Infections caused by non-tuberculous mycobacteria (NTM) are increasing globally and are notoriously difficult to treat due to intrinsic resistance of these bacteria to many common antibiotics. NTM are diverse and ubiquitous in the environment, with only a few species causing serious and often opportunistic infections in humans, including Mycobacterium abscessus. This rapidly growing mycobacterium is one of the most commonly identified NTM species responsible for severe respiratory, skin and mucosal infections in humans. It is often regarded as one of the most antibiotic-resistant mycobacteria, leaving us with few therapeutic options. In this Review, we cover the proposed infection process of M. abscessus, its virulence factors and host interactions and highlight the commonalities and differences of M. abscessus with other NTM species. Finally, we discuss drug resistance mechanisms and future therapeutic options. Taken together, this knowledge is essential to further our understanding of this overlooked and neglected global threat.

We aimed to address the knowledge gap that exists regarding the epidemiological, demographic, and clinical characteristics of nontuberculous mycobacterial pulmonary diseases (NTM-PDs) among smear-positive patients with symptoms suggestive of pulmonary tuberculosis (PTB) in China.Prospective and national surveillance of NTM-PD was performed from 17 hospitals within the China Nontuberculous Mycobacteria Surveillance Study (CNTMS). Patients were eligible for inclusion if they had positive smears during hospitalization. Sputum specimens were collected for molecular species identification.6,766 patients with valid results were included, consisting of 6,236 (92.2%) with PTB, 458 (6.8%) with NTM-PD, and 72 (1.0%) with colonisation. The proportion of NTM-PD in PTB patients exhibited significant geographic diversity, ranging from 3.2% in the northwest to 9.2% in the south. The most prevalent species was Mycobacterium intracellulare, followed by Mycobacterium abscessus complex. Females, elderly people, and patients with bronchiectasis or COPD are at high risk for developing NTM-PD, while patients with diabetes have a lower risk of NTM-PD when compared with non-diabetic patients. Regarding clinical symptoms, lower rates of persistent cough and weight loss were noted in NTM-PD patients than in PTB patients.Approximately one-fifteenth of PTB patients are afflicted with nontuberculous mycobacterial infections in China. The prevalence of NTM shows geographic diversity across the country, and it showed a gradual increase from north to south and from west to east. NTM-PD patients are prone to exhibit less severe clinical symptoms than PTB patients, highlighting the importance of raising awareness of NTM diseases to improve decision making on how to best screen, diagnose, and treat NTM in TB-endemic settings.Copyright © 2021. Published by Elsevier Ltd.

Nontuberculosis mycobacterium (NTM) is the emerging group of organisms being recognized as etiological agents for diverse clinical conditions such as lymphadenitis, cutaneous, and pulmonary or disseminated lesions. Diverse background patients can acquire these infections such as immunocompetent, immunocompromised patients, or postoperative settings. Rapid addition of newer strains to this group necessitates heightened suspicion in the clinical settings. Specific requirements for cultures, biochemical testing, and molecular methods are needed to diagnose these organisms.The prospective study conducted at Nizam's Institute of Medical Sciences from January 2019 to December 2021 using various clinical samples using molecular techniques such as line probe assay and hsp-65 gene sequencing to discover new NTM species. The management is challenging since it requires prolonged treatment, multiple drugs, drug resistance, and individualization of treatment in the combination of surgery if needed. In this article, we describe three different NTM species which were not reported in India and highlight to consider these organisms in adequate clinical situation.Mycobacterium iranicum is a rare strain with quick growth and scotochromogenic colonies that are orange-colored. Eight distinct strains were discovered in clinical samples from six different countries: Two each from Iran, Italy, Greece, the Netherlands, Sweden, and the United States. Two of the strains were recovered from cerebrospinal fluid, which is unusual. Mycobacterium species AW6 is an unidentified and unclassified Mycobacterium according to NCBI taxonomy. Mycobacteria malmoense has been linked to lymphadenitis, notably cervical adenitis in children, and pulmonary infection in the majority of cases. Using Line Probe Assay and hsp-65 gene sequencing, novel and uncommon species of NTM were detected from a clinical samples, including sputum and tissue.We report three unusual species of NTMs: M. iranicum, M. species-AW6, and M. malmoense for the first time in India. Novel and rare emerging species of NTMs need to be considered in diverse clinical situations for appropriate therapy and good clinical outcomes.

To date, the diagnosis of nontuberculous mycobacteria (NTM) disease primarily relies on clinical symptoms and radiological features. Our objective was to apply a sequence-based analysis method by using partial gene sequencing of heat shock protein 65 () to identify NTM species.A total of 32 stored isolates obtained from individuals suspected of having pulmonary NTM infection were subjected to solid Ogawa culture. Genomic DNA from each sample was extracted and used in a conventional polymerase chain reaction (PCR) targeting a specific region of gene. Identified amplicons from the PCR were then subjected to targeted sequencing. Analysis of the obtained sequence was performed using DNA Baser tool. The consensus sequences obtained were compared to references in the GenBank NCBI database to determine NTM species.We identified several important NTM species which posses opportunistic characteristics. and are the most frequent NTM species identified in this study (40.63% and 18.75%, respectively). These two species have the potential to cause significant infections in human, ranging from opportunistic pulmonary infection to localized skin infection. Additionally, pathogenic NTM members of, and were also found among all identified species.Sequence-based analysis is a promising method for identifying species of NTM. The gene has a high discriminatory power to identify opportunistic pathogen NTM species in specimens in Indonesia. Consequently, partial gene sequencing is considerable as an alternative and reliable approach for NTM speciation.© 2023 Pascapurnama et al.

