The Diagnostic Value of Metagenomic Next-Generation Sequencing in Lower Respiratory Tract Infection

Isolated neural arch tuberculosis with tuberculomas: case report

We reported a case of atypical spinal tuberculosis on the posterior elements of lumbar spine in a 52-year-old female. It was easy to be misdiagnosed as spinal tumor due to its imaging characteristics. We performed puncture biopsy to initially consider tuberculosis, and then the patient was accepted surgical treatment. The intraoperative removed specimen was sent to pathological examination, microbial culture, Xpert MTB/RIF and metagenomic next-generation sequencing (mNGS) and then the diagnosis of neural arch tuberculosis was confirmed. After operation, the patient obtained stable effect by anti-tuberculosis drug treatment. In a word, the uncommon case had an important reference significance for the diagnosis of atypical spine tuberculosis and differentiation from spinal tumors. It is critical to make right preliminary diagnosis by appropriate examination as it determined the next diagnosis and treatment in special and rare clinical cases.

Clinical application of nanopore-targeted sequencing technology in bronchoalveolar lavage fluid from patients with pulmonary infections

The rapid and effective identification of pathogens in patients with pulmonary infections has posed a persistent challenge in medicine, with conventional microbiological tests (CMTs) proving time-consuming and less sensitive, hindering early diagnosis of respiratory infections. While there has been some research on the clinical performance of targeted sequencing technologies, limited focus has been directed toward bronchoalveolar lavage fluid (BALF). This study primarily evaluates the pathogen detection capabilities of nanopore-targeted sequencing (NTS) in BALF, providing a comprehensive analysis. The retrospective study, spanning from January 2022 to November 2023, includes 223 patients exclusively sourced from a single center. We conducted a detailed comparative analysis among NTS, targeted next-generation sequencing (tNGS), and CMTs. Initially, we compared the detection capabilities of NTS and tNGS and found no significant differences in their sensitivity and specificity. Specifically, we observed that the sensitivity of NTS was significantly higher than that of CMTs (74.83% vs 33.11%, P < 0.001). Furthermore, NTS exhibited a higher positivity rate in common pulmonary infections (62.88% vs. 23.48%) and in clinically suspected tuberculosis patients compared to CMTs (87.18% vs. 48.72%). Additionally, NTS showed less susceptibility to antibiotic interference, indicating a more sensitive detection capability, especially in detecting fastidious organisms. It complements GeneXpert in tuberculosis diagnosis and offers excellent advantages in identifying pathogens challenging for CMTs, such as non-tuberculous mycobacteria and viruses. Moreover, NTS significantly shortens the reporting time and is only a quarter of the cost of metagenomic next-generation sequencing. Clearly, NTS can facilitate faster and more cost-effective early diagnosis of respiratory infections.IMPORTANCEThis study holds paramount significance in advancing the field of respiratory infection diagnostics. By assessing the pathogen detection capabilities in bronchoalveolar lavage fluid (BALF) of patients with pulmonary infections, we illuminate the promising potential of nanopore-targeted sequencing (NTS). The findings underscore NTS as a comparable yet distinct alternative to traditional methods like comprehensive conventional microbiological tests (CMTs). Notably, NTS demonstrates a pivotal edge, expanding the spectrum of identified pathogens, particularly excelling in the detection of challenging entities like non-tuberculous mycobacteria and viruses. The study also highlights the complementary role of NTS alongside GeneXpert in the identification of tuberculosis, providing a comprehensive overview of the diagnostic landscape for respiratory infections. This insight carries significant implications for clinicians seeking rapid, cost-effective, and accurate diagnostic tools in the realm of pulmonary infections.

Integrative analyses identify opportunistic pathogens of patients with lower respiratory tract infections based on metagenomic next-generation sequencing

Lower respiratory tract infections (LRTIs) represent some of the most globally prevalent and detrimental diseases. Metagenomic next-generation sequencing (mNGS) technology has effectively addressed the requirement for the diagnosis of clinical infectious diseases. This study aimed at identifying and classifying opportunistic pathogens from the respiratory tract-colonizing microflora in LRTI patients using data acquired from mNGS analyses. A retrospective study was performed employing the mNGS data pertaining to the respiratory samples derived from 394 LRTIs patients. Linear discriminant analysis effect size (LEfSe) analysis was conducted to discern the discriminant bacteria. Receiver operating characteristic curves (ROC) were established to demonstrate discriminant bacterial behavior to distinguish colonization from infection. A total of 443 discriminant bacteria were identified and segregated into three cohorts contingent upon their correlation profiles, detection frequency, and relative abundance in order to distinguish pathogens from colonizing microflora. Among them, 119 emerging opportunistic pathogens (cohort 2) occupied an average area under the curve (AUC) of 0.976 for exhibiting the most prominent predictability in distinguishing colonization from infection, 39 were colonizing bacteria (cohort 1, 0.961), and 285 were rare opportunistic pathogens (cohort 3, 0.887). The LTRIs patients appeared modular in the form of cohorts depicting complex microbial co-occurrence networks, reduced diversity, and a high degree of antagonistic interactions in the respiratory tract microbiome. The study findings indicate that therapeutic interventions should target interaction networks rather than individual microbes, providing an innovative perspective for comprehending and combating respiratory infections. Conclusively, this study reports a profile of LRTIs-associated bacterial colonization and opportunistic pathogens in a relatively large-scale cohort, which might serve as a reference panel for the interpretation of mNGS results in clinical practice.

Metagenome next-generation sequencing plays a key role in the diagnosis and selection of effective antibiotics on the treatment of Nocardia pneumonia: a case report

Nocardia disease is an opportunistic infection, the occurrence is rare and mostly occurs in patients with immune deficiency. Even if the patient is immunocompetent, it can still be life-threatening. This case report describes a previously healthy 78-year-old male farmer with lung lesions discovered on a computerized tomography scan. Combined with the patient's history of fever and the results of elevated laboratory markers associated with inflammation, the patient was diagnosed with a lung infection. After escalating empirical broad-spectrum antibiotics, antiviral and antifungal therapy, the patient continued to deteriorate to septic shock. In the meanwhile, the patient's sputum was cultured repeatedly, and no obvious positive pathogenic bacteria were found. Considering the patient was elderly and that these lesions were solid with burr signs, as well as the progression after antimicrobial therapy cancer was considered in the differential diagnosis. Artificial intelligence (YITU, Hangzhou Yitu Medical Technology Limited Company) was also applied, and it also calculated that these lesions were cancerous. The patient received a puncture biopsy of the largest lung lesion. During the puncture pus was withdrawn from largest lung lesion. Culture and metagenome next-generation sequencing (mNGS) detection performed on pus indicated Nocardia otitidiscaviarum. The test report of the mNGS is also attached with a susceptibility report of commonly used clinical antibiotics to this Nocardia spp. Using this result, the patient's disease was quickly controlled after selecting the targeted drug compound sulfamethoxazole and intravenous meropenem for treatment. In view of the high misdiagnosis rate and poor sensitivity of culture for Nocardia spp., this case emphasized mNGS playing a key role in the diagnosis and selection of effective antibiotics for the treatment of Nocardia spp. lung infections.

