Treatment of Nontuberculous Mycobacterial Pulmonary Disease: An Official ATS/ERS/ESCMID/IDSA Clinical Practice Guideline

Phage Therapy of Mycobacterium Infections: Compassionate Use of Phages in 20 Patients With Drug-Resistant Mycobacterial Disease

BACKGROUND

Nontuberculous Mycobacterium infections, particularly Mycobacterium abscessus, are increasingly common among patients with cystic fibrosis and chronic bronchiectatic lung diseases. Treatment is challenging due to intrinsic antibiotic resistance. Bacteriophage therapy represents a potentially novel approach. Relatively few active lytic phages are available and there is great variation in phage susceptibilities among M. abscessus isolates, requiring personalized phage identification.

METHODS

Mycobacterium isolates from 200 culture-positive patients with symptomatic disease were screened for phage susceptibilities. One or more lytic phages were identified for 55 isolates. Phages were administered intravenously, by aerosolization, or both to 20 patients on a compassionate use basis and patients were monitored for adverse reactions, clinical and microbiologic responses, the emergence of phage resistance, and phage neutralization in serum, sputum, or bronchoalveolar lavage fluid.

RESULTS

No adverse reactions attributed to therapy were seen in any patient regardless of the pathogen, phages administered, or the route of delivery. Favorable clinical or microbiological responses were observed in 11 patients. Neutralizing antibodies were identified in serum after initiation of phage delivery intravenously in 8 patients, potentially contributing to lack of treatment response in 4 cases, but were not consistently associated with unfavorable responses in others. Eleven patients were treated with only a single phage, and no phage resistance was observed in any of these.

CONCLUSIONS

Phage treatment of Mycobacterium infections is challenging due to the limited repertoire of therapeutically useful phages, but favorable clinical outcomes in patients lacking any other treatment options support continued development of adjunctive phage therapy for some mycobacterial infections.

Antimicrobial therapy for nontuberculous mycobacterial pulmonary disease improved hearing loss and normalized myeloperoxidase-anti-neutrophil cytoplasmic antibody level: A case report

Several case reports have indicated that nontuberculous mycobacterial pulmonary disease is associated with anti-neutrophil cytoplasmic antibody-associated vasculitides. However, the effect of the treatment for nontuberculous mycobacterial pulmonary disease on anti-neutrophil cytoplasmic antibody-associated vasculitides remains unclear. An asymptomatic 80-year-old woman presented with nodular bronchiectasis. After 1 year, she developed a productive cough. Mycobacterial culture of the respiratory specimen revealed Mycobacterium avium. She was diagnosed with nontuberculous mycobacterial pulmonary disease based on the criteria proposed by the American Thoracic Society. Concurrently, she had hearing loss, tinnitus, and weight loss. A blood test showed an elevated level of myeloperoxidase-anti-neutrophil cytoplasmic antibody (107 IU/mL, normal level: <3.5 IU/mL). Bilateral otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitis was diagnosed based on the diagnostic criteria proposed by the Japan Otological Society. After starting antimicrobial agents for the nontuberculous mycobacterial pulmonary disease, her pulmonary symptoms and hearing loss improved, and the level of myeloperoxidase-anti-neutrophil cytoplasmic antibody normalized. No immunosuppressive treatment was administered. The present case suggests that nontuberculous mycobacterial pulmonary disease can cause otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitides, and antimicrobial treatment for the nontuberculous mycobacterial pulmonary disease may resolve otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitides.

Taking the route less traveled: on the way to COpAT

Antimicrobial therapy is an essential practice within medicine. Over the last 4 years, complex outpatient antimicrobial therapy (COpAT) with oral antimicrobials has become a rapidly developing area of practice and is non-inferior to outpatient parenteral antimicrobial therapy (OPAT) in certain infectious syndromes. Currently, the available literature does not describe the implementation of oral antimicrobials within the current outpatient antimicrobial therapy process. Throughout this article, the authors present a review of current literature, a proposed definition of COpAT and offer methods readers can utilize to implement an integrated COpAT/OPAT program with oral antimicrobial-specific monitoring within their current practice.

Culture independent markers of nontuberculous mycobacterial (NTM) lung infection and disease in the cystic fibrosis airway

Nontuberculous mycobacteria (NTM) are opportunistic pathogens that affect a relatively small but significant portion of the people with cystic fibrosis (CF), and may cause increased morbidity and mortality in this population. Cultures from the airway are the only test currently in clinical use for detecting NTM. Culture techniques used in clinical laboratories are insensitive and poorly suited for population screening or to follow progression of disease or treatment response. The lack of sensitive and quantitative markers of NTM in the airway impedes patient care and clinical trial design, and has limited our understanding of patterns of acquisition, latency and pathogenesis of disease. Culture-independent markers of NTM infection have the potential to overcome many of the limitations of standard NTM cultures, especially the very slow growth, inability to quantitate bacterial burden, and low sensitivity due to required decontamination procedures. A range of markers have been identified in sputum, saliva, breath, blood, urine, as well as radiographic studies. Proposed markers to detect presence of NTM or transition to NTM disease include bacterial cell wall products and DNA, as well as markers of host immune response such as immunoglobulins and the gene expression of circulating leukocytes. In all cases the sensitivity of culture-independent markers is greater than standard cultures; however, most do not discriminate between various NTM species. Thus, each marker may be best suited for a specific clinical application, or combined with other markers and traditional cultures to improve diagnosis and monitoring of treatment response.

Inhaled nitric oxide for adults with pulmonary non-tuberculous mycobacterial infection

QUESTION

There is an increasing prevalence of nontuberculous mycobacteria pulmonary disease (NTM-PD) in the US. Treatment of NTM-PD typically requires multiple medications, which can be associated with unpleasant morbidity and eradication of infection is difficult. Therefore, there is a critical need for novel effective and well-tolerated therapies. Recent in vitro data and case reports have suggested that nitric oxide, inhaled as a gas (gNO), has antimicrobial activity against NTM. We sought to investigate the effect of gNO in patients with NTM-PD in an open-label proof of concept trial.

METHODS

Eligible participants had NTM-PD with persistently positive respiratory cultures for NTM even if on antibiotic treatment. Participants were treated with gNO for 50 min three times daily, five days per week, for three weeks (total of 15 treatment days).

RESULTS

Ten participants, of whom nine were on long-term NTM antibiotic therapy, were enrolled. All participants completed the regimen without interruption or discontinuation. Small increases in methemoglobin were noted during treatment, and all resolved to baseline within 2 h. Four participants (40%) met the primary outcome measure of negative sputum cultures after three weeks of therapy. Following treatment discontinuation, three of these participants were again culture positive during the 3-month post-treatment monitoring period, although with measures suggesting low bacterial burden.

ANSWER

Patients tolerated a 3-week regimen of gNO without safety concerns, and despite highly refractory disease four individuals completed the study with negative cultures, although three were again positive in subsequent months. These data support further investigation of gNO as a potential therapy for NTM-PD.