Nontuberculous mycobacterial (NTM) infections are growing worldwide especially in immunocompromised individuals. Since treatment of NTM infections is species-specific, the precise identification of NTM to species level is critical for an optimal treatment. This study was aimed to identify different NTM species by sequencing the rpoB gene and evaluating the effectiveness of argH and cya gene markers. In total 64 clinical isolates suspected to NTM were collected. The identification of the isolates was done by standard conventional methods and PCR-based rpoB gene and sequence analysis. PCR sequencing of argH and cya genes was performed to evaluate the efficacy of these genes in identifying and differentiating different species and subspecies of NTM. Among 64 isolates tested, 51 (79.68%) were detected by conventional tests as NTM. The results of rpoB sequence analysis revealed that the 56 clinical isolates were identified in 10 species of NTM and 8 remaining isolates which showed ambiguous results by rpoB sequencing, application of argH and cya sequencing could detect these isolates. Furthermore, by using cya gene sequencing, M. abscessus subspecies were properly differentiated. Although the rpoB sequencing as a standard method, is beneficial for detecting various species of NTM, however, based on our findings, argH and cya gene markers have a superb ability to discriminate closely related species. Further investigations are required to verify our outcomes.© 2022. The Author(s).

In the Netherlands, clinical isolation of nontuberculous mycobacteria (NTM) has increased over the past decade. Proper identification of isolates is important, as NTM species differ strongly in clinical relevance. Most of the currently applied identification methods cannot distinguish between all different Mycobacterium species and complexes within species. rpoB gene sequencing exhibits a promising level of discrimination among rapidly and slowly growing mycobacteria, including the Mycobacterium avium complex. In this study, we prospectively compared rpoB gene sequencing with our routine algorithm of reverse line blot identification combined with partial 16S rRNA gene sequencing of 455 NTM isolates. rpoB gene sequencing identified 403 isolates to species level as 45 different known species and identified 44 isolates to complex level, and eight isolates remained unidentifiable to species level. In contrast, our reference reverse line blot assay with adjunctive 16S rRNA gene sequencing identified 390 isolates to species level (30 distinct species) and identified 56 isolates to complex level, and nine isolates remained unidentified. The higher discriminatory power of rpoB gene sequencing results largely from the distinction of separate species within complexes and subspecies. Also, Mycobacterium gordonae, Mycobacterium kansasii, and Mycobacterium interjectum were separated into multiple groupings with relatively low sequence similarity (98 to 94%), suggesting that these are complexes of closely related species. We conclude that rpoB gene sequencing is a more discriminative identification technique than the combination of reverse line blot and 16S rRNA gene sequencing and could introduce a major improvement in clinical care of NTM disease and the research on the epidemiology and clinical relevance of NTM. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

The prevalence of nontuberculous mycobacteria (NTM) has increased in tuberculosis (TB)-suspected clinical samples. These bacteria are now recognized as important emerging pathogens, which affect both immunocompetent and immunocompromised individuals. The aim of this study was to evaluate the frequency of NTM in clinical samples and to efficacy of genomic loci as targets for detection of NTM species. This cross-sectional study was performed on 8166 clinical samples to determine the presence of NTM species from April 2013 to December 2015. The phenotypic methods were applied for preliminary NTM identification. The PCR-RFLP assay of heat shock protein-65 (hsp-65) gene and multilocus sequence analysis based on 16S-23S internal transcribes spacer (ITS), rpoB, and 16S rRNA genes were applied for species identification. In a total of 520 isolates from TB-suspected cases, 61 samples (11.7%) were identified as NTM. Overall, Mycobacterium (M.) fortuitum (63.9%) was the most frequently encountered species, followed by M. kansasii (9.8%), M. simiae (9.8%), M. abscessus (6.7%), M. gordonae (4.9%), M. flavescens (3.3%), and M. setense (1.6%). Moreover, sequencing of 16S rRNA and rpoB genes could identify all NTM species. In conclusion, we showed that the samples were infected by six NTM species, and M. fortuitum was the most frequent NTM strain. Based on the findings, 16S rRNA and rpoB genes were superior to ITS gene in identification of NTM species.

Many patients with nontuberculous mycobacteria pulmonary disease are asymptomatic. The disease diagnosis is confirmed in only a small proportion of patients with radiological findings suspicious for nontuberculous mycobacteria pulmonary disease. Thus, many patients remained undiagnosed. Here, we evaluated the diagnostic value of digital polymerase chain reaction (PCR) in nontuberculous mycobacteria pulmonary disease.We prospectively evaluated 123 patients with radiological findings suspicious for nontuberculous mycobacteria pulmonary disease. Digital PCR was performed using bronchial lavage fluid, sputum, saliva, blood, and urine.The culture of bronchial washing fluid was positive for nontuberculous mycobacteria in 53 patients and negative in 70. The positive detection rate of nontuberculous mycobacteria by digital PCR in patients with positive culture (n = 53) was as follows: bronchial lavage fluid 100%, sputum 62.9%, saliva 41.5%, blood 7.5%, and urine 3.8%. All patients with two or more positive partitions for nontuberculous mycobacteria in the digital PCR of bronchial lavage fluid showed nontuberculous mycobacteria growth in the bronchial lavage fluid culture. The digital PCR analysis of the bronchial lavage fluid showed a high sensitivity (100%), specificity (85.7%), positive predictive value (84.1%), negative predictive value (100%), and a high concordance rate (91.9%) with the bronchial lavage fluid culture results. In addition, the culture of bronchial lavage fluid was positive for nontuberculous mycobacteria in patients with two or more positive partitions in the digital PCR of sputum and saliva with a combined positive predictive value of 81.1%.Digital PCR analysis of nontuberculous mycobacteria in bronchial lavage fluid shows a high concordance rate with the bronchial lavage fluid culture results and a high positive predictive value using both sputum and saliva, suggesting the potential usefulness of dPCR for diagnosis of nontuberculous mycobacteria pulmonary disease in clinical practice.© 2021 Nishii et al.