Clinical applications of metagenomics next-generation sequencing in infectious diseases

Infectious diseases are a great threat to human health. Rapid and accurate detection of pathogens is important in the diagnosis and treatment of infectious diseases. Metagenomics next-generation sequencing (mNGS) is an unbiased and comprehensive approach for detecting all RNA and DNA in a sample. With the development of sequencing and bioinformatics technologies, mNGS is moving from research to clinical application, which opens a new avenue for pathogen detection. Numerous studies have revealed good potential for the clinical application of mNGS in infectious diseases, especially in difficult-to-detect, rare, and novel pathogens. However, there are several hurdles in the clinical application of mNGS, such as: (1) lack of universal workflow validation and quality assurance; (2) insensitivity to high-host background and low-biomass samples; and (3) lack of standardized instructions for mass data analysis and report interpretation. Therefore, a complete understanding of this new technology will help promote the clinical application of mNGS to infectious diseases. This review briefly introduces the history of next-generation sequencing, mainstream sequencing platforms, and mNGS workflow, and discusses the clinical applications of mNGS to infectious diseases and its advantages and disadvantages.

Osteomyelitis of the femur caused by Metamycoplasma orale in an immunocompromised patient using metagenomic next-generation sequencing: A case report

Background

Metamycoplasma orale (M.orale), a symbiotic bacterium observed in the human oral cavity, is generally regarded as non-pathogenic to humans. Although infrequent, symptomatic infections caused by M.orale may occur in individuals with compromised humoral immunity. Accurate identification and early diagnosis of M.orale still present significant challenges due the limitations associated with conventional detection methods. Although metagenomic next-generation sequencing (mNGS) is currently widely utilized in clinical practices and exhibits a remarkable specificity and sensitivity for detecting various pathogens, its application in the diagnosis of M.orale-induced osteomyelitis remains largely unexplored.

Case description

In this report, we present a case study of osteonecrosis caused by M.orale in a 20-year-old female patient with nephrotic syndrome and other comorbidities. She was administered long-term hormone therapy and immunosuppressants, leading to her admission to the hospital due to recurrent fever, hip abscess and left thigh pain. Imaging examination revealed bilateral mid-femoral lesions, with the extensive nature of the left femoral lesion suggesting a potential secondary infection. Although no pathogen was detected in pus culture, mNGS analysis identified M.orale in the sample. Following treatment with doxycycline and levofloxacin, the patient's symotoms improved and she was discharged with favorable outcomes.

Conclusion

mNGS enables rapid identification of etiology in patients with osteomyelitis caused by the rare pathogen M.orale. This case accentuate the strength of mNGS for early detection and targeted clinical treatment of infectious diseases caused by uncommon pathogens.

Assessment and clinical utility of metagenomic next-generation sequencing for suspected lower respiratory tract infections

OBJECTIVES

This study aims to compare the diagnostic efficacy of metagenomic next-generation sequencing (mNGS) to traditional diagnostic methods in patients with lower respiratory tract infections (LRTIs), elucidate the etiological spectrum of these infections, and explore the impact of mNGS on guiding antimicrobial therapy.

METHODS

We retrospectively analyzed data from 128 patients admitted to the Respiratory Department of Anqing 116 Hospital between July 2022 and July 2023. All patients had undergone both mNGS and conventional microbiological techniques (CMT) for LRTI diagnosis. We assessed the diagnostic performance of these methods and examined the influence of mNGS on antimicrobial decision-making.

RESULTS

Overall, mNGS demonstrated superior sensitivity (96.8%) and accuracy (96.8%) compared to CMT. For Mycobacterium tuberculosis detection, the accuracy and sensitivity of mNGS was 88.8% and 77.6%, which was lower than the 94.7% sensitivity of the T-spot test and the 79.6% sensitivity of CMT. In fungal pathogen detection, mNGS showed excellent sensitivity (90.5%), specificity (86.7%), and accuracy (88.0%). Bacteria were the predominant pathogens detected (75.34%), with Mycobacterium tuberculosis (41.74%), Streptococcus pneumoniae (21.74%), and Haemophilus influenzae (16.52%) being most prevalent. Bacterial infections were most common (62.10%), followed by fungal and mixed infections (17.74%). Of the 118 patients whose treatment regimens were adjusted based on mNGS results, 102 (86.5%) improved, 7 (5.9%) did not respond favorably, and follow-up was lost for 9 patients (7.6%).

CONCLUSIONS

mNGS offers rapid and precise pathogen detection for patients with suspected LRTIs and shows considerable promise in diagnosing Mycobacterium tuberculosis and fungal infections. By broadening the pathogen spectrum and identifying polymicrobial infections, mNGS can significantly inform and refine antibiotic therapy.

Airway necrosis and granulation tissue formation caused by Rhizopus oryzae leading to severe upper airway obstruction: a case report

Pulmonary Mucormycosis is a fatal infectious disease with high mortality rate. The occurrence of Mucormycosis is commonly related to the fungal virulence and the host's immunological defenses against pathogens. Mucormycosis infection and granulation tissue formation occurred in the upper airway was rarely reported. This patient was a 60-year-old male with diabetes mellitus, who was admitted to hospital due to progressive cough, sputum and dyspnea. High-resolution computed tomography (HRCT) and bronchoscopy revealed extensive tracheal mucosal necrosis, granulation tissue proliferation, and severe airway stenosis. The mucosal necrotic tissue was induced by the infection of Rhizopus Oryzae, confirmed by metagenomic next-generation sequencing (mNGS) in tissue biopsy. This patient was treated with the placement of a covered stent and local instillation of amphotericin B via bronchoscope. The tracheal mucosal necrosis was markedly alleviated, the symptoms of cough, shortness of breath, as well as exercise tolerance were significantly improved. The placement of airway stent and transbronchial microtube drip of amphotericin B could conduce to rapidly relieve the severe airway obstruction due to Mucormycosis infection.

COVID-19 in pulmonary critically ill patients: metagenomic identification of fungi and characterization of pathogenic microorganisms

Background

Fungal co-infection is prevalent in critically ill patients with COVID-19. The conventional approach applied to fungal identification has relatively low sensitivity and is time-consuming. The metagenomic next-generation sequencing (mNGS) technology can simultaneously detect a variety of microorganisms, and is increasingly being used for the rapid detection and diagnosis of pathogens.

Methods

In this single-center retrospective study, we described the clinical presentation and outcomes of COVID-19 and mNGS positive for fungi in pulmonary critically ill patients during the outbreak of Omicron infection from December 2022 to January 2023.

Results

Among 43 COVID-19 patients with acute respiratory distress syndrome (ARDS) on a single intensive care unit (ICU), 10 were reported to be fungal positive using the mNGS test. The number of pathogenic microorganisms detected by mNGS was significantly higher than that via traditional methods, especially in the detection of fungi and viruses. Aspergillus infection was dominant, and most of these patients also had concurrent bacterial or viral infections. Probable or possible COVID-19-associated pulmonary aspergillosis (CAPA) was diagnosed in all 10 patients, and the prognosis was poor.

Conclusion

Patients with COVID-19 may be at increased risk of developing fungal infections as well as concurrent bacterial or viral infections, and mNGS can be a powerful tool in identifying these infections. Clinicians should be aware of the increased risk of fungal infections in COVID-19 patients, particularly those who have underlying immunocompromising conditions, and should monitor for early signs of infection.

Determination of the diagnostic accuracy of nanopore sequencing using bronchoalveolar lavage fluid samples from patients with sputum-scarce pulmonary tuberculosis

PURPOSE

The early and efficient diagnosis of patients suspected of having pulmonary tuberculosis (PTB) remains challenging. This study aimed to evaluate the accuracy of nanopore sequencing for PTB diagnosis using bronchoalveolar lavage fluid (BALF) samples and compared it with other techniques such as acid-fast bacilli smear, culture, Xpert MTB/RIF, and CapitalBio Mycobacterium reverse transcription-polymerase chain reaction (MTB RT-PCR).

