High-resolution 2D solid-state NMR provides insights into nontuberculous mycobacteria.

We present a high-resolution magic-angle spinning (MAS) solid-state NMR (ssNMR) study to characterize nontuberculous mycobacteria (NTM). We studied two different NTM strains, Mycobacterium smegmatis, a model, non-pathogenic strain, and Mycobacterium abscessus, an emerging and important human pathogen. Hydrated NTM samples were studied at natural abundance without isotope-labelling, as whole-cells versus cell envelope isolates, and native versus fixed sample preparations. We utilized 1D13C and 2D 1H-13C ssNMR spectra and peak deconvolution to identify NTM cell-wall chemical sites. More than ∼100 distinct 13C signals were identified in the ssNMR spectra. We provide tentative assignments for ∼30 polysaccharides by using well resolved 1H/13C chemical shifts from the 2D INEPT-based 1H-13C ssNMR spectrum. The signals originating from both the flexible and rigid fractions of the whole-cell bacteria samples were selectively analyzed by utilizing either CP or INEPT based 13C ssNMR spectra. CP buildup curves provide insights into the dynamical similarity of the cell-wall components for NTM strains. Signals from peptidoglycan, arabinogalactan and mycolic acid were identified. The majority of the 13C signals were not affected by fixation of the whole cell samples. The isolated cell envelope NMR spectrum overlap with the whole-cell spectrum to a large extent, where the latter has more signals. As an orthogonal way of characterizing these bacteria, electron microscopy (EM) was used to provide spatial information. ssNMR and EM data suggest that the M. abscessus cell-wall is composed of a smaller peptidoglycan layer which is more flexible compared to M. smegmatis, which may be related to its higher pathogenicity. Here in this work, we used high-resolution 2D ssNMR first time to characterize NTM strains and identify chemical sites. These results will aid the development of structure-based approaches to combat NTM infections.

Pulmonary Mycobacterium avium Complex With Adenocarcinoma of the Lung: A Case Report.

Nontuberculous mycobacteria are responsible for causing pulmonary as well as extrapulmonary diseases. These organisms are often multidrug resistant and management of these cases poses a therapeutic challenge. Lung cancer has been a prevalent challenge globally with a high mortality rate in affected individuals. Adenocarcinoma poses debilitating outcomes in most patients by inflicting a diagnostic and therapeutic challenge. The concomitant association of adenocarcinoma and Mycobacterium avium complex worsens the prognosis causing a challenge in managing such cases. We present a rare association between adenocarcinoma and pulmonary Mycobacterium avium complex complicating the traditional therapeutic regime. A different approach in the administration of therapy for this unique concomitant association between two debilitating diseases is outlined in the presented report.

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.

Introducción: La epidemiología de las micobacterias no tuberculosas (MNT) no se conoce bien. Nuestro objetivo fue determinar la incidencia de aislamientos de MNT y de enfermedad pulmonar por micobacterias no tuberculosas (EP-MNT) en cinco hospitales del norte de España, próximos entre sí, y analizar las diferencias entre ellos. Material y métodos: Se recopilaron retrospectivamente datos demográficos, microbiológicos, clínicos y radiológicos de todos los pacientes con una MNT aislada en muestra respiratoria entre 2012 y 2019 en los cinco hospitales. Se excluyeron los aislamientos de Mycobacterium gordonae. Una vez recogidos los datos, se determinó qué casos cumplían los criterios de EP-MNT. Resultados: Se incluyeron 594 pacientes. La tasa de incidencia media de aislamientos de NTM en los cinco hospitales fue de 4,15 por 100.000 personas-año y la tasa de EP-MNT fue de 1,2. El número anual de aislamientos mostró una tendencia creciente durante este periodo, pero no así el de EP-MNT. Las especies aisladas con mayor frecuencia fueron Mycobacterium avium complex (MAC) y Mycobacterium xenopi y las que causaron enfermedad con mayor frecuencia fueron MAC y Mycobacterium kansasii. Hubo diferencias significativas entre los cinco centros. Conclusiones: Nuestros resultados están en línea con estudios similares en Europa en términos de aislamiento de MNT, incidencia de EP-MNT y especies aisladas; sin embargo, no vemos la tendencia ascendente en las tasas de EP-MNT descrita en otros lugares. La gran variabilidad entre los cinco hospitales en las tasas de aislamiento y de enfermedad y en las especies aisladas resalta la importancia de los factores ambientales locales.

