Nontuberculous Mycobacterial Pulmonary Disease Research Articles

Nghiên cứu tỷ lệ phân bố các loài Nontuberculous mycobacteria phân lập được tại bệnh viện 74 Trung ương bằng phương pháp giải trình tự gen hsp65

In recent years, the burden of nontuberculous mycobacteria pulmonary disease has increased worldwide. Nontuberculous mycobacteria - NTM infection is often misdiagnosed with Mycobacterium tuberculosis - MTB because of their similar clinical manifestations and preclinical manifestations. For MTB, the National Tuberculosis Program and the Ministry of Health (Vietnam) have a standard treatment regimen, while for NTM, an individualized treatment regimen based on infectious NTM species. Therefore, accurate identification of the causative NTM species can help clinicians choosing an effective treatment regimen. Among 122 suspected NTM samples collected at National Hospital 74, we successfully identified 115 strains belonging to NTM. Analytical DNA sequences, building phylogenetic trees were analyzed by Bioedit, ClustalX2, and MEGA-X software; comparing and identifying reference species from gene bank were used BLAST-NCBI. Slow-growing mycobacteria accounted for 61.7%, consists of Mycobacterium avium complex (37.4%), Mycobacterium lentiflavum (7.0%), Mycobacterium simiae (7.0%), Mycobacterium gordonae complex (5.2%) and other species less than 2.0%. The detection rate of rapid-growing mycobacteria was 38.3% including Mycobacterium abscessus complex (31.3%), and Mycobacterium fortuitum (7.0%). The most prevalent NTM species belonged to Mycobacterium avium complex and Mycobacterium abscessus complex (68.7%). The proportion of NTM infection in patients 50 years and older is 2.3 times higher than in patients under 50 years. This proportion is 5 times higher in females while there is no significant difference in males.

Endobronchial Involvement of <i>Mycobacterium intracellulare</i> in a Patient with Previously Treated Lung Cancer

The incidence of nontuberculous mycobacterial pulmonary disease is increasing, and <i>Mycobacterium avium</i> complex (MAC) is the most common causal species. Patients with underlying structural lung disease or an immunosuppressive condition are at increased risk for MAC infections. Endobronchial lesions caused by MAC infection are extremely rare, especially in immunocompetent hosts. Here, we describe a case of a 58-year-old woman with pulmonary infiltration and endobronchial involvement caused by MAC. The patient had shortness of breath and a productive cough. She had undergone surgery and chemoradiotherapy for lung cancer 10 years prior. Radiological findings revealed small centrilobular nodules with consolidation in the right lung and mild stenosis at the right main bronchus. Bronchoscopy revealed yellowish-white caseous necrosis in the right main bronchus. <i>Mycobacterium intracellulare</i> was identified in bronchial washing fluid. She was treated with antimicrobial medications. After 6 months of treatment, bronchial lesions, radiological findings, and symptoms had improved remarkably and she showed culture conversion.

Pulmonary non-tuberculous mycobacteria in colonisation and disease in The Gambia

The clinical relevance of pulmonary non-tuberculous mycobacteria (PNTM) in The Gambia is unknown. The aim of this study was to estimate the prevalence of non-tuberculous mycobacteria (NTM) in colonisation, and the burden of clinically relevant pulmonary NTM (PNTM) disease in The Gambia. This was a cross-sectional study of the prevalence of NTM in participants aged ≥ 15 years, in a nationwide tuberculosis (TB) prevalence survey between December 2011 and January 2013. We enrolled 903 participants with suspected NTM and NTM cultures were confirmed by 16S rRNA gene sequencing analyses. We applied the American Thoracic Society/Infectious Disease Society of America (ATS/IDSA) diagnostic criteria to determine clinical relevance of NTM. A total of 575 participants had acid-fast bacilli (AFB) positive Mycobacterial Growth Indicator Tube (MGIT) cultures and 229 (39.8%) were NTM. M. avium complex was by far the most isolated NTM (71.0%), followed by M. fortuitum (9.5%) and M. nonchromogenicum (2.9%). Older participants (> 24 years old) were four times more likely to have NTM in their sputa. Only 20.5% (9/44) NTM cases met the ATS/IDSA criteria for NTM disease. This study provides important data on the prevalence of NTM in pulmonary samples of suspected TB cases with AFB positive cultures from a nationally representative population in The Gambia. Enhanced PNTM surveillance is recommended to better understand the contribution of NTM to pulmonary disease.

