Colony morphotype governs innate and adaptive pulmonary immune responses to Mycobacterium abscessus infection in C3HeB/FeJ mice.

Mycobacterium abscessus is an emerging pathogen that causes chronic pulmonary infection. Treatment is challenging owing in part to our incomplete understanding of M. abscessus virulence mechanisms that enable pathogen persistence, such as the differing pathogenicity of M. abscessus smooth (S) and rough (R) colony morphotype. While R M. abscessus is associated with chronic infection and worse patient outcomes, it is unknown how immune responses to S and R M. abscessus differ in an acute pulmonary infection setting. In this study, immunological outcomes of M. abscessus infection with S and R morphotypes were examined in an immune-competent C3HeB/FeJ murine model. R M. abscessus infection was associated with the rapid production of inflammatory chemokines and recruitment of activated, MHC-II+ Ly6C+ macrophages to lungs and mediastinal LN (mLN). While both S and R M. abscessus increased T helper 1 (Th1) phenotype T cells in the lung, this was markedly delayed in mice infected with S M. abscessus. However, histopathological involvement and bacterial clearance were similar regardless of colony morphotype. These results demonstrate the importance of M. abscessus colony morphotype in shaping the development of pulmonary immune responses to M. abscessus, which further informs our understanding of M. abscessus host-pathogen interactions.

Pharmacological validation of dihydrofolate reductase as a drug target in Mycobacterium abscessus.

The Mycobacterium abscessus drug development pipeline is poorly populated, with particularly few validated target-lead couples to initiate de novo drug discovery. Trimethoprim, an inhibitor of dihydrofolate reductase (DHFR) used for the treatment of a range of bacterial infections, is not active against M. abscessus. Thus, evidence that M. abscessus DHFR is vulnerable to pharmacological intervention with a small molecule inhibitor is lacking. Here, we show that the pyrrolo-quinazoline PQD-1, previously identified as a DHFR inhibitor active against Mycobacterium tuberculosis, exerts whole cell activity against M. abscessus. Enzyme inhibition studies showed that PQD-1, in contrast to trimethoprim, is a potent inhibitor of M. abscessus DHFR and over-expression of DHFR causes resistance to PQD-1, providing biochemical and genetic evidence that DHFR is a vulnerable target and mediates PQD-1's growth inhibitory activity in M. abscessus. As observed in M. tuberculosis, PQD-1 resistant mutations mapped to the folate pathway enzyme thymidylate synthase (TYMS) ThyA. Like trimethoprim in other bacteria, PQD-1 synergizes with the dihydropteroate synthase (DHPS) inhibitor sulfamethoxazole (SMX), offering an opportunity to exploit the successful dual inhibition of the folate pathway and develop similarly potent combinations against M. abscessus. PQD-1 is active against subspecies of M. abscessus and a panel of clinical isolates, providing epidemiological validation of the target-lead couple. Leveraging a series of PQD-1 analogs, we have demonstrated a dynamic structure-activity relationship (SAR). Collectively, the results identify M. abscessus DHFR as an attractive target and PQD-1 as a chemical starting point for the discovery of novel drugs and drug combinations that target the folate pathway in M. abscessus.

Mavintramycin A is a promising antibiotic for treating Mycobacterium avium complex infectious disease.

Mycobacterium avium complex (MAC) is a serious disease that is mainly caused by infection with the non-tuberculous mycobacteria (NTM), Mycobacterium avium and Mycobacterium intracellulare. Seven new compounds, designated mavintramycins A-G (1-7), were isolated along with structurally related compounds, including amicetin (9) and plicacetin (10), from the culture broth of Streptomyces sp. OPMA40551 as anti-MAC compounds that were active against M. avium and M. intracellulare. Among them, mavintramycin A showed the most potent and selective inhibition of M. avium and M. intracellulare. Furthermore, mavintramycin A was active against more than 40 clinically isolated M. avium, including multidrug-resistant strains, and inhibited the growth of M. avium in a persistent infection cell model using THP-1 macrophages. Mavintramycin A also exhibited in vivo efficacy in silkworm and mouse infection assays with NTM. An experiment to elucidate its mechanism of action revealed that mavintramycin A inhibits protein synthesis by binding to 23S ribosomal RNA in NTM. Mavintramycin A, with a different chemical structure from those of clinically used agents, is a promising drug candidate for the treatment of MAC infectious disease.

