UNASSIGNED: Mycobacterium kansasii (M. kansasii) is a non-tuberculosis bacterium with a highly prevalent that is transferred by aerosols from water and soil resources to the respiratory system. M. kansasii is one of the main species responsible for NTM pulmonary disease.
UNASSIGNED: Web of Science, Scopus, and PubMed databases were systematically explored. Relevant articles from 1971 to November 2023 were reviewed. \"The inclusion criteria\" included patients with M. kansasii infection, treatment follow-up, and treatment outcomes. \"The exclusion criteria\" were clinical samples from animals, environmental samples, and other laboratory investigations.
UNASSIGNED: 40 studies, including 1201 patients, were obtained through database search. Using the therapeutic regimens used in different studies, the therapy course for patients with M. kansasii infection ranged from 1 week to 118 months. In this study, the antibiotics prescribed in different treatment regimens for M. kansasii pulmonary infection were as follows: Rifampin, Ethambutol, Isoniazid, Clarithromycin, Streptomycin, and Pyrazinamide. Antibiotic combinations of three or four medicines, including rifampin, ethambutol, and isoniazid with or without streptomycin or pyrazinamide had the most therapeutic effect.
UNASSIGNED: The initial treatment involves rifampin, ethambutol, isoniazid, and pyridoxine, per the guidelines from the American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA). Understanding the treatment plan and its outcomes is crucial for managing and determining the most effective therapy approach.

Little is known about environmental transmission of Mycobacterium kansasii. We retrospectively investigated potential environmental acquisition, primarily water sources, of M. kansasii among 216 patients with pulmonary disease from an industrial city in Taiwan during 2015-2017. We analyzed sputum mycobacterial cultures using whole-genome sequencing and used hierarchical Bayesian spatial network methods to evaluate risk factors for genetic relatedness of M. kansasii strains. The mean age of participants was 67 years; 24.1% had previously had tuberculosis. We found that persons from districts served by 2 water purification plants were at higher risk of being infected with genetically related M. kansasii isolates. The adjusted odds ratios were 1.81 (1.25-2.60) for the Weng Park plant and 1.39 (1.12-1.71) for the Fongshan plant. Those findings unveiled the association between water purification plants and M. kansasii pulmonary disease, highlighting the need for further environmental investigations to evaluate the risk for M. kansasii transmission.

Species belonging to the Mycobacterium kansasii complex (MKC) are frequently isolated from humans and the environment and can cause serious diseases. The most common MKC infections are caused by the species M. kansasii (sensu stricto), leading to tuberculosis-like disease. However, a broad spectrum of virulence, antimicrobial resistance and pathogenicity of these non-tuberculous mycobacteria (NTM) are observed across the MKC. Many genomic aspects of the MKC that relate to these broad phenotypes are not well elucidated. Here, we performed genomic analyses from a collection of 665 MKC strains, isolated from environmental, animal and human sources. We inferred the MKC pangenome, mobilome, resistome, virulome and defence systems and show that the MKC species harbours unique and shared genomic signatures. High frequency of presence of prophages and different types of defence systems were observed. We found that the M. kansasii species splits into four lineages, of which three are lowly represented and mainly in Brazil, while one lineage is dominant and globally spread. Moreover, we show that four sub-lineages of this most distributed M. kansasii lineage emerged during the twentieth century. Further analysis of the M. kansasii genomes revealed almost 300 regions of difference contributing to genomic diversity, as well as fixed mutations that may explain the M. kansasii\'s increased virulence and drug resistance.