Characterizing and correcting immune dysfunction in non-tuberculous mycobacterial disease.

Non-tuberculous mycobacterial pulmonary disease (NTM-PD) is a chronic, progressive, and growing worldwide health burden associated with mounting morbidity, mortality, and economic costs. Improvements in NTM-PD management are urgently needed, which requires a better understanding of fundamental immunopathology. Here, we examine temporal dynamics of the immune compartment during NTM-PD caused by Mycobacterium avium complex (MAC) and Mycobactereoides abscessus complex (MABS). We show that active MAC infection is characterized by elevated T cell immunoglobulin and mucin-domain containing-3 expression across multiple T cell subsets. In contrast, active MABS infection was characterized by increased expression of cytotoxic T-lymphocyte-associated protein4. Patients who failed therapy closely mirrored the healthy individual immune phenotype, with circulating immune network appearing to 'ignore' infection in the lung. Interestingly, immune biosignatures were identified that could inform disease stage and infecting species with high accuracy. Additionally, programmed cell death protein 1 blockade rescued antigen-specific IFN-γ secretion in all disease stages except persistent infection, suggesting the potential to redeploy checkpoint blockade inhibitors for NTM-PD. Collectively, our results provide new insight into species-specific 'immune chatter' occurring during NTM-PD and provide new targets, processes and pathways for diagnostics, prognostics, and treatments needed for this emerging and difficult to treat disease.

Epidemiology and management of nontuberculous mycobacterial disease in people with cystic fibrosis, the Netherlands

BackgroundNontuberculous mycobacteria (NTM) are opportunistic, difficult to treat pathogens. With increasing prevalence of NTM infections in people with cystic fibrosis (pwCF) and the improved life expectancy, the burden is expected to grow. MethodsWe assessed the epidemiology and management of NTM isolation and disease in pwCF in the Netherlands using a survey and retrospective, case-controlled data from the Dutch CF Registry. We determined the isolation prevalence, treatment and outcomes from 2013-2019. ResultsNTM isolation prevalence increased from 1.0% to 3.6% (2013-2019). This was a single NTM isolation in 53.7% of the adults and 60.0% of the children. M. abscessus and M. avium complex (MAC) were most frequent (47.1 and 30.9%). Of the treated pwCF, 48.5% attained culture conversion of M. abscessus; 54.5% for MAC. Children with an NTM isolation showed more infections with S. maltophilia and/or A. fumigatus (p < 0.001) compared to controls. In the year prior to NTM isolation, children in the NTM group had a lower mean FEV1% predicted (81.5 ± 16.7 vs. 88.6 ± 15.3, p = 0.024), while adults in the NTM group had more IV antibiotic days compared to controls (60 vs. 17, p = 0.047). In the following years, FEV1% predicted declined faster in pwCF with NTM than the control group (children: -3.8% vs. -1.6%, p = 0.023; adults: -0.7% and 0.4%, ns). ConclusionsThe isolation prevalence of 3.6%, poor treatment outcomes and associated lung function decline emphasize that NTM pulmonary disease (NTM-PD) is a significant health issue among pwCF in the Netherlands. Its prevention and treatment require increased attention.