Metagenomic next-generation sequencing (mNGS) has been extensively used in the diagnosis of infectious diseases but has rarely been applied in non-tuberculous mycobacterial pulmonary disease (NTMPD). This study analyzed the diagnostic performance of mNGS in bronchoalveolar lavage fluid (BALF) samples to identify non-tuberculous mycobacteria (NTM).A total of 231 patients with suspected NTMPD were recruited from the First Affiliated Hospital, School of Medicine, Zhejiang University, from March 2021 to October 2022. A total of 118 cases were ultimately included. Of these patients, 61 cases were enrolled in the NTMPD group, 23 cases were enrolled in the suspected-NTMPD group, and 34 cases were enrolled in the non-NTMPD group. The diagnostic performance of traditional culture, acid-fast staining (AFS), and mNGS for NTMPD was assessed.Patients in the NTMPD group had a higher proportion of bronchiectasis (=0.007). Among mNGS-positive samples in the NTMPD group, a significantly higher reads number of NTM was observed in AFS-positive patients [61.50 (22.00, 395.00) vs 15.50 (6.00, 36.25), =0.008]. Meanwhile, mNGS demonstrated a sensitivity of 90.2%, which was far superior to AFS (42.0%) and culture (77.0%) (<0.001). The specificity of mNGS in detecting NTM was 100%, which was the same as that of traditional culture. The area under the receiver operating characteristic curve of mNGS was 0.951 (95% CI 0.906-0.996), which was higher than that of culture (0.885 [95% CI 0.818-0.953]) and AFS (0.686 [95% CI 0.562-0.810]). In addition to NTM, other pulmonary pathogens were also found by mNGS.mNGS using BALF samples is a rapid and effective diagnostic tool for NTMPD, and mNGS is recommended for patients with suspected NMTPD or NTM coinfected pneumonia.© 2023 Zhang et al.

Seventy years have passed since Ernest H. Runyon presented a phenotypic classification approach for nontuberculous mycobacteria (NTM), primarily as a starting point in trying to understand their clinical relevance. From numerical taxonomy (biochemical testing) to 16S rRNA gene sequencing to whole genome sequencing (WGS), our understanding of NTM has also evolved. Novel species are described at a rapid pace, while taxonomical relationships are re-defined in large part due to the accessibility of WGS. The evolutionary course of clonal complexes within species is better known for some NTM and less for others. In contrast with M. tuberculosis, much is left to learn about NTM as a whole.Copyright © 2019. Published by Elsevier B.V.

目的 探讨线性探针法用于分枝杆菌菌种快速鉴定的可行性和应用价值。方法 收集2017年1月至2018年12月深圳市慢性病防治中心、光明区人民医院和盐田区人民医院登记疑似结核病患者的分枝杆菌阳性培养物3420份。经GenoType MTBDRplus结核分枝杆菌耐药检测试剂盒初筛和剔除患者的重复样本后,筛选出127株非结核分枝杆菌（NTM）进行菌种鉴定。采用线性探针法和PCR基因测序法（16S rRNA和ITS）对NTM菌株进行菌种鉴定,并以测序结果为菌种鉴定的&#x0201c;金标准&#x0201d;。结果 127株NTM的菌种分布为：脓肿分枝杆菌47株（37.0%）,偶发分枝杆菌20株（15.8%）,胞内分枝杆菌18株（14.2%）,戈登分枝杆菌11株（8.7%）,堪萨斯分枝杆菌8株（6.3%）,鸟-胞内分枝杆菌复合群7株（5.5%）,慢生黄分枝杆菌6株（4.7%）,奇美拉分枝杆菌2株（1.6%）,龟分枝杆菌1株（0.8%）,蟾分枝杆菌1株（0.8%）,瘰疬分枝杆菌1株（0.8%）,外来分枝杆菌1株（0.8%）,土分枝杆菌1株（0.8%）,美容品分枝杆菌1株（0.8%）,熊本分枝杆菌1株（0.8%）和富养二氧分枝杆菌1株（0.8%）。与PCR相比,线性探针法对127株NTM全部检出,其中112株（112/127,88.2%）能准确鉴定到菌种,2株（2/127,1.6%）不能区分为瘰疬/胞内分枝杆菌,12株（12/127,9.4%）超出试剂盒鉴定范围,1株外来分枝杆（1/127,0.8%）鉴定错误。结论 线性探针法可以快速、准确地鉴定常见的分枝杆菌菌种,但菌种鉴定范围有限,不能完全满足临床菌种鉴定的需求。

In this study, to assess the performance of the AdvanSure Mycobacteria GenoBlot assay (AdvanSure assay), we compared its performance with that of the GenoType Mycobacterium CM/AS assay (GenoType assay) for the identification of non-tuberculous mycobacteria (NTM). Twenty-four reference strains and 103 consecutive clinical NTM isolates were analysed. The accuracy rates for the 24 reference strains were 87.5 and 95.8 % for the AdvanSure and GenoType assays, respectively. For the 103 clinical isolates, a 91.3 % (94/103) concordance rate was observed between the two assays. The majority (7/9) of discrepancies were isolates identified as Mycobacterium avium complex (MAC) by only the AdvanSure assay. All of these isolates except one were confirmed as MAC by sequence-based typing. The AdvanSure assay showed comparable performance to the GenoType assay and can be useful as a routine method for NTM identification in the clinical setting, especially where MAC is the main cause of NTM infection.

