27− and CD4+IFN-γ+CD27−CD38+ profiles in CD4+IFN−γ+ cells and the ratios of CD4+IFN-γ+CD38+, CD4+IFN-γ+CD27−, and CD4+IFN-γ+CD38+CD27− profiles in CD4+ cells in the ATB group were significantly higher than in the other groups. The area under the curve (AUC) of CD27−CD38+IFN-γ+CD4+/CD4+ for the diagnosis of ATB was the highest, with a value of 0.890. With the optimal cutoff value of 1.34 × 10–4, the sensitivity and specificity of CD27−CD38+IFN-γ+CD4+/CD4+ for ATB diagnosis was 0.869 and 0.849, respectively.ConclusionCD27−CD38+IFN-γ+CD4+/CD4+ might be a potential biomarker for active tuberculosis diagnosis.

A Novel Leucyl-tRNA Synthetase Inhibitor, MRX-6038, Expresses Anti-Mycobacterium abscessus Activity In Vitro and In Vivo.

ABSTRACTTherapeutic options for Mycobacterium abscessus infections are extremely limited, and new drugs are needed. The anti-M. abscessus activity of MRX-6038, a new leucyl-tRNA synthetase inhibitor, was evaluated in vitro and in vivo. Antimicrobial susceptibility testing was performed on 12 nontuberculosis mycobacteria (NTM) reference strains and 227 clinical NTM isolates. A minimum bactericidal concentration assay was conducted to distinguish the bactericidal versus bacteriostatic activity of MRX-6038. The synergy between MRX-6038 and 12 clinically important antibiotics was determined using a checkerboard assay. The activity of MRX-6038 against M. abscessus residing inside macrophages was also evaluated. Finally, the potency of MRX-6038 in vivo was determined in a neutropenic mouse model that mimicked a pulmonary M. abscessus infection. MRX-6038 exhibited high anti-M. abscessus activity against extracellular M. abscessus in culture, with a MIC50 of 0.063 mg/L and a MIC90 of 0.125 mg/L. Fifty percent of the activity was bactericidal, and fifty percent was bacteriostatic. A synergy between MRX-6038 and clarithromycin or azithromycin was found in 25% of strains. No antagonism was evident between MRX-6038 and 12 antibiotics commonly used to treat NTM infections. MRX-6038 also exhibited activity against intracellular NTM, which caused a significant reduction in the bacterial load in the lungs of M. abscessus-infected neutropenic mice. In conclusion, MRX-6038 was active against M. abscessus in vitro and in vivo, and it represents a potential candidate for incorporation into strategies by which M. abscessus infections are treated.

Short Signature rpoB Gene Sequence to Differentiate Species in Mycobacterium abscessus Group.

ABSTRACTMycobacterium abscessus group (MAG) are rapidly growing acid-fast bacteria that consist of three closely related species: M. abscessus (Ma), M. bolletii (Mb), and M. massiliense (Mm). Differentiation of these species can be difficult but is increasingly requested owing to recent infectious outbreaks and their differential drug resistance. We developed a novel and rapid pyrosequencing method using short signature sequences (35 to 45 bp) at a hypervariable site in the rpoB gene to differentiate the three MAG species, along with M. chelonae (Mc), and M. immunogenum (Mi). This method was evaluated using 111 M. chelonae-abscessus complex (MCAC) isolates, including six reference strains. All isolates were successfully differentiated to the species level (69 Ma, four Mb, six Mm, 23 Mc, and nine Mi). The species identifications by this method had 100% agreement with Sanger sequencing as well as an in-silico rpoB typing method. This short signature sequencing (SSS) method is rapid (6 to 7 h), accurately differentiates MAG species, and is useful for informing antimicrobial therapy decision.IMPORTANCE Mycobacterium abscessus group (MAG) are rapidly growing acid-fast bacteria that include three species: M. abscessus, M. massiliense, and M. bolletii. These species are among the leading causes of nontuberculosis mycobacteria infections in humans but difficult to differentiate using commonly used methods. The differences of drug resistance among the species shape the treatment regimens and make it significant for them to be differentiated accurately and quickly. We developed and evaluated a novel short signature sequencing (SSS) method utilizing a gene called rpoB to differentiate the three MAG species, as well as other two species (M. chelonae and M. immunogenum). The identification results had 100% agreement with both the reference method of Sanger sequencing and rpoB typing method via a computer-simulated analysis. This SSS method was accurate and quick (6 to 7 h) for species differentiation, which will benefit patient care. The technology used for this method is affordable and easy to operate.

Progression and Dissemination of Pulmonary Mycobacterium Avium Infection in a Susceptible Immunocompetent Mouse Model.