Variability of macrolide-resistant profile in Mycobacterium avium complex pulmonary disease.

This single-center retrospective study aimed to analyze the variability of macrolide resistance (MR) in 68 patients with Mycobacterium avium complex pulmonary disease. Among 25 patients treated without macrolides, 13 (52%) reverted to macrolide-susceptible (MS) profiles. Only one (2%) of 43 patients who continued macrolide treatment showed this change. We compared 30 MR isolates with recent specimens. Among them, seven shifted to MS (five attributed to clonally related strains; two resulting from reinfection or polyclonal infection).

Improved detection of mycobacteria in CF and tissue samples grown in mycobacteria growth indicator tube incubated at 30°C compared to conventional growth conditions of liquid and solid media.

This study evaluates the growth of mycobacteria in samples from cystic fibrosis (CF) patients and tissue samples using the mycobacteria growth indicator tube (MGIT) incubated at 30°C in comparison to conventional MGIT cultures incubated at 37°C in a BACTEC MGIT 960 device and solid media incubated at 36°C and 30°C. A total of 1,549 samples were analyzed, of which 202 mycobacterial isolates were cultured from 197 positive specimens, including five mixed cultures. The highest detection rate was achieved from MGIT at 30°C, with 84.2% of mycobacterial isolates (170 of 202), which was significantly higher than any other culture condition (P < 0.0001 for any condition). MGIT at 37°C yielded 61.4% (124 of 202) of the recovered isolates, whereas Löwenstein Jensen (LJ) and Stonebrink at 36°C, and LJ and Stonebrink at 30°C retrieved 47.0% (95), 49.5% (100), 50.0% (101), and 53.0% (107) of the isolates, respectively. Of the 53 isolates that were grown exclusively under one culture condition, the highest number of isolates (36) was recovered from MGIT incubated at 30°C. MGIT at 37°C recovered eight of the 53 isolates, whereas LJ incubated at 30°C and Stonebrink incubated at 30°C and 36°C recovered five, three, and one isolate, respectively. No isolates were grown exclusively from LJ incubated at 36°C. In CF patients and tissue samples, MGIT cultivated at 30°C for 8 weeks increases the performance of mycobacterial culture. IMPORTANCE: Our study shows that the addition of mycobacteria growth indicator tube (MGIT) liquid culture incubated at 30°C improves the detection of mycobacteria from CF and tissue samples. MGIT incubated at 30°C recovered significantly more mycobacterial isolates than MGIT incubated at 37°C and significantly more isolates than either Lowenstein Jensen or Stonebrink solid media incubated at either 36°C or 30°C. Of 202 mycobacterial isolates recovered from 1,549 specimens, 170 were recovered from MGIT incubated at 30°C, followed by MGIT incubated at 37°C with 124 isolates and solid media culture conditions that recovered between 95 and 107 mycobacterial isolates. All conventional culture conditions combined without MGIT incubated at 30°C recovered 166 isolates. MGIT incubated at 30°C recovered the highest number of isolates detected exclusively by a single culture condition and recovered mycobacterial isolates of highly relevant mycobacterial species, including Mycobacterium abscessus and Mycobacterium tuberculosis.

Profile of non-tuberculous mycobacteria amongst tuberculosis presumptive people in Cameroon.

