Nontuberculous Mycobacteria Research Articles

Negative outcome in cutaneous Mycobacterium marinum infection treated with surgical intervention: Two-case report.

Mycobacterium marinum (M marinum), a slow-growing nontuberculous mycobacterium (NTM), is widely distributed in aquatic environments. It is a well-known cutaneous pathogen, which causes sporotrichosis-like lesions. In this report, we describe 2 cases of subcutaneous M marinum infection. Both patients underwent several surgical procedures at local hospitals, and despite optimal surgical site healing, new lesions appeared in adjacent sites. Based on NTM culture, identification by gene sequencing, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry, the diagnosis of subcutaneous NTM infection was confirmed. The patients were treated with oral rifampicin 0.45 g/day and clarithromycin 1 g/day and oral doxycycline hydrochloride capsules (200 mg/day), respectively. Both patients were treated for 8 and 5 weeks, respectively, and the lesions healed. Surgical debridement cannot compete with or impede NTM lymphatic spread; antimicrobial therapy is the first choice for the treatment of M marinum infections.

Discovery and analysis of the relationship between organic components in exhaled breath and bronchiectasis

The prevalence of patients with bronchiectasis (BE) has been rising in recent years, which increases the substantial burden on the family and society. Exploring a convenient, effective, and low-cost screening tool for the diagnosis of BE is urgent. We expect to identify the accuracy (ACC) of breath biomarkers (BBs) for the diagnosis of BE through breathomics testing and explore the association between BBs and clinical features of BE. Exhaled breath samples were collected and detected by high-pressure photon ionization time-of-flight mass spectrometry in a cross-sectional study. Exhaled breath samples were from 215 patients with BE and 295 control individuals. The potential BBs were selected via the machine learning (ML) method. The overall performance was assessed for the BBs-based BE detection model. The significant BBs between different subgroups such as the severity of BE, acute or stable stage, combined with hemoptysis or not, with or without nontuberculous mycobacterium (NTM),P. aeruginosa(P.a) isolation or not, and the BBs related to the number of involved lung lobes and lung function were discovered and analyzed. The top ten BBs based ML model achieved an area under the curve of 0.940, sensitivity of 90.7%, specificity of 85%, and ACC of 87.4% in BE diagnosis. Except for the top ten BBs, other BBs were found also related to the severity, acute/stable status, hemoptysis or not, NTM infection,P.aisolation, the number of involved lobes, and three lung functional parameters in BE patients. BBs-based BE detection model showed good ACC for diagnosis. BBs have a close relationship with the clinical features of BE. The breath test method may provide a new strategy for BE screening and personalized management.

Draft genome sequence of Mycolicibacterium conceptionense isolated from the sputum sample of a patient with pulmonary tuberculosis.

We report the draft genome of Mycolicibacterium conceptionense, a rapidly growing nontuberculous mycobacterium, isolated from the sputum sample of a patient undergoing treatment for multidrug-resistant tuberculosis in Delhi, India. The 6,366,717-bp genome contains 6,124 coding sequences, one 5S rRNA, three 16S rRNAs, six 23S rRNAs, and 49 tRNAs.

Assays for Assessing Mycobacterium avium Immunity and Evaluating the Effects of Therapeutics.

In Europe and North America, the prevalence of pulmonary nontuberculous mycobacteria (NTM) is increasing. Most pulmonary NTM infections are caused by the Mycobacterium avium complex (MAC). Sadly, the treatment of pulmonary MAC is suboptimal with failure rates ranging from 37% to 58%. Therefore, there is a need to develop new therapeutics. Developing new immunotherapies and studying their interaction with standard or new drugs requires reliable assays. Four different assays including CFSE-based flow cytometry, in vitro protection assays, IFN-γ ELISPOT, and murine infection models were optimized using a reference strain of MAC (ATCC 700898) to help with the development of immunotherapies for MAC. Expansion of proliferating and IFN-γ producing human T cells is optimal after 7 days of stimulation with MAC at a multiplicity of infection (MOI) of 0.1, achieving a stimulation index of 26.5 ± 11.6 (mean ± SE). The in vitro protection assay for MAC works best by co-culturing T cells expanded for 7 days with MAC (MOI 1)-infected autologous macrophages. Aerosol MAC infection of mice allows measurement of the effects of the BCG vaccine and clarithromycin. IFN-γ ELISPOT assays with live MAC (MOI 3) stimulation of splenocytes from mice immunized with BCG help identify differences between unimmunized mice and mice immunized with BCG. In conclusion, multiple assays are available for use to identify MAC-specific effector T cells, which will help in the development of new therapeutics or vaccines against pulmonary MAC.