Accumulating evidence suggests that human infections caused by nontuberculous mycobacteria (NTM) are increasing worldwide, indicating that NTM disease is no longer uncommon in many countries. As a result of an increasing emphasis on the importance of differential identification of NTM species, several molecular tools have recently been introduced in clinical and experimental settings. These advances have led to a much better understanding of the diversity of NTM species with regard to clinical aspects and the potential factors responsible for drug resistance that influence the different outcomes of NTM disease. In this paper, we review currently available molecular diagnostics for identification and differentiation of NTM species by summarizing data from recently applied methods, including commercially available assays, and their relevant strengths and weaknesses. We also highlight drug resistance-associated genes in clinically important NTM species. Understanding the basis for different treatment outcomes with different causative species and drug-resistance mechanisms will eventually improve current treatment regimens and facilitate the development of better control measures for NTM diseases.Copyright © 2018 Elsevier B.V. All rights reserved.

Seventy-six nontuberculous mycobacterial isolates obtained from patients living in Greece were analyzed with the GenoType Mycobacterium CM (for common mycobacteria) and AS (for additional species) assays. GenoType correctly identified all but one of the mycobacterial species. For this species, additional probes should be designed and added to the strip.

Nontuberculous mycobacteria (NTM) causing human infectious disease have become increasingly common. Rapid and accurate identification to the species level is, therefore, critical. The Speed-Oligo Mycobacteria assay is an oligochromatographic method that was made available recently for the identification and differentiation of mycobacteria. The present study aimed to evaluate the performance of the Speed-Oligo Mycobacteria assay for the identification of NTM. We examined a total of 62 strains (9 type strains, 19 reference strains and 34 clinical isolates) belonging to 13 different species (Mycobacterium intracellulare, M. fortuitum, M. gordonae, M. kansasii, M. marinum, M. peregrinum, M. scrofulaceum, M. abscessus, M. bovis BCG, M. chelonae, M. avium, M. malmoense and M. xenopi). The Speed-Oligo Mycobacteria assay was performed according to the manufacturer's instructions. Discrepant results between Speed-Oligo Mycobacteria and the original identification were reassessed by the Speed-Oligo Mycobacteria assay and resolved by the GenoType Mycobacterium CM assay and by sequencing of 16S rRNA and protein-encoding genes. We found 93.5 % (58/62) concordance for the identification of NTM as compared with the original identification. Three strains were erroneously identified by Speed-Oligo Mycobacteria: one M. kansasii strain was identified as Mycobacterium tuberculosis complex, and one M. chelonae strain and one M. peregrinum strain were both identified as Mycobacterium abscessus. Moreover, one M. chelonae strain was not identified by Speed-Oligo Mycobacteria since it did not react with any species-specific probe. For these strains, sequencing of the genes hsp65, 16S rRNA and rpoB and the GenoType Mycobacterium CM assay were performed. The Speed-Oligo Mycobacteria assay can be a useful tool for the rapid and easy identification of the most common NTM. If applied in clinical practice it could reduce diagnostic delays and contribute to correct clinical and better management of infections caused by NTM.

Nontuberculous mycobacteria (NTM) infection associated with pulmonary and extrapulmonary disease has been increasing globally. Despite an increase in incidence rate of NTM infection, its prevalence, species diversity, and circulation pattern in India is largely unknown. This study sought to investigate the overall burden and diversity of NTM among both pulmonary and extrapulmonary clinical isolates from a Northern Indian population.The study was conducted in the Department of Microbiology, from January 2013 to December 2015. A total of 4620 clinical samples were collected from patients suspected to have pulmonary and extrapulmonary tuberculosis. Preliminary diagnosis was performed using Ziehl-Neelsen staining followed by liquid culture in BacT/ALERT three-dimensional system. A total of 906 positive cultures obtained were differentiated as either NTM or Mycobacterium tuberculosis complex using a biochemical and MPT64 antigen test. Further identification of NTM species was confirmed with a line probe assay.Out of 906 cultures isolates, 263 (29.0%) were confirmed as NTM and 643 (71.0%) were identified as Mycobacterium tuberculosis complex. A total of 79.4% of the NTM were recovered from pulmonary and 18.2% from extrapulmonary specimens. The diversity of NTM species was high (13 species) and predominated by Mycobacterium abscessus (31.3%) followed by Mycobacterium fortuitum (22%), Mycobacterium intracellulare (13.6%), Mycobacterium chelonae (9.1%), however, M. abscessus and M. fortuitum were the predominant species in both types of clinical isolates. Men (60.4%) and older patients aged greater than 55years were the predominated risk group for NTM infection.The high prevalence and species diversity of NTM suggests the need for immediate and accurate characterization of NTM for proper treatment and management of patients.Copyright © 2016 Asian-African Society for Mycobacteriology. Published by Elsevier Ltd. All rights reserved.

We studied the performance of a new line probe assay for identifying the subspecies and determining the macrolide and aminoglycoside resistance levels of 50 Mycobacterium abscessus isolates. Agreement of GenoType NTM-DR results with sequencing and phenotypic resistance results was 92% for subspecies identification and 98% for determining molecular and phenotypic resistance.Copyright © 2016, American Society for Microbiology. All Rights Reserved.

