Search

Context.—: Recent publications have featured immunohistochemistry (IHC) as a sensitive tool for detecting Mycobacterium tuberculosis and nontuberculous mycobacteria, but performance is limited to cases suspected to have mycobacterial infection., Objective.—: To examine cross-reactivity of a polyclonal antimycobacterial antibody with various types of pathogens, tissues, and inflammatory patterns., Design.—: Surgical pathology files during a period of 6 years were searched, and 40 cases representing a variety of pathogens, tissue types, and inflammatory responses were retrieved. Cases were stained with a rabbit polyclonal antimycobacterial antibody (Biocare Medical, Pacheco, California). The cases and associated histochemical stains, culture, and molecular results were reviewed by 3 pathologists., Results.—: All 8 cases of mycobacterial infection previously diagnosed by other methods were positive for mycobacteria by IHC. In addition, multiple bacterial and fungal organisms and 1 case of Leishmania amastigotes were also immunoreactive with the mycobacterial IHC., Conclusions.—: Although highly sensitive for mycobacteria, the polyclonal antibody shows significant cross-reactivity with other organisms. This is a sensitive but nonspecific stain that can be used as an alternative confirmation method for mycobacteria, but attention should be paid to inflammatory reaction and organism morphology when IHC is positive to avoid misdiagnosis., Competing Interests: The authors have no relevant financial interest in the products or companies described in this article., (© 2024 College of American Pathologists.)

Predicting the outbreak of infectious diseases and designing appropriate preventive health actions require interdisciplinary research into the processes that drive exposure to and transmission of disease agents. In the case of mycobacterial diseases, the epidemiological understanding of the scientific community hitherto was based on the clinical studies of infections in vertebrates. To evaluate the information gained by comprehensively accounting for the ecological and evolutionary constraints, we conducted literature searches assessing the role of mycobacteria interactions with non-vertebrate species in the origin of their pathogenicity and variations in disease risk. The reviewed literature challenges the current theory of person-to-person transmission for several mycobacterial infections. Furthermore, the findings suggest that diverse non-vertebrate organisms influence virulence, mediate transmission, and contribute to pathogen abundance in relation to vertebrate exposure. We advocate that an ecological and evolutionary framework provides novel insights to support a more comprehensive understanding of the prevention and management of diseases in vertebrates., Competing Interests: Declaration of interests We declare no competing interests. The content of the article is the sole responsibility of the authors, with no role played by the funding agencies., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Epidemiologic research on zoonotic tuberculosis historically used Mycobacterium bovis as a surrogate measure; however, increased reports of human tuberculosis caused by other animal-associated Mycobacterium tuberculosis complex members like Mycobacterium orygis necessitates their inclusion. We performed a retrospective cohort study including persons infected with any animal-lineage M tuberculosis complex species in Alberta, Canada, from January 1995 to July 2021, identifying 42 patients (20 M bovis, 21 M orygis, 1 M caprae). Demographic, epidemiologic, and clinical characteristics were compared against persons with culture-confirmed M tuberculosis infection. The proportion of culture-positive infections caused by M orygis increased continuously from 2016 to 2020. Significantly more females at a higher median age were impacted by M orygis, with all patients originating from South Asia. Mycobacterium bovis caused significantly more extrapulmonary disease and disproportionately impacted young females, particularly those pregnant or postpartum. All infections were acquired abroad. These findings can aid in developing targeted public health interventions., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed. Funding to pay the Open Access publication charges for this article was provided by the Canadian Research Knowledge Network (CRKN)., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

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 ., Competing Interests: The authors declare no conflict of interest.

The cytokine IFNγ is a principal effector of macrophage activation and immune resistance to mycobacterial infection; however, pathogenic mycobacteria are capable of surviving in IFNγ-activated macrophages by largely unknown mechanisms. In this study, we find that pathogenic mycobacteria, including M. bovis BCG and M. tuberculosis can sense IFNγ to promote their proliferative activity and virulence phenotype. Moreover, interaction with the host intracellular environment increases the susceptibility of mycobacteria to IFNγ through upregulating expression of mmpL10, a mycobacterial IFNγ receptor, thereby facilitating IFNγ-dependent survival and growth of mycobacteria in macrophages. Transmission electron microscopy analysis reveals that IFNγ triggers the secretion of extracellular vesicles, an essential virulence strategy of intracellular mycobacteria, while proteomics identifies numerous pivotal IFNγ-induced effectors required for mycobacterial infection in macrophages. Our study suggests that sensing host IFNγ is a crucial virulence mechanism used by pathogenic mycobacteria to survive and proliferate inside macrophages., (© 2024. The Author(s).)

Radiolabelled puromycin analogues will allow the quantification of protein synthesis through nuclear medicine-based imaging. A particularly useful application could be the non-invasive longitudinal visualisation of mycobacterial activity through direct quantification of puromycin binding. This study assesses the value of [ 68 Ga]Ga-DOTA-puromycin in the visualisation of mycobacteria through positron emission tomography combined with magnetic resonance imaging (µPET/MRI). The radiopharmaceutical was produced by previously published and validated methods. [ 68 Ga]Ga-DOTA-Puromycin imaging was performed on severe immunodeficient mice infected with Bacille Calmette-Guérin-derived M. Bovis (BCG). Acute and chronic infection stages were examined by µPET/MRI. A follow-up group of animals acted as controls (animals bearing S. aureus-derived infection and sterile inflammation) to assess tracer selectivity. [ 68 Ga]Ga-DOTA-puromycin-µPET/MRI images revealed the acute, widespread infection within the right upper shoulder and armpit. Also, [ 68 Ga]Ga-DOTA-puromycin signal sensitivity measured after a 12-week period was lower than that of [ 18 F]FDG-PET in the same animals. A suitable correlation between normalised uptake values (NUV) and gold standard histopathological analysis confirms accurate tracer accumulation in viable bacteria. The radiopharmaceutical showed infection selectivity over inflammation but accumulated in both M. Bovis and S. Aureus, lacking pathogen specificity. Overall, [ 68 Ga]Ga-DOTA-puromycin exhibits potential as a tool for non-invasive protein synthesis visualization, albeit without pathogen selectivity., (© 2024. The Author(s).)