Suppurative Granulomatous Osteomyelitis with Microcystic Changes Due to Mycobacterium chelonae- abscessus Complex

Abstract Introduction/Objective Mycobacterium chelonae and Mycobacterium abscessus are rapidly growing non-tuberculous mycobacterium found in soil and water, and represent rare causes of skin and soft tissue infection. Treatment typically involves an extended course of antimicrobial therapy and occasionally surgical debridement. Previous reports have described a distinctive pattern of suppurative granulomatous inflammation with microcystic changes in skin biopsies; however, the morphologic changes of M. chelonae-abscessus complex as a cause of osteomyelitis have not been well-documented in the literature. Methods/Case Report We searched our database from 2013 to 2024 for bone samples diagnosed as granulomatous inflammation in which M. chelonae or M. abscessus were identified on concurrent microbiology studies. Patient demographics, risk factors for infection, and treatment data were collected. Results (if a Case Study enter NA) Three patients with culture- or PCR-confirmed M. chelonae (2) or M. abscessus (1) were identified. All infections involved bones of the distal extremities. Patients were 57 years and older with risk factors for infection that included: diabetes (1), intravenous drug use (1), and long-term immunosuppressive therapy (1). All patients presented with osteomyelitis refractory to antibiotic therapy for which bone biopsy, bone resection, or amputation was performed. All cases showed suppurative granulomatous inflammation with microcystic changes. Cystic spaces were markedly enriched for acid-fast bacilli on Fite and/or Ziehl-Neelsen stains. In two patients, the antimicrobial regimen was changed as a result of the pathologic findings and microbiologic testing that provided additional information about speciation and susceptibilities. Conclusion Suppurative granulomatous inflammation has a broad differential that includes blastomycosis, sporotrichosis, cat scratch disease, non-tuberculous mycobacterial infection, and granulomatosis with polyangiitis, for which there are substantial treatment differences. When this pattern of microcystic suppurative granulomatous inflammation is encountered, it is important to perform special stains for acid-fast bacilli, particularly when seen in distal extremity lesions from patients with infections that are refractory to empiric antibiotic therapy.

Mycobacterium terrae Complex Associated Lymphadenitis: Negative AFB PCR

Abstract Introduction/Objective Nontuberculous mycobacteria included with the Mycobacterium terrae complex (MTC) include a ubiquitous, slow-growing collection of mycobacteria known for causing severe resistant skin, joint, and bone infections. There are limited reports of M. Arupensis, included under MTC, causing human infections despite environmental ubiquity. Low sequencing sensitivity for species such as M. Arupensis may result in negative preliminary PCR speciation thus influencing the negative predictive value of this method of organism detection. No prior case reports have described MTC infection presenting as subacute lymphadenitis. Methods/Case Report A 48 year old El Salvadorian male with known diagnosis of HIV presented with oral thrush and significant left-sided lymphadenopathy. He was initially diagnosed with HIV in El Salvador and on ART until immigrating to the US six months prior. HIV antigen and antibody was positive with positive reflex viral PCR. QuantiFERON-TB Gold resulted positive, but CXR was without evidence of pulmonary TB. TB1, TB2, and mitogen minus NIL were negative. He was referred for fine needle aspiration and core needle biopsy of the left cervical lymph node. AFB and AFB FITE stains were performed, but no definitive mycobacteria were identified. GMS was performed and negative for fungal elements. A final histological diagnosis of necrotizing granuloma was given and the tissue was sent for bacterial, AFB, and fungal DNA PCR; no organisms were detected. A sputum sample was obtained and cultured four months after initial presentation and was positive for acid fast bacilli: Mycobacterium terrae complex, most closely resembling Mycobacterium arupensis. The Fite and AFB stains were again reviewed, revealing one single acid fast bacilli organism identified on Fite stain in the necrotizing granuloma. Results (if a Case Study enter NA) N/A Conclusion The negative AFB DNA PCR result may have been a false negative result due to poor sensitivity or selectivity for M. arupensis. There are no former reported cases of M. Arupensis associated necrotizing granulomas in lymph node. This unusual MTC infection presenting as chronic unilateral lymphadenitis underscores the importance of broadening clinical laboratory AFB DNA PCR sensitivity especially in cases of suspected AFB or modified AFB associated necrotizing granulomas.