The objective of this study was to conduct a multicentre evaluation of the performance of the biochip assay in the rapid identification of mycobacteria in smear-positive sputum specimens.A total of 1751 sputum specimens were obtained from 7 cities in Zhejiang, China. All of the specimens were used for the discrimination of Mycobacterium species using the biochip assay, and the results were compared to the golden standard method of culture, hsp65, 16S rRNA and rpoB sequence analysis.In the 1751 sputum specimens, 1685 samples were cultured successfully; among these samples, 1361 were Mycobacterium tuberculosis, 323 were NTM and 1 was Nocadia farcinica. Of the 323 NTM, most of them were Mycobacterium intracellulare(52.5%) followed by Mycobacterium abscessus (20.7%), Mycobacterium avium (11.7%), Mycobacterium kansasii (9.6%) and Mycobacterium fortuitum (1.9%). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the biochip assay to differentiate TB and NTM from AFB positive specimens were 99.8%, 99.7%, 99.9%, 99.1%, 98.8%, 1, 1, and 99.7%, respectively. The concordance between the biochip assay and mycobacterial culture for the identification of NTM species was 95.4%.The biochip assay is a reliable tool for the rapid identification of most mycobacteria in clinical sputum specimens. This assay can be helpful for physicians in the early diagnosis and treatment of mycobacterium infections.Copyright © 2019 The Author(s). Published by Elsevier Ltd.. All rights reserved.

In addition to the obligatory pathogenic species of the Mycobacterium tuberculosis complex and Mycobacterium leprae, the genus Mycobacterium also includes conditionally pathogenic species that in rare cases can lead to the development of nontuberculous mycobacterial diseases. Because tuberculosis and mycobacteriosis have similar clinical signs, the accurate identification of the causative agent in a clinical microbiology laboratory is important for diagnostic verification and appropriate treatment. This report describes a low-density hydrogel-based microarray containing oligonucleotide probes based on the species-specific sequences of the gyrB gene fragment for mycobacterial species identification. The procedure included the amplification of a 352-nucleotide fragment of the gene and its hybridization on a microarray. The triple-species-specific probe design and the algorithm for hybridization profile recognition based on the calculation of Pearson correlation coefficients, followed by the construction of a profile database, allowed for the reliable and accurate identification of mycobacterial species, including mixed-DNA samples. The assay was used to evaluate 543 clinical isolates from two regions of Russia, demonstrating its ability to detect 35 mycobacterial species, with 99.8% sensitivity and 100% specificity when using gyrB, 16S, and internal transcribed spacer (ITS) fragment sequencing as the standard. The testing of clinical samples showed that the sensitivity of the assay was 89% to 95% for smear-positive samples and 36% for smear-negative samples. The large number of identified species, the high level of sensitivity, the ability to detect mycobacteria in clinical samples, and the up-to-date profile database make the assay suitable for use in routine laboratory practice. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

The rapid identification of mycobacteria from culture is of primary importance for the administration of empirical antibiotic therapy and for the implementation of public health measures, yet there are few commercially available assays that can easily and accurately identify the mycobacteria in culture in a timely manner. Here we report on the development of a multiplex, real-time PCR assay that can identify 93% of the pathogenic mycobacteria in our laboratory in two parallel reactions. The mycobacteria identified by this assay include the Mycobacterium tuberculosis complex (MTC), the M. avium complex (MAC), the M. chelonae-M. abscessus group (MCAG), the M. fortuitum group (MFG), and M. mucogenicum. The primer targets included the 16S rRNA gene and the internal transcribed spacer. The assay was initially validated with a repository of reference strains and was subsequently tested with 314 clinical cultures identified by the AccuProbe assay or high-performance liquid chromatography. Of the 314 cultures tested, multiplex, real-time PCR produced congruent results for 99.8% of the 1,559 targets evaluated. The sensitivity and the specificity were each 99% or greater for MTC (n = 96), MAC (n = 97), MCAG (n = 68), and M. mucogenicum (n = 9) and 95% and 100%, respectively, for MFG (n = 19). We conclude that this multiplex, real-time PCR assay is a useful diagnostic tool for the rapid and accurate identification of MTC and clinically relevant nontuberculous mycobacteria.

Over the last 30 years, there have been at least 17 published reports of nontuberculous mycobacteria (NTMs) being isolated from hospital ice or ice-making machines. Of these, 12 were reports of pseudo-outbreaks, i.e., the nosocomial transmission of organism from hospital ice/ice machines to patients, resulting in patient colonization, but with no disease manifestations. In addition, there were five outbreaks that resulted in clinical disease/pathology associated with NTM organism. Eleven different species of NTMs have been associated with these reports, where over half (59%) of the species identified were Mycobacterium fortuitum (18%), Mycobacterium gordonae (14%), Mycobacterium mucogenicum (14%), and Mycobacterium porcinum (14%). Several of these reports clearly documented that ice machines had been properly maintained, cleaned, and serviced in accordance with the CDC guidelines yet became contaminated with NTM organisms. These reports frequently detail that after extensive cleaning/disinfection following the discovery of NTM organisms, ice machines remained contaminated with NTM organisms, highlighting the difficulty in eradicating these from ice machines, once contaminated. Several reports identified that the only remedy to the contamination problem was to replace the ice machine with a new machine. Two qualitative risk assessment models are presented for (i) patients exposed to contaminated ice machine but before NTM colonization/infection and (ii) patients already colonized with NTMs from ice machines. Therefore, to protect immunocompromised/immunosuppressed patients' safety, especially during surgical or respiratory procedures, ice should not be sourced from the ice machine but should be made from sterile water and stored safely and separately away from the ice machine.