BACKGROUND: Cameroon is a tuberculosis (TB) burden country with a 12% positivity among TB presumptive cases. Of the presumptive cases with a negative TB test, some are infected with Non-tuberculous Mycobacteria (NTM). However, the diagnosis of NTM infections remains difficult due to the lack of tools in many laboratories, particularly in resource limited laboratories and remote setting. The present study was undertaken to determine NTM profile and associated comorbidities among TB presumptive people. METHODS: A retrospective study was conducted from December 2018 to December 2019 in the Tuberculosis-National Reference Laboratory (TB-NRL) for Bacteriological analysis of samples and Jamot Hospital of Yaounde (JHY) for clinical evaluation of confirmed NTM patients. We included in this study data of 5267 TB presumptive people previously diagnosed using three consecutive samples and having culture and SD Bioline results with or without Microscopy and reverse hybridization-based Line Probe Assay(LPA) results. The data on co-morbidities or history of people infected with NTM were then collected from the three participants with available clinical data. RESULTS: We collected data of 5267 presumptive TB people. Among them, 3436 (65.24%), have a positive culture with 3200 (60.75%) isolates belong to Mycobacterium tuberculosis Complex (MBTC) and 236 (4.48%) to NTM. Our results showed that, 123 (52.11%) NTM were isolated from people with negative microscopy and 113 (47.88%) from people with positive microscopy. Among the 236 NTM, 108 (45.8%) isolates were identified using LPA. M. fortuitum was the most represented species (32.41%) followed by M. intracellulare (19.44%). Sputum had the highest proportion of NTM (56%), followed by bronchial aspirations (31%). The extra-pulmonary samples presented lower proportions of isolates compared to pulmonary samples. Some patients affected with NTM presented comorbidities as HIV infection, Pulmonary tuberculosis, Type 2 diabetes, Chronic bronchitis and Alveolar pneumonia. CONCLUSIONS: Our study showed the presence of NTM strains among presumptive TB people with a predominance of M. fortuitum and M. intracellulare. It is important to implement a surveillance system of NTM in TB burden country and also to develop a point-of-care test for NTM identification in limited-resource settings.

Susceptibility to mycobacterial infection in VEXAS syndrome.

OBJECTIVES: VEXAS is a recently described acquired auto-inflammatory and hematologic syndrome caused by somatic mutations in UBA1. To date, VEXAS is not a recognized cause of acquired immunodeficiency. PATIENTS AND METHODS: Two of our 10 VEXAS patients developed a disseminated Mycobacterium avium infection. To shed light on this observation, we retrospectively studied all patients with disseminated non-tuberculous mycobacterial infections (NTMi) seen at our institution over 13 years. Inclusion criteria were a positive blood/bone marrow culture, or 2 positive cultures from distinct sites, or one positive culture with 2 involved sites. RESULTS: patient 1 presented with fever, rash, orbital cellulitis and lung infiltrates. Patient 2 presented with fever and purpura. In both cases, Mycobacterium avium was identified on bone marrow culture. Twenty cases of disseminated NTMi were reviewed. Among 11 HIV-negative patients, three had chronic immune-mediated disease; three had untreated myeloid neoplasm; two had VEXAS; one had undergone kidney transplantation; one had GATA-2 deficiency; and one had no identified aetiology. None had lymphoid neoplasia or had undergone bone marrow transplantation. HIV-negative cases had higher CD4 counts than HIV-positive patients (median CD4: 515/mm3  vs 38/mm3, p< 0.001). Monocytopenia was present in seven cases. At 2 years, six patients had died, including both VEXAS patients. DISCUSSION: VEXAS patients have an intrinsic susceptibility to disseminated NTMi, which may result from monocytic dysfunction. NTMi can mimic VEXAS flare. Clinicians should maintain a high suspicion for opportunistic infections before escalating immunosuppressive therapy. Further studies are needed to confirm and better decipher the herein reported observations.

The additional value of 18F-FDG PET/CT imaging in guiding the treatment strategy of non-tuberculous mycobacterial patients.