Facial cutaneous tuberculosis infected by non-tuberculous mycobacteria

BackgroundCutaneous infections caused by non-tuberculous mycobacteria (NTM) are extremely rare, particularly when they are localized to the facial area. This condition presents significant diagnostic challenges due to its unusual presentation and the need for precise microbiological identification.Case PresentationA two-year-old male patient presented with a progressively enlarging reddish-brown mass on the left side of his face. Despite the absence of systemic symptoms, the lesion’s growth warranted investigation due to its growth. Ultrasonography showed a hypoechoic mass in the dermis, indicating an underlying abscess. The subsequent aspiration resulted in pale yellow pus, which upon testing and culture, confirmed the presence of Mycobacterium avium complex infection, a species of NTM. This case exemplifies the synergy between imaging modalities and microbiological analysis, highlighting the crucial role of both in achieving favorable clinical outcomes in patients with suspected cutaneous NTM infections. Ultrasound can expedite diagnosis, improve treatment planning, and enhance patient care by enabling targeted interventions and monitoring response to therapy in these scenarios. However, it is the combination of pathogen-specific diagnostics that ensures accurate etiological attribution and appropriate antimicrobial stewardship.ConclusionAlthough rare, facial cutaneous infections caused by NTM still deserve thorough investigation to determine the exact cause. Ultrasound is used to identify cutaneous lesions, measure their extent, and guide surgical procedures. The ultimate diagnosis is based on microbiological confirmation.

Successful treatment of Keratitis caused by Mycobacterium chelonae and an overview of previous cases in Europe

Introduction and purposeMycobacterium (M.) chelonae is responsible for a half of relatively rare nontuberculous mycobacteria (NTM) keratitis. We report a case of M. chelonae keratitis in a woman following sclerocorneal suture extraction after cataract surgery.ResultsA 70-year-old woman presented with a red eye and corneal infiltration of her left eye six weeks following sclerocorneal suture extraction after an elective cataract surgery in another institute. She complained of a sharp, cutting pain and photophobia. Since initial corneal scrapes and conjunctival swabs proved no pathogen using culture and PCR methods, non-specific antibiotics and antifungal agents were administered. As keratitis was complicated by an inflammation in the anterior chamber and vitreous, samples of the vitreous fluid were sent for microbiologic examination. DNA of Epstein-Barr virus (EBV) was repeatedly detected. Since the intrastromal abscess had formed, corneal re-scrapings were performed and M. chelonae was detected using culture, MALDI-TOF MS and PCR methods. Therapy was changed to a combination of oral and topical clarithromycin, intravitreal, topical and intracameral amikacin, and oral and topical moxifloxacin. The successful therapy led to stabilization. The optical penetrating keratoplasty was performed and no signs of the infection recurrence were found.ConclusionsThe diagnosis of nontuberculous mycobacterial keratitis is difficult and often delayed. An aggressive and prolonged antimicrobial therapy should include systemic and topical antibiotics. Surgical intervention in the form of corneal transplantation may be required in the active and nonresponsive infection. In the presented case this was necessary for visual rehabilitation due to scarring.