Non-tuberculous mycobacteria (NTM) are emerging worldwide as significant causes of chronic pulmonary infection, posing a number of challenges for both clinicians and researchers. While a number of studies worldwide have described an increasing prevalence of NTM pulmonary disease over time, population-based data are relatively sparse and subject to ascertainment bias. Furthermore, the disease is geographically heterogeneous. While some species are commonly implicated worldwide (Mycobacterium avium complex, Mycobacterium abscessus), others (e.g., Mycobacterium malmoense, Mycobacterium xenopi) are regionally important. Thoracic computed tomography, microbiological testing with identification to the species level, and local epidemiology must all be taken into account to accurately diagnose NTM pulmonary disease. A diagnosis of NTM pulmonary disease does not necessarily imply that treatment is required; a patient-centered approach is essential. When treatment is required, multidrug therapy based on appropriate susceptibility testing for the species in question should be used. New diagnostic and therapeutic modalities are needed to optimize the management of these complicated infections.Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The clinical relevance of non-tuberculous mycobacteria (NTM) has been reported to be different dramatically by species or by regions, however, no such evaluation has been performed in China. A retrospective study was performed in Beijing Chest Hospital. All the NTM strains isolated from respiratory specimens in the past 5 years, and patients' clinical records (symptoms and radiographic information etc.) were investigated. The clinical relevance was evaluated according to the criteria recommended by the American Thoracic society. Totally 232 NTM strains were recruited, among them, M. intracellulare was the dominant species (40.5%), followed by M. abscessus (28.4%). 109 patients, with 185 total isolates, had full clinical records available for review. 84.4% (38/45), 85.7% (24/28%) and 63.6% (7/11) of patients with isolation of M. intracellulare, M. abscessus and M. kansasii, respectively, were categorized as definite NTM disease. Whereas all the 10 patients with isolation of M. gordonae were defined as unlikely NTM disease. The majority of NTMs isolates yielded from respiratory specimens in Beijing Chest Hospital were clinically significant, and M. intracellulare and M. abscessus was the dominated species of NTM lung disease. NTM lung infections demonstrated some specific chest radiograph characteristics.

The nontuberculous mycobacteria (NTM) are waterborne opportunistic pathogens of humans. They are normal inhabitants of premise plumbing, found, for example, in household and hospital shower heads, water taps, aerators, and hot tubs. The hydrophobic NTM are readily aerosolized, and pulmonary infections and hypersensitivity pneumonitis have been traced to the presence of NTM in shower heads. Hypersensitivity pneumonitis in automotive workers was traced to the presence of NTM in metal recovery fluid used in grinding operations. Recently, NTM bacteremia in heart transplant patients has been traced to the presence of NTM in water reservoirs of instruments employed in operating rooms to heat and cool patient blood during periods of mechanical circulation. Although NTM are difficult to eradicate from premise plumbing as a consequence of their disinfectant-resistance and formation of biofilms, measures such as reduction of turbidity and reduction in carbon and nitrogen for growth and the installation of microbiological filters can reduce exposure of NTM to susceptible individuals.

Non-tuberculous mycobacteria (NTM) include more than 160 ubiquitous, environmental, acid-fast-staining bacterial species, some of which may cause disease in humans. Chronic pulmonary infection is the most common clinical manifestation. Although patients suffering from chronic lung diseases are particularly susceptible to NTM pulmonary disease, many affected patients have no apparent risk factors. Host and pathogen factors leading to NTM pulmonary disease are not well understood and preventive therapies are lacking. NTM isolation and pulmonary disease are reported to rise in frequency in Europe as well as in other parts of the world. Differentiation between contamination, infection, and disease remains challenging. Treatment of NTM pulmonary disease is arduous, lengthy, and costly. Correlations between results of in vitro antibiotic susceptibility testing and clinical treatment outcomes are only evident for the Mycobacterium avium complex, M. kansasii, and some rapidly growing mycobacteria. We describe the epidemiology of NTM pulmonary disease as well as emerging NTM pathogens and their geographical distribution in non-cystic fibrosis patients in Europe. We also review recent innovations for the diagnosis of NTM pulmonary disease, summarize treatment recommendations, and identify future research priorities to improve the management of patients affected by NTM pulmonary disease. © 2016 The Author(s) Published by S. Karger AG, Basel.

NTM are ubiquitous bacteria that can cause colonisation and infection in immunocompetent and compromised hosts. The aim of this study was to elucidate the epidemiology of infection or colonisation with NTM for the metropolitan region of Frankfurt, Germany.All patients from whom NTM were isolated within the period from 2006 to 2016 were included in this retrospective analysis. Patient data were retrieved using the local patient data management system. Different groups were formed according to clinical manifestations, underlying diseases and mycobacterial species. They were compared in regard to mortality, duration of infection/colonisation and their geographical origins.A total of 297 patients with a median of 28 new patients each year were included. Most patients suffered from lung infection or colonisation (72.7%, n = 216), followed by disseminated mycobacteriosis (12.5%, n = 37). The majority were HIV-positive, suffering from malignoma or cystic fibrosis (29.3%, n = 87, 16.2%, n = 48, and 13.8%, n = 41, respectively). 17.2% of patients showed no predisposing condition (n = 51). Mycobacterium avium complex (MAC) species were most frequently isolated (40.7%, n = 121). Infection/colonisation was longest in CF patients (median of 1094 days). The mortality was highest in malignoma patients (52.4%), while CF patients had the lowest overall mortality rate (5.3%). But mortality analysis showed non-significant results within different mycobacterial species and clinical manifestations.NTM remain rare but underestimated pathogens in lung and disseminated disease. MAC were the species most frequently isolated. Depending on species and underlying predispositions, the duration of infection/colonisation can be unexpectedly long.