Severity of underweight affects the development of nontuberculous mycobacterial pulmonary disease; a nationwide longitudinal study

Regarding to known association between underweight and non-tuberculous mycobacterial pulmonary disease (NTM-PD), the underweight was simply categorized as body mass index (BMI) less than 18.5 kg/m2, mainly because of its low prevalence. We aimed to better define the impact of BMI severity on NTM-PD development. We analysed health data from 4,332,529 individuals examined in 2009 and followed up until December 2017 to determine the incidence of NTM-PD. Based on the BMI in kg/m2, the population was categorized into mild (17.00–18.49), moderate (16.00–16.99), and severe underweight (< 16.00) groups. Using Cox proportional-hazards analyses, hazard ratios for NTM-PD were calculated according to the severity of underweight in reference to normal BMI (18.50–22.99). Over a median follow-up of 5.6 ± 1.2 years, 6223 participants developed NTM-PD. Risk of NTM-PD increased significantly with the severity of underweight: multivariate adjusted hazard ratios (95% confidence intervals) for mild, moderate, and severe underweight were 2.34 (2.17–2.52), 3.50 (3.07–3.99), and 4.35 (3.63–5.21), respectively. In subgroup analysis, being younger (< 65 years old) or male exacerbated the effect of severe underweight on the risk of NTM-PD. This study proved that as underweight categories became more severe, the risk of NTM-PD increased proportionally.

Outcomes of Adjunctive Surgery in Patients With Nontuberculous Mycobacterial Pulmonary Disease: A Systematic Review and Meta-analysis

The burden of nontuberculous mycobacterial pulmonary disease (NTM-PD) is increasing worldwide. Amidst the poor treatment success of antibiotic therapy, adjunctive surgery is gaining attention; however, discrepancies in reported outcomes exist. What are the treatment outcomes and complications of patients with NTM-PD undergoing adjunctive surgery? The MEDLINE, Embase, and Cochrane databases were searched for eligible studies before January 2022. Studies reporting the outcomes of adjunctive surgery in adult patients who satisfied the diagnostic criteria for NTM-PD were included. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines. Data were extracted by two independent observers. Estimates of proportion were pooled using a random-effects model. Sputum mycobacterial culture negative conversion, recurrence, complications, and in-hospital mortality after surgery were primary outcomes that had been set before data collection began. Heterogeneity was evaluated by using the I2 statistic, and publication bias was assessed by using funnel plots and the Egger test. Fifteen of the 2,739 screened studies, with 1,071 patients, were assessed. The weighted proportion of postoperative sputum culture negative conversion was 93%(95%CI, 87%-97%), and recurrence was 9%(95%CI, 6%-14%) for a median follow-up of 34months. The proportion of patients who experienced postoperative complications was 17%(95%CI, 13%-23%), and in-hospital mortality was 0%(95%CI, 0%-2%). Studies that performed multilobar lung resection in > 30%of the study population showed comparable rates of complications with studies that did not. Adjunctive surgery is an effective therapeutic option with acceptable rates of complications for selected patients with NTM-PD. PROSPERO; No.: CRD42022310663; URL: https://www.crd.york.ac.uk/prospero/.

Clinical characteristics of rheumatoid arthritis patients complicated with pulmonary nontuberculous mycobacterial disease: A cross-sectional case series study.

Pulmonary nontuberculous mycobacterial disease (pNTM) is a common pulmonary complication of rheumatoid arthritis (RA), but their association has rarely been researched. We aimed to reveal the clinical characteristics of RA with pNTM. Among all the RA patients who visited Tenri hospital from April 2017 to March 2018, we enrolled those fulfilling the 2007 ATS/IDSA diagnostic criteria of pNTM, and sex- and age- matched control group at a ratio of 1:5. Demographic characteristics were compared between the two groups. Among 865 RA patients, 35 (4.0%) patients were complicated with pNTM. RA patients with pNTM had significantly lower BMI and higher rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) positivity. Bronchiectasis was the most frequent lesion, followed by clusters of small nodules, patchy consolidation and cavity. Multivariable logistic regression analysis revealed bronchiectasis as a strong independent associated factor of pNTM. Treatment for pNTM was needed in 14 of the 35 (40%) RA patients with pNTM and sputum negative conversion was accomplished in 11 of the 14 cases (78.6%). RA patients with lower BMI, RF/ACPA positivity, and bronchiectasis were associated with pNTM. Treatment for pNTM may attain sputum negative conversion and radiological improvement in patients with RA.