Evaluation of protein extraction protocols for MALDI-TOF Biotyper analysis of mycobacteria

Infections caused by Mycobacterium tuberculosis and nontuberculous mycobacteria represent a significant global threat and medical concern. Therefore, accurate and reliable methods must be employed to identify mycobacteria rapidly. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a technique that compares the cellular protein profiles of unknown isolates with reference mass spectra in a database to identify microorganisms. However, the thick and waxy lipid layer, which is rich in mycolic acids and is present in mycobacterial cells, makes protein extraction challenging. To identify the optimal protocol for correctly identifying bacilli using MALDI-TOF mass spectrometry, this study compared four different cellular protein extraction methods. Four strains of M. bovis BCG were selected as representatives of slow-growing mycobacteria, while three strains of fast-growing mycobacteria were also included: M. peregrinum, M. smegmatis, and M. farcinogenes. The extraction method that proved most effective was the extraction of inactivated cells with chloroform and methanol, which partially delipidates the cells. These cells were then extracted with formic acid, as is standard practice for protein extraction. The advantage of this method is that it allows the parallel analysis of cellular lipids and proteins from a single sample. It is therefore important to optimize mycobacterial protein extraction for MALDI-TOF MS analysis in clinical microbiology laboratories.

Genomic Epidemiology of Extrapulmonary Nontuberculous Mycobacteria Isolates at Emerging Infections Program Sites - United States, 2019-2020.

Nontuberculous mycobacteria (NTM) cause pulmonary and extrapulmonary infections. Although isolation of NTM from clinical specimens has increased nationally, few studies delineated the molecular characteristics of extrapulmonary NTM. Extrapulmonary isolates were collected by four Emerging Infections Program sites from October 2019 to March 2020 and underwent laboratory characterization, including matrix-assisted laser desorption ionization-time of flight mass spectrometry, Sanger DNA sequencing, and whole genome sequencing. Bioinformatics analyses were employed to identify species, sequence types (STs), antimicrobial resistance (AR), and virulence genes; isolates were further characterized by phylogenetic analyses. Among 45 isolates, the predominant species were Mycobacterium avium (n=20, 44%), Mycobacterium chelonae (n=7, 16%), and Mycobacterium fortuitum (n=6, 13%). The collection represented 31 STs across 10 species; the most common ST was ST11 (M. avium, n=7). Mycobacterium fortuitum and Mycobacterium abscessus isolates harbored multiple genes conferring resistance to aminoglycosides, beta-lactams, and macrolides. No known AR mutations were detected in rpoB, 16S, or 23S rRNAs. Slow-growing NTM species harbored multiple virulence genes including type-VII secretion components, adhesion factors, and phospholipase C. Continued active laboratory- and population-based surveillance will further inform the prevalence of NTM species and STs, monitor emerging clones, and allow AR characterization.

Diagnostic Value of Targeted Next-generation Sequencing in Pulmonary Mycobacterial Infections.

This study aimed to explore the diagnostic value of novel technique-targeted next-generation sequencing (tNGS) of bronchoalveolar lavage fluid (BALF) in pulmonary mycobacterial infections. This retrospective study was conducted on patients who underwent bronchoscopy and tNGS, smear microscopy, and mycobacterial culture of BALF. Patients with positive Mycobacterium tuberculosis (MTB) culture or GeneXpert results were classified into the tuberculosis case group. Those diagnosed with nontuberculous mycobacteria (NTM)-pulmonary disease (NTM-PD) composed the case group of NTM-PD patients. The control group comprised patients without tuberculosis or NTM-PD. Sensitivity, specificity, and receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance. For tuberculosis patients with positive mycobacterial culture results, the areas under the ROC curves (AUCs) for tNGS, GeneXpert, and smear microscopy were 0.975 (95% CI: 0.935, 1.000), 0.925 (95% CI: 0.859, 0.991), and 0.675 (95% CI: 0.563, 0.787), respectively. For tuberculosis patients with positive GeneXpert results, the AUCs of tNGS, culture, and smear microscopy were 0.970 (95% CI: 0.931, 1.000), 0.850 (95% CI: 0.770, 0.930), and 0.680 (95% CI: 0.579, 0.781), respectively. For NTM-PD, the AUCs of tNGS, culture, and smear-positive but GeneXpert-negative results were 0.987 (95% CI: 0.967, 1.000), 0.750 (95% CI: 0.622, 0.878), and 0.615 (95% CI: 0.479, 0.752), respectively. The sensitivity and specificity of tNGS in NTM-PD patients were 100% and 97.5%, respectively. tNGS demonstrated superior diagnostic efficacy in mycobacterial infection, indicating its potential for clinical application.