In this study, the distribution of nontuberculous mycobacteria (NTM) strains in patients with and without HIV/AIDS in Chongqing, China was evaluated.A retrospective study was performed in January-December 2020 at Chongqing Public Health Medical Center. NTM strains were assessed by a multi locus phylogenetic analysis. The distribution of NTM strains in HIV/AIDS and non-HIV/AIDS groups was compared. CD4+ cell counts, imaging changes, and characteristics of mycobacterial species were determined.In total, 324 patients with NTM infection (50 patients with HIV/AIDS and 274 patients without HIV/AIDS) were included. The most common etiological agent was M. abscessus (29%), followed by M. paraintracellulare (12%) and M. colombiense (11%). Predominant NTM species were M. avium (26%), M. colombiense (24%), and M. kansasii (18%) in patients with HIV/AIDS and were M. abscessus (32%), M. paraintracellulare (13%), M. fortuitum (10%), and M. intracellulare (10%) in patients without HIV/AIDS. For a CD4+ cell count of <200/μl, the predominant species were M. aviumin the HIV/AIDS group and M. abscessus in the non-HIV/AIDS group. With respect to radiologic characteristics, different NTM strains were associated with distinct imaging manifestations; for example, M. marseillense, M. kansasii, and M. parasenchytosis were more likely to induce cavities. Imaging cavities, bronchiectasis, and acinar-like changes were more common in the non-HIV/AIDS groups.The infection rates of HIV and NTM in Chongqing are high, while M. abscessus, M. paraintracellulare, and M. colombiense are the main pathogens causing NTM diseases in Chongqing, and NTM strains differed significantly between patients with and without HIV/AIDS. Monitoring these indicators can help develop prevention strategies.© 2022 British HIV Association.

China has a high burden of nontuberculous mycobacterial (NTM) infections. Immunocompromised populations, such as those with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), are at a higher risk of being infected with NTM than immunocompetent individuals. Yet, there is a paucity of information on the clinical features of positive NTM isolates from patients with HIV/AIDS in China. To address this gap, we conducted a systematic review and meta-analysis of existing studies, comparing them against current expert consensus to provide guidance for clinical practice.Two researchers independently searched eight databases (SinoMed, China National Knowledge Infrastructure, Wanfang, VIP, Cochrane Library, PubMed, Embase, and Web of Science) from inception to 26 December 2022 to retrieve published Chinese- and English-language studies reporting clinical features of NTM-positive isolates among patients with HIV/AIDS in China.We included 28 studies with 1861 patients. The rate of positive NTM isolates detected from men among all patients was 87.3%. NTM species distribution was mainly Mycobacterium avium complex (64.3%), which was predominant in different regions. The five most common clinical symptoms were fever (68.5%), cough or expectoration (67.0%), appetite loss (49.4%), weight loss (45.5%), and superficial lymphadenectasis (41.1%). The prevalence of laboratory tests were as follows: albumin <35 g/L (55.6%), erythrocyte sedimentation rate >20 mm/h (91.4%), anaemia (59.0%), predominantly mild, CD4+ T cell count ≤50 pieces/μL (70.3%), and CD4+ T cell count 51-200 pieces/μL (22.1%). Lesion manifestations in thoracic imaging mainly included bilateral lung involvement (83.8%), showed stripe shadows (60.3%), patchy shadows (42.9%), nodules (40.6%), and bronchiectasis (38.6%). Accompanied signs included thoracic lymph node enlargement (49.5%). Seventy per cent of symptoms improved after treatment.Focusing on clinical symptoms, laboratory tests, and thoracic imaging helps with initial screening for NTM infections. Physicians should raise awareness of the diagnosis and treatment of Mycobacterium avium complex, providing guidance for experimental treatment, screening of priority populations for NTM infections, and prophylactic treatment of NTM disease.PROSPERO CRD42023388185.Copyright © 2023 by the Journal of Global Health. All rights reserved.

This study aimed to identify the clinical characteristics of patients with concurrent rheumatoid arthritis (RA) and suspected non-tuberculous mycobacterial (NTM) infections as well as determine their prognostic factors.We retrospectively reviewed the medical records of 91 patients with RA whose computed tomography (CT) findings suggested NTM infection. Subsequently, we compared the clinical characteristics between patients with and without clinical or radiological exacerbation of NTM-pulmonary disease (PD) and investigated the risk factors for the exacerbation and associated mortality.The mean age of patients with RA and suspected NTM-PD was 65.0 ± 10.2 years. The nodular/bronchiectatic (NB) form of NTM-PD was the predominant radiographic feature (78.0%). During follow-up, 36 patients (41.9%) experienced a radiological or clinical exacerbation of NTM-PD, whereas 12 patients (13.2%) died. Combined interstitial lung disease (ILD), microbiologically confirmed NTM-PD, and NB with the fibrocavitary (FC) form on chest CT were identified as risk factors for the clinical or radiological exacerbation of NTM-PD. Hydroxychloroquine use was identified as a good prognostic factor. Conversely, history of tuberculosis, ILD, smoking, microbiologically confirmed NTM-PD, and NB with the FC form on chest CT were identified as poor prognostic factors for mortality in suspected NTM-PD.ILD and NB with the FC form on chest CT were associated with NTM-PD exacerbation and mortality. Hydroxychloroquine use may lower the risk of NTM-PD exacerbation. Therefore, radiographic features and presence of ILD should be considered when predicting the prognosis of patients with RA and suspected NTM-PD.