Nontuberculous mycobacteria infection and pulmonary disease in bronchiectasis.

Although interest in nontuberculous mycobacteria (NTM) infection has increased in the last decades, published data vary according to different geographical areas, diagnostic facilities and quality of study design. This study aims at assessing both prevalence and incidence of NTM infection and NTM pulmonary disease (NTM-PD) among adults with bronchiectasis, to describe patients' characteristics, therapeutic options and clinical outcomes. Bronchiectasis adults who had been tested for NTM were enrolled at the Bronchiectasis Program of the Policlinico Hospital in Milan, Italy, from 2016 to 2018. Among the 373 patients enrolled, 26.1% had at least one respiratory sample positive for NTM and 12.6% reached a diagnosis of NTM-PD. Incidence rates for NTM infection and NTM-PD were 13 (95% CI 10-16) and 4 (95% CI 2-6) per 100 person-years, respectively. The most prevalent NTM species causing NTM-PD were M. intracellulare (38.3%), M. avium (34.0%), M. abscessus (8.5%) and M. kansasii (8.5%). Once treatment for NTM-PD was initiated, a favourable outcome was documented in 52.2% of the patients, while a negative outcome was recorded in 32.6%, including recurrence (17.4%), treatment failure (10.9%), re-infection (2.2%) and relapse (2.2%). Treatment halted was experienced in 11 (23.9%) patients. NTM infection is frequent in bronchiectasis patients and the presence of NTM-PD is relevant. The low success rate of NTM-PD treatment in bronchiectasis patients requires a call to action to identify new treatment modalities and new drugs to improve patients' outcomes.

Long-range transport of airborne bacteria over East Asia: Asian dust events carry potentially nontuberculous Mycobacterium populations.

The nontuberculous mycobacterial pulmonary disease (NTM-PD) caused by Mycobacterium species has increased in prevalence all over the world. The distributions of NTM-PD are possibly determined by the westerly wind traveling at high altitudes over East Asia. However, the long-range transport of Mycobacterium species has not been demonstrated by analyzing the bacterial communities in aerosols such as desert mineral particles and anthropogenic pollutants transported by the westerly wind. Here, airborne bacterial compositions were investigated including Mycobacterium species in high-elevation aerosols, which were captured in the snow cover at 2,450m altitude on Mt. Tateyama. This was further compared to the ground-level or high-altitude aerosols collected at six sampling sites distributed from Asian-dust source region (Tsogt-Ovoo) to downwind areas in East Asia (Asian continental cities; Erenhot, Beijing, Yongin, Japanese cities; Yonago, Suzu, Noto Peninsula). The cell concentrations and taxonomic diversities of airborne bacteria decreased from the Asian continent to the Japan area. Terrestrial bacterial populations belonging to Firmicutes and Actinobacteria showed higher relative abundance at high-elevation and Japanese cities. Additionally, Mycobacterium species captured in the snow cover on Mt. Tateyama increased in relative abundance in correspondence to the increase of black carbon concentrations. The relative abundance of Mycobacterium sequences was higher in the aerosol samples of Asian continental cities and Japanese cities than in the desert area. Presumably, anthropogenic pollution over East Asia carries potential Mycobacterium species, which induce NTM-PD, thereby impacting upon the public health.

Nontuberculous Mycobacteria Lung Disease (NTM-LD): Current Recommendations on Diagnosis, Treatment, and Patient Management.

Nontuberculous mycobacteria (NTM) are a group of ubiquitous environmental bacteria that can be found in soil, dust, and water. Mycobacterium avium complex (MAC) is the most common pathogen and the one most associated with chronic pulmonary disease. In recent years, the prevalence of Mycobacterium avium complex-related pulmonary disease (MAC-PD) has increased and is an emerging public health concern. This is due to a combination of environmental and geographic factors, dynamic changes in organism virulence and antimicrobial susceptibility, and evolving host susceptibility. Given the dynamic nature of the disease, management of NTM pulmonary disease (NTM-PD) often includes a multimodal approach including antimicrobial therapy, airway clearance techniques, limiting environmental exposures, and reducing susceptibility to NTM through prevention of reflux and maintenance of body weight. This review will explore the most recent concepts in the diagnosis, treatment, and management of individuals with NTM pulmonary infection.