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.

Combination of Imipenem-Cilastatin-Relebactam and Amoxicillin in the Antibiotic Regimen in Two Cases of Mycobacterium abscessus Lung Infection.

Mycobacterium abscessus is a difficult-to-treat, multidrug-resistant human pathogen. Relebactam has been shown to inhibit M. abscessus ß-lactamase (BLAMab) and increase the activity of imipenem and amoxicillin. We present two cases of lung infection due to M. abscessus, one caused by M. abscessussubsp. massiliense and the other by subsp. abscessus. Both strains showed moderate sensitivity to imipenem, and the second strain was also resistant to macrolides. A multidrug antibiotic regimen was administered in both cases, which included imipenem/cilastatin/relebactam adjusted to the estimated glomerular filtration rate (eGFR) and amoxicillin for three months. The regimen was well tolerated and both patients improved both clinically and radiologically after the first phase of treatment. The results of our patients indicate that the combination of imipenem/cilastatin/relebactam and amoxicillin could be used in the future in difficult infections by M. abscessus.

Evaluation of GeneNAT Real-Time Polymerase Chain Reaction Analyzer and Pre-loaded Chip-Based Mycobacterium tuberculosis and Multidrug-Resistant Tuberculosis Detection in the Diagnosis of Pulmonary Tuberculosis.

BACKGROUND: Tuberculosis (TB) is still the second causative agent of death worldwide after COVID-19. It is caused by Mycobacterium tuberculosis (MTB) infection. OBJECTIVE: The aim of the current study was to compare the performance of GeneNAT real-time polymerase chain reaction analyzer and pre-loaded chip-based MTB screening and multidrug-resistant tuberculosis (MDR-TB) detection kit (Smart SureTM MTB & MDR-TB, Genetix Biotech Asia Pvt. Ltd., New Delhi, India) against the established WHO-approved GeneXpert Ultra (MTB/rifampicin (RIF)), line probe assay (LPA), and mycobacteria growth indicator tube (MGIT) culture at point of care (POC) level. METHODS: A total of 450 pulmonary TB (PTB) suspect patients were enrolled from October 2023 to March 2024 at the Intermediate Reference Laboratory, Department of Medicine, All India Institute of Medical Sciences, New Delhi, India. GeneXpert and GeneNAT tests were done directly from sputum specimens. However, processed sputum specimens were used for both LPA (GenoType MTBDRplus) and liquid culture and drug susceptibility testing (MGIT culture and drug susceptibility testing (DST)). RESULTS: On comparing with GeneXpert, for the detection of MTB and rifampicin (RIF), Smart SureTM showed a sensitivity of 98.18% and 97.5% with a specificity of 100% and 98.92%, respectively. While comparing mutations in the rpoB gene with LPA, the Smart SureTM MDR-TB kit exhibited sensitivity and specificity of 96.77% and 99.12%, respectively. For katG and inhA genes, sensitivity and specificity were 97.6% & 85.71% and 98.66% & 98.01%, respectively, for both genes. Smart SureTM MDR-TB showed comparable results with MGIT-DST with sensitivity and specificity of 96.88% & 96.15% and 98.99% & 99.02%, respectively, for both RIF and isoniazid (INH) drugs. CONCLUSION: The GeneNAT system test may provide the status of RIF and INH resistance in PTB cases in a short time with the use of minimal specimens. It required very little infrastructure with less skilled laboratory staff in comparison with other WHO-approved diagnostics used in resource-limited countries with TB and drug-resistant TB burdens.

Immune Reconstitution Syndrome Caused by Nontuberculous Mycobacteria: A Case Report and Review of Literature.

Immune reconstitution inflammatory syndrome (IRIS) is a potentially life-threatening phenomenon associated with the initiation of antiretroviral therapy in patients with acquired immunodeficiency syndrome due to a human immunodeficiency virus (HIV) infection. It is thought to be an exaggerated inflammatory response to an existing pathogen or even its antigen. We present a case of IRIS due to a non-tuberculous mycobacteria infection in a young patient with HIV infection who was recently started on therapy. This case highlights the challenges of making such a diagnosis and the importance of multidisciplinary team discussions with pulmonary and infectious diseases for optimal management of these patients.

Mycobacterium tuberculosis and Mycobacterium avium Coinfection in an Immunocompetent Patient.