Programmed cell death protein 4 (PDCD4) is instrumental in regulating a range of cellular processes such as translation, apoptosis, signal transduction, and inflammatory responses. There is a notable inverse correlation between PDCD4 and the mammalian target of rapamycin (mTOR) pathway, which is integral to cellular growth control. Activation of mTOR is associated with the degradation of PDCD4. Although the role of PDCD4 is well established in oncogenesis and immune response regulation, its function in mycobacterial infections and its interplay with the mTOR pathway necessitate further elucidation. This study investigates the modulation of PDCD4 expression in the context of mycobacterial infections, revealing a consistent pattern of downregulation across diverse mycobacterial species. This observation underscores the potential utility of PDCD4 as a biomarker for assessing mTOR pathway activation during such infections. Building on this finding, we employed a novel approach using PDCD4-based mTOR (Tor)-signal-indicator (TOSI) reporter cells for the high-throughput screening of FDA-approved drugs, focusing on mTOR inhibitors. This methodology facilitated the identification of several agents, inclusive of known mTOR inhibitors, which upregulated PDCD4 expression and concurrently exhibited efficacy in impeding mycobacterial proliferation within macrophages. These results not only reinforce the significance of PDCD4 as a pivotal marker in the understanding of infectious diseases, particularly mycobacterial infections, but also illuminate its potential in the identification of mTOR inhibitors, thereby contributing to the advancement of therapeutic strategies., Importance: This study emphasizes the critical role of the mammalian target of rapamycin (mTOR) pathway in macrophage responses to mycobacterial infections, elucidating how mycobacteria activate mTOR, resulting in PDCD4 degradation. The utilization of the (Tor)-signal-indicator (TOSI) vector for real-time monitoring of mTOR activity represents a significant advancement in understanding mTOR regulation during mycobacterial infection. These findings deepen our comprehension of mycobacteria's innate immune mechanisms and introduce PDCD4 as a novel marker for mTOR activity in infectious diseases. Importantly, this research laid the groundwork for high-throughput screening of mTOR inhibitors using FDA-approved drugs, offering the potential for repurposing treatments against mycobacterial infections. The identification of drugs that inhibit mTOR activation opens new avenues for host-directed therapies, marking a significant step forward in combating tuberculosis and other mycobacterial diseases., Competing Interests: The authors declare no conflict of interest.

Introduction: Dermatologic manifestations of diseases in solid organ transplant recipients are common due to long-term immunosuppression., Case Presentation: We present the case of a 63-year-old man with a kidney transplant who exhibited subcutaneous nodules on lower extremities, cytopenia, and asymptomatic pulmonary infiltrate. Through a skin biopsy and 16S ribosomal RNA (rRNA) sequencing, Mycobacterium haemophilum was identified. His clinical course was complicated by empyema, septic arthritis, and recurrence of his skin manifestations, despite ongoing antimicrobial treatment., Discussion: This case emphasizes the challenges and potential complications associated with M haemophilum infections in solid organ transplant recipients receiving long-term immunosuppressive therapy. It highlights the importance of employing advanced diagnostic techniques when evaluating dermatologic manifestations in these patients. The patient's complex clinical course also underscores the difficulties involved in effectively addressing and managing complications that may arise even after initiating therapy., (Copyright© Board of Regents of the University of Wisconsin System and The Medical College of Wisconsin, Inc.)

A 23-y-old gelding was presented to a veterinary teaching hospital with a history of chronic, refractory diarrhea. Clinically, the horse was in poor body condition, with a thickened and corrugated large intestine identified by transcutaneous abdominal ultrasonography. At postmortem examination following euthanasia, the large colon and cecum had segmental thickening of the intestinal wall with innumerable mucosal ulcers and prominent polypoid mucosal masses. Many mesenteric and hepatic lymph nodes were enlarged. Histology revealed granulomatous and ulcerative typhlocolitis and granulomatous lymphadenitis with myriad acid-fast, variably gram-positive, intrahistiocytic bacilli that stained by immunohistochemistry for mycobacteria. Molecular testing by PCR and sequencing identified the causative agent as Mycobacterium genavense , which is an unusual presentation of infection in a horse., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Here, we reported the diagnosis and treatment of a case of HIV infected person complicated by an extremely rare infection with Mycobacterium celatum . Due to the similarity of homologous sequence regions between Mycobacterium celatum and Mycobacterium tuberculosis complex, the identification of conventional Mycobacterium species was incorrect, which was corrected after first-generation 16S rRNA sequencing. This report aimed to improve the clinical understanding of Mycobacterium celatum infection and the level of differential diagnosis between non-tuberculous mycobacterial disease and tuberculosis.

Although the importance of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) sensors in controlling viral infection is well established, their role in promoting an effective immune response to pathogens other than viruses is less clear. This is particularly true for infections with mycobacteria, as studies point to both protective and detrimental roles for activation of nucleic acid sensors in controlling a mycobacterial infection. Some of the contradiction likely stems from the use of different model systems and different mycobacterial species/strains as well as from which nucleic acid sensors were studied and what downstream effectors were evaluated. In this review, we will describe the different nucleic acid sensors that have been studied in the context of mycobacterial infections, and how the different studies compare. We conclude with a section on how nucleic acid sensor agonists have been used therapeutically and what further information is needed to enhance their potential as therapeutic agents.

Background: Mycobacterium haemophilum has been increasingly found in severely immunocompromised patients but is scarcely reported in immunocompetent adults., Methods: We systematically reviewed previous literature to identify studies on infection in immunocompetent adults. Articles reporting at least one case of M. haemophilum infection were included. We excluded articles involving patients who had immunosuppression-related diseases and routinely used glucocorticoids or immunosuppressants. We also reported a case of a young immunocompetent woman infected by M. haemophilum along the eyebrows, which was probably due to the use of an eyebrow pencil retrieved from a sink drain., Results: Twelve qualifying articles reporting M. haemophilum infection in immunocompetent adults were identified. Among them, most cases report skin lesions along the eyebrows, and the remaining had cervicofacial lymphadenitis, lesions on the arm or fingers, inflammation in the eyeballs, or ulceration in the perineal region. Most cases were caused by tattoos, make-up, injury, or surgical operation. For diagnosis, specialized tissue culture sensitivity was roughly 75%, and polymerase chain reaction (PCR) test sensitivity was approximately 89%. Triple antibiotic therapy for 3 to 24 months, or surgical excision was effective in controlling infection., Conclusion: M. haemophilum infection should be considered if routine antibacterial and glucocorticoid treatments are ineffective against the disease, even in healthy adults. To definitively diagnose this infection, conditioned tissue culture or PCR testing is required. Treatment usually involves a combination of multiple antibiotics and, if necessary, surgical removal of infected tissue., (© 2023 the International Society of Dermatology.)