Pulmonary infections caused by the group of nontuberculosis mycobacteria (NTM), Mycobacterium avium complex (MAC), are a growing public health concern with incidence and mortality steadily increasing globally. Granulomatous inflammation is the hallmark of MAC lung infection, yet reliable correlates of disease progression, susceptibility, and resolution are poorly defined. Unlike widely used inbred mouse strains, mice that carry the mutant allele at the genetic locus sst1 develop human-like pulmonary tuberculosis featuring well-organized caseating granulomas. We characterized pulmonary temporospatial outcomes of intranasal and left intrabronchial M. avium spp. hominissuis (M.av) induced pneumonia in B6.Sst1S mice, which carries the sst1 mutant allele. We utilized traditional semi-quantitative histomorphological evaluation, in combination with fluorescent multiplex immunohistochemistry (fmIHC), whole slide imaging, and quantitative digital image analysis. Followingintrabronchiolar infection with the laboratory M.av strain 101, the B6.Sst1S pulmonary lesions progressed 12–16 weeks post infection (wpi), with plateauing and/or resolving disease by 21 wpi. Caseating granulomas were not observed during the study. Disease progression from 12–16 wpi was associated with increased acid-fast bacilli, area of secondary granulomatous pneumonia lesions, and Arg1+ and double positive iNOS+/Arg1+ macrophages. Compared to B6 WT, at 16 wpi, B6.Sst1S lungs exhibited an increased area of acid-fast bacilli, larger secondary lesions with greater Arg1+ and double positive iNOS+/Arg1+ macrophages, and reduced T cell density. This morphomolecular analysis of histologic correlates of disease progression in B6.Sst1S could serve as a platform for assessment of medical countermeasures against NTM infection.

Polycationic Glycopolymer Demonstrates Activity Against Persisters and Biofilms of Non-tuberculosis Mycobacteria Cystic Fibrosis Clinical Isolates in vitro.

Non-tuberculosis Mycobacterium (NTM) is a group of opportunistic pathogens associated with pulmonary infections that are difficult to diagnose and treat. Standard treatment typically consists of prolonged combination antibiotic therapy. Antibiotic resistance and the role of biofilms in pathogen communities, such as NTM persister cells, is an important unmet challenge that leads to increased toxicity, frequent relapse, poor clinical management, and an extended treatment period. Infection recurrence and relapse are not uncommon among individuals with cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD), where thick mucus supports bacterial biofilm production and impairs mucociliary clearance. The study evaluates a membrane-active cationic glycopolymer [poly (acetyl, arginyl) glucosamine (PAAG)] being developed to support the safe and effective treatment of NTM biofilm infections. PAAG shows antibacterial activity against a wide range of pathogenic bacteria at concentrations non-toxic to human epithelial cells. Time-kill curves demonstrated PAAG’s rapid bactericidal potential at concentrations as low as 1X MIC against all NTM strains tested and compared to the standard of care. PAAG treatment prevents persister formation and eradicates antibiotic-induced persister cells in planktonic NTM cultures below the limit of detection (10 colony-forming unit (CFU)/ml). Further, PAAG showed the ability to penetrate and disperse NTM biofilms formed by both rapidly and slowly growing strains, significantly reducing the biofilm biomass (p < 0.0001) compared to the untreated NTM biofilms. Microscopical examination confirmed PAAG’s ability to disrupt and disperse mycobacterial biofilms. A single PAAG treatment resulted in up to a 25-fold reduction in live-labeled NTM and a 78% reduction in biofilm thickness. Similar to other polycationic molecules, PAAG’s bactericidal and antibiofilm activities employ rapid permeabilization of the outer membrane of the NTM strains, and subsequently, reduce the membrane potential even at concentrations as low as 50 μg/ml (p < 0.001). The outcomes of these in vitro analyses suggest the importance of this polycationic glycopolymer, PAAG, as a potential therapeutic agent for opportunistic NTM infections.

Anti-Mycobacterial Drug Resistance in Japan: How to Approach This Problem?