Despite the increasing incidence of simultaneous mycobacterial and non-mycobacterial tuberculosis (TB) infection, little literature is available exploring the topic. Here, we present a case of a 22-year-old female diagnosed with pulmonary TB for four months with simultaneous multiple sputum cultures positive for non-tuberculous mycobacteria (NTM). Computed tomography of the chest without contrast reported linear areas of scarring involving both lung apices, more prominent on the left side. The patient completed intensive phase treatment for TB and is currently on isoniazid and rifampin with a referral to an infectious disease specialist for recommendations on treatment of Mycobacterium avium regimen in view of azithromycin allergy (intense cough and rash). While the coexistence of NTM is commonly attributed to colonization, differentiating colonization from disease is crucial considering the long duration of treatment, potential drug toxicity, risk of drug resistance, and significant cost of treatment. Clinical, microbiological, and radiological evidence should be considered for diagnosis of TB and NTM coinfection and expert consultation should be sought in formulating the treatment plan.

Mycobacterium gordonae: the canary in the coal mine?

Mycobacterium gordonae (M. gordonae) is a species of nontuberculous mycobacteria (NTM) that rarely causes infection. It has previously been labeled the most common NTM contaminant. Bronchiectasis is a disease characterized by abnormal airway dilation leading to chronic cough, sputum production and pulmonary infections. Patients with bronchiectasis are at higher risk of NTM-lung disease with more pathogenic NTM species including Mycobacterium avium complex (MAC) and Mycobacterium abscessus (M. abscessus). The relationship between bronchiectasis and less-pathogenic NTM species such as M. gordonae is less well understood. We performed a retrospective study on patients who had M. gordonae isolated from respiratory specimens at UConn Health between May 2nd, 2010 and October 18th, 2022. M. gordonae was isolated 74 times from 56 patients. It was isolated 35 (47.3%) times from 31 patients with bronchiectasis and 39 (52.7%) times from 26 patients without bronchiectasis. Data was available on all mycobacterial cultures sent from May 2nd 2018 to October 18th 2022. Mycobacterial cultures sent from patients with bronchiectasis were significantly more likely to grow M. gordonae than patients without bronchiectasis (4.3% vs. 1.6%, P=0.007). Furthermore, when considered at the patient level, there remained a significant increased rate of M. gordonae isolation among patients with bronchiectasis (7.1% vs. 2.2%, P<0.001). We then looked at past and future isolation of more pathogenic NTM species and found a non-statistically increased rate of isolation of more pathogenic NTM species including MAC and M. abscessus in patients with bronchiectasis (45.2% vs. 29%, P=0.09). Based on our results, isolation of M. gordonae should raise suspicion of chronic airway disease and defects in host immune response, such as those seen in bronchiectasis. Furthermore, isolation of M. gordonae may suggest increased risk of infection with more pathogenic NTM species such as MAC and M. abscessus.

Discovery of 2-phenylquinazolines as potent Mycobacterium avium efflux pump inhibitors able to synergize with clarithromycin against clinical isolate.

Nontuberculous mycobacteria (NTM), which include the Mycobacterium avium complex, are classified as difficult-to-treat pathogens due to their ability to quickly develop drug resistance against the most common antibiotics used to treat NTM infections. The overexpression of efflux pumps (EPs) was demonstrated to be a key mechanism of clarithromycin (CLA) resistance in NTM. Therefore, in this work, 24 compounds from an in-house library, characterized by chemical diversity, were tested as potential NTM EP inhibitors (EPIs) against Mycobacterium smegmatis mc2 155 and M. avium clinical isolates. Based on the acquired results, 12 novel analogs of the best derivatives 1b and 7b were designed and synthesized to improve the NTM EP inhibition activity. Among the second set of compounds, 13b emerged as the most potent NTM EPI. At a concentration of 4 µg/mL, it reduced the CLA minimum inhibitory concentration by 16-fold against the clinical isolate M. avium 2373 overexpressing EPs as primary mechanism of CLA resistance.

Lady Windermere Syndrome: A Rare Differential Diagnosis for Hemoptysis.