METHODS

We retrospectively analyzed the clinical data of 195 patients with suspected PTB who were admitted to our hospital. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC) of these assays were calculated and compared.

RESULTS

The overall sensitivity, specificity, PPV, NPV, and AUC of nanopore sequencing were 90.70%, 84.85%, 92.13%, 82.35%, and 0.88; those of acid-fast bacilli smear were 12.40%, 98.48%, 94.12%, 36.52%, and 0.55; those of culture were 36.43%, 100%, 100%, 44.59%, and 0.68; those of Xpert MTB/RIF were 41.09%, 100%, 100%, 46.48%, and 0.71; and those of CapitalBio MTB RT-PCR were 34.88%, 98.48%, 97.83%, 43.62%, and 0.67, respectively.

CONCLUSION

The nanopore sequencing assay using BALF samples showed the best diagnostic accuracy for sputum-scarce PTB. Moreover, it can improve the clinical diagnosis of PTB.

Clinical application of metagenomic next-generation sequencing in patients with different organ system infection: A retrospective observational study

Microbiological identification is essential for appropriate treatment, but conventional methods are time-consuming and have a low sensitivity. In contrast, metagenomic next-generation sequencing (mNGS) is a culture-free and hypothesis-free technique that can detect a wide array of potential pathogens. This study aimed to reveal the overall diagnostic value of mNGS for infectious diseases of different organ systems and compare the sensitivity and specificity of mNGS with conventional methods. In a retrospective cohort study, 94 patients with mNGS results were enrolled, and clinical data were recorded and analyzed to compare the positive rate of mNGS with traditional methods including as smears, serological tests, and traditional PCR, etc. In this study, mNGS and culture were both positive in 12.77% cases and were both negative in 23.4% cases. There were positive results in 56 cases (54.26%) only by mNGS and 4 cases (4.26%) were positive only by culture. There were significant differences in sensitivity of pathogen detection between of ID and NID group for mNGS (χ2 = 10.461, P = .001)and conventional methods(χ2 = 7.963, P = .005). The positive predictive values and negative predictive values of diagnosing infectious disease by mNGS were 94.12% and 30.77%, respectively. mNGS increased the sensitivity rate by approximately 53.66% compared with that of culture (78.05% vs24.39%; χ2 = 47.248, P < .001) and decreased the specificity rate by 12.5% compared with that of culture (66.67% vs 100.0%; χ2 = 4.8, P = .028). mNGS can identify emerging or rare pathogen and further guide treatment regimens. mNGS has advantages in identifying overall pathogens and bacteria, however, there was no obvious advantage in identifying fungi, virus and tuberculosis. mNGS has higher specificity than conventional methods in identifying pathogens and advantages in detecting emerging or rare pathogens.

[Metagenomic next-generation sequencing for the diagnosis of Pneumocystis jirovecii pneumonia after allogeneic hematopoietic stem cell transplantation]

Objectives: To investigate the value of metagenomic next-generation sequencing (mNGS) in the diagnosis of Pneumocystis jirovecii pneumonia (PJP) in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: The data of 98 patients with suspected pulmonary infection after allo-HSCT who underwent pathogen detection from bronchoalveolar lavage fluid between June 2016 and August 2023 at Nanfang Hospital were analyzed. The diagnostic performance of mNGS, conventional methods, and real-time quantitative polymerase chain reaction (qPCR) for PJP were compared. Results: A total of 12 patients were diagnosed with PJP, including 11 with a proven diagnosis and 1 with a probable diagnosis. Among the patients with a proven diagnosis, 1 was positive by both conventional methods and qPCR, and 10 were positive by qPCR only. Pneumocystis jirovecii was detected by mNGS in all 12 patients. The diagnostic sensitivity of mNGS for PJP was 100%, which was greater than that of conventional methods (8.3%, P=0.001) and similar to that of qPCR (91.6%, P=1.000) . A total of 75% of the patients developed mixed pulmonary infections, and cytomegalovirus and Epstein-Barr virus were the most common pathogens. Mixed infection was detected in eight patients by mNGS and in five patients by qPCR, but not by conventional methods (P=0.008) . Conclusions: mNGS had good sensitivity for diagnosing PJP after allo-HSCT and was advantageous for detecting mixed infectious pathogens; therefore, mNGS might be an effective supplement to regular detection methods and qPCR.

Impact of Metagenomic Next-Generation Sequencing of Bronchoalveolar Lavage Fluid on Antimicrobial Stewardship in Patients With Lower Respiratory Tract Infections: A Retrospective Cohort Study

BACKGROUND

The impact of metagenomic next-generation sequencing (mNGS) on antimicrobial stewardship in patients with lower respiratory tract infections (LRTIs) is still unknown.

METHODS

This retrospective cohort study included patients who had LRTIs diagnosed and underwent bronchoalveolar lavage between September 2019 and December 2020. Patients who underwent both mNGS and conventional microbiologic tests were classified as the mNGS group, while those with conventional tests only were included as a control group. A 1:1 propensity score match for baseline variables was conducted, after which changes in antimicrobial stewardship between the 2 groups were assessed.

RESULTS

A total of 681 patients who had an initial diagnosis of LRTIs and underwent bronchoalveolar lavage were evaluated; 306 patients were finally included, with 153 in each group. mNGS was associated with lower rates of antibiotic escalation than in the control group (adjusted odds ratio, 0.466 [95% confidence interval, .237-.919]; P = .02), but there was no association with antibiotic de-escalation. Compared with the control group, more patients discontinued the use of antivirals in the mNGS group.

CONCLUSIONS

The use of mNGS was associated with lower rates of antibiotic escalation and may facilitate the cessation of antivirals, but not contribute to antibiotic de-escalation in patients with LRTIs.

Clinical utility of metagenomic next-generation sequencing in fever of undetermined origin

Background

Metagenomic next-generation sequencing (mNGS) is a novel diagnostic tool increasingly used in the field of infectious diseases. Little guidance is available regarding its appropriate use in different patient populations and clinical syndromes. We aimed to review the clinical utility of mNGS in patients with a specific clinical syndrome and identify factors that may increase its utility.

Methods

We retrospectively reviewed charts of 72 non-immunocompromised adults hospitalized with the clinical syndrome of 'fever of undetermined origin' and underwent mNGS testing. Standardized criteria from a previously published study were used to determine the clinical impact of mNGS testing. We applied logistic regression to identify factors associated with a positive clinical impact.

Results

Of the 72 patients identified, 62.5% were males with a median age of 56. All patients had a fever at the time of evaluation. At least one organism was identified in 65.3% of cases; most commonly were Epstein-Barr virus (13.9%), cytomegalovirus (12.5%), and Rickettsia typhi (11.1%). Of those determined to have an infectious etiology of their febrile syndrome, 89.5% (n = 34/38) had a positive mNGS. Consistency between the organism(s) on mNGS and the clinically determined infectious etiology was 82.4%. mNGS had a positive clinical impact in 40.3% of cases, a negative impact in 2.8%, and no impact in 56.9% of cases. Besides age, we did not identify other factors associated with a higher likelihood of positive clinical impact.

Conclusion

In our review, mNGS had a positive clinical impact in a large proportion of adults with fever of undetermined origin, with minimal negative impact. However, mNGS results should be interpreted carefully given the high rate of detection of pathogens of unclear clinical significance. Randomized clinical trials are needed to assess the clinical utility of this novel diagnostic tool.