Detecting clusters of high nontuberculous mycobacteria infection risk for persons with cystic fibrosis - An analysis of U.S. counties

Nontuberculous mycobacteria are ubiquitous environmental bacteria that frequently cause disease in persons with cystic fibrosis (pwCF). The risks for NTM infection vary geographically. Detection of high-risk areas is important for focusing prevention efforts. In this study, we apply five cluster detection methods to identify counties with high NTM infection risk. Four clusters were detected by at least three of the five methods, including twenty-five counties in five states. The geographic area and number of counties in each cluster depended upon the detection method used. Identifying these clusters supports future studies of environmental predictors of infection and will inform control and prevention efforts.

Isoniazid pharmacokinetics/pharmacodynamics as monotherapy and in combination regimen in the hollow fiber system model of Mycobacterium kansasii

BACKGROUND

There is limited high quality evidence to guide the optimal doses of drugs for the treatment of Mycobacterium kansasii pulmonary disease (Mkn-PD).

METHODS

We performed (1) minimum inhibitory concentration experiment, (2) isoniazid dose-response study using the hollow fiber system model (HFS-Mkn) to determine PK/PD optimized exposure, and (3) another HFS-Mkn study to determine the efficacy of high dose isoniazid (15 mg/kg/day) with standard dose rifampin (10 mg/kg/day) and ethambutol (15 mg/kg/day). Inhibitory sigmoid maximal effect model and linear regression was used for data analysis.

RESULTS

MIC of the 20 clinical isolates ranged between 0.5 mg/L to 32 mg/L. In the HFS-Mkn, isoniazid monotherapy failed to control the bacterial growth beyond day 7. On day 7, when the maximal Mkn kill was observed, the optimal isoniazid exposure for Mkn kill was calculated as 24hr area under the concentration-time curve to the MIC of 12.41. Target attainment probability of 300 mg/day dose fell below 90% above the MIC of 1 mg/L. High dose isoniazid combination sterilized the HFS-Mkn in 30-days with a kill rate of -0.15 ± 0.02 log10 CFU/mL/day.

CONCLUSION

Despite initial kill, isoniazid monotherapy failed due to resistance emergence. Our pre-clinical model derived results suggest that higher than currently recommended 300 mg/day isoniazid dose may achieve better clinical efficacy against Mkn-PD.

Performance of Interferon-γ Release Assays in Patients with Mycobacterium kansasii Infection

Objective

To evaluate the performance of interferon-γ release assays (IGRAs) in patients with Mycobacterium kansasii infection.

Methods

Consecutive patients between May 2012 and June 2021 who had positive for mycobacterial cultures and who underwent IGRAs (T-SPOT.TB or QuantiFERON-TB Gold [QFT-G]) were included in the analysis. The IGRA positivity rates among patients with M. kansasii isolates were then calculated. If M. kansasii was identified in at least two sputum samples or in sterile samples, M. kansasii disease was then diagnosed. Otherwise, colonisation was considered.

Results

During the study period, 54 patients with M. kansasii infection underwent T-SPOT.TB (n=48) or QFT-G (n=6) assays. The mean age was 44.1±13.4 years, 85.2% (46/54) were male. Eight patients were diagnosed with M. kansasii disease and another 46 patients were considered to have colonisation. Twenty-four patients (T-SPOT.TB, n=23; QFT-G, n=1) were positive for IGRAs, for an overall rate of 44.4% (24/54; T-SPOT.TB, 47.9% [23/48]; QFT-G, 16.7% [1/6]) for IGRAs, 25.0% (2/8) for M. kansasii disease, and 47.8% (22/46) for colonisation.

Conclusion

Positive IGRA rates were relatively low in patients with M. kansasii infection. More efforts are required to improve the performance of IGRAs in diagnosing M. kansasii infection.

Variability of Mycobacterium avium Complex Isolates Drug Susceptibility Testing by Broth Microdilution

Non-tuberculous mycobacteria are widely distributed in environments and are capable of infecting humans, particularly those with a compromised immune system. The most prevalent species that cause nontuberculous mycobacterial lung diseases are slow-growing bacteria from the Mycobacterium avium complex (MAC), mainly M. avium or M. intracellulare. The key treatment of MAC infections includes macrolides, ethambutol, and rifampicin; however, the therapy outcomes are unsatisfactory. Phenotypic drug susceptibility testing is a conditional recommendation prior to treatment, and critical concentrations for clarithromycin, amikacin, moxifloxacin, and linezolid have been established. In this review, data from studies on the determination of MIC of clinical isolates using the broth microdilution method were summarized. A significant variation in the MIC distributions from different studies was found. The main reasons could impact the findings: insufficient reproducibility of the phenotypic testing and variation in species lineages identified in different laboratories, which could have various intrinsic susceptibility to drugs. For most of the drugs analyzed, the MICs are too high, which could undermine the treatment efficiency. Further improvement of treatment outcomes demands the validation of microbiological resistance criteria together with the identification of molecular mechanisms of resistance.

Mycobacterial infections in adults with haematological malignancies and haematopoietic stem cell transplants: guidelines from the 8th European Conference on Infections in Leukaemia

Mycobacterial infections, both tuberculosis and nontuberculous, are more common in patients with haematological malignancies and haematopoietic stem cell transplant recipients than in the general population-although these infections remain rare. Mycobacterial infections pose both diagnostic and therapeutic challenges. The management of mycobacterial infections is particularly complicated for patients in haematology because of the many drug-drug interactions between antimycobacterial drugs and haematological and immunosuppressive treatments. The management of mycobacterial infections must also consider the effect of delaying haematological management. We surveyed the management practices for latent tuberculosis infection (LTBI) in haematology centres in Europe. We then conducted a meticulous review of the literature on the epidemiology, diagnosis, and management of LTBI, tuberculosis, and nontuberculous mycobacterial infections among patients in haematology, and we formulated clinical guidelines according to standardised European Conference on Infections in Leukaemia (ECIL) methods. In this Review, we summarise the available literature and the recommendations of ECIL 8 for managing mycobacterial infections in patients with haematological malignancies.

Mycobacterium abscessus Pneumonia in an Immunonormal Infant

A 2-month-old male with failure to thrive and respiratory symptoms was found to have bilateral pneumonia secondary to Mycobacterium abscessus . M. abscessus pulmonary infections have mainly been noted in immunocompromised children; prior reports presented similarly, though our patient is unique given the young age of presentation and lack of diagnosed immunodeficiency or underlying disease.

Host-directed immunotherapy to fight infectious diseases

PURPOSE OF REVIEW

This review provides readers with examples of refractory infections due to inborn errors of immunity, highlighting how they may be successfully treated by deducing and targeting the underlying immunodeficiency.

RECENT FINDINGS

The use of host-directed immunotherapy to treat infectious disease in inborn errors of immunity is currently limited but growing. Different strategies include depleting the cellular reservoir for pathogens with restricted cell-tropism; augmenting the diminished effector response; and restoring molecular equipoise. The immunotherapies illustrated are existing drugs that have been re-purposed and rationally used, depending on the molecular or cellular impact of the mutation. As more biologic response modifiers and molecular targeted therapies are developed for other indications, they open the avenues for their use in inborn errors of immunity. Conversely, as more molecular pathways underlying defective immune responses and refractory infections are elucidated, they lend themselves to tractability with these emerging therapies.

