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The role of gut microbiota in host defense against nontuberculous mycobacterial lung disease (NTM-LD) was poorly understood. Here, we showed significant gut microbiota dysbiosis in patients with NTM-LD. Reduced abundance of Prevotella copri was significantly associated with NTM-LD and its disease severity. Compromised TLR2 activation activity in feces and plasma in the NTM-LD patients was highlighted. In the antibiotics-treated mice as a study model, gut microbiota dysbiosis with reduction of TLR2 activation activity in feces, sera, and lung tissue occurred. Transcriptomic analysis demonstrated immunocompromised in lung which were closely associated with increased NTM-LD susceptibility. Oral administration of P. copri or its capsular polysaccharides enhanced TLR2 signaling, restored immune response, and ameliorated NTM-LD susceptibility. Our data highlighted the association of gut microbiota dysbiosis, systematically compromised immunity and NTM-LD development. TLR2 activation by P. copri or its capsular polysaccharides might help prevent NTM-LD.

Purpose: The presence of anti-interferon-γ autoantibodies (AutoAbs-IFN-γ) is not rare in patients suffering from persistent non-tuberculous mycobacterial (NTM) infections that are characteristic of adult-onset immunodeficiency syndrome. The immune disturbances in this distinct disorder remain to be elucidated., Methods: Patients with NTM infections but without effective response over 3 months' treatment were referred to our institute to quantify their level of AutoAbs-IFN-γ after excluding defective IL12/23-IFN-γ circuit and reactive oxygen species production. The AutoAbs-IFN-γ and percentage of lymphocyte subpopulations most relevant to T and B cell pools were assessed and compared with age-matched healthy controls., Results: A total of 31 patients were enrolled during the 15-year study period (2008-2022), 20 patients with > 50% suppression of IFN-γ detection at 1:100 serum dilution were classified into the Auto-NTM group. The remaining 11 with negligible suppression were assigned to the No Auto-NTM group. Mycobacterium chimaera-intracellulare group (MAC), M. kansasii, and M. abscessus were the most common pathogens. Pneumonia (19 vs 7), lymphadenitis (11 vs 5), Salmonella sepsis (6 vs 2), osteomyelitis (5 vs 1), and cutaneous herpes zoster (4 vs 4) were the main manifestations in both the Auto-NTM and No Auto-NTM groups who had similar onset-age (55.3 vs 53.6 years; p = 0.73) and follow-up duration (71.9 vs 54.6 months; p = 0.45). The Auto-NTM group had significantly higher transitional (IgM +  + CD38 + +), CD19 + CD21-low, and plasmablast (IgM-CD38 + +) in the B cell pool, with higher effector memory (CD4 + /CD8 + CD45RO + CCR7 -), senescent CD8 + CD57 + , and Th17 cells, but lower naïve (CD4 + /CD8 + CD45RO - CCR7 +) and Treg cells in the T cell pool when compared to the No Auto-NTM and healthy groups. NTM patients with/without AutoAbs-IFN-γ had lower Th1-like Tfh (CD4 + CXCR5 + CXCR3 + CCR6 -) cells. All Auto-NTM patients still had non-remitted mycobacterial infections and higher AutoAbs-IFN-γ despite anti-CD20 therapy in 3 patients., Conclusion: In patients with suspected adult-onset immunodeficiency syndrome, two thirds (20/31) were recognized as