Chlamydia psittaci Pneumonia in a patient with motor neuron disease: a case report

BACKGROUND

Motor neuron disease (MND) is a fatal neurodegenerative disorder that leads to progressive loss of motor neurons. Chlamydia psittaci (C. psittaci) is a rare etiology of community-acquired pneumonia characterized primarily by respiratory distress. We reported a case of C. psittaci pneumonia complicated with motor neuron disease (MND).

CASE PRESENTATION

A 74-year-old male was referred to the Shaoxing Second Hospital at January, 2022 complaining of fever and fatigue for 2 days. The patient was diagnosed of MND with flail arm syndrome 1 year ago. The metagenomic next-generation sequencing (mNGS) of sputum obtained through bedside fiberoptic bronchoscopy showed C. psittaci infection. Then doxycycline was administrated and bedside fiberoptic bronchoscopy was performed to assist with sputum excretion. Computed Tomography (CT) and fiberoptic bronchoscopy revealed a significant decrease in sputum production. On day 24 after admission, the patient was discharged with slight dyspnea, limited exercise tolerance. One month later after discharge, the patient reported normal respiratory function, and chest CT showed significant absorption of sputum.

CONCLUSIONS

The mNGS combined with bedside fiberoptic bronchoscopy could timely detect C. psittaci infection. Bedside fiberoptic bronchoscopy along with antibiotic therapy may be effective for C. psittaci treatment.

Global burden of influenza lower respiratory tract infections in older people from 1990 to 2019

BACKGROUND

Infections with influenza viruses cause severe illness, substantial number of hospitalization and death, especially in older adults. However, few studies have focused on the burden of influenza lower respiratory tract infections (LRTIs) solely in older adults, particularly in low-resource settings.

AIMS

We aimed to estimate the mortality and DALYs of influenza LRTIs for people aged 55 years and older in 204 countries and territories from 1990 to 2019.

METHODS

The Global Burden of Disease (GBD) 2019 study was used to obtain data on mortality and DALYs of influenza LRTIs at the global, regional, and country levels.

RESULTS

In 2019, the global rates for mortality and DALYs of influenza LRTIs were 6.46 per 100,000 [95% uncertainty interval (UI): 2.37-12.62] and 97.39 per 100,000 (95% UI: 34.70-187.03). Although the rates for mortality and DALYs in people aged 55 years and older decreased from 1990 to 2019, the absolute numbers for both increased by 85.84% and 66.56%, respectively. Both the absolute numbers and rates of deaths and DALYs of influenza LRTIs were higher in male than in female in all age groups. Although low-socio-demographic index (SDI) regions experienced the largest declines for the rates of mortality and DALYs of influenza LRTIs over the past three decades, they still had the highest rates for mortality and DALYs in all age groups. Moreover, the absolute numbers and rates of deaths and DALYs of influenza LRTIs showed an increasing trend with age, reaching the peak in the people over 85 years old.

DISCUSSION

Burden of influenza LRTIs in older adults is still high and could continue to grow along with global aging.

CONCLUSION

Efforts to improve vaccination for influenza are needed for preparedness of another influenza pandemic, especially in low-SDI regions.

Clinical Evaluation of Metagenomic Next-Generation Sequencing and Identification of Risk Factors in Patients with Severe Community-Acquired Pneumonia

Purpose

Severe community-acquired pneumonia (SCAP) is the leading cause of death among patients with infectious diseases worldwide. This study aimed to evaluate the effectiveness of metagenomic next-generation sequencing (mNGS) through detecting pathogens in bronchoalveolar lavage fluid (BALF) and identifying risk factors for recovery in SCAP patients.

Patients and Methods

This prospective study recruited 158 SCAP patients admitted to respiratory intensive care unit that were randomly divided into control and study groups, with receiving conventional tests and the same conventional tests plus mNGS, respectively. The diagnostic efficiency of mNGS was evaluated by comparing with conventional tests. Furthermore, univariate and multivariate logistic regression analyses were performed to determine the independent risk factors for recovery in SCAP patients, and a nomogram prediction model was established based on these factors.

Results

Within the study group, the pathogen detection rate was significantly higher with mNGS than that with conventional tests (84.81% vs 45.57%, P < 0.001), with a positive coincidence rate of 94.44%. Acinetobacter baumannii (21.52%, 17/79), Candida albicans (17.72%, 14/79), and Klebsiella pneumonia (15.19%, 12/79) were the top three common pathogens detected by mNGS. Of note, the improvement rate of patients in the study group was significantly higher than that in the control group. The further analysis revealed that the increased levels of interleukin-6, blood urea nitrogen, procalcitonin, the longer length of hospital stay, and bacterial infection were independent risk factors for recovery of SCAP patients, while mNGS detection status was a protective factor. The predictive model showed a good performance for the modeling and validation sets.

Conclusion

Early mNGS exhibited a superior diagnostic efficiency to conventional tests in SCAP patients, which can reduce the risk of death in SCAP patients. Moreover, the clinical factors could also be used for the management and prognosis prediction of SCAP patients.

Recent updates in the development of molecular assays for the rapid identification and susceptibility testing of MRSA

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of healthcare- and community-associated infections. Nasal carriage of MRSA is a risk factor for subsequent MRSA infections. Increased morbidity and mortality are associated with MRSA infections and screening and diagnostic tests for MRSA play an important role in clinical management.

AREAS COVERED

A literature search was conducted in PubMed and supplemented by citation searching. In this article, we provide a comprehensive review of molecular-based methods for MRSA screening and diagnostic tests including individual nucleic acid detection assays, syndromic panels, and sequencing technologies with a focus on their analytical performance.

EXPERT OPINION

Molecular based-assays for the detection of MRSA have improved in terms of accuracy and availability. Rapid turnaround enables earlier contact isolation and decolonization for MRSA. The availability of syndromic panel tests that include MRSA as a target has expanded from positive blood cultures to pneumonia and osteoarticular infections. Sequencing technologies allow detailed characterizations of novel methicillin-resistance mechanisms that can be incorporated into future assays. Next generation sequencing is capable of diagnosing MRSA infections that cannot be identified by conventional methods and metagenomic next-generation sequencing (mNGS) assays will likely move closer to implementation as front-line diagnostics in the near future.

Clinical metagenomics-challenges and future prospects

Infections lacking precise diagnosis are often caused by a rare or uncharacterized pathogen, a combination of pathogens, or a known pathogen carrying undocumented or newly acquired genes. Despite medical advances in infectious disease diagnostics, many patients still experience mortality or long-term consequences due to undiagnosed or misdiagnosed infections. Thus, there is a need for an exhaustive and universal diagnostic strategy to reduce the fraction of undocumented infections. Compared to conventional diagnostics, metagenomic next-generation sequencing (mNGS) is a promising, culture-independent sequencing technology that is sensitive to detecting rare, novel, and unexpected pathogens with no preconception. Despite the fact that several studies and case reports have identified the effectiveness of mNGS in improving clinical diagnosis, there are obvious shortcomings in terms of sensitivity, specificity, costs, standardization of bioinformatic pipelines, and interpretation of findings that limit the integration of mNGS into clinical practice. Therefore, physicians must understand the potential benefits and drawbacks of mNGS when applying it to clinical practice. In this review, we will examine the current accomplishments, efficacy, and restrictions of mNGS in relation to conventional diagnostic methods. Furthermore, we will suggest potential approaches to enhance mNGS to its maximum capacity as a clinical diagnostic tool for identifying severe infections.