OBJECTIVES: Non-tuberculous mycobacteria (NTM) infection is an increasing health problem due to delaying an effective treatment. However, there are few data on 18F-FDG PET/CT for evaluating the status of NTM patients. The aim of this study was to investigate the potential value of 18F-FDG PET/CT in guiding the treatment strategy of NTM patients. METHODS: We retrospectively analyzed the cases of 23 NTM patients who underwent 18F-FDG PET/CT. The clinical data, including immune status and severity of NTM pulmonary disease (NTM-PD), were reviewed. The metabolic parameters of 18F-FDG included maximum standardized uptake value (SUVmax), SUVmax of the most FDG-avid lesion (SUVTop), SUVTop/SUVmax of the liver (SURLiver), SUVTop/SUVmax of the blood (SURBlood), metabolic lesion volume (MLV), and total lesion glycolysis (TLG). The optimal cut-off values of these parameters were determined using receiver operating characteristic curves. RESULTS: There were 6 patients (26.09%) with localized pulmonary diseases and 17 patients (73.91%) with disseminated diseases. The NTM lesions had high or moderate 18F-FDG uptake (median SUVTop: 8.2 ± 5.7). As for immune status, the median SUVTop in immunocompromised and immunocompetent patients were 5.2 ± 2.5 and 10.0 ± 6.4, respectively, with a significant difference (P = 0.038). As for extent of lesion involvement, SURLiver and SURBlood in localized pulmonary and disseminated diseases were 1.9 ± 1.1 vs. 3.8 ± 1.6, and 2.7 ± 1.8 vs. 5.5 ± 2.6, respectively, with a significant difference (P = 0.016 and 0.026). Moreover, for disease severity, SUVmax of the lung lesion (SUVI-lung) and SUVmax of the marrow (SUVMarrow) in the severe group were 7.7 ± 4.3 and 4.4 ± 2.7, respectively, significantly higher than those in the non-severe group (4.4 ± 2.0 and 2.4 ± 0.8, respectively) (P = 0.027 and 0.036). The ROC curves showed that SUVTop, SURLiver, SURBlood, SUVI-lung, and SUVMarrow had a high sensitivity and specificity for the identification of immune status, lesion extent, and severity of disease in NTM patients. CONCLUSION: 18F-FDG PET/CT is a useful tool in the diagnosis, evaluation of disease activity, immune status, and extent of lesion involvement in NTM patients, and can contribute to planning the appropriate treatment for NTM.

Cutaneous infection due to Mycobacterium marinum: A series of four cases from Kerala, India.

Mycobacterium marinum is a non-tuberculous mycobacterium which can be found in naturally occurring, non-chlorinated water sources and is a known pathogen that affects fish. In humans, M. marinum typically results in cutaneous lesions, it can occasionally lead to more invasive disorders. We discuss four cases of M. marinum-related cutaneous infections examined in a tertiary care facility. We want to draw attention to the challenges of accurately diagnosing this infection, stress the significance of having a high level of clinical suspicion in order to identify it, and discuss the available treatment choices.

Mycolicibacterium cyprinidarum sp. nov., a rapidly growing species isolated from diseased koi carp, Cyprinus carpio.

A rapidly growing nontuberculous mycobacterium was isolated from diseased koi carp in Niigata, Japan, which was identified as representing a novel Mycolicibacterium species through whole genome sequence analysis. The bacterial isolates (NGTWS0302, NGTWS1803T and NGTWSNA01) were found to belong to the genus Mycolicibacterium through phylogenetic analysis using whole genome sequences of mycobacteria species. The bacterial colony was smooth, moist and non-chromogenic on 1% Ogawa medium at 30 °C. In biochemical characteristic tests, the bacterial isolates showed positive reactions for catalase activity, Tween 80 hydrolysis and tellurite reduction. The isolates were sensitive to 2-4 µg ml-1 ampicillin, kanamycin and rifampicin. Based on these results, we propose a novel Mycolicibacterium species, Mycolicibacterium cyprinidarum sp. nov. The type strain is NGTWS1803T (=JCM 35117T=ATCC TSD-289T).

