Mycobacterium lentiflavum como causa principal de linfadenitis en población pediátrica

Applications and advances in molecular diagnostics: revolutionizing non-tuberculous mycobacteria species and subspecies identification

Non-tuberculous mycobacteria (NTM) infections pose a significant public health challenge worldwide, affecting individuals across a wide spectrum of immune statuses. Recent epidemiological studies indicate rising incidence rates in both immunocompromised and immunocompetent populations, underscoring the need for enhanced diagnostic and therapeutic approaches. NTM infections often present with symptoms similar to those of tuberculosis, yet with less specificity, increasing the risk of misdiagnosis and potentially adverse outcomes for patients. Consequently, rapid and accurate identification of the pathogen is crucial for precise diagnosis and treatment. Traditional detection methods, notably microbiological culture, are hampered by lengthy incubation periods and a limited capacity to differentiate closely related NTM subtypes, thereby delaying diagnosis and the initiation of targeted therapies. Emerging diagnostic technologies offer new possibilities for the swift detection and accurate identification of NTM infections, playing a critical role in early diagnosis and providing more accurate and comprehensive information. This review delineates the current molecular methodologies for NTM species and subspecies identification. We critically assess the limitations and challenges inherent in these technologies for diagnosing NTM and explore potential future directions for their advancement. It aims to provide valuable insights into advancing the application of molecular diagnostic techniques in NTM infection identification.

Meningoencephalitis due to Mycobacterium lentiflavum in an immunocompromised patient: Case report

The first case of meningoencephalitis due to Mycobacterium lentiflavum in an immunocompromised patient is reported. Clinical and radiological characteristics are described, as well as the treatment and prognosis of the patient.

Beyond Tuberculosis: Diversity and implications of non-tuberculous mycobacteria at the wildlife-livestock interface

Non-tuberculous mycobacteria (NTM) circulate between the environment, animals and humans entailing a double concern: their ability to interfere with tuberculosis diagnosis and their potential to cause infections in their hosts. However, published records on NTM infections in animals are still scarce. The aims of the present study were to describe the diversity of NTM circulating among wild and domestic species from Spain, and to analyse their implications as potential pathogenic microorganisms or as sources of interferences in the diagnosis of bovine tuberculosis. Overall, 293 NTM isolates of 277 animals were obtained from tissue samples collected between 2012 and 2019, and analysed through a multigene approach for mycobacteria identification. Thirty-one species were identified, being M. avium subsp. avium (Maa) and M. avium subsp. hominissuis (Mah), but also M. bouchedurhonense, M. nonchromogenicum and M. lentiflavum, the most abundant ones. Maa and M. lentiflavum were isolated in several animals showing tuberculosis-like lesions. Maa, Mah and M. nonchromogenicum were recovered from many cattle that had reacted to the tuberculin skin test (TST). Other NTM were also associated to these phenomena. These four mycobacterial species were geographically associated between wild boar and other hosts. The findings of the present study suggest that a high diversity of NTM circulates among wildlife and livestock. Wild boar and M. avium seem to play a relevant role in this epidemiological scenario. This article is protected by copyright. All rights reserved.

Diagnosis of nontuberculous mycobacterial lymphadenitis: the role of fine-needle aspiration

Nontuberculous mycobacterial lymphadenitis often presents a diagnostic challenge. This study aimed to evaluate the role of fine-needle aspiration cytology in the diagnosis of nontuberculous mycobacterial lymphadenitis in children. We conducted a retrospective review of fine-needle aspiration cytology performed in patients < 17 year-old with subacute lymphadenitis from 2003 to 2016 in a tertiary hospital in Spain. Confirmed nontuberculous mycobacterial lymphadenitis (isolation of nontuberculous mycobacterial in culture from fine-needle aspiration cytology or biopsy samples) and probable nontuberculous mycobacterial lymphadenitis ("granulomatous inflammation" in cytopathologic examinations from fine-needle aspiration cytology or biopsy and clinical-epidemiological history compatible with nontuberculous mycobacterial) were selected. Forty-one patients with nontuberculous mycobacterial lymphadenitis were included: 14 confirmed and 27 probable. Fine-needle aspiration cytology was done in all of them. For 34 patients with excised lymphadenopathy, cytopathology from fine-needle aspiration cytology was concordant with biopsy in 100% cases. Culture results were available from 78.0% (32/41) of patients with fine-needle aspiration cytology and from 85.3% (29/34) with excisional biopsy. Among 22 patients with microbiological results from fine-needle aspiration cytology and biopsy, fine-needle aspiration cytology allowed advanced results in concordance with biopsy or with positive isolation not found in biopsy in 90.1% (20/22) of patients. Sensitivity of nontuberculous mycobacterial cultures obtained by fine-needle aspiration cytology compared to biopsy was 45.5% vs. 36.4% (p = 0.07). Two patients with previous skin alterations presented fistulas after fine-needle aspiration cytology (4.9%); no other complications were described.Conclusion: Fine-needle aspiration cytology provides quick cytopathologic information and is an accurate and safe technique for the diagnosis of nontuberculous mycobacterial lymphadenitis, especially in cases with challenging work-up. What is Known: • Nontuberculous mycobacterial (NTM) infection is an important cause of subacute lymphadenitis in children. • Fine-needle aspiration cytology (FNAC) is an available technique for the diagnosis of lymphadenitis of unknown etiology. What is New: • FNAC is an accurate and safe technique for the diagnosis of NTM lymphadenitis in children. • FNAC can provide reliable samples for cytopathological studies and even a better sensitivity for microbiological culture than excisional biopsy in the study of suspected NTM lymphadenitis.