Diagnostic performance and clinical impact of blood metagenomic next-generation sequencing in ICU patients suspected monomicrobial and polymicrobial bloodstream infections

Introduction

Early and effective application of antimicrobial medication has been evidenced to improve outcomes of patients with bloodstream infection (BSI). However, conventional microbiological tests (CMTs) have a number of limitations that hamper a rapid diagnosis.

Methods

We retrospectively collected 162 cases suspected BSI from intensive care unit with blood metagenomics next-generation sequencing (mNGS) results, to comparatively evaluate the diagnostic performance and the clinical impact on antibiotics usage of mNGS.

Results and discussion

Results showed that compared with blood culture, mNGS detected a greater number of pathogens, especially for Aspergillus spp, and yielded a significantly higher positive rate. With the final clinical diagnosis as the standard, the sensitivity of mNGS (excluding viruses) was 58.06%, significantly higher than that of blood culture (34.68%, P<0.001). Combing blood mNGS and culture results, the sensitivity improved to 72.58%. Forty-six patients had infected by mixed pathogens, among which Klebsiella pneumoniae and Acinetobacter baumannii contributed most. Compared to monomicrobial, cases with polymicrobial BSI exhibited dramatically higher level of SOFA, AST, hospitalized mortality and 90-day mortality (P<0.05). A total of 101 patients underwent antibiotics adjustment, among which 85 were adjusted according to microbiological results, including 45 cases based on the mNGS results (40 cases escalation and 5 cases de-escalation) and 32 cases on blood culture. Collectively, for patients suspected BSI in critical condition, mNGS results can provide valuable diagnostic information and contribute to the optimizing of antibiotic treatment. Combining conventional tests with mNGS may significantly improve the detection rate for pathogens and optimize antibiotic treatment in critically ill patients with BSI.

Metagenomics characterization of respiratory viral RNA pathogens in children under five years with severe acute respiratory infection in the Free State, South Africa

Prompt detection of viral respiratory pathogens is crucial in managing respiratory infection including severe acute respiratory infection (SARI). Metagenomics next-generation sequencing (mNGS) and bioinformatics analyses remain reliable strategies for diagnostic and surveillance purposes. This study evaluated the diagnostic utility of mNGS using multiple analysis tools compared with multiplex real-time PCR for the detection of viral respiratory pathogens in children under 5 years with SARI. Nasopharyngeal swabs collected in viral transport media from 84 children admitted with SARI as per the World Health Organization definition between December 2020 and August 2021 in the Free State Province, South Africa, were used in this study. The obtained specimens were subjected to mNGS using the Illumina MiSeq system, and bioinformatics analysis was performed using three web-based analysis tools; Genome Detective, One Codex and Twist Respiratory Viral Research Panel. With average reads of 211323, mNGS detected viral pathogens in 82 (97.6%) of the 84 patients. Viral aetiologies were established in nine previously undetected/missed cases with an additional bacterial aetiology (Neisseria meningitidis) detected in one patient. Furthermore, mNGS enabled the much needed viral genotypic and subtype differentiation and provided significant information on bacterial co-infection despite enrichment for RNA viruses. Sequences of nonhuman viruses, bacteriophages, and endogenous retrovirus K113 (constituting the respiratory virome) were also uncovered. Notably, mNGS had lower detectability rate for severe acute respiratory syndrome coronavirus 2 (missing 18/32 cases). This study suggests that mNGS, combined with multiple/improved bioinformatics tools, is practically feasible for increased viral and bacterial pathogen detection in SARI, especially in cases where no aetiological agent could be identified by available traditional methods.

Integrated host/microbe metagenomics enables accurate lower respiratory tract infection diagnosis in critically ill children

BACKGROUNDLower respiratory tract infection (LRTI) is a leading cause of death in children worldwide. LRTI diagnosis is challenging because noninfectious respiratory illnesses appear clinically similar and because existing microbiologic tests are often falsely negative or detect incidentally carried microbes, resulting in antimicrobial overuse and adverse outcomes. Lower airway metagenomics has the potential to detect host and microbial signatures of LRTI. Whether it can be applied at scale and in a pediatric population to enable improved diagnosis and treatment remains unclear.METHODSWe used tracheal aspirate RNA-Seq to profile host gene expression and respiratory microbiota in 261 children with acute respiratory failure. We developed a gene expression classifier for LRTI by training on patients with an established diagnosis of LRTI (n = 117) or of noninfectious respiratory failure (n = 50). We then developed a classifier that integrates the host LRTI probability, abundance of respiratory viruses, and dominance in the lung microbiome of bacteria/fungi considered pathogenic by a rules-based algorithm.RESULTSThe host classifier achieved a median AUC of 0.967 by cross-validation, driven by activation markers of T cells, alveolar macrophages, and the interferon response. The integrated classifier achieved a median AUC of 0.986 and increased the confidence of patient classifications. When applied to patients with an uncertain diagnosis (n = 94), the integrated classifier indicated LRTI in 52% of cases and nominated likely causal pathogens in 98% of those.CONCLUSIONLower airway metagenomics enables accurate LRTI diagnosis and pathogen identification in a heterogeneous cohort of critically ill children through integration of host, pathogen, and microbiome features.FUNDINGSupport for this study was provided by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Heart, Lung, and Blood Institute (UG1HD083171, 1R01HL124103, UG1HD049983, UG01HD049934, UG1HD083170, UG1HD050096, UG1HD63108, UG1HD083116, UG1HD083166, UG1HD049981, K23HL138461, and 5R01HL155418) as well as by the Chan Zuckerberg Biohub.

Potential of metagenomic next-generation sequencing in detecting infections of ICU patients

BACKGROUND

Due to the limitations of traditional microbiological detection techniques in evaluating complicated infections in ICU patients, it is necessary to explore novel and effective methods to improve the clinical detection of ICU patients' infections.

OBJECTIVE

This study aimed to evaluate the efficiency and specificity of mNGS in screening pathogens in the blood, deep phlegm, urine, and other sample types of ICU patients exploring an effective method for infection detection.

METHODS

A total of 56 ICU patients with 131 samples were included in this study. The sample types included blood, deep phlegm, urine, drainage, anal swabs, and other types. Samples were analyzed by both conventional detection method and mNGS tests. The diagnosis efficiency and consistency of the two methods were compared. The distribution of the identified pathogens was analyzed. Moreover, the clinical features of patients with mNGS-positive or mNGS-negative results were compared.

RESULTS

The positive rate of mNGS was 81.7% (107/131) including 3.1% (4/131) weakly positive, while the positive rate of traditional detection was only 30.5%, including 29 strong positive results and 11 weak positive results. Additionally, there were 41 patients chose to adjust anti-infection strategies according to the results of mNGS, which significantly saved treatment costs. The mNGS-positive patients showed a shorter ICU hospitalization and higher intention to adjust anti-infection strategies than the mNGS-negative patients.

CONCLUSION

mNGS is of great potential for the pathogen detection of ICU patients, and has a higher detection rate than traditional detection methods. Further clinical application investigations can be carried out to expand the application of mNGS.

Risk factors associated with Pneumocystis jirovecii pneumonia in non-HIV immunocompromised patients and co-pathogens analysis by metagenomic next-generation sequencing

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is one of the most common opportunistic infections in immunocompromised patients. However, the accurate prediction of the development of PJP in non-HIV immunocompromised patients is still unclear.