Deciphering microbiome and fungi-bacteria interactions in chronic wound infections using metagenomic sequencing.

Chronic wounds caused by infections impose a considerable global healthcare burden. The microbial features of these infections and possible correlations between bacteria and fungi may influence wound healing. However, metagenomic next-generation sequencing (mNGS) analyses of these features remain sparse. Therefore, we performed mNGS on chronic wound infection samples to investigate features and correlations between the bacteriome and mycobiome in 66 patients (28: chronic wounds; 38: non-chronic wounds). Microbial community characteristics in patients with wound infections, microbiome-systemic inflammation associations, and bacteria-fungi correlations were analyzed. Infections constituted the primary cause of wounds in this study. Nontuberculous mycobacteria (23%) and Mycobacterium tuberculosis (13%) were the most common pathogens associated with chronic wounds, whereas Staphylococcus aureus (15%) was the most prevalent in non-chronic wound infections. Patients with chronic wound infections had a higher abundance of Pseudomonas aeruginosa than those without chronic wounds. Microbes with a high relative abundance in chronic wound infections were less significantly associated with plasma inflammatory factors than those in non-chronic wound infections. Additionally, a positive correlation between Candida glabrata and P. aeruginosa and an association between Malassezia restricta and anaerobic species were detected in patients with chronic wound infections. Our results further support the hypothesis that P. aeruginosa is a microbial biomarker of chronic wound infection regardless of the causative pathogens. Moreover, we propose a positive correlation between C. glabrata and P. aeruginosa in chronic wound infections, which advances the current understanding of fungi-bacteria correlations in patients with chronic wound infections.

Incidence of an Identifiable Organism in Children Who Underwent a Surgical Procedure for Granulomatous Cervical Lymphadenopathy.

Objectives: The incidence of cervical lymphadenopathy due to nontuberculous mycobacteria is rising in the pediatric population. Our goal with this study was to review the number of pediatric patients with granulomatous cervical adenitis and determine the incidence of identification of a specific organism as both healthcare providers and parents are interested in identifying the causative pathogen. Methods: A retrospective chart review was conducted of patients at a high-volume tertiary care children's hospital between 2017 and 2023. Children were included if they underwent a surgical procedure for lymphadenopathy. Pathology, microbiology, and other laboratory reports were reviewed to document the presence of granulomatous cervical adenitis and the incidence of identification of a specific organism. Additional data collected included patient demographics and type of procedure. Results: Of the 1538 charts reviewed, 163 patients underwent an inclusionary procedure. Mean patient age was 10.7 years (range 2.4 months-20 years), 70 (43%) were female, 25 (15%) had granulomatous cervical adenitis, and a specific organism was identified in 9 of these. Conclusion: Despite the availability of a number of ancillary tests, our data demonstrate that the identification of a specific pathogen in cases of granulomatous cervical lymphadenitis is rare. As a result, physicians should be prepared to rely primarily on the history and physical exam findings to determine a working diagnosis as well as a medical and/or surgical treatment plan.

Multicenter study of the performance of NTM Elite agar for the detection of nontuberculous mycobacteria from patients with cystic fibrosis.