To investigate mycobacterial cases of farmed yellowtail fish in coastal areas of western Japan (Kagoshima, Kyushu), where aquaculture fisheries are active, Mycobacterium pseudoshottsii, the causative agent, was isolated from six neighboring fishing ports in 2012 and 2013. A phylogenetic ana-lysis revealed that the strains isolated from one fishing port were closely related to those isolated from other regions of Japan, suggesting the nationwide spread of a single strain. However, strains from Japan were phylogenetically distinct from those from the Mediterranean and the United States; therefore, worldwide transmission was not observed based on the limited data obtained on the strains exami-ned in this study. The present results demonstrate that a bacterial genomic ana-lysis of infected cases, a mole-cular epidemiology strategy for public health, provides useful data for estimating the prevalence and transmission pathways of M. pseudoshottsii in farmed fish. A bacterial genome ana-lysis of strains, such as that performed herein, may play an important role in monitoring the prevalence of this pathogen in fish farms and possible epidemics in the future as a result of international traffic, logistics, and trade in fisheries.

Degus ( Octodon degus ) that were kept at a breeding facility presented with neurological or respiratory symptoms and died. Necropsies were performed on 9 individuals, and no significant gross lesions were found. Histologically, spinal cord necrosis was observed in all 9 cases and granulomatous myelitis in 5 of the 9 cases. Locally extensive necrosis of the brain and encephalitis were observed in 7 of the 9 cases. Acid-fast bacteria were found in the spinal cords, brains, and lungs from all 9 cases. Immunohistochemically, Mycobacterium tuberculosis antigen was observed in the spinal cords, brains, and lungs from all 9 cases. Double-labeling immunofluorescence revealed M. tuberculosis antigen in IBA1- and myeloperoxidase-immunopositive cells. Extracted genomic DNA from 8 of the 9 cases was successfully amplified with the primers for Mycobacterium genavense ITS1 and hypothetical 21 kDa protein genes, and the polymerase chain reaction products were identified as M. genavense by DNA sequencing. This report highlights the susceptibility of degus to M. genavense infection in the central nervous system., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Rationale: Injection-related abscesses are a common complication in clinical practice, but the identification of infected bacteria might be difficult., Patient Concerns: A 51-year-old female patient was admitted to the hospital due to a lump on her right buttock that emerged after receiving intramuscular injections to treat left shoulder joint pain. The lump gradually enlarged into a 3.0 to 4.5 cm mass at the time of admission with symptoms such as skin redness, itching, and pain., Diagnoses: The patient received ultrasonic and other laboratory examinations. Laboratory results from the drainage indicated that the infection was caused by a rapidly growing mycobacteria and was confirmed as Mycobacterium fortuitum by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry., Interventions: The patient was treated with antibiotics for 12 days after incision and drainage of the abscess in the right buttock. Local dressings were changed regularly. A migration lesion that appeared 3 days after treatment was drained and cleaned when it matured., Outcomes: The lesion substantially decreased in size and the patient was discharged after 2 months of treatment., Lessons: Rapidly growing mycobacteria are rare but important pathogens that should be considered in patients with injection-related abscesses. Early identification and appropriate treatment can result in a favorable prognosis., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Mycobacterium chimaera causes pulmonary disease, but little is known of gradations in isolate virulence. Previously, 17 M. chimaera isolates were screened for survival in THP1 macrophages. "M. chimaera 1" was categorized as "more virulent" because it showed the greatest survival in macrophages, whereas "M. chimaera 2" was categorized as "less virulent" with reduced survival. Herein, we infected C3HeB/FeJ mice to compare the in vivo immune responses to M. chimaera 1 and 2. Unlike macrophages, significantly lower M. chimaera 1 counts were recovered from mouse lung tissue and BAL cells with less lung histopathologic changes compared to M. chimaera 2. Compared to M. chimaera 2, significantly more IL-1β, IL-6, and TNFα was produced early after M. chimaera 1 infection. LC-MS metabolomics analyses of BAL fluid revealed divergence in sphingolipid, phospholipid metabolism between M. chimaera 1 versus M. chimaera 2 mice. From pan-GWAS analyses, virulence and organizing DNA/molecular structure genes were associated with more virulent M. chimaera isolates. Vigorous lung-specific immune responses to M. chimaera 1 may influence effective bacterial control, but for a different isolate M. chimaera 2, subvert immune control. Continued studies of the gradations in virulence among the same NTM species will advance our understanding of NTM pathogenesis., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

The BACT/ALERT® MP Reagent System is a broth culture medium for optimal detection and recovery of mycobacteria from clinical samples. The MP formulation was recently modified to improve detection and recovery times. A multicenter prospective matched pair study design was conducted to validate the performance of improved MP (MP-I) versus current MP (MP-C) bottles utilizing nonsterile and normally sterile samples, except blood, from patients suspected of having mycobacterial infections. A total of 1488 clinical samples were collected to obtain 212 mycobacteria samples by either or both MP culture bottles. MP-I and MP-C sensitivities were 86.6% and 81.4%, respectively, but the difference was not significant (P = 0.163) while specificities were 96.8% and 93.8%, respectively, and that difference was significant (P = 0.002). Overall recovery was 94.34% for MP-I and 88.68% for MP-C (recovery was 100% for both bottles with 52 seeded samples). Overall performance of MP-I was better than MP-C for sensitivity, specificity, and recovery., Competing Interests: Declaration of Competing Interest HPD, KM, JK, CDG, and DHP are employees of bioMérieux, Inc. SG was an employee of bioMérieux, Inc and has since relocated to another institution. As this was a Clinical Trial, bioMérieux employees were involved in study design and data analysis. Study sites were responsible for testing and data collection. This study was funded by bioMérieux, Inc. BACT/ALERT® MP Reagent Systems are FDA 510(k) cleared., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Mycolicibacterium neoaurum is a rapidly growing mycobacterium and an emerging cause of human infections. M. neoaurum infections are uncommon but likely underreported, and our understanding of the disease spectrum and optimum management is incomplete. We summarize demographic and clinical characteristics of a case of catheter-related M. neoaurum bacteremia in a child with leukemia and those of 36 previously reported episodes of M. neoaurum infection. Most infections occurred in young to middle-aged adults with serious underlying medical conditions and commonly involved medical devices. Overall, infections were not associated with severe illness or death. In contrast to other mycobacteria species, M. neoaurum was generally susceptible to multiple antimicrobial drugs and responded promptly to treatment, and infections were associated with good outcomes after relatively short therapy duration and device removal. Delays in identification and susceptibility testing were common. We recommend using combination antimicrobial drug therapy and removal of infected devices to eradicate infection.