METHODS

Non-HIV immunocompromised patients confirmed diagnosis of PJP by the clinical symptoms, chest computed tomography and etiological results of metagenomic next-generation sequencing (mNGS) were enrolled as observation group. Another group of matched non-HIV immunocompromised patients with non-PJP pneumonia were enrolled to control group. The risk factors for the development of PJP and the co-pathogens in the bronchoalveolar lavage fluid (BALF) detected by mNGS were analyzed.  RESULTS: A total of 67 (33 PJP, 34 non-PJP) participants were enrolled from Fujian Provincial Hospital. The ages, males and underlying illnesses were not significantly different between the two groups. Compared to non-PJP patients, PJP patients were more tends to have the symptoms of fever and dyspnea. The LYM and ALB were significantly lower in PJP patients than in non-PJP patients. Conversely, LDH and serum BDG in PJP patients were significantly higher than in non-PJP controls. For immunological indicators, the levels of immunoglobulin A, G, M and complement C3, C4, the numbers of T, B, and NK cells, had no statistical difference between these two groups. Logistic multivariate analysis showed that concomitant use of corticosteroids and immunosuppressant (OR 14.146, P = 0.004) and the lymphocyte counts < 0.7 × 10⁹/L (OR 6.882, P = 0.011) were risk factors for the development of PJP in non-HIV immunocompromised patients. 81.82% (27/33) and 64.71% (22/34) mixed infections were identified by mNGS in the PJP group and non-PJP group separately. CMV, EBV and Candida were the leading co-pathogens in PJP patients. The percentages of CMV and EBV identified by mNGS in PJP group were significantly higher than those in the control group(p < 0.005).  CONCLUSIONS: Clinicians should pay close attention to the development of PJP in non-HIV immunocompromised patients who possess the risk factors of concomitant use of corticosteroids and immunosuppressant and the lymphocyte counts < 0.7 × 10⁹/L. Prophylaxis for PJP cannot rely solely on CD4⁺ T counts in non-HIV immunocompromised patients. Whether CMV infection increases the risk of PJP remains to be further investigated.

Clinical Evaluation of Metagenomic Next-Generation Sequencing for the detection of pathogens in BALF in severe community acquired pneumonia

BACKGROUND

Rapid and accurate identification of pathogens is very important for the treatment of Severe community-acquired pneumonia (SCAP) in children. Metagenomic Next-generation sequencing (mNGS) has been applied in the detection of pathogenic bacteria in recent years, while the overall evaluation the application of SCAP in children is lacking.

METHODS

In our study, 84 cases of SCAP were enrolled. Bronchoalveolar lavage fluid (BALF) samples were analysed using mNGS; and sputum, blood, and BALF samples were analysed using conventional technology (CT).

RESULTS

Among the 84 children, 41 were boys, and 43 were girls, with an average age ranging from 2 months to 14 years. The pathogen detection rate of mNGS was higher than that of CT (83.3% [70/84] vs. 63.1% [53/84], P = 0.003). The mNGS was much greater than that of the CT in detecting Streptococcus pneumoniae (89.2% [25/29] vs. 44.8% [13/29], P = 0.001) and Haemophilus influenzae (91.7% [11/12] vs. 33.3% [4/12], P < 0.005). The mNGS also showed superior fungal detection performance compared with that of the CT (81.8% [9/11] vs. 18.2% [2/11], P = 0.004). The mNGS test can detect viruses, such as bocavirus, rhinovirus, and human metapneumovirus, which are not frequently recognised using CT. However, the mNGS detection rate was lower than that of the CT (52.4% [11/21] vs. 95.2% [20/21], P = 0.004) for Mycoplasma pneumoniae (MP). The detection rate of mNGS for mixed infection was greater than that of the CT, although statistical significance was not observed (26.3% [20/39] vs. 21.1% [16/39], P > 0.005). Treatment for 26 (31.0%) children was changed based on mNGS results, and their symptoms were reduced; nine patients had their antibiotic modified, five had antibiotics added, nine had their antifungal medication, and seven had their antiviral medication.

CONCLUSION

mNGS has unique advantages in the detection of SCAP pathogens in children, especially S. pneumoniae, H. influenzae, and fungi. However, the detection rate of MP using mNGS was lower than that of the CT. Additionally, mNGS can detect pathogens that are not generally covered by CT, which is extremely important for the modification of the treatment strategy.

Deciphering Microbiota of Acute Upper Respiratory Infections: A Comparative Analysis of PCR and mNGS Methods for Lower Respiratory Trafficking Potential

Although it is clinically important for acute respiratory tract (co)infections to have a rapid and accurate diagnosis, it is critical that respiratory medicine understands the advantages of current laboratory methods. In this study, we tested nasopharyngeal samples (n = 29) with a commercially available PCR assay and compared the results with those of a hybridization-capture-based mNGS workflow. Detection criteria for positive PCR samples was Ct < 35 and for mNGS samples it was >40% target coverage, median depth of 1X and RPKM > 10. A high degree of concordance (98.33% PPA and 100% NPA) was recorded. However, mNGS yielded positively 29 additional microorganisms (23 bacteria, 4 viruses, and 2 fungi) beyond PCR. We then characterized the microorganisms of each method into three phenotypic categories using the IDbyDNA Explify^® Platform (Illumina^® Inc, San Diego, CA, USA) for consideration of infectivity and trafficking potential to the lower respiratory region. The findings are significant for providing a comprehensive yet clinically relevant microbiology profile of acute upper respiratory infection, especially important in immunocompromised or immunocompetent with comorbidity respiratory cases or where traditional syndromic approaches fail to identify pathogenicity. Accordingly, this technology can be used to supplement current syndrome-based tests, and data can quickly and effectively be phenotypically characterized for trafficking potential, clinical (co)infection, and comorbid consideration-with promise to reduce morbidity and mortality.

The rapid detection of respiratory pathogens in critically ill children

PURPOSE

Respiratory infections are the most common reason for admission to paediatric intensive care units (PICU). Most patients with lower respiratory tract infection (LRTI) receive broad-spectrum antimicrobials, despite low rates of bacterial culture confirmation. Here, we evaluated a molecular diagnostic test for LRTI to inform the better use of antimicrobials.

METHODS

The Rapid Assay for Sick Children with Acute Lung infection Study was a single-centre, prospective, observational cohort study of mechanically ventilated children (> 37/40 weeks corrected gestation to 18 years) with suspected community acquired or ventilator-associated LRTI. We evaluated the use of a 52-pathogen custom TaqMan Array Card (TAC) to identify pathogens in non-bronchoscopic bronchoalveolar lavage (mini-BAL) samples. TAC results were compared to routine microbiology testing. Primary study outcomes were sensitivity and specificity of TAC, and time to result.

RESULTS

We enrolled 100 patients, all of whom were tested with TAC and 91 of whom had matching culture samples. TAC had a sensitivity of 89.5% (95% confidence interval (CI₉₅) 66.9-98.7) and specificity of 97.9% (CI₉₅ 97.2-98.5) compared to routine bacterial and fungal culture. TAC took a median 25.8 h (IQR 9.1-29.8 h) from sample collection to result. Culture was significantly slower: median 110.4 h (IQR 85.2-141.6 h) for a positive result and median 69.4 h (IQR 52.8-78.6) for a negative result.

CONCLUSIONS

TAC is a reliable and rapid adjunct diagnostic approach for LRTI in critically ill children, with the potential to aid early rationalisation of antimicrobial therapy.