The performance of a novel selective agar was evaluated against the performance of conventional mycobacterial cultures, i.e., a combination of the mycobacterial growth indicator tube (MGIT) with Löwenstein-Jensen (LJ), for the detection of nontuberculous mycobacteria (NTM) in sputum samples from people with cystic fibrosis (pwCF). Two hundred eighty-three sputum samples (231 fresh sputum and 52 spiked sputum) from 143 pwCF were collected. They were inoculated without prior decontamination on NTM Elite agar (30°C ± 2°C for 28 days) and inoculated on both MGIT and LJ (35°C-37°C for 6-8 weeks) after N-acetyl-L-cysteine-2% sodium hydroxide decontamination. NTM were identified by Matrix-Assisted Laser Desorption Ionization/Time of Flight Mass Spectrometry and/or PCR, and whole-genome sequencing. A total of 67 NTM were recovered overall by the combination of all culture media. NTM Elite agar allowed the recovery of 65 NTM (97%), compared to 22 for the conventional MGIT and LJ media combination (32.8%), including 22 NTM for MGIT (32.8%) and 3 NTM with the LJ medium (4.5%). For Mycobacterium abscessus complex, the sensitivity of NTM Elite agar was 95% compared with a sensitivity of 30% for the conventional MGIT and LJ media combination. Overall, 17.3% of cultures on NTM Elite agar were contaminated with other micro-organisms vs 46.3% on MGIT and 77% on LJ. This study shows that the novel selective agar (NTM Elite agar) significantly outperforms the conventional MGIT and LJ media combination in terms of sensitivity, selectivity, and ease of culture, without the requirement of an L3 laboratory.IMPORTANCENontuberculous mycobacteria (NTM) are significant pulmonary pathogens in patients with pre-existing structural lung conditions such as cystic fibrosis, bronchiectasis, or chronic obstructive pulmonary disease. Mycobacterium avium complex and Mycobacterium abscessus complex (MABSC) are the most frequently isolated organisms. Compared to the recommended culture method for NTM, which combines solid and liquid culture media, NTM Elite agar enables a faster/easier diagnosis and speeds up identification and susceptibility testing as the final reading is at 28 days instead of 6-8 weeks for the conventional mycobacterial cultures. In addition, for the NTM Elite agar, no decontamination stage before inoculation is necessary, unlike the conventional mycobacterial cultures. NTM Elite agar is derived from a formulation of medium adapted to rapidly growing mycobacteria (RGM). The medium enables the growth of RGM while suppressing other flora. It is supported with published clinical data showing the benefits of this medium.

Emergence of Mycobacterium gordonae in heater–cooler units: a five-year prospective surveillance of devices frequently subjected to chloramine-T booster disinfection

Worldwide, the detection of Mycobacterium chimaera in LivaNova heater-cooler units (HCUs) has led to their replacement with other HCUs, although non-tuberculous mycobacteria (NTM) have been reported also for HCUs produced by other manufacturers. In almost all hospitals of our region, LivaNova HCUs have been replaced with Maquet HCU40s, regularly disinfected with chloramine-T. To report the results of the surveillance over a 63-month operation period of the Maquet devices, and to provide a trend in NTM positivity over time. Twenty-nine Maquet devices (HCU40 and HU35) were monitored by two culture methods and PMA-PCR method. The trend in NTM positivity rate was evaluated through the Locally Estimated Scatterplot Smoothing regression and then modelled over time through segmented logistic regression. The data acquired during the study period demonstrate a remarkable increase in the positivity rate, especially after their third year (maximum slope change at 1280 days). Non-tuberculous mycobacteria were isolated in 150 water samples (37.2%); 100% and 62% of HCU40 and HU35 devices respectively were colonized with non-tuberculous mycobacteria. The most frequently detected species were Mycobacterium gordonae (73%) followed by Mycobacterium chelonae (41%) and Mycobacterium paragordonae (11%). Preventive strategies by disinfection with chloramine-T did not effectively reduce non-tuberculous mycobacteria colonization of Maquet devices. Although, to date, no cases of post-operative invasive infections linked to Maquet devices have been reported, our microbiological results emphasize the need for 1) designing changes to increase safety of devices and 2) researching and developing new disinfection protocols including alternative molecules.

Managing Complicated Nontuberculous Mycobacteria Infections in Plastic Surgery.