SUMMARY

Infections that fail appropriate antimicrobial therapy are a harbinger of underlying inborn errors of immunity. Dissecting the mechanism by which the immune system fails provides opportunities to target the host response and make it succeed.

Identification and drug susceptibility testing of the subspecies of Mycobacterium avium complex clinical isolates in mainland China

OBJECTIVES

The Mycobacterium avium complex (MAC), comprising a series of subspecies, has a worldwide distribution, with differences in drug susceptibility among subspecies. This study aimed to assess the composition of MAC and susceptibility differences among subspecies in mainland China.

METHODS

A total of 287 MAC clinical strains were included in the study. Multitarget sequences were applied to accurately identify subspecies, and a microdilution method was used to evaluate minimum inhibitory concentrations (MICs) among subspecies using Sensititre SLOMYCO plates.

RESULTS

Mycobacterium intracellular (N = 169), Mycobacterium avium (N = 52), Mycobacterium chimaera (N = 22), Mycobacterium marseillense (N = 25), Mycobacterium colombiense (N = 14), Mycobacterium yongonense (N = 4), Mycobacterium vulneris (N = 3) and Mycobacterium timonense (N = 2) were isolated from MAC. Clarithromycin, amikacin and rifabutin showed lower MIC₅₀ and MIC₉₀ values than other drugs, and the resistance rates of clarithromycin, amikacin, linezolid and moxifloxacin were 6.3%, 10.5%, 51.9% and 46.3%, respectively. The resistance rates of clarithromycin and moxifloxacin in the initial treatment group were significantly lower than those in the retreatment group (4.09% vs. 12.94%; 30.41% vs. 75.29%; P < 0.05). Drug susceptibility differences were observed in clarithromycin and moxifloxacin among the five major subspecies (P < 0.05); however, those statistically significant differences disappeared when MACs were divided into two groups according to previous anti-tuberculosis (anti-TB) treatment history.

CONCLUSION

This study revealed that MAC, primarily comprising M. intracellulare, was susceptible to clarithromycin, amikacin and rifabutin. Drug susceptibility among subspecies did not exhibit intrinsic differences in our study. Previous anti-TB treatment patients are more resistant to drugs; thus, attention should be given to those patients in the clinic.

Nontuberculous Mycobacterial Infections in Cystic Fibrosis

Nontuberculous mycobacteria (NTM) are important pathogens, with a longitudinal prevalence of up to 20% within the cystic fibrosis (CF) population. Diagnosis of NTM pulmonary disease in people with CF (pwCF) is challenging, as a majority have NTM infection that is transient or indolent, without evidence of clinical consequence. In addition, the radiographic and clinical manifestations of chronic coinfections with typical CF pathogens can overlap those of NTM, making diagnosis difficult. Comprehensive care of pwCF must be optimized to assess the true clinical impact of NTM and to improve response to treatment. Treatment requires prolonged, multidrug therapy that varies depending on NTM species, resistance pattern, and extent of disease. With a widespread use of highly effective modulator therapy (HEMT), clinical signs and symptoms of NTM disease may be less apparent, and sensitivity of sputum cultures further reduced. The development of a disease-specific approach to the diagnosis and treatment of NTM infection in pwCF is a research priority, as a lifelong strategy is needed for this high-risk population.

Liposomal amikacin and Mycobacterium abscessus: intimate interactions inside eukaryotic cells

BACKGROUND

Mycobacterium abscessus (Mabs), a rapidly growing Mycobacterium species, is considered an MDR organism. Among the standard antimicrobial multi-drug regimens against Mabs, amikacin is considered as one of the most effective. Parenteral amikacin, as a consequence of its inability to penetrate inside the cells, is only active against extracellular mycobacteria. The use of inhaled liposomal amikacin may yield improved intracellular efficacy by targeting Mabs inside the cells, while reducing its systemic toxicity.

OBJECTIVES

To evaluate the colocalization of an amikacin liposomal inhalation suspension (ALIS) with intracellular Mabs, and then to measure its intracellular anti-Mabs activity.

METHODS

We evaluated the colocalization of ALIS with Mabs in eukaryotic cells such as macrophages (THP-1 and J774.2) or pulmonary epithelial cells (BCi-NS1.1 and MucilAir), using a fluorescent ALIS and GFP-expressing Mabs, to test whether ALIS reaches intracellular Mabs. We then evaluated the intracellular anti-Mabs activity of ALIS inside macrophages using cfu and/or luminescence.

RESULTS

Using confocal microscopy, we demonstrated fluorescent ALIS and GFP-Mabs colocalization in macrophages and epithelial cells. We also showed that ALIS was active against intracellular Mabs at a concentration of 32 to 64 mg/L, at 3 and 5 days post-infection. Finally, ALIS intracellular activity was confirmed when tested against 53 clinical Mabs isolates, showing intracellular growth reduction for nearly 80% of the isolates.

CONCLUSIONS

Our experiments demonstrate the intracellular localization and intracellular contact between Mabs and ALIS, and antibacterial activity against intracellular Mabs, showing promise for its future use for Mabs pulmonary infections.

Comparison of frailty in patients with nontuberculous mycobacterial lung disease and bronchiectasis: a prospective cohort study

BACKGROUND

The incidence of nontuberculous mycobacterial lung disease (NTM-LD) peaks in middle- and old age groups, coinciding with senescence; thus, chronic infectious diseases can accelerate frailty and worsen mental health in the elderly. In this study, we aimed to compare the prevalence of physical and psychiatric frailty between patients with NTM-LD and bronchiectasis (BE).

METHODS

The Kihon Checklist Questionnaire (KCQ) was used to assess physical and psychiatric frailties and identify those at risk of requiring care among patients with newly diagnosed NTM-LD and BE. Additionally, the Hospital Anxiety and Depression Scale (HADS) scores and chronic inflammatory biomarkers of the alveolar region (surfactant protein [SP]-A, SP-D, and human cationic antibacterial protein [hCAP]/LL-37) were assessed and compared between NTM-LD and BE patients.

RESULTS

There were no significant differences in the background characteristics between the 33 NTM and 36 BE patients recruited. The KCQ revealed that the proportion of frail NTM patients at diagnosis was higher than that of frail BE patients (48.5% vs. 22.2%, p = 0.026). HADS scores were significantly higher in the NTM group than in the BE group (p < 0.01). Bronchoalveolar lavage fluid (BALF) hCAP/LL-37 and SP-D levels were significantly higher (p = 0.001), but serum hCAP/LL-37 levels were significantly lower in the NTM group than in the BE group (p = 0.023). However, there were no significant differences in the BALF and serum SP-D levels between the two groups.