A 6-year-old male intact pet rabbit was evaluated for chronic weight loss. A large mass was detected by palpation in the mid-abdomen and ultrasound examination suggested a jejunal location. Explorative laparotomy revealed a nodular mass within the jejunal wall. Histological examination of a biopsy revealed mycobacterial granulomatous enteritis with an atypical lymphoblastic proliferation suggestive of lymphoma. Neoplastic lymphocytes were immunopositive for Pax-5 but negative for CD3, which is diagnostic of a B-cell neoplasm. Numerous acid-fast bacteria were seen within histiocytes and identified by polymerase chain reaction as Mycobacterium genavense, which is a non-tuberculous and opportunistic mycobacterium with zoonotic potential. To the best of our knowledge, this is the first documented case of a concurrent B-cell lymphoma and M. genavense infection in a rabbit. Concomitant mycobacteriosis and lymphoma have been rarely described in animals and the coexistence of neoplasia and mycobacterial infection within the jejunum suggests a potential pathogenetic association. Interestingly, the rabbit owner worked in an anti-tuberculosis clinic, and an anthropic origin of the mycobacterial infection could not be excluded., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Introduction: The clinical practicability of DNA microarray chip in detecting the presence of mycobacterial species/isolates directly in the skin tissues has not been evaluated, nor the efficacy of DNA microarray chip as a novel diagnostic tool for the early diagnosis of cutaneous mycobacterial infections is known., Methods: The present study analyzed the incidence of cutaneous mycobacterial infections in Shanghai and explored the efficacy of a novel DNA microarray chip assay for the clinical diagnosis of the disease from skin tissue specimens compared to traditional detection methods. A total of 60 participants fulfilling the defined diagnostic criteria and confirmed positive for cutaneous mycobacterial infections from 2019 to 2021 were enrolled in the study. Subsequent to recording the participants' medical history and clinical characteristics, the skin tissue specimens were collected for analyses. The specimens underwent histopathological analyses, skin tissue culture, and DNA microarray chip assay., Results: Increased incidence of cutaneous mycobacterial infection was detected from 2019 to 2021. The most common infecting pathogen was M. marinum followed by M. abscessus . The sensitivity, specificity and accuracy of the skin tissue culture method were 70%, 100% and 76.62%, respectively, while that of the DNA microarray chip assay were 91.67%, 100% and 93.51%, respectively. The sensitivity and accuracy of the DNA microarray chip assay were significantly higher than those of the skin tissue culture method. The positive likelihood and diagnostic odds ratio were >10 and >1, respectively for both the methods. The negative likelihood ratio was significantly higher (30% vs 8.33%) and the Youden's index was significantly lower (70.00% vs 91.67%) in the skin culture method compared to that of the DNA microarray chip assay. There was a significant association of false negative results with a history of antibiotic use in the skin tissue culture method., Discussion: Given the increasing incidence of cutaneous mycobacterial infections, early diagnosis remains a prime clinical focus. The DNA microarray chip assay provides a simple, rapid, high-throughput, and reliable method for the diagnosis of cutaneous mycobacterial infections with potential for clinical application., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yu, Wang, Gao, Yang, Liu, Tan and Yang.)

Canine leproid granuloma (CLG) is a chronic form of dermatitis that has been associated with nontuberculous mycobacterial infections in Africa, Oceania, the Americas, and Europe. We report here a case of CLG associated with a member of the Mycobacterium tuberculosis complex (MTBC), which could be of public health concern. An 8-y-old pet dog developed 0.5-1-cm diameter, raised, firm, nonpruritic, alopecic, painless skin nodules on the external aspects of both pinnae. Histologic examination revealed severe pyogranulomatous dermatitis with intracellular Ziehl-Neelsen-positive bacilli that were immunoreactive by immunohistochemistry using a polyclonal primary antibody that recognizes tuberculous and nontuberculous Mycobacterium species. DNA extracted from formalin-fixed, paraffin-embedded skin sections was tested by a Mycobacterium genus-specific nested PCR assay targeting the 16S rRNA gene. BLAST sequence analysis of 214-bp and 178-bp amplicons showed 99.5% identity with members of the MTBC; however, the agent could not be identified at the species level. Although CLG has been associated traditionally with nontuberculous mycobacterial infections, the role of Mycobacterium spp. within the MTBC as a cause of this condition, and the role of dogs with CLG as possible sources of MTBC to other animals and humans, should not be disregarded given its zoonotic potential.

We present a case of Mycobacterium genavense infection in a man in his 60s with a history of sarcoidosis, treated for 24 years with systemic corticosteroids and later methotrexate as monotherapy. He presented with low grade fever, dyspnoea and right-sided thoracic pain and was admitted due to a treatment-refractory infection. After a prolonged period of symptoms and diagnostics, acid-fast bacilli were demonstrated in pleural fluid and PCR revealed M. genavense The patient was treated with intravenous amikacin, peroral azithromycin, rifampicin and ethambutol for a total of 18 months, with a good clinical and radiological treatment response. Infection with M. genavense is rare in HIV-negative immunocompromised hosts. Diagnosing and treating mycobacterial infections, especially for more rare species, remains a challenge as clinical evidence is sparse. Nonetheless, the disease-causing infection must be considered in symptomatic and immunocompromised patients., Competing Interests: Competing interests: VND and AF participate on the advisory board for Nordicinfu Care Denmark who distributes ARIKAYCE (amikacin liposome inhalation suspension) for Insmed. All other authors had no conflict of interests to declare., (© BMJ Publishing Group Limited 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Mycobacterium abscessus is the most pathogenic species among the predominantly saprophytic fast-growing mycobacteria. This opportunistic human pathogen causes severe infections that are difficult to eradicate. Its ability to survive within the host was described mainly with the rough (R) form of M. abscessus, which is lethal in several animal models. This R form is not present at the very beginning of the disease but appears during the progression and the exacerbation of the mycobacterial infection, by transition from a smooth (S) form. However, we do not know how the S form of M. abscessus colonizes and infects the host to then multiply and cause the disease. In this work, we were able to show the hypersensitivity of fruit flies, Drosophila melanogaster, to intrathoracic infections by the S and R forms of M. abscessus. This allowed us to unravel how the S form resists the innate immune response developed by the fly, both the antimicrobial peptides- and cellular-dependent immune responses. We demonstrate that intracellular M. abscessus was not killed within the infected phagocytic cells, by resisting lysis and caspase-dependent apoptotic cell death of Drosophila infected phagocytes. In mice, in a similar manner, intra-macrophage M. abscessus was not killed when M. abscessus-infected macrophages were lysed by autologous natural killer cells. These results demonstrate the propensity of the S form of M. abscessus to resist the host's innate responses to colonize and multiply within the host., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Touré et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

A 32-year-old male salmon-crested cockatoo ( Cacatua moluccensis ) was diagnosed by cytology with bilateral cubital lymphoma and mycobacteriosis. Polymerase chain reaction assay testing confirmed Mycobacterium genavense . This patient was subsequently humanely euthanized. Postmortem histopathology confirmed both diagnoses with findings of multicentric lymphoma, acid-fast bacilli, and severe degenerative changes in all synovial joints examined. Immunohistochemical staining for paired box protein 5 of the cubital mass was positive for a high percentage of B-cell lymphocytes, consistent with B-cell lymphoma. This unusual case of two major diseases presenting concurrently in one patient raises the question of whether the pathogenesis could have an interdependent relationship. Mycobacteriosis, severe degenerative joint changes, or both may have stimulated lymphocytes, eventually leading to lymphoma. Additional screening and monitoring for comorbidities may be advised if 1 of these diseases are diagnosed in companion avian species.