Vanadium in groundwater aquifers increases the risk of MAC pulmonary infection in O'ahu, Hawai'i.

To identify whether trace metals influence the risk of NTM infection in O'ahu, Hawai'i. A population-based ecologic cohort study was conducted using NTM infection incidence data from patients enrolled at Kaiser Permanente Hawai'i during 2005-2019. We obtained sociodemographic, microbiologic, and geocoded residential data for all Kaiser Permanente Hawai'i beneficiaries. To estimate the risk of NTM pulmonary infection from exposure to groundwater constituents, we obtained groundwater data from three data sources: (1) Water Quality Portal; (2) the Hawai'i Department of Health; and (3) Brigham Young University, Department of Geological Science faculty. Data were aggregated by an aquifer and were associated with the corresponding beneficiary aquifer of residence. We used Poisson regression models with backward elimination to generate models for NTM infection risk as a function of groundwater constituents. We modeled two outcomes: Mycobacterium avium complex (MAC) species and Mycobacterium abscessus group species. For every 1-unit increase in the log concentration of vanadium in groundwater at the aquifer level, infection risk increased by 22% among MAC patients. We did not observe significant associations between water-quality constituents and infection risk among M. abscessus patients. Concentrations of vanadium in groundwater were associated with MAC pulmonary infection in O'ahu, Hawai'i. These findings provide evidence that naturally occurring trace metals influence the presence of NTM in water sources that supply municipal water systems.

CLINICAL AND MICROBIOLOGIC FEATURES OF PATIENTS WITH BRONCHIECTASIS AND AUTOIMMUNITY

CLINICAL AND MICROBIOLOGIC FEATURES OF PATIENTS WITH BRONCHIECTASIS AND AUTOIMMUNITY

Outcomes of Robotic Surgery for Patients with Pulmonary Nontuberculous Mycobacterial Disease

Treatment for patients with pulmonary nontuberculous mycobacterial (NTM) disease includes long, multi-drug, and toxic medication regimens. Surgical resection is an alternative treatment for patients with localized or refractory NTM infection. Robot-assisted operations have not been performed routinely in this population.

T-SPOT with CT image analysis based on deep learning for early differential diagnosis of nontuberculous mycobacteria pulmonary disease and pulmonary tuberculosis

ObjectivesThis study aimed to establish a diagnostic algorithm combining T-SPOT with computed tomography image analysis based on deep learning (DL) for early differential diagnosis of nontuberculous mycobacteria pulmonary disease (NTM-PD) and pulmonary tuberculosis (PTB). MethodsA total of 1049 cases were enrolled, including 467 NTM-PD and 582 PTB cases. A total of 320 cases (160 NTM-PD and 160 PTB) were randomized as the testing set and were analyzed using T-SPOT combined with the DL model. The testing cases were first divided into T-SPOT-positive and -negative groups, and the DL model was then used to separate the cases into four subgroups further. ResultsThe precision was found to be 91.7% for the subgroup of T-SPOT-negative and DL classified as NTM-PD, and 89.8% for T-SPOT-positive and DL classified as PTB, which covered 66.9% of the total cases, compared with the accuracy rate of 80.3% of T-SPOT alone. In the other two remaining groups, where the T-SPOT prediction was inconsistent with the DL model, the accuracy was 73.0% and 52.2%, separately. ConclusionOur study shows that the new diagnostic system combining T-SPOT with DL based computed tomography image analysis can greatly improve the classification precision of NTM-PD and PTB when the two methods of prediction are consistent.

Global burden of nontuberculous mycobacteria in the cystic fibrosis population: a systematic review and meta-analysis.