Comparison of clinical, laboratory and radiological characteristics between Chlamydia psittaci and adenovirus pneumonias: a multicenter retrospective study

OBJECTIVES

Pneumonia caused by Chlamydia psittaci is a significant global public health issue. Symptom onset and laboratory characteristics may be confused with those of other respiratory viral infections, including adenovirus pneumonia. We aimed to determine differences in clinical presentations and establish a simple nomogram to differentiate C. psittaci and adenovirus pneumonias.

METHODS

We conducted a multicenter retrospective study in 10 tertiary general hospitals to compare patients with either C. psittaci (n = 78) or adenovirus (n = 102) pneumonia. A multivariable logistic regression model was used to identify risk factors of C. psittaci pneumonia that were used to establish a nomogram.

RESULTS

C. psittaci and adenovirus pneumonia showed certain similar clinical symptoms, including fever, dyspnea, and fatigue, but differed in other characteristics. The multivariate logistic regression showed that age, sex, nervous system symptoms, lymphocyte count, C-reactive protein level, and bilateral lung lesions were risk factors for C. psittaci pneumonia. After incorporating these six factors, the established nomogram achieved a good concordance value (0.949 [95% CI 0.917-0.982]) in differentiating the types of pneumonia, with well-fitting calibration curves.

CONCLUSION

Despite having similar clinical features, the variables of age, sex, nervous system symptoms, lymphocytes, C-reactive protein levels, and bilateral lung lesions were combined into a clinically useful nomogram for the rapid and early differentiation of C. psittaci pneumonia from adenovirus pneumonia. This nomogram may help improve treatments and clinical outcomes.

Unusual Talaromyces marneffei and Pneumocystis jirovecii coinfection in a child with a STAT1 mutation: A case report and literature review

Talaromyces marneffei and Pneumocystis jirovecii are the common opportunistic pathogens in immunodeficient patients. There have been no reports of T. marneffei and P. jirovecii coinfection in immunodeficient children. Signal transducer and activator of transcription 1 (STAT1) is a key transcription factor in immune responses. STAT1 mutations are predominately associated with chronic mucocutaneous candidiasis and invasive mycosis. We report a 1-year-2-month-old boy diagnosed with severe laryngitis and pneumonia caused by T. marneffei and P. jirovecii coinfection, which was confirmed by smear, culture, polymerase chain reaction and metagenome next-generation sequencing of bronchoalveolar lavage fluid. He has a known STAT1 mutation at amino acid 274 in the coiled-coil domain of STAT1 according to whole exome sequencing. Based on the pathogen results, itraconazole and trimethoprim-sulfamethoxazole were administered. This patient's condition improved, and he was discharged after two weeks of targeted therapy. In the one-year follow-up, the boy remained symptom-free without recurrence.

Significance of pleural effusion detected by metagenomic next-generation sequencing in the diagnosis of aspiration pneumonia

Objective

Using metagenomic next-generation sequencing (mNGS) to profile the bacterial pathogen of pleural infection in aspiration pneumonia for therapeutic decision-making.

Methods

Collection and analysis of the clinical and laboratory data of aspiration pneumonia patients who underwent mNGS detection of pleural effusion at the Second Hospital of Jilin University from November 2020 and March 2022.

Results

Nine males and one female were included, aged 33 to 69 years. All patients had chest pain, fever, cough, and hypoxemia symptoms; 90% had expectoration. The laboratory tests revealed that all patients had elevated white blood cell, neutrophil, and C-reactive protein (CRP) levels. Furthermore, erythrocyte sedimentation rate (ESR) increased in 8 patients, and procalcitonin increased in only one patient. Chest CT indicated different degrees of lobar pneumonia and pleural effusion in all patients, and biochemical results implied exudative effusion according to Light criteria. Most routine culture results were negative. Among bacteria identified by mNGS, Fusobacterium nucleatum (n=9) was the most common, followed by Parvimonas micra (n=7) and Filifactor alocis (n=6). Three patients underwent surgical treatment after applying targeted antibiotics, thoracic puncture and drainage, and fibrinolytic septum treatment. After the adjusted treatment, the number of white blood cells, neutrophils, and lymphocytes decreased significantly, indicating the eradication of the infection.

Conclusions

Improving the vigilance of atypical people suffering from aspiration pneumonia is essential. The mNGS detection of pleural effusion clarified the microbial spectrum of aspiration pneumonia, allowing targeted antibiotic administration.

The clinical application of metagenomic next-generation sequencing in infectious diseases at a tertiary hospital in China

Background

Compared with traditional diagnostic methods (TDMs), rapid diagnostic methods for infectious diseases (IDs) are urgently needed. Metagenomic next-generation sequencing (mNGS) has emerged as a promising diagnostic technology for clinical infections.

Methods

This retrospective observational study was performed at a tertiary hospital in China between May 2019 and August 2022. The chi-square test was used to compare the sensitivity and specificity of mNGS and TDMs. We also performed a subgroup analysis of the different pathogens and samples.

Results

A total of 435 patients with clinical suspicion of infection were enrolled and 372 (85.5%) patients were finally categorized as the ID group. The overall sensitivity of mNGS was significantly higher than that of the TDMs (59.7% vs. 30.1%, P < 0.05). However, there was no significant difference in the overall specificity between the two methods (83.3% vs. 89.6%, P = 0.37). In patients with identified pathogens, the positive rates of mNGS for detecting bacteria (88.7%), fungi (87.9%), viruses (96.9%), and Nontuberculous mycobacteria (NTM; 100%) were significantly higher than those of TDMs (P < 0.05). The positive rate of mNGS for detecting Mycobacterium tuberculosis was not superior to that of TDMs (77.3% vs. 54.5%, P = 0.11). The sensitivity rates of mNGS for pathogen identification in bronchoalveolar lavage fluid, blood, cerebrospinal fluid, pleural fluid, and tissue were 72.6%, 39.3%, 37.5%, 35.0% and 80.0%, respectively.

Conclusion

With the potential for screening multiple clinical samples, mNGS has an overall advantage over TDMs. It can effectively identify pathogens, especially those that are difficult to identify using TDMs, such as NTM, chlamydia, and parasites.

Global morbidity and mortality of lower respiratory infections: A population -based study

BACKGROUND

This study provides a comprehensive, comparative and updated estimates of temporal patterns of lower respiratory infections (LRIs) globally over the past three decades.

METHODS

The data on morbidity and mortality of patients with LRIs at the global, regional and national levels were retrieved from the Global Burden of Disease (GBD) 2019 study.

RESULTS

Globally, the incident cases of LRIs increased from 414,342,866 [95% uncertainty interval (UI):383,529,625 to 449, 086,938]in 1990 to 488,902,504(95% UI: 457,572,987 to 522,635,542)in 2019 with the age standardized incidence rate (ASIR) decreased from 8,276/100,000 persons (95% UI: 7,727 to 8,892) to 6,295/100,000 persons (95% UI: 5,887 to 6,737) between 1990 and 2019. Number of LRIs deaths were 2,493,200 (95% UI: 2,268,184 to 2,736,184) in 2019, a decrease of 24.9% (95% UI: -34.4 to -15.4) in the past 30 years. Meanwhile, the age-standardized death rate (ASDR) declined also from 67/100,000 persons (95% UI: 61 to 73) in 1990 to 34/100,000 persons (95% UI: 31 to 38) in 2019. Moreover, the numbers and age-standardized rates per 100,000 persons of morbidity and mortality varied widely by age, sex, Socio-Demographic Index (SDI) quintiles, and geographical locations in 2019.