Background: Mycobacterium chimaera colonizes water-based heater-cooler units (HCUs), from which it can spread to patients during surgery. Vermamoeba vermiformis is a free-living waterborne amoeba, which was consistently present within HCUs., Aim: To determine whether these amoebae can be involved in the persistent presence of M. chimaera., Methods: An in-vitro disinfection model., Findings: Increased survival of M. chimaera was observed after chlorine exposure in the presence of V. vermiformis. Confocal microscopy demonstrated the intracellular presence of M. chimaera in V. vermiformis., Conclusion: In this way, V. vermiformis can contribute to the persistent presence of M. chimaera in HCUs. Cleaning and disinfection protocols should take this phenomenon into account., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

71.759 surgical procedures were performed in 2019 with the aid of cardiopulmonary bypass in Germany. To adjust the patient's body temperature on extracorporeal circulation, the application of a heater-cooler unit (HCU) is mandatory. However, in case of insufficient sanitisation of HCU, life-threatening infections can be transmitted by the device to the patients, including Legionella bacteria, Mycobacterium chimaera, Pseudomonas aeruginosa. To avoid disease transmission, as a requirement for safe medical practice established by regulatory authorities, HCUs must be regularly disinfected by hazardous chemicals posing a danger for both handling humans and the environment. Therefore, to comply with regulations, HCU manufacturers have introduced both timely and financially extensive sanitisation procedures. Our paper describes a novel, effective and easy to handle disinfection method for the above problematics without utilising hazardous chemicals. The method's technical principle is electrolysis, resulting in drinking water quality regarding the analysed germs in the worldwide most commonly utilised heater-cooler device. The main aim of the study was to prove the efficacy and reliability of the device cleansing process. Furthermore, the economic impact of the novel method was evaluated. Therefore, we have undertaken 60 microbiological sampling series between December 2019 and November 2020 from a conventional HCU (3T LivaNova, Germany). During the total investigational period, no contamination with Pseudomonas aeruginosa or Legionellae could have been demonstrated in the HCU. The extreme slow-growing nontuberculous M. chimaera was detected only in one sample obtained from diamond electrode cleansed HCU water, and source of contamination was promptly eliminated by a simple technical modification of the device test-site. Additionally, the diamond electrode application is beneficial for eliminating potentially hazardous cleansing material from the process, which may affect otherwise both patients operated on cardiopulmonary bypass and the perfusionists.

Mycobacterium chimaera is ubiquitously spread in the environment, including factory and hospital water systems. Invasive cases of M. chimaera infection have been associated with aerosols produced by the use of heater-cooler units (HCU) during cardiac surgery. The aim of this study was to evaluate for the first time the performance of IR-Biotyper system on a large number of M. chimaera isolates collected from longitudinal environmental HCUs samples and water sources from hospitals located in three Italian provinces. In addition, IR-Biotyper results were compared with whole-genome sequencing (WGS) analysis, the reference method for molecular epidemiology, to investigate the origin of M. chimaera contamination of HCUs. From November 2018 to May 2021, 417 water samples from 52 HCUs (Stockert 3T, n  = 41 and HCU40, n  = 11) and 23 hospital taps (used to fill the HCU tanks) were concentrated, decontaminated, and cultured for M. chimaera . Positive cultures ( n  = 53) were purified by agar plate subcultures and analyzed by IR-Biotyper platform and Ion Torrent sequencing system. IR-Biotyper spectra results were analyzed using a statistical approach of dimensionality reduction by linear discriminant analysis (LDA), generating three separate clusters of M. chimaera , ascribable to each hospital. Furthermore, the only M. chimaera- positive sample from tap water clustered with the isolates from the HCUs of the same hospital, confirming that the plumbing system could represent the source of HCU contamination and, potentially, of patient infection. According to the genome-based phylogenies and following the classification proposed by van Ingen and collaborators in 2017, three distinct M. chimaera groups appear to have contaminated the HCU water systems: subgroups 1.1, 2.1, and branch 2. Most of the strains isolated from HCUs at the same hospital share a highly similar genetic profile. The nonrandom distribution obtained with WGS and IR-Biotyper leads to the hypothesis that M. chimaera subtypes circulating in the local plumbing colonize HCUs through the absolute filter, in addition with the current hypothesis that contamination occurs at the HCU production site. This opens the possibility that other medical equipment, such as endoscope reprocessing device or hemodialysis systems, could be contaminated by M. chimaera . IMPORTANCE Our manuscript focuses on interventions to reduce waterborne disease transmission, improve sanitation, and control infection. Sanitary water can be contaminated by nontuberculous Mycobacteria, including M. chimaera , a causative agent of invasive infections in immunocompromised patients. We found highly similar genetic and phenotypic profiles of M. chimaera isolated from heater-cooler units (HCU) used during surgery to thermo-regulate patients' body temperature, and from the same hospital tap water. These results lead to the hypothesis that M. chimaera subtypes circulating in the local plumbing colonize HCUs through the absolute filter, adding to the current hypothesis that contamination occurs at the HCU production site. In addition, this opens the possibility that other medical equipment using sanitized water, such as endoscope reprocessing devices or hemodialysis systems, could be contaminated by nontuberculous Mycobacteria, suggesting the need for environmental surveillance and associated control measures.