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare condition characterized by clinical disease caused by weakly virulent mycobacteria. All genes mutated in MSMD patients are involved in IFN-γ immunity. Autosomal partial dominant (PD) interferon-γ receptor 1 (IFN-γR1) deficiency is the most frequent abnormality affecting the group of MSMD patients leading to impaired response of IFN-γ. We describe here a patient from India with disseminated infection due to Mycobacterium avium intracellulare (MAC) including multifocal osteomyelitis and BCG disease. A heterozygous mutation in exon 6 of IFNGR1 gene was identified, conferring an autosomal PD IFN-γR1 deficiency. Patient had recurrence of mycobacterial disease during antibiotic therapy for which subcutaneous IFN-γ was added as a modality of treatment for resistant MAC infection.

Macrolides are a key drug class used for the treatment of Mycobacterium abscessus complex disease.To verify the relationship between phenotypic susceptibility and genotypic resistance to clarithromycin (CLM).Subspecies of M. abscessus complex from 145 consecutive patients were identified using hsp65 and rpoB gene sequencing, and tested for CLM susceptibility, classification into the erm(41) sequevars responsible for inducible resistance and the presence of rrl mutations associated with acquired resistance.The isolates comprised 74 M. abscessus subsp. abscessus, 69 M. abscessus subsp. massiliense and two M. abscessus subsp. bolletii. M. abscessus subsp. abscessus isolates comprised 15 sequevars, with the majority corresponding to sequevar 1 (n = 24), sequevar 6 (n = 13) and sequevar 2 (n = 8). Interestingly, seven M. abscessus subsp. abscessus isolates (9.5%) presented genetically functional, but not phenotypic, inducible resistance. Moreover, rrl was mutated in only 14.3% (1/7) of acquired resistance isolates. However, M. abscessus subsp. massiliense and M. abscessus subsp. bolletii isolates with acquired resistance at day 3 showed mutations at positions 2057-2059 (P < 0.05).Our study indicates that genotypic inducible and acquired resistance in M. abscessus subsp. abscessus does not always coincide with phenotypic susceptibility. Rigorous phenotypic evaluation is thus important because of the considerable impact on patients.

Non-tuberculous mycobacteria (NTM) are emerging pathogens causing difficult-to-treat infections. We tested a new assay (GenoType NTM-DR) that detects natural and acquired resistance mechanisms to macrolides and aminoglycosides in frequently isolated NTM species.Performance was assessed on 102 isolates including reference strains [16 Mycobacterium avium, 10 Mycobacterium intracellulare, 8 Mycobacterium chimaera, 15 Mycobacterium chelonae and 53 Mycobacterium abscessus (including subsp. abscessus isolates, 18 with a t28 in erm(41) and 10 with a c28, 13 subsp. bolletii isolates and 12 subsp. massiliense isolates)]. Genotypes were determined by PCR sequencing of erm(41) and rrl for clarithromycin resistance and of the 1400-1480 rrs region for aminoglycoside resistance. Phenotypes were determined by MIC microdilution.GenoType NTM-DR yielded results concordant with Sanger sequencing for 100/102 (98%) isolates. The erm(41) genotypic pattern was accurately identified for M. abscessus isolates. Mutations in rrl were detected in 15 isolates (7 M. avium complex, 5 M. abscessus and 3 M. chelonae ) with acquired clarithromycin resistance harbouring rrl mutations (a2057c, a2058g, a2058t or a2059c). Mutations in rrs were detected in five isolates with amikacin resistance harbouring the rrs mutation a1408g. In two isolates, the NTM-DR test revealed an rrl mutation (initial sequencing being WT), which was confirmed by re-sequencing. The test results were concordant with phenotypic susceptibility testing in 96/102 (94.1%) isolates, with four clarithromycin-resistant and two amikacin-resistant isolates not harbouring mutations.The GenoType NTM-DR test is efficient in detecting mutations predictive of antimicrobial resistance in M. avium complex, M. abscessus and M. chelonae.© 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.

Amikacin is a major drug used for the treatment of Mycobacterium avium complex (MAC) disease, but standard laboratory guidelines for susceptibility testing are not available. This study presents in vitro amikacin MICs for 462 consecutive clinical isolates of the MAC using a broth microdilution assay. Approximately 50% of isolates had amikacin MICs of 8 μg/ml, and 86% had MICs of ≤16 μg/ml. Of the eight isolates (1.7%) with MICs of 64 μg/ml, five had an MIC of 32 μg/ml on repeat testing. Ten isolates (2.1%) had an initial amikacin MIC of >64 μg/ml, of which seven (1.5%) had MICs of >64 μg/ml on repeat testing. These seven isolates had a 16S rRNA gene A1408G mutation and included M. avium, Mycobacterium intracellulare, and Mycobacterium chimaera. Clinical data were available for five of these seven isolates, all of which had received prolonged (>6 months) prior therapy, with four that were known to be treated with amikacin. The 16S mutation was not detected in isolates with MICs of ≤64 μg/ml. We recommend primary testing of amikacin against isolates of the MAC and propose MIC guidelines for breakpoints that are identical to the CLSI guidelines for Mycobacterium abscessus: ≤16 μg/ml for susceptible, 32 μg/ml for intermediate, and ≥64 μg/ml for resistant. If considered and approved by the CLSI, this will be only the second drug recommended for primary susceptibility testing against the MAC and should facilitate its use for both intravenous and inhaled drug therapies.