CONCLUSION

LRIs remain a major public health concern . Some differences in age, sex, SDI quintiles, and geographical locations contribute to LRIs-related global health policy development and health system resource optimization.

Metagenomic next-generation sequencing may assist diagnosis of cat-scratch disease

Bartonella henselae, the pathogen that causes cat-scratch disease (CSD), is relatively rare in the clinic. CSD usually causes mild clinical manifestations, which self-heal in a matter of weeks. However, in immunocompromised patients, CSD may cause systemic disorders that can lead to critical illness. Due to the diversity of symptom signs and the lack of a golden standard for diagnosis, identifying atypical CSD in a timely manner presents a challenge. Metagenomic next-generation sequencing (mNGS), is a promising technology that has been widely used in the detection of pathogens in clinical infectious diseases in recent years. mNGS can detect multiple pathogens quickly and accurately from any given source. Here, we present a case of atypical CSD, which was diagnosed using mNGS. The patient manifested a fever of unknown infectious origin, and routine antibiotic treatment was ineffective. mNGS was employed to test the patient’s peripheral blood, which led to the detection of B. henselae. This was rarely seen in previous CSD reports. We surmised that the patient presented with atypical CSD and thus a targeted therapy was recommended. Crucially, the patient recovered rapidly. Based on this case study findings, we recommend that CSD should be included in the differential diagnosis for fever of unknown origin and that mNGS may be helpful in the diagnosis of CSD.

Improving Suspected Pulmonary Infection Diagnosis by Bronchoalveolar Lavage Fluid Metagenomic Next-Generation Sequencing: a Multicenter Retrospective Study

Metagenomic next-generation sequencing (mNGS) has been gradually applied to clinical practice due to its unbiased characteristics of pathogen detection. However, its diagnostic performance and clinical value in suspected pulmonary infection need to be evaluated. We systematically reviewed the clinical data of 246 patients with suspected pulmonary infection from 4 medical institutions between January 2019 and September 2021. The diagnostic performances of mNGS and conventional testing (CT) were systematically analyzed based on bronchoalveolar lavage fluid (BALF). The impacts of mNGS and CT on diagnosis modification and treatment adjustment were also assessed. The positive rates of mNGS and CT were 47.97% and 23.17%, respectively. The sensitivity of mNGS was significantly higher than that of CT (53.49% versus 23.26%, P < 0.01), especially for infections of Mycobacterium tuberculosis (67.86% versus 17.86%, P < 0.01), atypical pathogens (100.00% versus 7.14%, P < 0.01), viruses (92.31% versus 7.69%, P < 0.01), and fungi (78.57% versus 39.29%, P < 0.01). The specificity of mNGS was superior to that of CT, with no statistical difference (90.32% versus 77.42%, P = 0.167). The positive predictive value (PPV) and negative predictive value (NPV) of mNGS were 97.46% and 21.88%, respectively. Diagnosis modification and treatment adjustment were conducted in 32 (32/246, 13.01%) and 23 (23/246, 9.35%) cases, respectively, according to mNGS results only. mNGS significantly improved the diagnosis of suspected pulmonary infection, especially infections of M.tuberculosis, atypical pathogens, viruses, and fungi, and it demonstrated the pathogen distribution of pulmonary infections. It is expected to be a promising microbiological detection and diagnostic method in clinical practice.

IMPORTANCE Pulmonary infection is a heterogeneous and complex infectious disease with high morbidity and mortality worldwide. In clinical practice, a considerable proportion of the etiology of pulmonary infection is unclear, microbiological diagnosis being challenging. Metagenomic next-generation sequencing detects all nucleic acids in a sample in an unbiased manner, revealing the microbial community environment and organisms and improving the microbiological detection and diagnosis of infectious diseases in clinical settings. This study is the first multicenter, large-scale retrospective study based entirely on BALF for pathogen detection by mNGS, and it demonstrated the superior performance of mNGS for microbiological detection and diagnosis of suspected pulmonary infection, especially in infections of Mycobacterium tuberculosis, atypical pathogens, viruses, and fungi. It also demonstrated the pathogen distribution of pulmonary infections in the real world, guiding targeted treatment and improving clinical management and prognoses.

The performance of detecting Mycobacterium tuberculosis complex in lung biopsy tissue by metagenomic next-generation sequencing

Background

Tuberculosis (TB) is a chronic infectious disease caused by the Mycobacterium tuberculosis complex (MTBC), which is the leading cause of death from infectious diseases. The rapid and accurate microbiological detection of the MTBC is crucial for the diagnosis and treatment of TB. Metagenomic next-generation sequencing (mNGS) has been shown to be a promising and satisfying application of detection in infectious diseases. However, relevant research about the difference in MTBC detection by mNGS between bronchoalveolar lavage fluid (BALF) and lung biopsy tissue specimens remains scarce.

Methods

We used mNGS to detect pathogens in BALF and lung biopsy tissue obtained by CT-guide percutaneous lung puncture (CPLP) or radial endobronchial ultrasound transbronchial lung biopsy (R-EBUS-TBLB) from 443 hospitalized patients in mainland China suspected of pulmonary infections between May 1, 2019 and October 31, 2021. Aim to evaluate the diagnostic performance of mNGS for detecting MTBC and explore differences in the microbial composition in the 2 specimen types.

Results

Among the 443 patients, 46 patients finally were diagnosed with TB, of which 36 patients were detected as MTBC positive by mNGS (8.93%). Striking differences were noticed in the higher detection efficiency of lung biopsy tissue compared with BALF (P = 0.004). There were no significant differences between the 2 specimen types in the relative abundance among the 27 pathogens detected by mNGS from the 36 patients.

Conclusions

This study demonstrates that mNGS could offer an effective detection method of MTBC in BALF or lung tissue biopsy samples in patients suspected of TB infections. When it comes to the situations that BALF samples have limited value to catch pathogens for special lesion sites or the patients have contraindications to bronchoalveolar lavage (BAL) procedures, lung biopsy tissue is an optional specimen for MTBC detection by mNGS. However, whether lung tissue-mNGS is superior to BALF-mNGS in patients with MTBC infection requires further prospective multicenter randomized controlled studies with more cases.

Early detection of gram‑negative bacteria using metagenomic next‑generation sequencing in acute respiratory distress syndrome: A case report

Metagenomic next-generation sequencing (mNGS) is an effective method that can be used for the identification of early pathogens in patients with suspected severe pneumonia. However, the potential of mNGS for evaluating the prognosis of acute respiratory distress syndrome (ARDS) in patients with severe pneumonia remains unclear. In the present report, hospital-acquired gram-negative bacteria infections were detected in a case using metagenomic next-generation sequencing (mNGS) in a sample of bronchoalveolar fluid. This was obtained from a 58-year-old male patient with traumatic wet lung after a neurosurgery. According to the results, of which the profiles of the resistance genes were detected by mNGS, drugs designed to control infection were adjusted, namely to polymyxin B (500,000 U/12 h), azithromycin (0.5 g/24 h) and ganciclovir (0.25 g/12 h). Following adjusting treatment for 8 days, the symptoms of lung infection and hypoxemia were markedly improved, resulting in the patient being transferred out of the intensive care unit 15 days after treatment. To conclude, observations from the present report suggest that mNGS is a useful method for the early identification of pathogens in patients with pneumonia caused by ARDS. However, further studies are required to identify the complementary role of mNGS in supporting conventional microbiological methods in routine clinical practice.