CONCLUSIONS

The number of frail NTM patients at diagnosis was significantly higher than that of frail BE patients. Biomarker analysis suggested that the former had more localized lung inflammation than the latter.

TRIAL REGISTRATION

This trial was prospectively registered in the Clinical Trials Registry (UMIN 000027652).

Mycobacterium marinum: A brief update for clinical purposes

Mycobacterium marinum (M. marinum) is a free-living, slow grower nontuberculous mycobacteria (NTM), strictly related to Mycobacterium tuberculosis, that causes disease in fresh and saltwater fish and it is one of the causes of extra-pulmonary mycobacterial infections, ranging in human from simple cutaneous lesions to disseminated forms in immunocompromised hosts. The first human cases of M. marinum infection were reported from skin lesions of swimmers in a contaminated pool, in 1951, in Sweden by Norden and Linell. Two conditions are required to develop M. marinum infection: (1) skin solution of continuity and (2) exposure to the contaminated water or direct contact with fish or shellfish. The so-called "fish-tank granuloma", the most frequent cutaneous manifestation of M. marinum infection, is characterized by a single papulonodular, verrucose and/or ulcerated granulomatous lesion in the inoculum site. Careful patient's history collection, high clinical suspicion and appropriate sample (e.g. cutaneous biopsy) for microbiological culture are crucial for a timely diagnosis. The treatment is not standardized yet and relies on administration of two active antimycobacterial agents, always guided by antimicrobial susceptibility test on culture, with macrolides and rifampin as pivotal drugs, as well as prompt surgery when feasible. In this narrative review, we provide to Clinicians an updated report of epidemiology, microbiological characteristics, clinical presentation, diagnosis, and management of M. marinum infection.

Tuberkulose im Erwachsenenalter

Die Tuberkulose ist in Deutschland eine seltene, überwiegend gut behandelbare Erkrankung. Weltweit ist sie eine der häufigsten Infektionserkrankungen mit ca. 10 Millionen Neuerkrankungen/Jahr. Auch bei einer niedrigen Inzidenz in Deutschland bleibt Tuberkulose insbesondere aufgrund der internationalen Entwicklungen und Migrationsbewegungen eine wichtige Differenzialdiagnose. In Deutschland besteht, aufgrund der niedrigen Prävalenz der Erkrankung und der damit verbundenen abnehmenden klinischen Erfahrung, ein Informationsbedarf zu allen Aspekten der Tuberkulose und ihrer Kontrolle. Diese Leitlinie umfasst die mikrobiologische Diagnostik, die Grundprinzipien der Standardtherapie, die Behandlung verschiedener Organmanifestationen, den Umgang mit typischen unerwünschten Arzneimittelwirkungen, die Besonderheiten in der Diagnostik und Therapie resistenter Tuberkulose sowie die Behandlung bei TB-HIV-Koinfektion. Sie geht darüber hinaus auf Versorgungsaspekte und gesetzliche Regelungen wie auch auf die Diagnosestellung und präventive Therapie einer latenten tuberkulösen Infektion ein. Es wird ausgeführt, wann es der Behandlung durch spezialisierte Zentren bedarf.

Die Aktualisierung der S2k-Leitlinie „Tuberkulose im Erwachsenenalter“ soll allen in der Tuberkuloseversorgung Tätigen als Richtschnur für die Prävention, die Diagnose und die Therapie der Tuberkulose dienen und helfen, den heutigen Herausforderungen im Umgang mit Tuberkulose in Deutschland gewachsen zu sein.

Outcomes of Adjunctive Surgery in Patients With Nontuberculous Mycobacterial Pulmonary Disease: A Systematic Review and Meta-analysis

BACKGROUND

The burden of nontuberculous mycobacterial pulmonary disease (NTM-PD) is increasing worldwide. Amidst the poor treatment success of antibiotic therapy, adjunctive surgery is gaining attention; however, discrepancies in reported outcomes exist.

RESEARCH QUESTION

What are the treatment outcomes and complications of patients with NTM-PD undergoing adjunctive surgery?

STUDY DESIGN AND METHODS

The MEDLINE, Embase, and Cochrane databases were searched for eligible studies before January 2022. Studies reporting the outcomes of adjunctive surgery in adult patients who satisfied the diagnostic criteria for NTM-PD were included. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines. Data were extracted by two independent observers. Estimates of proportion were pooled using a random-effects model. Sputum mycobacterial culture negative conversion, recurrence, complications, and in-hospital mortality after surgery were primary outcomes that had been set before data collection began. Heterogeneity was evaluated by using the I² statistic, and publication bias was assessed by using funnel plots and the Egger test.

RESULTS

Fifteen of the 2,739 screened studies, with 1,071 patients, were assessed. The weighted proportion of postoperative sputum culture negative conversion was 93% (95% CI, 87%-97%), and recurrence was 9% (95% CI, 6%-14%) for a median follow-up of 34 months. The proportion of patients who experienced postoperative complications was 17% (95% CI, 13%-23%), and in-hospital mortality was 0% (95% CI, 0%-2%). Studies that performed multilobar lung resection in > 30% of the study population showed comparable rates of complications with studies that did not.

INTERPRETATION

Adjunctive surgery is an effective therapeutic option with acceptable rates of complications for selected patients with NTM-PD.

TRIAL REGISTRY

PROSPERO; No.: CRD42022310663; URL: https://www.crd.york.ac.uk/prospero/.

Alternatives to Antibiotics against Mycobacterium abscessus

Mycobacterium abscessus complex is extremely difficult to treat. Intrinsic and acquired bacterial resistance makes this species one of the most challenging pathogens and treatments last from months to years, associated with potential risky antibiotic toxicity and a high number of failures. Nonantibiotic antimicrobial agents against this microorganism have recently been studied so as to offer an alternative to current drugs. This review summarizes recent research on different strategies such as host modulation using stem cells, photodynamic therapy, antibiofilm therapy, phage therapy, nanoparticles, vaccines and antimicrobial peptides against M. abscessus both in vitro and in vivo.

Sclerosing mesenteritis due to Mycobacterium genavense infection: A case report

RATIONALE

Since its first identification in the early 1990s, Mycobacterium genavense has been considered and opportunistic pathogen. It mainly causes gastrointestinal symptoms, but also disseminated infections in severely immunosuppressed patients. Sclerosing mesenteritis is a long-term complication with high morbidity and mortality. As it is a rare condition, there are no specific guidelines for its management. We report a challenging case of persistent M. genavense infection, and propose surgery as an alternative treatment strategy.

PATIENT CONCERNS

A 38-year-old Caucasian man presented to the emergency room with fever, abdominal pain, and night sweats for 3 months. HIV screening revealed a previously unknown HIV-1 infection, with a CD4 cell count of 216 cell/µL and viral load of 361.000 copies/mL at diagnosis. A body CT-scan showed mild splenomegaly as well as mesenteric and retroperitoneal enlarged lymph nodes. Fine needle aspiration revealed the presence of acid-fast bacilli, but mycobacterial cultures were negative. In the second sample, 16S RNA sequencing yielded a diagnosis of M. genavense infection. Despite 2 years of corticosteroids and antimycobacterial treatment excluding rifampicin due to a severe cutaneous reaction, there was no clinical improvement and an increase in the mesenteric lymph node size was observed, with a sclerosing transformation of the mesentery. A surgical approach was proposed to release small bowel loops and to remove fibrin. A second surgery was required due to an acute peritonitis ought to yeyunal segmental isquemia and perforation. Finally, the patient evolved favorably, and antimycobacterial drugs were suspended without relapse.

