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Background: Acute exacerbation of fibrosing interstitial lung diseases (AE-ILD) is a serious life-threatening event per year. Methylprednisolone and/or immunosuppressive agents (ISA) are a mainstay in any regimen, under the premise that pulmonary infection has been promptly identified and controlled. We investigated the value of bronchoalveolar lavage fluid (BALF) metagenomic next-generation sequencing (mNGS) on the treatment adjustment of AE-ILD., Methods: We conducted a cross-sectional observational study. All data were collected prospectively and retrospectively analyzed. We included fifty-six patients with AE-ILD and nineteen stable ILD who underwent BALF mNGS at the beginning of admission., Results: Patients with a variety of ILD classification were included. Connective-tissue disease related ILD (CTD-ILD) occupy the most common underlying non-idiopathic pulmonary fibrosis (non-IPF). The infection-triggered AE accounted for 39.29%, with the majority of cases being mixed infections. The microorganisms load in the AE-ILD group was significantly higher. After adjusted by mNGS, the therapy coverage number of pathogens was significantly higher compared to the initial treatment (p < 0.001). After treatment, the GGO score and the consolidation score were significantly lower during follow up in survivors (1.57 ± 0.53 vs. 2.38 ± 0.83 with p < 0.001, 1.11 ± 0.24 vs. 1.49 ± 0.47 with p < 0.001, respectively). Some detected microorganisms, such as Tropheryma whipplei, Mycobacterium, Aspergillus, and mixed infections were difficult to be fully covered by empirical medication. BALF mNGS was also very helpful for excluding infections and early administration of methylprednisolone and/or ISA., Conclusions: mNGS has been shown to be a useful tool to determine pathogens in patients with AE-ILD, the results should be fully analyzed. The comprehensive treatment protocol based on mNGS has been shown crucial in AE-ILD patients., (© 2024. The Author(s).)

Background: RGM medium is an agar-based, selective culture medium designed for the isolation of nontuberculous mycobacteria (NTM) from the sputum of patients with cystic fibrosis (CF). We evaluated RGM medium for the detection of NTM in patients with CF (405 samples), bronchiectasis (323 samples) and other lung diseases necessitating lung transplantation (274 samples)., Methods: In total, 1002 respiratory samples from 676 patients were included in the study. Direct culture on RGM medium, with incubation at two temperatures (30 °C and 37 °C), was compared with conventional culture of decontaminated samples for acid-fast bacilli (AFB) using both a solid medium (Löwenstein-Jensen medium) and a liquid medium (the Mycobacterial Growth Indicator Tube; MGIT)., Results: For all three patient groups, significantly more isolates of NTM were recovered using RGM medium incubated at 30 °C than by any other method (sensitivity: 94.6% vs. 22.4% for conventional AFB culture; P < 0.0001). Significantly more isolates of Mycobacterium abscessus complex were isolated on RGM at 30 °C than by AFB culture (sensitivity: 96.1% vs. 58.8%; P < 0.0001). The recovery of Mycobacterium avium complex was also greater using RGM medium at 30 °C compared to AFB culture (sensitivity: 83% vs. 70.2%), although this difference was not statistically significant and a combination of methods was necessary for optimal recovery (P = 0.21)., Conclusions: In the largest study of RGM medium to date, we reaffirm its utility for isolation of NTM from patients with CF. Furthermore; we show that it also provides an effective tool for culture of respiratory samples from patients with bronchiectasis and other lung diseases.