People living with cystic fibrosis have an increased risk of lung infection with nontuberculous mycobacteria (NTM), the prevalence of which is reportedly increasing. We conducted a systematic review of the literature to estimate the burden (prevalence and incidence) of NTM in the cystic fibrosis population. Electronic databases, registries and grey literature sources were searched for cohort and cross-sectional studies reporting epidemiological measures (incidence and prevalence) of NTM infection or NTM pulmonary disease in cystic fibrosis. The last search was conducted in September 2021; we included reports published since database creation and registry reports published since 2010. The methodological quality of studies was appraised with the Joanna Briggs Institute tool. A random effects meta-analysis was conducted to summarise the prevalence of NTM infection, and the remaining results are presented in a narrative synthesis. This review included 95 studies. All 95 studies reported on NTM infection, and 14 of these also reported on NTM pulmonary disease. The pooled estimate for the point prevalence of NTM infection was 7.9% (95% CI 5.1-12.0%). In meta-regression, sample size and geographical location of the study modified the estimate. Longitudinal analysis of registry reports showed an increasing trend in NTM infection prevalence between 2010 and 2019. The overall prevalence of NTM infection in cystic fibrosis is 7.9% and is increasing over time based on international registry reports. Future studies should report screening frequency, microbial identification methods and incidence rates of progression from NTM infection to pulmonary disease.

Gastroesophageal Reflux Disease Increases Susceptibility to Nontuberculous Mycobacterial Pulmonary Disease

Gastroesophageal reflux disease (GERD) is a common comorbidity of nontuberculous mycobacteria (NTM) pulmonary disease (PD). Although GERD is associated with more symptoms and severe disease in patients with NTM PD, whether GERD is associated with an increased risk of NTM PD developing is unknown. Does GERD influence the development of NTM PD? Are there any factors associated with an increased risk of NTM PD among patients with GERD? What is the impact of NTM PD on the health-care use of patients with GERD? Data from the Korean National Health Insurance Service National Sample Cohort between 2002 and 2015 were used. The incidence and risk of NTM PD were compared between patients with GERD (GERD cohort; n= 17,424) and patients matched for age, sex, type of insurance, and Charlson Comorbidity Index (matched cohort; n= 69,696). Using the GERD cohort, the factors associated with incident NTM PD also were evaluated. During a median follow-up duration of 5.1 years, the age- and sex-adjusted incidence of NTM PD was significantly higher in the GERD cohort (34.8 per 100,000 person-years [PY]) than in the matched cohort (10.5 per 100,000 PY; P< .001), with a subdistribution hazard ratio (HR) of 3.36 (95%CI, 2.10-5.37). Regarding risk factors associated with NTM PD, age of 60 years or older (adjusted HR, 3.57; 95%CI, 1.58-8.07) and bronchiectasis (adjusted HR, 18.69; 95%CI, 6.68-52.28) were associated with an increased risk of incident NTM PD in the GERD cohort. Compared with patients with GERD who did not demonstrate NTM PD, those with NTM PD showed higher all-cause (13,321 PY vs5,932 PY; P= .049) and respiratory disease-related (5,403 vs801; P= .011) ED visits or hospitalizations. GERD is associated with an increased incidence of NTM PD. Older age and bronchiectasis are risk factors for NTM PD in patients with GERD. NTM PD in patients with GERD is associated with increased health-care use.

Clinical significance and safety of combined treatment with chemotherapy and pulmonary rehabilitation regarding health-related quality of life and physical function in nontuberculous mycobacterial pulmonary disease.