Purpose: To investigate the clinical significance of Mycobacterium seoulense (M. seoulense) and the ideal gene for species determination., Methods: Clinical symptoms, laboratory examinations, and radiological examinations were retrospectively reviewed. The hsp65, 16S rRNA, rpoB and ITS region of M. seoulense, were sequenced and phylogenetic trees of mycobacterium strains were constructed., Results: Four M. seoulense strains isolated from 4 patients caused pulmonary infections based on the symptoms and radiological results. The 16S rRNA sequence identified 2 strains as M. intracellulare and the other 2 as Stenotrophomonas maltophilia. In contrast, the rpoB, 16S-23S inter-region (ITS), and hsp65 sequences shared high identity with M. seoulense. Notably, the phylogenetic tree based on the ITS, hsp65, and rpoB sequences clustered 4 M. seoulense strains identified in this study with M. seoulense strains in the database., Conclusion: M. seoulense strains can cause infection in humans. They can be identified by sequencing ITS, hsp65, and rpoB genes., Competing Interests: Declaration of competing interest None., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Anti-interferon (IFN)-γ autoantibodies (AIGAs) are a pathogenic factor in late-onset immunodeficiency with disseminated mycobacterial and other opportunistic infections. AIGAs block IFN-γ function, but their effects on IFN-γ signaling are unknown. Using a single-cell capture method, we isolated 19 IFN-γ-reactive monoclonal antibodies (mAbs) from patients with AIGAs. All displayed high-affinity (KD < 10-9 M) binding to IFN-γ, but only eight neutralized IFN-γ-STAT1 signaling and HLA-DR expression. Signal blockade and binding affinity were correlated and attributed to somatic hypermutations. Cross-competition assays identified three nonoverlapping binding sites (I-III) for AIGAs on IFN-γ. We found that site I mAb neutralized IFN-γ by blocking its binding to IFN-γR1. Site II and III mAbs bound the receptor-bound IFN-γ on the cell surface, abolishing IFN-γR1-IFN-γR2 heterodimerization and preventing downstream signaling. Site III mAbs mediated antibody-dependent cellular cytotoxicity, probably through antibody-IFN-γ complexes on cells. Pathogenic AIGAs underlie mycobacterial infections by the dual blockade of IFN-γ signaling and by eliminating IFN-γ-responsive cells., (© 2022 Shih et al.)

Introduction: Mycobacterium simiae ( M.simiae ), a non-tuberculous mycobacterium (NTM), rare causes infection including localized pulmonary to disseminated disease in immunocompromised patients. An optimal pharmacological management practice has not yet been defined for this infection. This study investigates drug regimens and treatment outcomes in patients with M. simiae to describe different drug regimen with the therapeutic response., Areas Covered: The three databases PubMed, Scopus, and Web of science were systematically searched from June 1994 to June 2021 to retrieve relevant articles. The inclusion criterion included studies, which reported treatment outcomes in patients with M. simiae infections. Treatment success was defined as the achievement of culture conversion, and the improvement of the symptoms and radiologic signs among the patients., Expert Opinion: Data of 223 patients were retrieved from 40 studies. Duration of the treatment regimens used in different studies ranged from 2 to 12 months. The most common treatment regimens administered for M. simiae infection were as follows: clarithromycin, rifampin, ethambutol, moxifloxacin, or ciprofloxacin and amikacin plus cotrimoxazole or pyrazinamide in some regimens. Macrolides, such as clarithromycin, combined with quinolones (such as moxifloxacin) and TMP/SMX, which are used in combination, had the most significant effect on eliminating the pulmonary signs of M. simiae .

Background: Catheter-related bloodstream infection (CRBSI), caused by rapidly growing mycobacteria (RGM), is a rare infectious complication in hematopoietic stem cell transplant (HSCT) recipients and can often be misdiagnosed as Gram-positive rod (GPR) bacteremia., Case Presentation: We present a case of CRBSI caused by Mycobacterium wolinskyi, a rare RGM, in a 44-year-old female patient who received an umbilical cord blood transplant., Conclusions: Rapidly growing mycobacteria can stain as GPRs and may grow in routine blood culture media after 3-4 days of incubation. These features are not widely known to clinicians, and acid-fast staining is therefore recommended when unidentifiable GPRs are detected in blood cultures, especially in immunocompromised patients, such as those with hematologic malignancies or intravascular devices., (© 2022. The Author(s).)

Background: Mycobacterium farcinogenes-senegalense group mostly cause bovine farcy, which rarely infect human beings. We reported one case of cutaneous Mycobacterium farcinogenes-senegalense group infection in an immunocompetent victim., Case Presentation: A 66-year-old Taiwanese woman with hypertension developed tender nodules on her left dorsal foot for 2 months. Tissue culture identified Mycobacterium farcinogenes-senegalense group. The lesion was treated successfully with clarithromycin and sulfamethoxazole/trimethoprim, followed by surgical excision., Conclusions: Mycobacterium farcinogenes-senegalense group infection should be considered as a potential pathogen of skin infection in immunocompetent patients., (© 2022. The Author(s).)

A slowly growing mycobacteria, identified as strain TY59 T , was isolated from sputum of an elderly man with pneumonia. Sequencing of the 16S rRNA gene indicated that this strain was similar to members of the Mycobacterium avium complex and closely related species. Strain TY59 T has highest 16S rRNA gene sequence similarities to the type strains of Mycobacterium colombiense (99.80 % sequence similarity), Mycobacterium vulneris (99.74 %), Mycobacterium timonense (99.54 %), Mycobacterium avium subsp. avium (99.54 %) and Mycobacterium avium subsp. silvaticum (99.54 %). Analysis of the internal transcribed spacer (ITS) and DNA-directed RNA polymerase subunit beta ( rpoB ) sequences gave similar results to the 16S rRNA gene analysis. The closest species to strain TY59 T were M. colombiense and M. vulneris with 97.90-98.25 % identity in ITS and 96.4-96.6 % in rpoB . The strain's 65 kDa heat shock protein ( hsp65 ) gene was different from those of M. vulneris , M. colombiense and M. avium subsp. silvaticum with 72.4-74.2 % identity. Average nucleotide identity results showed a 93.4 % match to M. vulneris as the maximum value. Phenotypically, the non-chromogenicity, rough colonies, growth at 42 °C, negative results for nitrate reduction, β-glucosidase and Tween 80 hydrolysis, and positive results for catalase activity set this strain apart from closely related species. We propose that Mycobacterium senriense sp. nov. is a novel species of slowly growing mycobacteria. The type strain is TY59 T (RIMD 1371001 T =CIP 111917 T ).

The freshwater ornamental fish trade represents a major contributor to the livelihoods of many producers in Trinidad and Tobago, with stocks destined for local, regional and international markets. A review of clinical cases presented to the Aquatic Animal Health Unit at the University of the West Indies, School of Veterinary Medicine for the period September 2010 to December 2012 suggested that piscine mycobacteriosis may be widespread throughout the local ornamental fish industry. Thus, to determine the prevalence of mycobacteriosis in ornamental fish sold in pet stores, a total of 122 specimens were sourced from 24 retail suppliers across Trinidad. Fish were killed and internal organs were examined for lesions suggestive of granulomas. All wet-mount slides were acid-fast stained, regardless of the presence or absence of observed granuloma-like lesions. Histological analysis was performed on one randomly selected whole specimen from each facility. Mycobacterium sp. was identified using real-time PCR detecting the 16S rRNA gene in tissue samples. Associations between parasitism, facility biosecurity and presence of positive animals were determined. The prevalence of Mycobacterium sp. infection was 61 ± 7% (74/122), with positive specimens being acquired from 54.2% (13/24) of facilities examined. Further, 100% of facilities did not employ optimum biosecurity measures., (© 2022 John Wiley & Sons Ltd.)