Olink proteomics and lipidomics analysis of serum from patients infected with non-tuberculous mycobacteria and Mycobacterium tuberculosis.

BACKGROUND: Non-tuberculous mycobacterial (NTM) and Mycobacterium tuberculosis (MTB) infections are difficult to diagnose and treat, significantly burdening global health. The host immune status is generally believed to be associated with the onset and progression of NTM and MTB infections, but its specific impact remains unclear. METHODS: In the present study, proteomics and lipidomics analysis of serum from normal controls (n = 26) and patients with MTB (n = 26), rapidly growing NTM (RGM, n = 15), and slowly growing NTM (SGM, n = 21) were conducted using the Olink technique based on a highly sensitive and specific neighborhood extension assay and the lipidomics technique. RESULTS: IFN-γ, CXCL9, CXCL10, CXCL11, and CXCL13, etc. were simultaneously upregulated in MTB, RGM, and SGM, while lipids FAHFA 22:3, FAHFA 26:4, FAHFA 24:4, FAHFA 20:5, FAHFA 18:2 simultaneously downregulated. IL8, CCL3, CXCL5, and MCP-2, etc. were simultaneously upregulated in RGM and SGM compared to MTB, as well as PCs, LPCs, PEs, and LPEs. Compared with RGM, IL7, CD27, CCL17, CXCL12, and LPC 28:7-SN2 were downregulated in SGM. Pathway analyses revealed that tuberculosis, sphingolipid signaling pathway, and adipocytokine signaling pathway were regulated at the protein level and metabolite level. Diagnostic panels comprising immune-associated proteins and lipids greatly enhance diagnostic specificity and sensitivity. CONCLUSION: This integrated multi-omics analysis provides a more comprehensive understanding of the molecular landscape of NTM and MTB, which may provide molecular targets for specialized therapies.

Prescription habits and drugs accessibility for the treatment of non-tuberculous mycobacteria infections in Italy: a multicentric survey from the IRENE study group.

PURPOSE: Non-tuberculous mycobacteria (NTM) account for high clinical burden, and treatment can be challenging. Moreover, accessibility of NTM medications varies across centers. These challenges may lead to unplanned therapeutic changes, discontinuations, potentially affecting patient outcomes. Aim of this survey was to evaluate the accessibility of NTM-targeting drugs in Italy (with a particular focus on clofazimine) in centers associated with the IRENE Registry, a collaborative network of healthcare professionals. METHODS: A cross-sectional, internet-based, questionnaire-survey on the use and availability of clofazimineand other NTM-targeting drugs was sent to 88 principal investigators of the IRENE network in Italyin 2020. The questionnaires were designed with closed-ended and open-ended questions and distributed using the SurveyMonkey® platform. RESULTS: The surveys underscore the more frequent involvement of pulmonologists (42%) and infectious disease specialists (34%) in NTM treating strategies. Respondents were distributed across 18 out of20 Italian regions, with a significant concentration in the north, encompassing university hospitalsand outpatient clinics. Molecular testing is available in 40% of the involved centers, while phenotypic in 30% of the centers. Centers have a multidisciplinary team and an appointed pharmacy service for NTM drugs distribution in 10 and 75% of the cases, respectively. Substantial variability was observed in drug availability and accessibility, drug regimen composition, and drug dosage, particularly for medications like clofazimine. CONCLUSIONS: This study shows the high heterogeneity of anti-NTM drug availability in Italy and prompts toward a harmonization in antibiotic prescription and access; it also emphasizes the challenges in determining the optimal therapeutic strategies for treating NTM-infections.

Facial cutaneous tuberculosis infected by non-tuberculous mycobacteria.