State-of-the-art treatment strategies for nontuberculous mycobacteria infections

INTRODUCTION

Non-tuberculous Mycobacteria (NTM) are a group of organisms whose importance in medicine seems to be increasing in recent times. The increasing number of patients susceptible to these diseases make it necessary to expand our knowledge of therapeutic options and to explore future possibilities for the development of a therapeutic arsenal.

AREAS COVERED

In this review, the authors provide a brief introduction about the present importance of NTM and describe the present recommendations of the available guidelines for their treatment. They include a description of the future options for the management of these patients, especially focusing on new antibiotics. The authors also look at possibilities for future therapeutic options, such as antibiofilm strategies.

EXPERT OPINION

No actual changes have been made to the current recommendations for the management of most NTM infections (except perhaps the availability of nebulized amikacin). However, it is also true that we have increased the number of available antibiotic treatment options with good in vitro activity against NTM. The use of these drugs in selected cases could increase the therapeutic possibilities. However, some problems are still present, such as the knowledge of the actual meaning of a NTM isolate, and will probably be a key part of future research.

Epidemiology of Non-Tuberculous Mycobacteria isolated from clinical specimens in Madrid, Spain, from 2013 to 2017

The epidemiology of non-tuberculous mycobacteria (NTM) in Spain is largely unknown because systematic reporting is not compulsory. The aim of our study was to describe the frequency and diversity of NTM species in our region and their distribution according to the source sample, gender, and age of the patients. We performed a multicenter study of all NTM isolated in 24 public hospitals in Madrid from 2013 to 2017. A total of 6.923 mycobacteria were isolated: 4535 (65.5%) NTM, and 2.388 (34.5%) Mycobacterium tuberculosis complex (MTB). Overall, 61 different NTM species were identified. The most frequently isolated species were Mycobacterium avium complex (47.7%), M. lentiflavum (12.2%), M. gordonae (9.2%), M. fortuitum (8.9%), and M. abscessus (3.9%). Whereas MTB cases were stable during the study period, the number of NTM isolates increased considerably from 930 isolates in 2013 to 1012 in 2017; a sharp increase occurred in the last year. The rise in NTM isolates was mostly due to M. lentiflavum, M. kansasii, and M. abscessus mainly isolated from respiratory specimens in patients older than 60. The increase in isolation rate of NTM in our region is consistent with the increasing rates reported worldwide in the last decades. The rise in NTM isolates was mainly attributed to M. lentiflavum but it also should be noted the increasing of species with high pathogenic potential such as M. kansasii and M. abscessus.

HMGN2 regulates non-tuberculous mycobacteria survival via modulation of M1 macrophage polarization

Non‐tuberculous mycobacteria (NTM), also known as an environmental and atypical mycobacteria, can cause the chronic pulmonary infectious diseases. Macrophages have been suggested as the main host cell to initiate the innate immune responses to NTM infection. However, the molecular mechanism to regulate the antimicrobial immune responses to NTM is still largely unknown. Current study showed that the NTM clinical groups, Mycobacterium abscessus and Mycobacterium smegmatis, significantly induced the M1 macrophage polarization with the characteristic production of nitric oxide (NO) and marker gene expression of iNOS, IFNγ, TNF‐α, IL1‐β and IL‐6. Interestingly, a non‐histone nuclear protein, HMGN2 (high‐mobility group N2), was found to be spontaneously induced during NTM‐activated M1 macrophage polarization. Functional studies revealed that HMGN2 deficiency in NTM‐infected macrophage promotes the expression of M1 markers and the production of NO via the enhanced activation of NF‐κB and MAPK signalling. Further studies exhibited that HMGN2 knock‐down also enhanced IFNγ‐induced M1 macrophage polarization. Finally, we observed that silencing HMGN2 affected the survival of NTM in macrophage, which might largely relevant to enhanced macrophage polarization into M1 phenotype under the NTM infection. Collectively, current studies thus suggested a novel function of HMGN2 in regulating the anti‐non‐tuberculous mycobacteria innate immunity of macrophage.