Mycobacterium avium complex (MAC) is often observed in immunocompromised individuals. However, when pulmonary MAC infection occurs in immunocompetent individuals, particularly elderly females, characteristically involving the middle lobe and lingula lobe of the lung, it is known as Lady Windermere syndrome (LWS). A 64-year-old female patient with no significant comorbidities presented with a history of low-grade intermittent fever and dry cough for one-month duration complicated with hemoptysis for two days. Her initial investigations and imaging were negative, except for the high-resolution CT (HRCT) finding of bronchiectasis involving the middle lobe and lingula lobe suggestive of MAC infection, which was further confirmed by positive sputum culture for MAC. LWS is a condition that is rarely encountered in clinical settings and seldom described in the literature. Especially in resource-limited settings, arriving at a diagnosis is further hindered by the scarce availability of advanced imaging such as HRCT. In clinical settings where pulmonary tuberculosis is endemic, the differentiation of the two conditions is of paramount importance as the treatment regimens for the two conditions are quite different.

Amikacin Liposome Inhalation Suspension in the Real-World Management of Refractory Mycobacterium avium Complex Pulmonary Disease.

The increasing prevalence of Mycobacterium avium complex (MAC) pulmonary disease poses a significant therapeutic challenge, particularly due to the limited efficacy and systemic toxicity associated with conventional guideline-based therapy. Amikacin liposome inhalation suspension (ALIS) has been developed, yet its real-world application remains underreported. This retrospective analysis, conducted from March 2021 to February 2024, examined ALIS's clinical use in patients aged 20 years or older with refractory MAC pulmonary disease at our institution. The primary objective of this study is to describe the patient characteristics and clinical trajectories associated with the initiation of ALIS therapy in real-world settings for individuals diagnosed with MAC pulmonary disease. Of 11 patients initiated on ALIS, one was excluded due to financial constraints impacting continuation. The analysis proceeded with the remaining 10 subjects. The mean age of participants was 70.2 years, with a predominance of female patients (n = 7, 70%) and a higher incidence of M. avium infections (n = 6, 60%). Forty percent of the cohort (n = 4) had a history of ethambutol-induced optic neuritis leading to the cessation of the drug. The average interval from the initiation of guideline-based therapy to the start of ALIS was 8.5 ± 6.9 years (mean ± standard deviation). The majority (80%) presented with positive Gaffky scores at ALIS initiation, and a significant proportion exhibited resistance to clarithromycin and ethambutol. Comorbid conditions, including diabetes and previous cancer, were noted. The study also observed elevated anti-MAC antibody levels. Treatment duration varied, with fatigue leading to discontinuation in two cases. Treatment-emergent adverse events were documented in individual patients, each presenting with grade 1 severity: hemoptysis (n = 1, 10%), elevated creatinine levels (n = 1, 10%), and dysphonia (n = 2, 20%) were observed, respectively. Correlation analysis revealed a significant inverse relationship between body mass index (BMI) and ALIS discontinuation due to fatigue, and a positive correlation between Gaffky scores and C-reactive protein (CRP) levels. These results underscore the potential benefits and limitations of ALIS, suggesting that timely intervention and comprehensive healthcare support are crucial for optimal outcomes in the treatment of advanced MAC pulmonary disease.

Mycobacterium porcinum Disseminated Infection in Non-severely Immunocompromised Host.

Mycobacterium porcinum is a nontuberculous mycobacteria (NTM) recently identified to cause human infection. Correct speciation of NTMs can be difficult and result in misdiagnosis and delayed treatment. Because of the paucity of the literature, there is a lack of awareness of the possibility of serious infections caused by M. porcinum. Although severe infections tend to occur in individuals with certain risk factors, the primary being an immunocompromised state, our case illustrates that it can also be possible in non-severely immunocompromised individuals. A 65-year-old male with a medical history of diabetes mellitus (DM), end-stage renal disease (ESRD) on hemodialysis (HD), congestive heart failure (CHF), and chronic obstructive pulmonary disease (COPD) was admitted to the emergency room due to a laceration on his right lower leg following a fall. He reported shortness of breath but denied other respiratory symptoms. On examination, he showed signs of infection and increased oxygen requirement compared to baseline. Blood culture was positive for acid-fast bacilli (AFB), initially reported as M. avium complex (MAC) and later confirmed as M. porcinum through gene sequencing and morphology analysis. Interval blood cultures taken a week later confirmed true M. porcinum bacteremia. Treatment initially involved intravenous antibiotics- imipenem and ciprofloxacin before transitioning to oral linezolid and ciprofloxacin based on sensitivities. Following 10 days of antibiotic therapy, subsequent blood cultures returned negative, and treatment with oral antibiotics was advised, with continued outpatient follow-up with infectious disease in two weeks. M. porcinum, typically considered a contaminant in healthy individuals, was identified as the causative agent of a disseminated infection in a non-severely immunocompromised patient. This case underscores the importance of accurately identifying the specific mycobacterial species, confirming true infection, and conducting antibiotic susceptibility testing due to the distinct antibiotic susceptibility profile of M. porcinum compared to other NTM like MAC.