Background: Extracellular vesicles (EVs) play a key role in cell communication and the pathogenesis of some diseases. EVs may accelerate cell death during the course of mycobacterial infection and are also considered as a new vaccine design, drug delivery, and biomarker candidates. The current study evaluates the effects of EVs from serum samples of mycobacteria-infected patients on THP-1 monocytes and PBMC cells., Method: EVs were purified from the serum, then cultured separately with THP-1 monocytes and PBMCs. The cell death was determined through annexin V-FITC and PI staining. GW4869, an EVs inhibitor, was used to determine if EVs released from serum could increase THP-1 monocytes cell death., Results: The cell death was significantly increased in the presence of 10 µg/ml and 5 µg/ml concentrations of the purified EVs (p < 0.05). Minimal cell death was determined in 2.5 µg/ml and 1.2 µg/ml (p < 0.05). Up to 85% of the cells were viable in the presence of the GW4869 inhibitor (p < 0.05)., Conclusion: Direct infection of the cells with EVs released from mycobacteria-infected patients samples, the multiplicity of infection with the EVs, and virulent or avirulent mycobacteria may change the status of the cell death. The isolated EVs  from serum samples of patients with mycobacterial  infection accelerated cell death, which means that they might   not be considered as an optimal tool for developing drug delivery and vaccine against tuberculosis., (© 2022. The Author(s).)

The two human pathogens Helicobacter pylori and Mycobacterium tuberculosis (Mtb) co-exist in many geographical areas of the world. Here, using a co-infection model of H. pylori and the Mtb relative M. bovis bacillus Calmette-Guérin (BCG), we show that both bacteria affect the colonization and immune control of the respective other pathogen. Co-occurring M. bovis boosts gastric Th1 responses and H. pylori control and aggravates gastric immunopathology. H. pylori in the stomach compromises immune control of M. bovis in the liver and spleen. Prior antibiotic H. pylori eradication or M. bovis-specific immunization reverses the effects of H. pylori. Mechanistically, the mutual effects can be attributed to the redirection of regulatory T cells (Treg cells) to sites of M. bovis infection. Reversal of Treg cell redirection by CXCR3 blockade restores M. bovis control. In conclusion, the simultaneous presence of both pathogens exacerbates the problems associated with each individual infection alone and should possibly be factored into treatment decisions., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare monogenetic disease, which is characterized by susceptibility to some weakly virulent mycobacteria. Here, we explored the pathogenic genes and molecular mechanisms of MSMD patients. We recruited three patients diagnosed with MSMD from two families. Two novel mutations (c.1228A > G, p.K410E and c.2071A > G, p.M691V) in STAT1 gene were identified from two families. The translocation of K410E mutant STAT1 protein into nucleus was not affected. The binding ability between gamma-activating sequence (GAS) and K410E mutant STAT1 protein was significantly reduced, which will reduce the interaction between STAT1 protein with the promoters of target genes. The M691V mutant STAT1 protein cannot translocate into the nucleus after IFN-γ stimulation, which will affect the STAT1 protein form gamma-activating factors (GAF) and bind the GAS in the promoter region of downstream target genes. Taken together, our results showed that the mutation of K410E led to impaired binding of STAT1 to target DNA, and the mutation of M691V prevented the transport of STAT1 into the nucleus, which led to MSMD. Together, we identified two novel mutations (c.1228A > G, p.K410E and c.2071A > G, p.M691V) in STAT1 gene in MSMD patients, and deciphered the molecular mechanism of MSMD caused by STAT1 mutations., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Aims: Fungal and mycobacterial periprosthetic joint infections (PJI) are rare events. Clinicians are wary of missing these diagnoses, often leading to the routine ordering of fungal and mycobacterial cultures on periprosthetic specimens. Our goal was to examine the utility of these cultures and explore a modern bacterial culture technique using bacterial blood culture bottles (BCBs) as an alternative., Methods: We performed a retrospective review of patients diagnosed with hip or knee PJI between 1 January 2010 and 31 December 2019, at the Mayo Clinic in Rochester, Minnesota, USA. We included patients aged 18 years or older who had fungal, mycobacterial, or both cultures performed together with bacterial cultures. Cases with positive fungal or mycobacterial cultures were reviewed using the electronic medical record to classify the microbiological findings as representing true infection or not., Results: There were 2,067 episodes of PJI diagnosed within the study period. A total of 3,629 fungal cultures and 2,923 mycobacterial cultures were performed, with at least one of these performed in 56% of episodes (n = 1,157). Test positivity rates of fungal and mycobacterial cultures were 5% (n = 179) and 1.2% (n = 34), respectively. After a comprehensive review, there were 40 true fungal and eight true mycobacterial PJIs. BCB were 90% sensitive in diagnosing true fungal PJI and 100% sensitive in detecting rapidly growing mycobacteria (RGM). Fungal stains were performed in 27 true fungal PJI but were only positive in four episodes (14.8% sensitivity). None of the mycobacterial stains was positive., Conclusion: Routine fungal and mycobacterial stains and cultures should not be performed as they have little clinical utility in the diagnosis of PJI and are associated with significant costs. Candida species and RGM are readily recovered using BCB. More research is needed to predict rare non- Candida fungal and slowly growing mycobacterial PJI that warrant specialized cultures. Cite this article: Bone Joint J  2022;104-B(1):53-58.

The mycobacterium genus contains a broad range of species, including the human pathogens M. tuberculosis and M. leprae . These bacteria are best known for their residence inside host cells. Neutrophils are frequently observed at sites of mycobacterial infection, but their role in clearance is not well understood. In this review, we discuss how neutrophils attempt to control mycobacterial infections, either through the ingestion of bacteria into intracellular phagosomes, or the release of neutrophil extracellular traps (NETs). Despite their powerful antimicrobial activity, including the production of reactive oxidants such as hypochlorous acid, neutrophils appear ineffective in killing pathogenic mycobacteria. We explore mycobacterial resistance mechanisms, and how thwarting neutrophil action exacerbates disease pathology. A better understanding of how mycobacteria protect themselves from neutrophils will aid the development of novel strategies that facilitate bacterial clearance and limit host tissue damage., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Parker, Forrester, Kaldor, Dickerhof and Hampton.)

Mycobacterium ulcerans is the causal agent of Buruli ulcer, a chronic infectious disease and the third most common mycobacterial disease worldwide. Without early treatment, M. ulcerans provokes massive skin ulcers, caused by the mycolactone toxin, its main virulence factor. However, spontaneous healing may occur in Buruli ulcer patients several months or years after the disease onset. We have shown, in an original mouse model, that bacterial load remains high and viable in spontaneously healed tissues, with a switch of M. ulcerans to low levels of mycolactone production, adapting its strategy to survive in such a hostile environment. This original model offers the possibility to investigate the regulation of mycolactone production, by using an RNA-seq strategy to study bacterial adaptation during mouse infection. Pathway analysis and characterization of the tissue environment showed that the bacillus adapted to its new environment by modifying its metabolic activity and switching nutrient sources. Thus, M. ulcerans ensures its survival in healing tissues by reducing its secondary metabolism, leading to an inhibition of mycolactone synthesis. These findings shed new light on mycolactone regulation and pave the way for new therapeutic strategies.