In the treatment of patients with nontuberculous mycobacterial pulmonary disease (NTM-PD), pulmonary rehabilitation (PR) has been recommended as a non-pharmacological therapy. However, no study has validated the combination of chemotherapy and PR in this context. This study investigated the effect of chemotherapy and supervised PR on health-related quality of life (HRQoL) and physical function in NTM-PD patients. This prospective cohort study included patients diagnosed with NTM-PD who had a planned hospitalization of at least 3 weeks for chemotherapy and PR. HRQoL (Leicester Cough Questionnaire [LCQ] and chronic obstructive pulmonary disease assessment test [CAT]), physical function (incremental shuttle walk distance [ISWD], quadriceps force), and C-reactive protein levels were assessed before and after treatment, and the corresponding data were analyzed in conjunction with clinical data. The adverse events of PR were also investigated. Forty-two patients who met the study criteria were included in the analysis. After treatment, all LCQ item scores, total CAT score and sub-item scores related to respiratory symptoms, ISWD, quadriceps force, and C-reactive protein levels were found to have improved significantly. In the chronic cough with excessive sputum production (CCS) group, the proportions of responders who showed improvements in LCQ and CAT scores and ISWD greater than the corresponding minimal clinically important difference were significantly greater than those in the non-CCS group. No PR-related adverse events were reported. Combined treatment with chemotherapy and PR may improve HRQoL and physical function, and supervised PR can be provided safely.

Computed Tomography Comparative Analysis of Nontuberculous Mycobacterial Lung Disease in the Elderly and Secondary Pulmonary Tuberculosis.

The study aimed to explore the key points of computed tomography (CT) differential diagnosis of nontuberculous mycobacteria (NTM) and secondary pulmonary tuberculosis in elderly patients. We retrospectively analyzed 45 patients with NTM pulmonary disease and 65 patients with secondary pulmonary tuberculosis. All patients were older than 60 years. The diseases were confirmed by laboratory examination. The general data and CT images of the 2 groups were compared and analyzed using χ 2 tests, single-factor analysis, and multivariate logistic regression analysis. Single-factor analysis showed significant differences between the 2 groups in 9 factors: bronchiectasis of the left upper lobe lingual segment, bronchiectasis of the right middle lobe, small nodules, large nodules, thin-walled cavities, thick-walled cavities, nonsubpleural hollows, strip opacity, and mediastinal lymph node enlargement ( P < 0.05). Multivariate logistic regression analysis showed that thin-walled cavities, bronchiectasis of the right middle lobe, small nodules, and large nodules were important factors in the differential diagnosis of the two groups. Nontuberculous mycobacteria show certain characteristics on CT, which are helpful for differential diagnosis when coupled with clinical and sputum smear examinations.

Mycobacterium intracellulare among TB suspected patients in Bulgaria &amp;ndash; microbiological aspects

Introduction: Nontuberculous mycobacteria (NTM) are representatives of the genus Mycobacterium with a worldwide distribution, associated mainly with water, soil, and biofilms. Some of NTMs, such as Mycobacterium avium complex (MAC), are etiological agents of human diseases &amp;ndash; disseminated or with different localization, most often pulmonary. Aim: In the present study, we analyzed Mycobacterium intracellulare isolates recovered from clinical specimens of tuberculosis (TB) suspected patients in Bulgaria, 2018-2020. Materials and methods: The cultures were grown on solid and liquid media. For species identification, we used immune chromatographic (TB Ag MPT64) test and Line Probe Assay (LPA) from the positive cultures. Results: M. intracellulare was identified in 32 patients from 82,780 specimens. It was predominantly isolated in females &amp;ndash; 62.5% vs. 37.5% in males. The most affected age group was 65 years and over (38%). The distribution of the isolates in Bulgaria was uneven. Most of them (65.6%) were concentrated in two districts of the country: Plovdiv and Sofia-city. All strains were sensitive to macrolides and aminoglycosides except one with macrolide resistance. NTM pulmonary disease was confirmed in 16 patients with M. intracellulare isolate. Conclusions: Analysing the 32 M. intracellulare isolates identified among TB suspected patients in Bulgaria between 2018 and 2020, we found that only half of them met the American Thoracic Society (ATS) diagnostic criteria for NTM pulmonary disease. For the remaining patients with M. intracellulare isolates we did not have sufficient data to support this diagnosis. Efforts by Bulgarian respiratory and microbiological societies are needed for adherence to the international guidelines.