Mycobacteriosis is mainly caused by two groups of species: Mycobacterium tuberculosis and non-tuberculosis mycobacteria (NTM). The pathogens cause not only respiratory infections, but also general diseases. The common problem in these pathogens as of today is drug resistance. Tuberculosis (TB) is a major public health concern. A major challenge in the treatment of TB is anti-mycobacterial drug resistance (AMR), including multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis. Recently, the success rate of the treatment of drug-resistant tuberculosis (DR-TB) has improved significantly with the introduction of new and repurposed drugs, especially in industrialized countries such as Japan. However, long-term treatment and the adverse events associated with the treatment of DR-TB are still problematic. To solve these problems, optimal treatment regimens designed/tailor-made for each patient are necessary, regardless of the location in the world. In contrast to TB, NTM infections are environmentally oriented. Mycobacterium avium-intracellulare complex (MAC) and Mycobacterium abscessus species (MABS) are the major causes of NTM infections in Japan. These bacteria are naturally resistant to a wide variation of antimicrobial agents. Macrolides, represented by clarithromycin (CLR) and amikacin (AMK), show relatively good correlation with treatment success. However, the efficacies of potential drugs for the treatment of macrolide-resistant MAC and MABS are currently under evaluation. Thus, it is particularly difficult to construct an effective treatment regimen for macrolide-resistant MAC and MABS. AMR in NTM infections are rather serious in Japan, even when compared with challenges associated with DR-TB. Given the AMR problems in TB and NTM, the appropriate use of drugs based on accurate drug susceptibility testing and the development of new compounds/regimens that are strongly bactericidal in a short-time course will be highly expected.

Development of a nucleic acid chromatography assay for the detection of commonly isolated rapidly growing mycobacteria.

Introduction. Non-tuberculosis mycobacterium infections are increasing worldwide, including those caused by rapidly growing mycobacteria (RGM).Gap Statement. The identification of the aetiological agent in the context of infections is essential for the adoption of an adequate therapeutic approach. However, the methods for the rapid distinction of different RGM species are less than optimal.Aim. To develop a nucleic acid chromatography kit to identify clinically common RGM.Methodology. We tried to develop a nucleic acid chromatography kit designed to detect four RGM species (including three subspecies) i.e. Mycobacterium abscessus subsp. abscessus, Mycobacterium abscessus subsp. bolletii (detected as M. abscessus/bolletii) Mycobacterium abscessus subsp. massiliense, Mycobacterium fortuitum, Mycobacterium chelonae and Mycobacterium peregrinum. The amplified target genes for each species/subspecies using multiplex PCR were analysed using a nucleic acid chromatography assay.Results. Among the 159 mycobacterial type strains and 70 RGM clinical isolates tested, the developed assay correctly identified all relevant RGM without any cross-reactivity or false-negatives. The limits of detection for each species were approximately 0.2 pg µl-1.Conclusion. The rapid and simple nucleic acid chromatography method developed here, which does not involve heat denaturation, may contribute to the rapid identification and treatment of RGM infections.

Pathological humerus fracture due to anti-interferon-gamma autoantibodies: A case report

BACKGROUNDVarious etiologies contribute to pathological fractures, including bone infections. Recently, non-tuberculosis Mycobacterium-related bone infections among patients with anti-interferon-gamma autoantibody-induced adult-onset immunodeficiency has raised concerns in Southeast Asia, with the common presentations including osteomyelitis. However, it also rarely manifests as traumatic fractures, as reported in this case.CASE SUMMARYA diabetic female fractured her humerus after a traumatic accident and received fixation surgery. Abnormal necrotic bone tissue and abscess formation were noted, and she was diagnosed with a pathological fracture due to non-tuberculosis Mycobacterium infection. Multiple bone involvement was also revealed in a bone scan. Anti-interferon-gamma autoantibodies were then checked due to an unexplained immunocompromised status and found to be positive. Her humerus fracture and multiple bone infections healed after steroid and anti-non-tuberculosis Mycobacterium medication treatment following fixation surgery.CONCLUSIONComprehensive preoperative evaluations may help identify pathological fractures and guide the treatment course.

Pulmonary nontuberculous mycobacterial disease in Florida and association with large-scale natural disasters

BackgroundLittle is known about the impact of the ecosystem disruption and its contribution on the non-tuberculosis mycobacteria (NTM) diseases (cases) rate in Florida (FL), a state with a high prevalence of NTM in the United States. We aimed to evaluate the epidemiological distribution of NTM in FL and identify its association with extreme weather events.MethodsWe used OneFlorida Clinical Research Consortium dataset and extracted data on NTM cases using ICD codes 9- CM 031.0 and ICD-10 A31 during 2012–2018. The number of hurricanes during the study period which affected FL were extracted data from the National Hurricane Center (NHC) and the National Oceanic and Atmospheric Administration (NOAA).ResultsPrevalence of NTM gradually increased during the study period. The rate was 2012: 14.3/100,000, 2015; 20.1/100,000 and 2018; 22.6/100,00 except in 2014 where there was an 8% decrease. The incidences were 2012; 6.5/100,00, 2015; 4.9/100,000 and in 2015; 5.4/100,000. Geographical analysis demonstrated a gradual expansion of the NTM cases in Alachua, and Marion Counties throughout the study period. Notably, the 2018 heat map showed higher prevalence of NTM in the northwestern, panhandle region of FL which had been absent in the heat maps for years 2012–2018. High number of the hurricanes was associated with the higher number of the new cases of NTM infection for years 2012, 2016–2018, while the lower number of the hurricanes was associated with the lower number of the new cases of NTM infection for years 2014–2015.ConclusionThe current study found the prevalence rates of NTM disease in FL rose from 2012 to 2018. A higher prevalence was seen following the hurricanes.