Mycobacterium kansasii is a bacterium included in non-tuberculous mycobacteria (NTM) that can cause lung disease. It shares a significant number of antigens with Mycobacterium tuberculosis (Mtb), suggesting that it has the potential to be used as a tuberculosis (TB) vaccine. Therefore, we subcutaneously vaccinated mice with reference strain, M. kansasii-ATCC12478 [M. kansasii-American Type Culture Collection (ATCC)], and clinically isolated strain, M. kansasii-SM-1 to evaluate potential as a TB vaccine by comparing with bacille Calmette-Guerin (BCG) vaccine. Ten weeks after vaccination, we evaluated immunogenicity of M. kansasii-ATCC and M. kansasii-SM-1, and M. kansasii-SM-1 immunization induces potent Mtb antigen-specific IFN-γ-producing CD4+ T cells than M. kansasii-ATCC. Upon Mtb infection, M. kansasii-SM-1 provided better protection than M. kansasii-ATCC, which was comparable to the efficacy of BCG. These results showed that the clinical strain M. kansasii-SM-1, which exhibits an enhanced Mtb antigen-specific Th1 response, shows greater vaccine efficacy compared to M. kansasii-ATCC. In this study, we demonstrated that vaccine efficacy can vary depending on the strain of M. kansasii and that its efficacy can be comparable to BCG. This suggests that M. kansasii has the potential to be a live TB vaccine candidate.IMPORTANCEMycobacterium kansasii, a non-tuberculous mycobacteria (NTM) species causing lung disease, shares key antigens with Mycobacterium tuberculosis (Mtb), indicating its potential for TB vaccine development. Subcutaneous vaccination of mice with M. kansasii strains reference strain M. kansasii-ATCC12478 [(M. kansasii-American Type Culture Collection (ATCC)] and clinically isolated strain M. kansasii-SM-1 revealed differences in immunogenicity. M. kansasii-SM-1 induced a robust Mtb antigen-specific IFN-γ-producing CD4+ T cell response compared to M. kansasii-ATCC. Additionally, M. kansasii-SM-1 conferred better protection against Mtb infection than M. kansasii-ATCC, which is comparable to bacille Calmette-Guerin (BCG). These findings underscore the variable vaccine efficacy among M. kansasii strains, with M. kansasii-SM-1 exhibiting promising potential as a live TB vaccine candidate, suggesting its comparative effectiveness to BCG.

This report details a rare case of surgical site infection (SSI) caused by Mycobacterium kansasii following allogeneic hematopoietic stem cell transplantation (allo-HSCT) in a 53-year-old patient with IgA-κ type multiple myeloma. After undergoing multiple chemotherapy regimens and two stem cell transplants, the patient developed an SSI 31-month post-transplantation, manifesting as an intracranial abscess at the site of a previous craniotomy. M. kansasii was isolated from the drainage fluid, marking this instance as a unique case in the literature of nontuberculous mycobacteria (NTM) infection post-allo-HSCT with such a delayed onset. The patient\'s treatment included targeted antimicrobial therapy based on susceptibility testing, resulting in eventual resolution of the infection, although the patient later succumbed to multiple myeloma relapse. This case underscores the critical need to consider NTM infections in the differential diagnosis of persistent fevers and SSIs in immunocompromised patients, particularly those with chronic graft-versus-host disease. It highlights the importance of early diagnostic and therapeutic interventions to manage these infections effectively. This report contributes to the limited but growing body of literature on NTM infections post-allo-HSCT and emphasizes the need for vigilance in monitoring postoperative patients, especially those with prolonged immunosuppression.

The association between Hairy Cell Leukemia (HCL) and non-tuberculous mycobacterial infections (NTMs) is well described, most notably Mycobacterium kansasii. The exact pathophysiology is not known. We report a case of a 31-year-old male with concomitantly diagnosed HCL and disseminated M kansasii infection who presented with rash, pancytopenia, and bulky axillary lymphadenopathy. The M kansasii was initially diagnosed through use of cell-free DNA detection and confirmed by bone marrow and lymph node cultures. Hairy Cell Leukemia was diagnosed with peripheral flow cytometry and confirmed via the same bone marrow sample. His HCL was put into remission with a single course of cladribine and rituximab chemotherapy; however, his M kansasii infection persisted for 6 months despite aggressive antimicrobial and surgical therapy. It was finally controlled using high-dose rifampin in combination with azithromycin and ethambutol. This case highlights the known link between HCL and M kansasii. Furthermore, it hints at potential causes beyond chemotherapy-induced immunocompromise. Notable possibilities include HCL cells acting as sanctuary sites for M kansasii to evade the immune system, and subclinical M kansasii infections causing NLRP3 inflammasome overactivation to trigger the oncogenic transformation to HCL. More research into the pathophysiologic link between HCL and M kansasii infections would allow for more effective prevention, diagnosis, and treatment of these severe atypical infections which are the major cause of morbidity in the cladribine era of HCL treatment.