Early detection and treatment are paramount for the timely control of Mycobacterium avium infections. Herein, we designed a LAMP assay targeting a widely used species-specific marker IS1245 for the rapid detection of M. avium and evaluated its applicability using human (n = 137) and pig (n = 91) M. avium isolates from Japan. The developed assay could detect as low as 1 genome copy of M. avium DNA within 30 minutes. All 91 (100%) M. avium isolates from pigs were detected positive while all other tested bacterial species were negative. Interestingly, among the 137 clinical M. avium isolates, 41 (30%) were undetectable with this LAMP assay as they lacked IS1245, the absence of which was revealed by PCR and whole-genome sequencing. These findings highlighted genotypic differences in M. avium strains from humans and pigs in Japan and how this diversity can influence the applicability of a detection tool across different geographic areas and hosts., (Copyright © 2021 Elsevier Inc. All rights reserved.)

L-Arginine is the precursor of nitric oxide (NO), a host immune effector against intracellular pathogens including Mycobacterium tuberculosis (M. tb). Pathogens including M. tb have evolved various strategies targeting arginine to block the production of NO for better survival and proliferation. However, L-arginine metabolism and regulation in Mycobacterium are poorly understood. Here, we report the identification of M. smegmatis MSMEG&#95;1415 (homolog of M. tb Rv2324) as an arginine-responsive transcriptional factor regulating the arginase pathway. In the absence of L-arginine, MSMEG&#95;1415 acts as a repressor to inhibit the transcription of the roc (for arginine, ornithine catabolism) gene cluster, thereby switching off the arginase pathway. Treatment with L-arginine relieves the transcriptional inhibition of MSMEG&#95;1415 on the roc gene cluster to activate the arginase pathway. Moreover, the L-arginine-MSMEG&#95;1415 complex activates the transcription of the roc gene cluster by recognizing and binding a 15-bp palindrome motif, thereby preventing the excess accumulation of L-arginine in M. smegmatis. Physiologically, MSMEG&#95;1415 confers mycobacteria resistance to starvation and fluoroquinolones exposure, suggestive of its important role in M. smegmatis persistence. The results uncover a unique regulatory mechanism of arginine metabolism in mycobacteria and identify M. tb Rv2324 as an attractive candidate target for the design of drugs against tuberculosis., Competing Interests: Conflict of interest None declared., (Copyright © 2021 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.)

Background: Recent studies report very low adherence of practitioners to ATS/IDSA recommendations for the treatment of nontuberculous mycobacteria pulmonary disease (NTM-PD), as well as a great variability of practices. Type of management could impact prognosis., Methods: To evaluate management and prognosis of patients with NTM-PD cases with respect to ATS recommendations, we conducted a multicenter retrospective cohort study (18 sentinel sites distributed throughout France), over a period of six years. We collected clinical, radiological, microbiological characteristics, management and outcome of the patients (especially death or not)., Results: 477 patients with NTM-PD were included. Respiratory comorbidities were found in 68% of cases, tuberculosis sequelae in 31.4% of patients, and immunosuppression in 16.8% of cases. The three most common NTM species were Mycobacterium avium complex (60%), M. xenopi (20%) and M. kansasii (5.7%). Smear-positive was found in one third of NTM-PD. Nodulobronchiectatic forms were observed in 54.3% of cases, and cavitary forms in 19.1% of patients. Sixty-three percent of patients were treated, 72.4% of patients with smear-positive samples, and 57.5% of patients with smear-negative samples. Treatment was in adequacy with ATS guidelines in 73.5%. The 2-year mortality was 14.4%. In the Cox regression, treatment (HR = 0.51), age (HR = 1.02), and M. abscessus (3.19) appeared as the 3 significant independent prognostic factors., Conclusion: These findings highlight the adequacy between French practices and the ATS/IDSA guidelines. Treatment was associated with a better survival., (© 2021. The Author(s).)

Background: Mycobacterium chimaera infections subsequent to cardiac surgery are related to contaminated heater-cooler devices, with high mortality. Nevertheless, few studies have been reported in Asia., Case Presentation: We described the case of a 55-year-old man with Mycobacterium chimaera infection following cardiac surgery in the mainland of China. He was diagnosed with endocarditis caused by Mycobacterium chimaera subsequent to open heart surgery. Metagenomic next-generation sequencing (mNGS) and 16S rRNA gene PCR analysis were used to identify potential pathogens. The patient underwent redo valve replacement surgery and received combination therapy with azithromycin, ethambutol, linezolid, and amikacin. No signs of relapse were observed during the 11-month follow-up visit., Conclusions: This is the first documented case of Mycobacterium chimaera infection following cardiac surgery in the mainland of China and the first documented transnational imported case worldwide. Moreover, mNGS is a novel diagnostic technology that can guide antimicrobial therapy prior to obtaining fluid/tissue culture results for Mycobacterium chimaera, providing a new approach for the detection of potential Mycobacterium chimaera infection., (© 2021. The Author(s).)

Abstract: Although pulmonary mycobacterial infection is associated with acute respiratory distress syndrome (ARDS) in critically ill patients, its clinical implication on patients with ARDS has not been clearly elucidated. The aim of study was to investigate the clinical significance of pulmonary mycobacterial infection in patients with ARDS.Between January 2014 and April 2019, medical records of 229 patients with ARDS who met the Berlin criteria and received invasive mechanical ventilation in medical intensive care unit were reviewed. Clinical characteristics and the rate of mortality between patients with and without pulmonary mycobacterial infection were compared. Factors associated with a 28-day mortality were analyzed statistically.Twenty two (9.6%) patients were infected with pulmonary mycobacteria (18 with tuberculosis and 4 with non-tuberculous mycobacteria). There were no differences in baseline characteristics, the severity of illness scores. Other than a higher rate of renal replacement therapy required in those without pulmonary mycobacterial infection, the use of adjunctive therapy did not differ between the groups. The 28- day mortality rate was significantly higher in patients with pulmonary mycobacterial infection (81.8% vs 58%, P = .019). Pulmonary mycobacterial infection was significantly associated with 28-day mortality (hazard ratio 1.852, 95% confidence interval 1.108-3.095, P = .019).Pulmonary mycobacterial infection was associated with increased 28-day mortality in patients with ARDS., Competing Interests: The authors have no conflicts of interests to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)