Nontuberculous mycobacteria (NTM) infections after cosmetic surgery have become an increasing concern. These infections are often initially misdiagnosed and treated with standard antibiotic regimens, which fail to resolve the underlying infection, leading to prolonged patient suffering. In this case study, we describe a chronic wound infection caused by Mycobacterium abscessus subsp. bolletii after a muscle-repair abdominoplasty. This case illustrates the diagnostic and therapeutic challenges plastic surgeons face in successfully treating such infections. Initial obstacles included the isolation of co-contaminating bacteria that masked the NTM infection, the use of antibiotics ineffective against the specific NTM species, and the failure to identify the infection source. In this instance, contaminated skin marker ink used to mark the rectus muscle, combined with a nonabsorbable (permanent) suture for muscle repair, led to the development of a biofilm that acted as a persistent reservoir for the infection, resistant to antibiotic treatments. Complete resolution was achieved only after evaluation by a plastic surgeon experienced in treating NTM infections and the subsequent removal of the permanent suture. The delayed suture removal contributed to a 15-month recovery period. This case underscores the importance of early recognition of NTM infections after cosmetic procedures. By sharing this case, we aim to raise awareness of NTM infections and help prevent future cases of misdiagnosis and prolonged antibiotic treatments. Key points regarding the diagnosis, sources of infection, and treatment options for NTM infections are highlighted in this article using "text boxes" to emphasize the most important information and provide concise summaries of critical insights.

Effect of comorbidities on mortality in patients with nontuberculous mycobacterial infection in Korea: National Health Insurance Service-National Sample Cohort data

Patients with nontuberculous mycobacteria (NTM) infection have multiple comorbidities, but the impact of comorbidities on mortality are not well known. We aimed to compare the mortality between people with and without NTM infection and associated comorbidities and their prognostic value on mortality using National Health Insurance Service-National Sample Cohort data from 2006 to 2019. In this matched cohort study, people with and without NTM infection aged 20–89 years were matched 1:4 by sex, age, region, and income. The hazard ratios (HRs) with 95% confidence intervals (CIs) of mortality in patients with NTM infection were estimated using a Cox proportional hazard regression model. In total, 2421 patients with NTM infection (mean age, 54.8 years) and 9684 controls were included. NTM-infected patients had a significantly increased risk of mortality than matched controls in the multivariable model adjusted for age, sex, region, income, and Charlson comorbidity index (aHR = 1.88, 95% CI 1.65–2.14). Among patients with NTM infection, respiratory comorbidities including chronic obstructive pulmonary disease, asthma, interstitial lung disease, and moderate to severe liver disease and malignancy were positively associated with mortality. NTM infection was independently associated with an increased risk of mortality, and mortality risk in patients with NTM infection may be increased by coexisting comorbidities.

Evaluation of Multiplex loop-mediated isothermal amplification assay for the detection of Mycobacterium tuberculosis complex from clinically suspected cases of pulmonary tuberculosis

Tuberculosis (TB) is the second leading cause of death from a single infectious agent worldwide. Bangladesh ranks 7th among the 30 high TB burdened countries in the world. Accurate detection of Mycobacterium tuberculosis complex (MTBC) is challenging for developing countries as most of the resource poor settings are not suitable to perform molecular techniques.The purpose of the study was to compare the multiplex TB-LAMP assay with MTB/NTM qPCR, culture, Z-N staining, and fluorescence microscopy in order to assess the effectiveness of the LAMP assay for detecting cases of pulmonary tuberculosis.This research work was done from March 2022 to February 2023. Fulfilling the inclusion criteria 130 sputum samples were collected. TB-LAMP assay, qPCR, culture in L-J media, Z-N staining and fluorescence microscopy were performed.Out of 130 samples qPCR detected MTBC in 56.92% cases and TB-LAMP detected 53.85%. MTBC was detected by culture 46.15%, by Fluorescence microscopy 40.77% and Z-N staining 36.92%. TB-LAMP detected 16.93% more cases than Z-N staining and 13.08% more cases than fluorescence microscopy. The sensitivity, specificity, positive, and negative predictive values of multiplex-LAMP assay were 95%, 81.4%, 81.4% and 95% respectively considering culture as a gold-standard. MTBC negative culture samples (18.57%) showed positivity by LAMP assay as well as by qPCR. This study detected 7.69% non-tuberculous mycobacteria (NTM) by qPCR. All NTM positive samples were negative by TB-LAMP.TB-LAMP is an easy to perform, cost-effective, reliable assay with high sensitivity and specificity. World Health Organization recommended TB-LAMP as a rapid molecular test for rapid detection of tuberculosis and as replacement of microscopy in resource poor settings/hard to reach areas. Bangladesh being a high TB burden country it is essential to implement TB-LAMP to achieve End TB Strategy by 2035.