LESSONS

Despite a prolonged multidrug strategy, some patients develop persistent M. genavense infection. Once sclerosing mesenteritis is established, clinicians have few treatment options. Surgery should be considered in patients with sclerosing mesenteritis or bowel obstruction. The combination of medical and surgical treatment could be a potential cure for these patients.

Identification of Small Molecule Inhibitors against Mycobacteria in Activated Macrophages

Mycobacterial pathogens are intrinsically resistant to many available antibiotics, making treatment extremely challenging, especially in immunocompromised individuals and patients with underlying and chronic lung conditions. Even with lengthy therapy and the use of a combination of antibiotics, clinical success for non-tuberculous mycobacteria (NTM) is achieved in fewer than half of the cases. The need for novel antibiotics that are effective against NTM is urgent. To identify such new compounds, a whole cell high-throughput screen (HTS) was performed in this study. Compounds from the Chembridge DIVERSet library were tested for their ability to inhibit intracellular survival of M. avium subsp. hominissuis (MAH) expressing dtTomato protein, using fluorescence as a readout. Fifty-eight compounds were identified to significantly inhibit fluorescent readings of MAH. In subsequent assays, it was found that treatment of MAH-infected THP-1 macrophages with 27 of 58 hit compounds led to a significant reduction in intracellular viable bacteria, while 19 compounds decreased M. abscessus subsp. abscessus (Mab) survival rates within phagocytic cells. In addition, the hit compounds were tested in M. tuberculosis H37Ra (Mtb) and 14 compounds were found to exhibit activity in activated THP-1 cells. While the majority of compounds displayed inhibitory activity against both replicating (extracellular) and non-replicating (intracellular) forms of bacteria, a set of compounds appeared to be effective exclusively against intracellular bacteria. The efficacy of these compounds was examined in combination with current antibiotics and survival of both NTM and Mtb were evaluated within phagocytic cells. In time-kill dynamic studies, it was found that co-treatment promoted increased bacterial clearance when compared with the antibiotic or compound group alone. This study describes promising anti-NTM and anti-Mtb compounds with potential novel mechanisms of action that target intracellular bacteria in activated macrophages.

Lungenerkrankung durch seltenere nicht-tuberkulöse Mykobakterien – Neue internationale Empfehlungen

Therapie von NTM-Infektionen Für die Behandlung von NTM-Infektionen der Lungen stehen erstmals Evidenz-basierte internationale Leitlinien zur Verfügung. Nach der ersten Publikation der neuen ATS/ERS/ESCMID- und IDSA-Leitlinien zur Behandlung von Lungenerkrankungen durch M. avium complex, M. kansasii, M. xenopi und M. abscessus von 2020 liegen nun weitere Empfehlungen zur Behandlung von selteneren Lungenerkrankungen durch NTM vor.

Relevante NTM-Spezies Die neuen Empfehlungen umfassen Lungenerkrankungen durch die schnellwachsenden Mykobakterien M. chelonae und M. fortuitum sowie durch die langsam-wachsenden Mykobakterien M. genavense, M. gordonae, M. malmoense, M. simiae und M. szulgai.

[Clinical Characteristics of Nontuberculous Mycobacterium Infection Cases in Sichuan, China in 2016-2021: A Retrospective Study]

Objective

To study the distribution of nontuberculous mycobacterium (NTM) strains, clinical characteristics and drug sensitivity data of NTM infections so as to provide support for the prevention and treatment of diseases caused by NTM infection in Sichuan.

Methods

The clinical data of NTM infection cases treated at the Public Health Clinical Center of Chengdu between July 2016 and July 2021 were collected and the characteristics of the infections were retrospectively reviewed.

Results

There were differences in sex, age and underlying diseases among the NTM infection cases in Sichuan. Specifically, young and middle-aged men aged between 20 and 40 were susceptible to AIDS, older men aged over 60 were susceptible to lung diseases, and middle-aged and older women over 40 were susceptible to bronchiectasis. Respiratory tract was the main route of NTM infection. The dominant strain in Sichuan was M. chelonae/ abscessus. The drug resistance rate of M. avium and M. chelonae/ abscessus were relatively higher.

Conclusion

For NTM infection patients with different demographic characteristics and underlying diseases, the NTM infection sites, strains, and drug resistance are also different. Definite etiological diagnosis is essential to the treatment of NTM infection. We should highlight the importance of adopting individualized treatment for different NTM infections.

Mycobacterium abscessus pathogenesis identified by phenogenomic analyses

The medical and scientific response to emerging and established pathogens is often severely hampered by ignorance of the genetic determinants of virulence, drug resistance and clinical outcomes that could be used to identify therapeutic drug targets and forecast patient trajectories. Taking the newly emergent multidrug-resistant bacteria Mycobacterium abscessus as an example, we show that combining high-dimensional phenotyping with whole-genome sequencing in a phenogenomic analysis can rapidly reveal actionable systems-level insights into bacterial pathobiology. Through phenotyping of 331 clinical isolates, we discovered three distinct clusters of isolates, each with different virulence traits and associated with a different clinical outcome. We combined genome-wide association studies with proteome-wide computational structural modelling to define likely causal variants, and employed direct coupling analysis to identify co-evolving, and therefore potentially epistatic, gene networks. We then used in vivo CRISPR-based silencing to validate our findings and discover clinically relevant M. abscessus virulence factors including a secretion system, thus illustrating how phenogenomics can reveal critical pathways within emerging pathogenic bacteria.

Structure-Activity Relationship of Penem Antibiotic Side Chains Used against Mycobacteria Reveals Highly Active Compounds

The rise of antibiotic-resistant Mycobacterium tuberculosis and non-tuberculous mycobacterial infections has placed ever-increasing importance on discovering new antibiotics to treat these diseases. Recently, a new penem, T405, was discovered to have strong antimicrobial activity against M. tuberculosis and Mycobacteroides abscessus. Here, a penem library of C2 side-chain variants was synthesized, and their antimicrobial activities were evaluated against M. tuberculosis H₃₇Rv and M. abscessus ATCC 19977. Several new penems with antimicrobial activity stronger than the standard-of-care carbapenem antibiotics were identified with some candidates improving on the activity of the lead compound, T405. Moreover, many candidates showed little or no increase in the minimum inhibitory concentration in the presence of serum compared to the highly protein-bound T405. The penems with the strongest activity identified in this study were then biochemically characterized by reaction with the representative l,d-transpeptidase Ldt_Mt2 and the representative penicillin-binding protein d,d-carboxypeptidase DacB2.