Prevalence of pulmonary artery dilation in non-cystic fibrosis bronchiectasis: a computed tomography analysis from a cohort of the US Bronchiectasis and Nontuberculous Mycobacteria Research Registry.

Although pulmonary artery (PA) dilation is independently associated with significant morbidity and mortality in patients with pulmonary diseases irrespective of diagnosed pulmonary hypertension, its relationship with nontuberculous mycobacteria (NTM) is unknown. The Bronchiectasis and NTM Research Registry is a multicenter registry created to foster research in non-cystic fibrosis (CF) bronchiectasis and NTM lung disease. The majority of patients with non-CF bronchiectasis at Oregon Health & Science University have NTM infections. To determine the prevalence of PA dilation in these patients and its association with supplemental oxygen use, severity of bronchiectasis, tobacco use, and NTM in the sputum culture, we evaluated the chest computed tomography (CT) scans from 321 patients in a cross-sectional analysis. We measured the severity of bronchiectasis by applying modified Reiff criteria and measured the diameters of the PA and aorta (Ao), with PA dilation defined as a PA:Ao ratio >0.9. In our cohort, the mean age was 67.3 years and 83.2% were female. The mean modified Reiff score was 7.1, indicating moderate disease severity. Forty-two patients (13.1%) were found to have PA dilation. PA dilation was positively associated with the use of supplemental oxygen (P<0.001), but there was no association between PA dilation and NTM infection.

Mycobacterium gordonae Infection in a Patient With Non-small Cell Lung Cancer.

Mycobacterium gordonae (MG) is one of the least pathogenic nontuberculous mycobacteria (NTM). We report an unusual case of MG infection in a patient with newly diagnosed lung cancer. A 61-year-old woman presented with shortness of breath and weight loss. Six months prior to admission, she was diagnosed with MG infection based on positive sputum cultures and bronchioalveolar lavage. Despite anti-mycobacterial therapy, her symptoms worsened and she lost approximately 100 pounds. A transbronchial biopsy obtained one week prior to admission revealed adenocarcinoma of the lung. At admission, vital signs were normal, and a physical exam revealed bilateral crackles. Computed tomography (CT) scan of the chest revealed infiltrates with ground-glass opacity. The patient was admitted to the oncology service for evaluation. Our findings suggest that symptomatic individuals with positive cultures of MG should proceed with extensive workup for possible underlying lung cancer especially if not responding to anti-mycobacterial therapy.

Comparing minimum inhibitory concentrations of amikacin for pulmonary Mycobacterium avium complex disease: An analysis of culture media differences.

Mycobacterium avium complex (MAC) is considered a paramount microbe, especially in East Asia, including Japan. The commonly used commercial Minimum Inhibitory Concentrations (MIC) assay using Middlebrook 7H9 (7H9) medium deviates from the latest Clinical and Laboratory Standards Institute (CLSI) guidelines. Alternatively, measurement with cation-adjusted Mueller-Hinton broth (CAMHB) that conforms to CLSI standards is not yet widely available. Following the approval and commercialization of amikacin liposome inhalation suspension (ALIS) in 2021, a more precise evaluation of amikacin (AMK) susceptibility in MAC is necessary for treatment decisions. In the present study, 33 sputum samples were extracted from 27 patients, and MICs of AMK were compared between the frequently used 7H9 and the recommended CAMHB of the isolated MAC strains. The history of exposure to aminoglycosides for each sample was also added as clinical information. The findings indicated that there was only an 18% concordance rate in MIC between the two media, with 19 samples (58%) indicating lower MICs in 7H9 relative to CAMHB. The 17 samples had a history of exposure to aminoglycosides for periods ranging from 1.5 to 28 months. Specifically, 10 samples were exposed to amikacin by inhalation and intravenous injection, and the remaining seven samples had a history of ALIS inhalation. Samples with a prior utilization of aminoglycosides were significantly predisposed to developing resistance to ALIS compared to those without such a history (P = 0.046). Physicians are encouraged to scrutinize the findings of susceptibility testing utilizing CLSI-endorsed MIC assay using CAMHB medium to ascertain the optimal therapeutic approach.