having significantly inhibitory AutoAbs-IFN-γ with higher antibody-enhancing transitional, CD19 + CD21-low and plasmablast B cells; as well as higher effector memory, senescent CD8 + CD57 + and Th17 cells, but lower naïve T and Treg cells in contrast to those with negligible AutoAbs-IFN-γ. Such immunophenotyping disturbances might correlate with the presence of AutoAbs-IFN-γ. However, the mutual mechanisms need to be further clarified., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Our previous study identified that the Mycobacterium abscessus subsp. abscessus T28 sequevar does not fully represent inducible macrolide resistance. Thus, we initiated a correlation study between genotypes and phenotypes. In total, 75 isolates from patients with skin and soft tissue infections were enrolled in the study. These strains were tested against 11 antimycobacterial agents using Sensitire RAPMYCO plates and the CLSI-recommended broth microdilution method. In order to analyze erm (41) and partial hsp65 , rpoB , secA1 , and rrl genes, bacterial genomic DNA was extracted from bacteria. The MEGA X software was used for phylogenetic analyses. The most active agents against most M. abscessus species were amikacin and tigecycline. Clarithromycin was effective toward M. abscessus subsp. massiliense and nearly all M. abscessus subsp. abscessus C28 sequevars. Two varieties of M. abscessus subsp. abscessus T28 sequevars did not represent inducible macrolide resistance. Most M. abscessus species showed intermediate susceptibility to cefoxitin and imipenem. Six additional agents were less effective against M. abscessus species. Following phylogenetic analyses, two outliers of M. abscessus subsp. abscessus T28 sequevars seem to represent no inducible macrolide resistance. In addition, we discovered genetic mosaicism of hsp65 , rpoB , and secA1 in M. abscessus species was common. T28 sequevars of M. abscessus subsp. abscessus do not fully represent inducible macrolide resistance. The outlier of erm (41) phylogeny of the M. abscessus subsp. abscessus T28 sequevar is possibly due to macrolide susceptibility. Evaluation of the antimicrobial susceptibility of M. abscessus species is a reliable tool for assisting physicians in selecting the most effective antimycobacterial agent(s). IMPORTANCE Macrolides are the mainstays of the antimycobacterial regimens against Mycobacterium abscessus species (formerly Mycobacterium abscessus complex). erm (41) confers inducible macrolide resistance for M. abscessus subsp. bolletii strains, and the majority of M. abscessus subsp. abscessus T28 sequevars. Furthermore, the acquired macrolide resistance of M. abscessus species is due to a point mutation in rrl . However, not all M. abscessus subsp. abscessus T28 sequevars have inducible macrolide resistance. Exploration of the mechanism of macrolide resistance requires an understanding of genetic diversity. The genetic mosaicism of the erm (41), rpoB , hsp65 , and secA1 genes within three subspecies of M. abscessus species is not uncommon. The T28 sequevar of erm (41) confers inducible macrolide resistance to the genetic mosaic strain. The development of new anti-M. abscessus species infection overcoming inducible macrolide resistance and/or acquired macrolide resistance is a crucial issue.