BACKGROUND: Cutaneous infections caused by non-tuberculous mycobacteria (NTM) are extremely rare, particularly when they are localized to the facial area. This condition presents significant diagnostic challenges due to its unusual presentation and the need for precise microbiological identification. CASE PRESENTATION: A two-year-old male patient presented with a progressively enlarging reddish-brown mass on the left side of his face. Despite the absence of systemic symptoms, the lesion's growth warranted investigation due to its growth. Ultrasonography showed a hypoechoic mass in the dermis, indicating an underlying abscess. The subsequent aspiration resulted in pale yellow pus, which upon testing and culture, confirmed the presence of Mycobacterium avium complex infection, a species of NTM. This case exemplifies the synergy between imaging modalities and microbiological analysis, highlighting the crucial role of both in achieving favorable clinical outcomes in patients with suspected cutaneous NTM infections. Ultrasound can expedite diagnosis, improve treatment planning, and enhance patient care by enabling targeted interventions and monitoring response to therapy in these scenarios. However, it is the combination of pathogen-specific diagnostics that ensures accurate etiological attribution and appropriate antimicrobial stewardship. CONCLUSION: Although rare, facial cutaneous infections caused by NTM still deserve thorough investigation to determine the exact cause. Ultrasound is used to identify cutaneous lesions, measure their extent, and guide surgical procedures. The ultimate diagnosis is based on microbiological confirmation.

Comparative analysis of non-tuberculous mycobacterial lung disease and lung colonization: a case-control study.

BACKGROUND: Non-tuberculous mycobacteria (NTM) are common opportunistic pathogens, and the most common infection site is lung. NTM are found commonly in the environment. Many patients have NTM lung colonization (NTM-Col). NTM lung disease (NTM-LD) have no specific sympotms, though it is hard to differentiate NTM-LD and NTM-Col under this circumstance. The aim of this study is to explore the differences between NTM-LD and NTM-Col for future clinical diagnosis and treatment. METHODS: We retrospectively enrolled patients who had a history of NTM isolated from respiratory specimens in Peking Union Medical College Hospital (PUMCH) from January 1st, 2013 to December 31st, 2022. Patients were classified into NTM-LD group and NTM-Col group. Demographic characteristics, clinical manifestations, laboratory tests and imaging findings of the two groups were compared. Comparative analysis was also performed in peripheral blood lymphocyte subsets among three groups. RESULTS: A total of 127 NTM-LD patients and 37 NTM-Col patients were enrolled. Proportion of patients with bronchiectasis was higher in NTM-LD group than in NTM-Col group (P = 0.026). Predominant NTM isolates were Mycobacterium avium complex (MAC). NTM-LD group had a higher proportion of Mycobacterium intracellulare (P = 0.004). CD4+ T cells counts was lower in NTM-LD group (P = 0.041) than in NTM-Col group. Imaging finding of bronchiectasis (P = 0.006) was higher in NTM-LD group than in NTM-Col group. Imaging findings of bronchiectasis (OR = 6.282, P = 0.016), and CD4+ T cell count (OR = 0.997, P = 0.012) were independent associated factors for differential diagnosis between NTM-LD and NTM-Col. CONCLUSION: NTM isolates from both NTM-LD and NTM-Col patients were predominantly MAC, with a higher Mycobacterium intracellulare isolation rate in NTM-LD group. Imaging findings of bronchiectasis and lower peripheral blood CD4+ T cell count may be helpful to separate the diagnosis of NTM-LD from NTM-Col.

Bigger problems from smaller colonies: emergence of antibiotic-tolerant small colony variants of Mycobacterium avium complex in MAC-pulmonary disease patients.