Epidemiology of Nontuberculous Mycobacterial Infection in Tuberculosis Suspects.

Nontuberculosis mycobacteria (NTM) are opportunistic pathogens that cause a wide range of illnesses. Here, the species distribution and prevalence of NTM infections in tuberculosis suspects was analyzed. A total of 7,073 specimens from pulmonary and extrapulmonary sites were analyzed, and 709 (10%) were found to be culture positive for mycobacteria. Of these, 85.2% were identified as Mycobacterium tuberculosis complex and 14.8% as NTM (65.7% rapid growers and 34.3% slow growers). Speciation of the NTM isolates (n = 69) identified 19 NTM species. M. abscessus (33.3%) and M. fortuitum (24.6%) were the most dominant NTM species isolated from the patients, followed by M. porcinum (5.8%) and M. parascrofulaceum (4.3%). We also report peritonitis caused by rapidly growing NTM among the patients undergoing continuous ambulatory peritoneal dialysis and a case of M. senegalense peritonitis. A low prevalence but high species diversity of NTM was detected in our study. The high species diversity of NTM necessitates the need to unequivocally identify mycobacterial isolates for appropriate treatment.

The frequency and related factors of non-tuberculosis mycobacteria infections among patients with cystic fibrosis.

Non-tuberculous mycobacteria (NTM) can cause chronic lung infection particularly in patients who have structural lung disease such as cystic fibrosis (CF). We evaluated the incidence and management of NTM infections in patients with CF in our center. A retrospective cohort study was carried out on CF patients having at least one positive NTM isolate between 2012 and 2020. Ten patients (2.1%) had at least one positive NTM culture from respiratory samples. All of them were vaccinated with Bacille Calmette-Guérin (BCG) vaccine, which is in the national vaccination program in our country. Eight patients had the Mycobacterium abscessus complex, one had Mycobacterium avium, and one had Mycobacterium szulgai growth in their respiratory samples. Three patients had transient NTM infection, two had persistent, and five had active NTM infection (NTM pulmonary disease). Patients with NTM pulmonary disease received antibiogram-directed antimycobacterial therapy. In patients with NTM pulmonary disease, the median ppFEV1 and BMI decreased by 17% and 1%, respectively, at the time of the first NTM isolation when compared with the values one year before the first NTM isolation. Culture conversion was not seen in any patient infected with Mycobacteriunm abscessus complex. The NTM infection incidence is lower in our country than in those countries where the BCG vaccine is not routinely applied. The BCG vaccine may be a protective factor for NTM infection. Further studies are needed about the prevalence of NTM infections, facilitating and protective factors, and appropriate management of NTM infections in patients with CF.

165: Volatile metabolites are novel, noninvasive markers of nontuberculosis mycobacteria infection and disease status in the cystic fibrosis airway

165: Volatile metabolites are novel, noninvasive markers of nontuberculosis mycobacteria infection and disease status in the cystic fibrosis airway

Therapeutic Drug Monitoring in Non-Tuberculosis Mycobacteria Infections.

Nontuberculous mycobacteria can cause minimally symptomatic self-limiting infections to progressive and life-threatening disease of multiple organs. Several factors such as increased testing and prevalence have made this an emerging infectious disease. Multiple guidelines have been published to guide therapy, which remains difficult owing to the complexity of therapy, the potential for acquired resistance, the toxicity of treatment, and a high treatment failure rate. Given the long duration of therapy, complex multi-drug treatment regimens, and the risk of drug toxicity, therapeutic drug monitoring is an excellent method to optimize treatment. However, currently, there is little available guidance on therapeutic drug monitoring for this condition. The aim of this review is to provide information on the pharmacokinetic/pharmacodynamic targets for individual drugs used in the treatment of nontuberculous mycobacteria disease. Lacking data from randomized controlled trials, in vitro, in vivo, and clinical data were aggregated to facilitate recommendations for therapeutic drug monitoring to improve efficacy and reduce toxicity.