Nontuberculous mycobacterial lung disease (NTM-LD) prevalence has been increasing over the recent decades. Numerous host factors are associated with NTM-LD development, including susceptible phenotypes such as ciliary defect and lung structural change, pulmonary clearance defect with poor clearance of secretions, and immune suppression. Specifically, regarding the susceptible host phenotypes without clear pathogenesis, a slender body, pectus excavatum, and postmenopausal female status are common. Also, decreased host immunity to NTM, especially T helper 1 cell responses is frequently observed. Even so, the underlying mechanisms remain unclear and relevant large-scale studies are lacking. Infections due to host genetics associated defects are mostly untreatable but rare in Asia, particularly Taiwan. Nevertheless, some risks for NTM-LD are controllable over disease progression. We suggest that clinicians first manage host factors and deal with the controllable characteristics of NTM-LD, followed by optimizing anti-NTM treatment. Further researches focusing on NTM-LD pathogenesis, especially the host-NTM interaction may advance understanding the nature of the disease and develop efficient therapeutic regimens., Competing Interests: Declaration of Competing Interest The authors do not have any conflicts of interest to declare., (Copyright © 2020 Formosan Medical Association. Published by Elsevier B.V. All rights reserved.)

In developed countries, pulmonary nontuberculous mycobacteria (NTM) infections are more prevalent than Mycobacterium tuberculosis infections. Given the differences in the pathogenesis of NTM and M. tuberculosis infections, separate studies are needed to investigate the pathological effects of NTM pathogens. Our previous study showed that anti-IFN-γ autoantibodies are detected in NTM-infected patients. However, the role of NK cells and especially NK cell-derived IFN-γ in this context has not been studied in detail. In the current study, we show that NK1.1 cell depletion increases bacterial load and mortality in a mouse model of pulmonary NTM infection. NK1.1 cell depletion exacerbates NTM-induced pathogenesis by reducing macrophage phagocytosis, dendritic cell development, cytokine production, and lung granuloma formation. Similar pathological phenomena are observed in IFN-γ-deficient (IFN-γ -/- ) mice following NTM infection, and adoptive transfer of wild-type NK cells into IFN-γ -/- mice considerably reduces NTM pathogenesis. Injection of rIFN-γ also prevents NTM-induced pathogenesis in IFN-γ -/- mice. We observed that NK cells represent the main producers of IFN-γ in the lungs and production starts as soon as 1 d postinfection. Accordingly, injection of rIFN-γ into IFN-γ -/- mice 1 d (but not 2 wk) postinfection significantly improves immunity against NTM infection. NK cells also stimulate mycobacterial killing and IL-12 production by macrophages. Our results therefore indicate that IFN-γ production by NK cells plays an important role in activating and enhancing innate and adaptive immune responses at early stages of pulmonary NTM infection., (Copyright © 2018 by The American Association of Immunologists, Inc.)

Background: Mycobacterium abscessus complex (MABC) is the most common non-tuberculous mycobacterium that causes complicated skin and soft tissue infections (cSSTIs). The selection of antimycobacterial agents for successful treatment of such infections is a critical issue., Objectives: To investigate the antimicrobial susceptibility patterns of MABC isolates from skin and soft tissue to a variety of antimycobacterial agents., Methods: Sixty-seven MABC isolates were collected and partial gene sequencing of secA1, rpoB and hsp65 was used to classify them into three subspecies: M. abscessus subsp. abscessus (MAB), M. abscessus subsp. massiliense (MMA) and M. abscessus subsp. bolletii (MBO). The MICs of 11 antimycobacterial agents for these 67 isolates were determined using a broth microdilution method and commercial Sensititre RAPMYCOI MIC plates, as recommended by CLSI., Results: In total, 28 MAB, 38 MMA and 1 MBO were isolated from patients with cSSTIs at our hospital. Most MABC strains were resistant to ciprofloxacin, doxycycline, imipenem, linezolid, minocycline, moxifloxacin and trimethoprim/sulfamethoxazole. In addition, most MABC strains were intermediately susceptible or resistant to cefoxitin. Eighteen of the 28 MABs and 1 MBO isolate harboured the T28 polymorphism in the erm(41) gene. Two of the 38 MMA isolates had an rrl A2059G point mutation. Most of the MABC strains were susceptible to amikacin and tigecycline., Conclusions: In Taiwan, amikacin, clarithromycin and tigecycline have good activity against MMA and MAB erm(41) C28 sequevar isolates, whereas amikacin and tigecycline, rather than clarithromycin, have good activity against both MBO and MAB erm(41) T28 sequevar isolates. Clinical trials are warranted to correlate these data with clinical outcomes., (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Neutralizing anti-interferon-γ autoantibody (nAIGA)-associated immunodeficiency is an emerging medical issue worldwide. In the present study, we describe and discuss the clinical features and outcomes of patients with nAIGAs and disseminated infections by nontuberculous mycobacteria (dNTM).We thoroughly reviewed the medical records of all patients. Microorganisms and nAIGAs were identified using previously described methods with modifications. All data were calculated and analyzed using SPSS software.Among 46 adult patients with dNTM infections, we identified 45 cases (97.8%) with nAIGAs. The average patient age was 58.6 years, and there was no sex predominance. Cervical lymphadenitis (81.8%) was the most common clinical manifestation. Endocrine disorder was the leading comorbidity (7 cases). Malignancies were found in 4 patients, and all of the malignancies originated from the T-cell/macrophage lineage. More than half of the identifiable isolates were slow-growing NTMs. Twenty-eight (62.2%) and 18 (40.0%) patients had a history of zoster and salmonellosis, respectively. A high proportion of patients with recurrent episodes of NTM infection or a history of zoster and dNTM infection had initial nAIGA titers ≥10 dilution (P < 0.05). Twenty-seven patients (60.0%) required long-term antimycobacterial therapy and had at least 1 episode of recurrent NTM disease. No mortality was related to dNTM infection.In Taiwan, nAIGAs are a recently recognized mechanism of dNTM infection. Long term of antibiotic treatment and adherence to medical advice are necessary to improve the clinical outcome of patients with nAIGAs., Competing Interests: All authors declare no conflicts of interest.