Mycobacterium paragordonae is an emerging pathogen in human pulmonary disease: clinical features, antimicrobial susceptibility testing and outcomes

Objectives: Mycobacterium paragordonae (MPG) is an emerging and less common type of Non-tuberculous mycobacteria (NTM) and we know little about its characteristics and prognosis, hence we constructed this retrospective cohort study. Methods: MPG was identified using MALD-TOF MS, multi-target combined gene sequencing and WGS. Clinical information was collected, antimicrobial susceptibility testing was measured using the SLOMYCO panel, and optimal growth temperature testing was measured using Lowenstein-Jensen medium. Results: Eight MPGs were isolated from 1730 NTMs (0.46%); the mean age of MPG pulmonary disease (MPG-PD) patients was 42.38 ± 9.92 years, 37.5% were male, and the average BMI was 18.4 ± 0.51 kg/m². All patients had the symptoms of cough and sputum and CT images mainly presented in patchy or streaky shadows, MPG grew at 25°C, 30°C and 37°C, and the optimal growth temperature is 37°C. MPGs were sensitive to clarithromycin, rifabutin, amikacin, linezolid, moxifloxacin, cotrimoxazole and ciprofloxacin, two isolates were resistant to rifampicin. Two patients had follow up information, their imaging remained stable during the follow-up. Conclusions: MPG-PD is a rare NTM disease and is more likely to develop in middle-aged, female, and low BMI patients. The patients present with no specific features within the symptoms as well as the CT imaging. The optimal growth temperature of MPG is at 37°C, MPG-PD has excellent sensitivity to drugs recommended by CLSI and presents with a stable disease.

Incidence of Nontuberculous Mycobacterial Pulmonary Infection, by Ethnic Group, Hawaii, USA, 2005-2019

To further clarify differences in the risk for nontuberculous mycobacterial pulmonary infection (NTM-PI) among ethnic populations in Hawaii, USA, we conducted a retrospective cohort study among beneficiaries of Kaiser Permanente Hawaii (KPH). We abstracted demographic, socioeconomic, clinical, and microbiological data from KPH electronic health records for 2005-2019. An NTM-PI case-patient was defined as a person from whom >1 NTM pulmonary isolate was obtained. We performed Cox proportional hazards regression to estimate incidence of NTM-PI while controlling for confounders. Across ethnic groups, risk for NTM-PI was higher among persons who were underweight (body mass index [BMI] <18.5 kg/m²). Among beneficiaries who self-identified as any Asian ethnicity, risk for incident NTM-PI was increased by 30%. Low BMI may increase susceptibility to NTM-PI, and risk may be higher for persons who self-identify as Asian, independent of BMI.

An Unfavorable Outcome of M. chimaera Infection in Patient with Silicosis

Mycobacterium chimaera is a slow-growing, nontuberculous mycobacterium (NTM) belonging to the Mycobacterium avium complex (MAC). It was identified as a unique species in 2004. Since 2013 it has been reported as a cause of disseminated infection in patients after cardiac surgeries. Only a few cases associated with underlying lung diseases have been noted. M. chimaera infection is characterized by ambiguous symptoms. There is no treatment with proven effectiveness, and it has a poor prognosis. Silicosis is a disease that can predispose to mycobacterial infection. Silica damages pulmonary macrophages, inhibiting their ability to kill mycobacteria. We present a case of M. chimaera infection in a patient with silicosis and without other comorbidities. To our knowledge, it is the first case of silicosis associated with M. chimaera disease. A 45-year-old man presented with a persistent low-grade fever. Based on the clinical and radiological picture, positive cultures, and histological examination, the nontuberculous mycobacterial disease was diagnosed. First, multidrug therapy according to the treatment guidelines for MAC was implemented, then antibiotics were administrated, based on drug sensitivity. Despite the treatment, eradication was not achieved and the patient died. The analysis of M. chimaera infection cases could contribute to developing recommendations and thus improve the prognosis.

The Impact of Nontuberculous Mycobacteria Species on Mortality in Patients With Nontuberculous Mycobacterial Lung Disease

Patients with nontuberculous mycobacterial lung disease (NTM-LD) have increased mortality. The impact of NTM species on the risk of mortality remains unclear, especially that of death by non-cancer causes. We conducted a retrospective cohort study from 2006 to 2018 in a tertiary-care hospital in Taiwan. We enrolled patients who fulfilled the microbiological diagnostic criteria of NTM-LD. The mortality causes within 8 years after diagnosis were identified, and the Cox proportional hazard regression was performed for risk factors of mortality. A total of 1,652 subjects with NTM-LD were included. Among them, 723 (43.8%) were infected by Mycobacterium avium complex (MAC), 408 (24.7%) by M. abscessus complex (MABC), 120 (7.3%) by Mycobacterium kansasii (MK), 304 (18.4%) by other rapid-growing mycobacteria (RGM), and 97 (5.9%) by other slow-growing mycobacteria (SGM) groups. The 8-year all-cause mortality was 45.2% for all and the highest in the MK-LD group (59.2%), followed by the MABC-LD and MAC-LD groups. The adjusted hazard ratios were 2.20 (95% confidence interval: 1.40–3.46) in the MK-LD, 1.85 (1.54–2.22) in the MABC-LD, and 1.65 (1.12–2.41) in the MAC-LD groups for all-cause mortality, compared with the SGM group. Kaplan–Meier survival curves showed that all-cause mortality, non-cancer mortality, and mortality due to chronic airway diseases were significantly correlated with NTM species (log-rank p = 0.0031, < 0.001, and 0.001, respectively). High 8-year mortality rates were found in patients with NTM-LDs according to different NTM species. Notably, the difference was significant in non-cancer mortality causes, especially in chronic airway diseases.

Clinical significance and safety of combined treatment with chemotherapy and pulmonary rehabilitation regarding health-related quality of life and physical function in nontuberculous mycobacterial pulmonary disease

BACKGROUND

In the treatment of patients with nontuberculous mycobacterial pulmonary disease (NTM-PD), pulmonary rehabilitation (PR) has been recommended as a non-pharmacological therapy. However, no study has validated the combination of chemotherapy and PR in this context. This study investigated the effect of chemotherapy and supervised PR on health-related quality of life (HRQoL) and physical function in NTM-PD patients.

METHODS

This prospective cohort study included patients diagnosed with NTM-PD who had a planned hospitalization of at least 3 weeks for chemotherapy and PR. HRQoL (Leicester Cough Questionnaire [LCQ] and chronic obstructive pulmonary disease assessment test [CAT]), physical function (incremental shuttle walk distance [ISWD], quadriceps force), and C-reactive protein levels were assessed before and after treatment, and the corresponding data were analyzed in conjunction with clinical data. The adverse events of PR were also investigated.

RESULTS

Forty-two patients who met the study criteria were included in the analysis. After treatment, all LCQ item scores, total CAT score and sub-item scores related to respiratory symptoms, ISWD, quadriceps force, and C-reactive protein levels were found to have improved significantly. In the chronic cough with excessive sputum production (CCS) group, the proportions of responders who showed improvements in LCQ and CAT scores and ISWD greater than the corresponding minimal clinically important difference were significantly greater than those in the non-CCS group. No PR-related adverse events were reported.