Microbiological persistence in patients with Mycobacterium abscessus complex lung disease: The prevalence, predictors, and the impact on progression.

OBJECTIVES: Persistent growth of Mycobacterium abscessus complex (MABC) in the respiratory system is not uncommon and may indicate continuous infection of MABC lung disease (MABC-LD), but its prevalence, risk factors, and clinical impact have not been investigated. METHODS: The present study was conducted in two medical centers in northern Taiwan. We enrolled patients with MABC-LD and investigated the prevalence and predictors of persistent culture positivity (MABC-PP). Furthermore, we analyzed the association between MABC-PP and radiographic or clinical progression. RESULTS: Among 189 patients with MABC-LD, 58 were in the MABC-PP group. Independent predictors for MABC-PP included an increasing radiographic score and highest acid-fast stain (AFS) of strong positivity (3-4+) at initial diagnosis (compared with negative AFS). MABC-PP and highest AFS were independently associated with MABC-LD progression by the multivariable analysis model. The adjusted hazard ratio increased to 3.56 when the two independent factors existed. CONCLUSIONS: MABC-PP accounted for 30.7% and was predicted by initial AFS grade and radiographic score. Patients with MABC-PP, and highest AFS grade might have disease progression.

Extended water stagnation in buildings during the COVID-19 pandemic increases the risks posed by opportunistic pathogens.

The regrowth and subsequent exposure of opportunistic pathogens (OPs) whilst reopening buildings that have been locked down due to the stay-at-home restrictions to limit the spread of COVID-19, is a public health concern. To better understand such microbiological risks due to lowered occupancy and water demand in buildings, first and post-flush water samples (n = 48) were sampled from 24 drinking water outlets from eight university buildings in two campuses (urban and rural), with various end-user occupancies. Both campuses were served with chlorinated water originating from a single drinking water distribution system in South-East Queensland, situated 14 km apart, where the rural campus had lower chlorine residuals. Culture-dependent and culture-independent methods (such as flow cytometry, qPCR and 16S rRNA gene amplicon sequencing) were used concurrently to comprehensively characterise the OPs of interest (Legionella spp., Pseudomonas aeruginosa, and nontuberculous mycobacteria (NTM)) and the premise plumbing microbiome. Results showed that buildings with extended levels of stagnation had higher and diverse levels of microbial growth, as observed in taxonomic structure and composition of the microbial communities. NTM were ubiquitous in all the outlets sampled, regardless of campus or end-user occupancy of the buildings. qPCR and culture demonstrated prevalent and higher concentrations of NTM in buildings (averaging 3.25 log10[estimated genomic copies/mL]) with extended stagnation in the urban campus. Furthermore, flushing the outlets for 30 minutes restored residual and total chlorine, and subsequently decreased the levels of Legionella by a reduction of 1 log. However, this approach was insufficient to restore total and residual chlorine levels for the outlets in the rural campus, where both Legionella and NTM levels detected by qPCR remained unchanged, regardless of building occupancy. Our findings highlight that regular monitoring of operational parameters such as residual chlorine levels, and the implementation of water risk management plans are important for non-healthcare public buildings, as the levels of OPs in these environments are typically not assessed.

Postoperative wound infection by nontuberculous mycobacteria; case series in Dhaka Medical College Hospital of Bangladesh.

The incidence of nontuberculous mycobacterial (NTM) infections after operations is increasing in Bangladesh but data regarding clinical presentation, diagnosis, treatment, and prognosis after treatment are lacking. In this case series, three patients having persistent serous discharge from incision wound after operation were studied. Discharge from wounds were collected, wet film microscopy was performed for pus cells and fungus, Gram stain, Ziehl-Neelsen (ZN) stain, culture in routine culture media and Lowenstein-Jensen (LJ) media, Xene-Xpert for mycobacterium tuberculosis (MTB), polymerase chain reaction (PCR) for NTM were done. NTM-positive patients were treated initially for 6 weeks with four drugs regimen (clarithromycin 500 mg 12 hourly, ciprofloxacin 500 mg 12 hourly, linezolid 400 mg 12 hourly, and amikacin 500 mg 12 hourly), followed by 5 months with three drugs regimen (clarithromycin 500 mg 12 hourly, ciprofloxacin 500 mg 12 hourly, and linezolid 400 mg 12 hourly) as a maintenance dose. Cessation of discharge occurred within 3-4 weeks after starting treatment, and the wounds were healed.