BACKGROUND: Drug susceptibility testing (DST) protocol of omadacycline against non-tuberculous mycobacteria has not yet been established. We developed a method to accurately determine MIC omadacycline MIC against Mycobacterium abscessus (Mab), Mycobacterium avium-complex (MAC), and Mycobacterium kansasii (Mkn).
METHODS: First, we identified the oxyrase concentration not affecting Mab, MAC, and Mkn growth followed by omadacycline MIC experiments with and without oxyrase using reference and clinical strains.
RESULTS: Oxyrase 0.5 % (v/v) stabilized omadacycline in the culture medium. The median omadacycline MIC was 1 mg/L for Mab and 8 mg/L for Mkn. For MAC, the median omadacycline MIC was 2 mg/L for M. avium, 256 mg/L for M. intracellulare, and 4 mg/L for M. chimaera (p < 0.0001). Wilcoxon matched-pairs signed rank test revealed statistically lower MICs with oxyrase for all MAC subspecies (p < 0.0001), all Mab subspecies (p < 0.0001), and Mkn (p = 0.0002). The decrease in MICs with oxyrase was 17/18 of Mab, 14/19 of Mkn, 8/8 of M. avium, 4/5 M. chimera, but only 11/18 of M. intracellulare (p < 0.013).
CONCLUSIONS: Use of 0.5 % oxyrase could be a potential solution to reliable and reproducible omadacycline MIC of Mab. However, oxyrase demonstrated a variable effect in reducing MICs against MAC and Mkn.

OBJECTIVE: To investigate the spatial heterogeneity of nontuberculous mycobacterial pulmonary disease (NTM-PD) in Shanghai.
METHODS: A population-based retrospective study was conducted using presumptive pulmonary tuberculosis surveillance data of Shanghai between 2010 and 2019. The study described the spatial distribution of NTM-PD notification rates, employing hierarchical Bayesian mapping for high-risk areas and the Getis-Ord Gi* statistic to identify hot spots and explore associated factors.
RESULTS: Of 1652 NTM-PD cases, the most common species was Mycobacterium kansasii complex (MKC) (41.9%), followed by Mycobacterium avium complex (MAC) (27.1%) and Mycobacterium abscessus complex (MABC) (16.2%). MKC-PD patients were generally younger males with a higher incidence of pulmonary cavities, while MAC-PD patients were more often farmers or had a history of tuberculosis treatment. MKC-PD hot spots were primarily located in the areas alongside the Huangpu River, while MAC-PD hot spots were mainly in the western agricultural areas. Patients with MKC-PD and MAC-PD exhibited a higher risk of spatial clustering compared to those with MABC-PD.
CONCLUSIONS: Different types of NTM-PD exhibit distinct patterns of spatial clustering and are associated with various factors. These findings underscore the importance of environmental and host factors in the epidemic of NTM-PD.

UNASSIGNED: Mycobacterium kansasii infection is one of the most common causes of non-tuberculosis mycobacterial (NTM) disease worldwide. However, accurate information on the global prevalence of this bacterium is lacking. Therefore, this study was conducted to investigate the prevalence of M. kansasii in clinical and environmental isolates.
UNASSIGNED: Databases, including PubMed, Scopus, and the Web of Science, were utilized to gather articles on the prevalence of M. kansasii in clinical and environmental isolates. The collected data were analyzed using Comprehensive Meta-Analysis software.
UNASSIGNED: A total of 118 and 16 studies met the inclusion criteria and were used to analyze the prevalence of M. kansasii in clinical and environmental isolates, respectively. The prevalence of M. kansasii in NTM and environmental isolates were 9.4 and 5.8%, respectively. Subsequent analysis showed an increasing prevalence of M. kansasii over the years. Additionally, the results indicated a significant difference in the prevalence of this bacteria among different regions.
UNASSIGNED: The relatively high prevalence of M. kansasii among NTM isolates suggests the need for further implementation of infection control strategies. It is also important to establish appropriate diagnostic criteria and management guidelines for screening this microorganism in environmental samples in order to prevent its spread, given its high prevalence in environmental isolates.

Nontuberculous mycobacterial pulmonary disease caused by the less common nontuberculous mycobacteria have distinct features depending on the species. Diagnostic evaluation follows the established criteria for all nontuberculous mycobacteria, but with certain qualifications given species-specific and regional differences in pathogenicity. Clinicians should first institute nonpharmacologic management and evaluate clinical, radiologic, and microbiologic factors in the decision regarding antimycobacterial therapy. Treatment is challenging, and evidence-based recommendations are limited for most species. Drug susceptibility testing is used to help with regimen selection; however, this approach is imperfect given the uncertain correlation between in vitro activity and clinical response for most drugs.