CONCLUSIONS

Combined treatment with chemotherapy and PR may improve HRQoL and physical function, and supervised PR can be provided safely.

Old age is associated with worse treatment outcome and frequent adverse drug reaction in Mycobacterium avium complex pulmonary disease

Background

The number of patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) is rapidly increasing globally, especially in the older population. However, there is a dearth of evidence regarding the impact of aging on the treatment outcomes of NTM-PD.

Methods

We analyzed consecutive patients who satisfied the diagnostic criteria for Mycobacterium avium complex (MAC)-PD and received antibiotic treatment between January 2009 and December 2020 at a tertiary referral hospital in Korea. The main outcomes were (1) long-term treatment success, defined by negative culture conversion for more than 12 months; and (2) adverse drug reactions (ADRs). Multivariable logistic regression model was used to evaluate the association between age and main outcomes.

Results

A total of 614 patients (median age, 65 years, interquartile range [IQR] 57–73 years; men, 35.3%) were included. Median treatment duration (530 days, IQR 290–678 days; P for trend < 0.001) and long-term treatment success (P for trend = 0.026) decreased, whereas ADRs (P for trend < 0.001) increased significantly with age. Multivariable analyses demonstrated that age ≥ 80 years was an independent factor associated with ADRs (adjusted odds ratio [aOR] 3.29; 95% confidence interval [CI] 1.05–10.28) and worse treatment outcome (aOR 0.42; 95% CI 0.19–0.91).

Conclusions

Aging is associated with worse treatment outcome and frequent ADRs of patients with MAC-PD. Individualized treatment with reduced-intensity may be a reasonable alternative for older adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02063-2.

Acupuncture-Associated Mycobacterium massiliense and Scedosporium Infections Superimposed by Tetanus

Background

Tetanus has rarely been reported in Thailand since 1982 due to 100% tetanus vaccination coverage during the neonatal period of life. However, the reemergence of tetanus has been observed in our country during the past decade, mainly due to the increasing number of migrants traveling from neighboring countries in search of work. Acupuncture has become an essential part of alternative and complementary medicine. To our knowledge, acupuncture-associated Mycobacterium abscessus and Scedosporium infections superimposed by tetanus have never been reported. Case Presentation. A 55-year-old Thai female with schizophrenia was hospitalized due to a 4-day course of trismus, dysphagia, and back muscle spasms. Upon admission, a clinical diagnosis of tetanus was made, which included muscle rigidity and reflex muscle spasms, despite a recent history of diphtheria-tetanus (dT) vaccination for tetanus prophylaxis after 2 episodes of falling complicated by two lacerations on the left shoulder and head. Endotracheal intubation for airway protection was given, in addition to tetanus immunoglobulin, metronidazole, and diazepam which were prescribed to the patient. Incision and drainage of the wound on the left shoulder yielded 40 mL of pus, which subsequently grew Clostridium species, Mycobacterium massiliense, and Scedosporium on anaerobic bacterial, mycobacterial, and fungal cultures, respectively. An incision of an acupuncture wound on the abdominal wall yielded 1 mL of pus, which exhibited positive acid-fast bacilli (AFB) on AFB stain. Mycobacterial culture finally grew M. massiliense. The organism was susceptible to amikacin and clarithromycin. Amikacin, clarithromycin, ciprofloxacin, and voriconazole were then added. The patient gradually improved and was discharged after one month of hospitalization. The patient was reported to be doing well, with no neurological sequelae, when last seen one month after discharge.

Conclusions

To our knowledge, this is the first case of acupuncture-associated M. massiliense and Scedosporium infections superimposed by tetanus. In Thailand, the occurrence of acupuncture by nonqualified individuals and the reemergence of tetanus remain prevalent. Hence, it is not uncommon to see tetanus in association with acupuncture-related nontuberculous mycobacterial/fungal infection.

Prosthetic joint infections caused by Mycobacterium avium complex: a series of five cases

Prosthetic joint infection (PJI) due to Mycobacterium avium complex (MAC) is a rare entity. There is limited guidance on management strategies and outcomes. In this paper, we describe the demographics, comorbidities, and clinical course of five patients at two academic institutions, constituting the largest series described to date.

Early-Phase Adverse Effects and Management of Liposomal Amikacin Inhalation for Refractory Mycobacterium avium Complex Lung Disease in Real-World Settings

Purpose

Amikacin liposome inhalation suspension (ALIS), which efficiently allows amikacin to reach the pulmonary periphery for effect while minimising systemic adverse effects, was recently approved for treating Mycobacterium avium complex (MAC) infections. The international Phase 3 open-label clinical trials showed promising results, contributing to sputum culture conversion, but few studies have examined the efficacy and adverse effects of ALIS using real-world data. We identified the clinical outcome and adverse effects of ALIS in the early phase of treatment, for more effective and safe use in clinical practice.

Patients and Methods

The study population consisted of patients with MAC lung disease (MAC-LD), introduced to ALIS therapy after July 2021 at Keio University Hospital due to poor response to multidrug therapy. The sputum smear/culture results, symptoms, adverse effects, and the serum amikacin concentrations of the early phase of ALIS inhalation therapy were examined.

Results

A total of 11 patients (9 women; median age 64.6 years) were included in this study. The median disease duration of MAC-LD was 13.7 years, and all patients exhibited a positive culture at the beginning of ALIS inhalation. Three of the six patients (50.0%) who were initially sputum-smear-positive were confirmed to have become sputum-smear-negative within one month, including one culture conversion. ALIS inhalation therapy caused some adverse effects in nine patients (81.8%); however, no serious systemic adverse effects were observed. The most common adverse effect was hoarseness (72.7%), which mostly occurred around 1 week after initiation. The medians of peak serum amikacin concentrations were 1.4 and 2.3 μg/mL for the first and third inhalations, respectively. Trough serum concentrations just before the third inhalation were <1.2 μg/mL in all patients.

Conclusion

ALIS therapy might be a treatment option for patients with refractory MAC infection with long disease duration and a poor response to guideline-based therapy.