Genome-scale analysis of Mycobacterium avium complex isolates from Portugal reveals extensive genetic diversity

Opportunist infections caused by nontuberculous mycobacteria (NTM) have emerged as a significant public health problem. Among these, species of the Mycobacterium avium complex (MAC) are the main responsible for the increase in the number of human disease cases. In order to address the current needs in the detection and surveillance of MAC disease cases, we evaluated different species classification methodologies (BLASTn-based marker-gene approach, Kraken v2, rMLST and MLST databases) and their congruence with a core-SNP phylogenetic approach, based on whole genome sequencing (WGS) data. For this purpose, we used a collection of 142 MAC isolates from Portuguese patients diagnosed between 2014 and 2022. The marker-gene approach (based on the rpoB, hsp65 and groEL genes), showed the best results, allowing the identification of the 142 MAC isolates to the species/subspecies level (M. avium subsp. hominissuis, M. intracellulare, M. intracellulare subsp. chimaera, M. intracellulare subsp. yongonense, M. marseillence and M. colombiense). Additionally, we performed drug susceptibility testing that confirmed clarithromycin efficacy as a first-line treatment for MAC disease, as 93 % of the Portuguese isolates were susceptible. Using a core-SNP approach we also performed an in-depth phylogenetic analysis within each identified species group, and despite the high genetic diversity within the MAC species, we were able to clearly distinguish all the species/subspecies and identify genetic clusters with epidemiological potential.We highlight not only the need for the standardization of an appropriate genotyping approach for species identification and management of MAC disease, but also a more robust large-scale WGS data analysis, in a One Health perspective, in order to identify potential routes of transmission.

Epidemiology of chronic pulmonary aspergillosis: A nationwide descriptive study

BackgroundChronic pulmonary aspergillosis (CPA) has recently gained attention owing to its substantial health burden. However, the precise epidemiology and prognosis of the disease are still unclear due to the lack of a nationwide descriptive analysis. This study aimed to elucidate the epidemiology of patients with CPA and to investigate their prognosis. MethodsUsing a national administrative database covering >99% of the population in Japan, we calculated the nationwide incidence and prevalence of CPA from 2016 to 2022. Additionally, we clarified the survival rate of patients diagnosed with CPA and identified independent prognostic factors using multivariate Cox proportional hazard analysis. ResultsDuring the study period, while the prevalence of CPA remained stable at 9.0–9.5 per 100,000 persons, its incidence declined to 2.1 from 3.5 per 100,000 person-years. The 1-, 3-, and 5-year survival rates were 65%, 48%, and 41%, respectively. During the year of CPA onset, approximately 50% of patients received oral corticosteroids (OCS) at least once, while about 30% underwent frequent OCS treatment (≥4 times per year) within the same timeframe. Increased mortality was independently associated with older age (>65 years) (hazard ratio [HR], 2.65; 95% confidence interval (CI), 2.54–2.77), males (1.24; 1.20–1.29), a history of chronic obstructive pulmonary disease (1.05; 1.02–1.09), lung cancer (1.12; 1.06–1.18); and ILD (1.19; 1.14–1.24); and frequent OCS use (1.13; 1.09–1.17). Conversely, decreased mortality was associated with a history of tuberculosis (HR, 0.81; 95% CI, 0.76–0.86), non-tuberculous mycobacteria (0.91; 0.86–0.96), and other chronic pulmonary diseases (0.89; 0.85–0.92). ConclusionsThe incidence of CPA decreased over the past decade, although the prevalence was stable and much higher than that in European countries. Moreover, the patients’ prognosis was poor. Physicians should be vigilant about CPA onset in patients with specific high-risk underlying pulmonary conditions.