Introduction: Mycobacterium marinum causes skin and soft tissue, bone and joint, and rare disseminated infections. In this study, we aimed to investigate the relationship between treatment outcome and antimicrobial susceptibility patterns. A total of 27 patients with M. marinum infections were enrolled., Methods: Data on clinical characteristics and therapeutic methods were collected and analyzed. We also determined the minimum inhibitory concentrations of 7 antibiotics against 30 isolates from these patients., Results: Twenty-seven patients received antimycobacterial agents with or without surgical debridement. Eighteen patients were cured, 8 failed to respond to treatment, and one was lost to follow-up. The duration of clarithromycin (147 vs. 28; p = 0.0297), and rifampicin (201 vs. 91; p = 0.0266) treatment in the cured patients was longer than that in the others. Surgical debridement was performed in 10 out of the 18 cured patients, and in 1 of another group (p = 0.0417). All the 30 isolates were susceptible to clarithromycin, amikacin, and linezolid; 29 (96.7%) were susceptible to ethambutol; 28 (93.3%) were susceptible to sulfamethoxazole; and 26 (86.7%) were susceptible to rifampicin. However, only 1 (3.3%) isolate was susceptible to doxycycline., Discussion: Early diagnosis of the infection and appropriate antimicrobial therapy with surgical debridement are the mainstays of successful treatment. Clarithromycin and rifampin are supposed to be more effective agents.

Objectives: Mycobacterium kansasii causes a variety of infections. Although previous reports on the prognosis of antimicrobial therapy have been mostly satisfactory, problems involving treatment failure or relapse have been encountered. The purpose of this study was to establish a relationship between the clinical treatment outcomes of M. kansasii infections and bacterial drug susceptibility, and their clonality., Methods: A total of 37 M. kansasii clinical isolates and clinical information on 34 patients were retrospectively collected in a tertiary medical centre in Taiwan. Bacterial drug susceptibility was determined by the microdilution method. The phylogenetic relationship was analysed by PFGE analysis., Results: Results of PFGE typing revealed a major cluster (cluster I) and eight other divergent patterns. Two/three strains leading to treatment failure were also multidrug resistant and belonged to cluster I., Conclusions: A relationship between high drug resistance and genetic relatedness of some M. kansasii strains was established. This was associated with clinical treatment failure.

Mycobacterium marinum often causes skin infections, tenosynovitis, arthritis, and osteomyelitis, and occasionally results in severe disseminated infections in immunocompromised patients. In this study, the clinical features of 14 cases of M. marinum infection were retrospectively analyzed. One patient had septic arthritis, the other 13 had skin infections and/or tenosynovitis. It usually took 2 months or longer for a definite diagnosis to be made in these patients. Three of the 14 patients were cured using clarithromycin alone or in combination with rifampin plus ethambutol. Most patients did not respond to conventional antituberculosis agents. Pulsed-field gel electrophoresis and infrequent-restriction-site polymerase chain reaction are efficient tools for the molecular typing of M. marinum. Both methods yielded a concordant result, and 4 of 12 isolates were genetically closely related to each other based on their banding patterns. This study indicates that these isolates were derived from the same clone. Because M. marinum infection is curable, early diagnosis is important. Poor healing of wounds after exposure to aquatic animals appears to be the most important clinical clue indicating the need for culture and inclusion of M. marinum infection in the differential diagnosis.