Potential Cross-Transmission of Mycobacterium abscessus among Non-Cystic Fibrosis Patients at a Tertiary Hospital in Japan

Mycobacterium abscessus (M. abscessus) is a highly antimicrobial-resistant pathogen that causes refractory pulmonary disease. Recently, the possibility of M. abscessus cross-transmission among cystic fibrosis (CF) patients has been reported. CF is rare in Asia, but M. abscessus pulmonary disease is common. Therefore, we investigated the possibility of M. abscessus cross-transmission in a Japanese hospital setting. Of 104 M. abscessus isolates, 25 isolates from 24 patients were classified into four clusters based on their variable number of tandem repeat profiles and were subjected to whole-genome sequencing (WGS). The epidemiological linkages among our patients were investigated by integrating the WGS data of previously reported nosocomial outbreak-related M. abscessus clinical isolates in the United Kingdom and the United States. Eight transmissible clusters (TCs) were identified. The United Kingdom and United States isolates were assigned to four clusters (TC1, TC2, TC5, and TC8) and one cluster (TC3), respectively. A total of 12 isolates from our hospital belonged to 4 clusters (TC4, TC5, TC6, and TC7). Epidemiological linkage analysis inferred direct or indirect transmission between patients in our hospital in TC4 and TC5 but not in TC6 and TC7. In TC5, the single nucleotide polymorphism distance between isolates from Japanese and United Kingdom patients was less than 21; however, there was no contact. This study revealed that genetically closely related isolates exist, even in non-CF patients. However, the transmission route remains unclear, and further research is warranted to clarify whether cross-transmission is involved. IMPORTANCE Although the possibility of Mycobacterium abscessus (M. abscessus) cross-transmission in cystic fibrosis (CF) patients has often been reported, it is not clear whether similar events have occurred in Asian non-CF patients. Whole-genome sequencing analysis of M. abscessus isolates from Fukujuji Hospital in Japan indicated that genetically closely related M. abscessus isolates exist. In addition, according to epidemiological linkage analysis, some clusters were suspected of direct or indirect transmission between patients within our hospital. However, the transmission route of M. abscessus remains unclear, because interestingly, one cluster showed a single nucleotide polymorphism distance of less than 21 from the United Kingdom isolates, but no epidemiological linkage was identified.

Pharmacologic management of Mycobacterium chimaera Infections: A Primer for Clinicians

Mycobacterium chimaera, a member of the Mycobacterium avium complex, can cause infections in individuals after open heart surgery due to contaminated heater-cooler units. The diagnosis can be challenging, as the incubation period can be quite variable, and symptoms are nonspecific. In addition to aggressive surgical management, combination pharmacologic therapy is the cornerstone of therapy, which should consist of a macrolide, a rifamycin, ethambutol, and amikacin. Multiple second-line agents may be utilized in the setting of intolerances or toxicities. In vitro susceptibility of these agents is similar to activity against other species in the Mycobacterium avium complex. Drug–drug interactions are frequently encountered, as many individuals have chronic medical comorbidities and are prescribed medications that interact with the first-line agents used to treat M. chimaera. Recognition of these drug–drug interactions and appropriate management are essential for optimizing treatment outcomes.

Clinical Characteristics and Mortality of Non-tuberculous Mycobacterial Infection in Immunocompromised vs. Immunocompetent Hosts

Immunosuppression and host vulnerability play a key role in non-tuberculous mycobacteria (NTM) pathogenesis. The objective of this study was to compare the clinical characteristics and mortality of NTM infections in immunocompromised and immunocompetent patients. We used a retrospective dataset obtained from our large, tertiary, urban, teaching hospital which is the medical records of hospitalized patients with NTM infections between January 1, 2013 to December 31, 2020. The information including clinical manifestations, imaging, and NTM etiological data were obtained from the hospital's clinical data system. A total of 480 patients with NTM infections completed species identification. 118 hospitalized NTM patients who met ATS/IDSA NTM diagnostic criteria and had complete medical records were included in the study. The average age was 49.4 years, 57 (48.3%) were female, and 64 (54.2%) were immunosuppressed hosts. In our study, the most common species in order of frequency were: M. intracellulare, M. abscessus, M. avium, and M. kansasii among NTM patients. The most common comorbidity was history of previous tuberculosis (30.5%). Besides malignancy, the most common immunodeficiencies were adult-onset immunodeficiency induced by anti-interferon-gamma autoantibody, SLE, and vasculitis. The immunocompromised patients with NTM had more clinical symptoms, comorbidities and lower lymphocyte counts compared to immunocompetent patients. The mortality we observed in immunocompromised patients of NTM disease was significantly higher than that of immunocompetent patients (HR 3.537, 95% CI 1.526–8.362). Immunosuppressed NTM patients with lower B and CD4⁺ T lymphocyte counts may more frequently present with disseminated NTM infections, clinical exacerbations, and higher mortality than immunocompetent patients.

Drug development challenges in nontuberculous mycobacterial lung disease: TB to the rescue

Nontuberculous mycobacterial pulmonary disease (NTM-PD) is treated with multiple repurposed drugs. Chemotherapy is long and often toxic, includes parenteral drugs, and suffers from poor cure rates. There is an urgent need for more efficacious, tolerated, and oral antibiotics optimized towards the treatment of NTM-PD, adapted to the spectrum of disease. In contrast to the empty NTM pipeline, drug development for the related tuberculosis lung disease has experienced a renaissance. Here, we argue that applying lessons learned from tuberculosis will facilitate the discovery of curative oral regimens for NTM-PD.

Beyond antibiotics: recent developments in the diagnosis and management of nontuberculous mycobacterial infection

Nontuberculous mycobacteria (NTM) pulmonary disease represents a significant clinical challenge with suboptimal therapy and increasing prevalence globally. Although clinical practice guidelines seek to standardise the approach to diagnosis and treatment of NTM disease, a lack of robust evidence limits their utility and significant variability exists in clinical practice. Here we walk through some novel approaches in diagnosis and therapy that are under development to tackle a disease where traditional strategies are failing.

Prevalence of NTM disease is rising globally, yet current diagnostic and therapeutic strategies are lacking. This review describes some burgeoning diagnostic and therapeutic approaches, but it is clear that real progress will need more focused attention.https://bit.ly/3O0K2SP

Respiratory etiological surveillance among quarantined patients with suspected lower respiratory tract infection at a medical center in southern Taiwan during COVID-19 pandemic

Background

A comprehensive study of respiratory pathogens was conducted in an area with a low prevalence of COVID-19 among the adults quarantined at a tertiary hospital.

Methods

From March to May 2020, 201 patients suspected lower respiratory tract infection (LRTI) were surveyed for etiologies by multiplex polymerase chain reaction (PCR: FilmArray TM Respiratory Panel) test combination with cultural method, viral antigen detection and serologic surveys.

Results

Total 201 patients tested with FilmArray TM Respiratory Panel were enrolled, of which 68.2% had sputum bacterial culture, 86.1% had pneumococcus and Legionella urine antigen test. Their median age was 72.0 year-old with multiple comorbidities, and 11.4% were nursing home residents. Bacteria accounted for 59.7% of identified pathogens. Atypical pathogens were identified in 31.3% of total pathogens, of which viruses accounted for 23.9%. In comparison to patients with bacterial infection, patients with atypical pathogens were younger (median= 77.2 vs 67.1, years, P = 0.017) and had shorter length of hospital (8.0 vs 4.5, days, P = 0.007).

Conclusions

Patients with LRTI caused by atypical pathogens was indistinguishable from those with bacterial pathogens by clinical manifestations or biomarkers. Multiplex PCR providing rapid diagnosis of atypical pathogens enhance patient care and decision making when rate of sputum culture sampling was low in quarantine ward during pandemic.