BACKGROUND: Mycobacterium avium complex (MAC) is a group of slow-growing mycobacteria that includes Mycobacterium avium and Mycobacterium intracellulare. MAC pulmonary disease (MAC-PD) poses a threat to immunocompromised individuals and those with structural pulmonary diseases worldwide. The standard treatment regimen for MAC-PD includes a macrolide in combination with rifampicin and ethambutol. However, the treatment failure and disease recurrence rates after successful treatment remain high. RESULTS: In the present study, we investigated the unique characteristics of small colony variants (SCVs) isolated from patients with MAC-PD. Furthermore, revertant (RVT) phenotype, emerged from the SCVs after prolonged incubation on 7H10 agar. We observed that SCVs exhibited slower growth rates than wild-type (WT) strains but had higher minimum inhibitory concentrations (MICs) against multiple antibiotics. However, some antibiotics showed low MICs for the WT, SCVs, and RVT phenotypes. Additionally, the genotypes were identical among SCVs, WT, and RVT. Based on the MIC data, we conducted time-kill kinetic experiments using various antibiotic combinations. The response to antibiotics varied among the phenotypes, with RVT being the most susceptible, WT showing intermediate susceptibility, and SCVs displaying the lowest susceptibility. CONCLUSIONS: In conclusion, the emergence of the SCVs phenotype represents a survival strategy adopted by MAC to adapt to hostile environments and persist during infection within the host. Additionally, combining the current drugs in the treatment regimen with additional drugs that promote the conversion of SCVs to RVT may offer a promising strategy to improve the clinical outcomes of patients with refractory MAC-PD.

Rapid lateral flow test for Mycobacterium tuberculosis complex and non-tuberculous mycobacteria differentiation.

The diagnosis of mycobacterial infections, including both the Mycobacterium tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM), poses a significant global medical challenge. This study proposes a novel approach using immunochromatographic (IC) strip tests for the simultaneous detection of MTBC and NTM. Traditional methods for identifying mycobacteria, such as culture techniques, are hindered by delays in distinguishing between MTBC and NTM, which can affect patient care and disease control. Molecular methods, while sensitive, are resource-intensive and unable to differentiate between live and dead bacteria. In this research, we developed unique monoclonal antibodies (mAbs) against Ag85B, a mycobacterial secretory protein, and successfully implemented IC strip tests named 8B and 9B. These strips demonstrated high concordance rates with conventional methods for detecting MTBC, with positivity rates of 93.9% and 85.9%, respectively. For NTM detection, the IC strip tests achieved a 63.2% detection rate compared to culture methods, considering variations in growth rates among different NTM species. Furthermore, this study highlights a significant finding regarding the potential of MPT64 and Ag85B proteins as markers for MTBC detection. In conclusion, our breakthrough method enables rapid and accurate detection of both MTBC and NTM bacteria within the BACTEC MGIT system. This approach represents a valuable tool in clinical settings for distinguishing between MTBC and NTM infections, thereby enhancing the management and control of mycobacterial diseases. KEY POINTS: • Panel of mAbs for differentiating MTB versus NTM • IC strips for diagnosing MTBC and NTM after the BACTEC MGIT • Combined detection of MTP64 and Ag85B enhances diagnostic accuracy.

Drug repositioning identifies histone deacetylase inhibitors that promote innate immunity in non-tuberculous mycobacterial infection.

Non-tuberculosis infections in immunocompromised patients represent a cause for concern, given the increased risks of infection, and limited treatments available. Herein, we report that molecules for binding to the catalytic site of histone deacetylase (HDAC) inhibit its activity, thus increasing the innate immune response against environmental mycobacteria. The action of HDAC inhibitors (iHDACs) was explored in a model of type II pneumocytes and macrophages infection by Mycobacterium aurum. The results show that the use of 1,3-diphenylurea increases the expression of the TLR-4 in M. aurum infected MDMs, as well as the production of defb4, IL-1ß, IL-12, and IL-6. Moreover, we observed that aminoacetanilide upregulates the expression of TLR-4 together with TLR-9, defb4, CAMP, RNase 6, RNase 7, IL-1ß, IL-12, and IL-6 in T2P. Results conclude that the tested iHDACs selectively modulate the expression of cytokines and antimicrobial peptides that are associated with reduction of non-tuberculous mycobacteria infection.

Distinct clinical parameters were associated with shorter spontaneous resolution in children with non-tuberculous mycobacterial lymphadenitis.

AIM: Non-tuberculous mycobacteria (NTM) lymphadenitis typically resolves spontaneously, yet factors influencing the duration remain explored. We aimed to identify clinical parameters associated with shorter spontaneous resolution. METHODS: This cohort study included children with NTM lymphadenitis from 1 January 2015 to 1 March 2021 at Copenhagen University Hospital. Time-to-event analysis assessed clinical parameters associated with the duration of NTM lymphadenitis. RESULTS: Sixty children (57% boys) with a median age of 24 months (range 11-84) were included; 13 (22%) received primary surgery, 13 (22%) underwent surgery after a wait-and-see period and 34 (57%) received no intervention. In children without intervention, the median duration was 10 months (range 2-25). Faster resolution was associated with parental-reported lymph node enlargement within 2 weeks (HR 2.3, 95% CI 1.0-5.0; p = 0.044), abscess on ultrasound examination (HR 3.3, 95% CI 1.5-7.3; p = 0.003) and skin discoloration and/or perforation within 3 months of onset (HR 4.3, 95% CI 1.3-14.4; p = 0.017 and HR 3.7, 95% CI 1.5-9.1; p = 0.005). CONCLUSION: Knowledge of predictors for shorter spontaneous resolution of NTM lymphadenitis, such as rapid initial lymph node enlargement, abscess on ultrasound examination, and skin discoloration and/or perforation within 3 months of disease onset, may guide clinical management decisions concerning surgery versus a conservative approach.

Antibiotic resistance and genomic characterization of Mycobacterium abscessus complex isolates from patients with pulmonary tuberculosis in Iran: A multi-center study (2010-2021).

One hundred and eighteen sputum specimens suspected of Mycobacterium abscessus infection were collected. Species level identification of M. abscessus was performed by rpoB sequencing. Clonality analysis was done by multilocus sequence typing (MLST) for M. abscessus. Antibiotic susceptibility testing was performed for clarithromycin, amikacin, ciprofloxacin and moxifloxacin. Altogether 128 isolates were obtained and were subjected to rpoB gene sequencing for definite identification. Among them 59 were identified as M. abscessus, and these included 22 (37.28%) isolates of M. abscessus subsp. abscessus, 22 (37.28%) isolates of M. abscessus subsp. massiliense, and 15 (25.42%) isolates of M. abscessus subsp. bolletii. All 59 M. abscessus complex isolates were analyzed by MLST in this study. Certain sequence types (STs) were identified among the 59 isolates and were specific for each subspecies. Two STs (ST40 and ST33) were specific to M. abscessus subsp. abscessus, one ST (ST20) was specific to M. abscessus subsp. bolletii, and one ST (ST15) was specific to M. abscessus subsp. massiliense. In antibiotic resistance, clarithromycin susceptibility testing of 22 M. abscessus subsp. abscessus strains detected 15 (68.18%) resistant strains, while among 22 M. abscessus subsp. massiliense strains 5 (22.72%) exhibited resistance, and among 15 M. abscessus subsp. bolletii 8 (53.33%) were resistant. Our study revealed a significant level of antibiotic resistance in isolates of the M. abscessus complex.

ADP-ribosylation-resistant rifabutin analogs show improved bactericidal activity against drug-tolerant M. abscessus in caseum surrogate.

Necrotic lesions and cavities filled with caseum are a hallmark of mycobacterial pulmonary disease. Bronchocavitary Mycobacterium abscessus disease is associated with poor treatment outcomes. In caseum surrogate, M. abscessus entered an extended stationary phase showing tolerance to killing by most current antibiotics, suggesting that caseum persisters contribute to the poor performance of available treatments. Novel ADP-ribosylation-resistant rifabutin analogs exhibited bactericidal activity against these M. abscessus persisters at concentrations achievable by rifamycins in caseum.