Metagenomic next-generation sequencing for the diagnosis of suspected pneumonia in immunocompromised patients

Pneumocystis jirovecii and Nocardia pneumonia in a middle-aged male with Nephrotic syndrome: a case report and literature review

INTRODUCTION

Nephrotic syndrome (NS) is a common chronic kidney disease that is often accompanied by a state of immunodeficiency. Immunosuppression increases the risk of infections, with Pneumocystis jirovecii and Nocardia brasiliensis being two opportunistic pathogens that can cause severe infections in patients with compromised immune function. This study presents a case of a middle-aged male patient with NS concurrently infected with Pneumocystis jirovecii and Nocardia brasiliensis. It aims to synthesize the pertinent diagnostic approaches and treatment experiences. Notably, there have been no reported cases of NS occurring simultaneously with both Pneumocystis jirovecii pneumonia and Nocardia pneumonia.

CASE PRESENTATION

A 58-year-old male farmer presented to the hospital with a one-week history of persistent fever, cough, and sputum production. His maximum body temperature was recorded at 39 °C, and he produced yellow viscous sputum. This patient had a one-year history of NS, managed with long-term oral corticosteroid and cyclophosphamide therapy. Admission chest computed tomography displayed interstitial changes in both lungs. After failing to detect any pathogens through routine etiological tests, we successfully identified Nocardia brasiliensis, Pneumocystis jirovecii, and Lodderomyces elongisporus using bronchoscopy-guided sputum samples through metagenomic next-generation sequencing (mNGS) technology. Subsequently, we initiated a combined treatment regimen for the patient using trimethoprim-sulfamethoxazole, meropenem, and moxifloxacin, which yielded remarkable therapeutic outcomes.

CONCLUSION

The adoption and promotion of mNGS technologies have significantly resolved the difficulty in early pathogen detection, guiding clinicians from empirical to genomic diagnosis, achieving prevention before treatment, and thereby enhancing patient survival rates.

Comparing the diagnostic value of targeted with metagenomic next-generation sequencing in immunocompromised patients with lower respiratory tract infection

BACKGROUND

Accurate identification of the etiology of lower respiratory tract infections (LRTI) is crucial, particularly for immunocompromised patients with more complex etiologies. The advent of next-generation sequencing (NGS) has enhanced the effectiveness of pathogen detection. However, assessments of the clinical diagnostic value of targeted NGS (tNGS) in immunocompromised patients with LRTI are limited.

METHODS

To evaluate the diagnostic value of tNGS in immunocompromised patients with LRTI, a total of 88 patients, of whom 54 were immunocompromised, were enrolled. These patients underwent tNGS testing of bronchoalveolar lavage fluid (BALF). Results from both metagenomic next-generation sequencing (mNGS) and conventional microbiological tests (CMT) were also available for all participants. The performance of tNGS was assessed by comparing its findings against mNGS, CMT, and the clinical composite diagnosis.

RESULTS

In the cohort of 88 patients, tNGS showed comparable diagnostic value to mNGS and was significantly superior to CMT. Compared to CMT and composite reference standard, tNGS showed sensitivity of 94.55% and 90.48%, respectively. In immunocompromised patients, despite a more diverse pathogen variety, tNGS maintained similar sensitivity to mNGS and outperformed CMT. tNGS positively influenced etiologic diagnosis and antibiotic decision-making in 72.72% of cases, leading to a change in antibiotic regimen in 17.05% of cases. We also compared the detection of microbial nucleic acids by tNGS with mNGS and found that tNGS could identify 87.99% of the microbial nucleic acids identified by mNGS.

CONCLUSION

In summary, our study demonstrated that tNGS offers promising clinical diagnostic accuracy in immunocompromised patients, as evidenced by its favorable comparison with CMT, the composite reference standard, and mNGS.

Advantages of metagenomic next-generation sequencing in the management of ANCA-associated vasculitis patients with suspected pulmonary infection as a rule-out tool

OBJECTIVE

Pulmonary infection is one of the leading causes of death in patients with ANCA-associated vasculitis (AAV). It is sometimes difficult to differentiate pulmonary infection from pulmonary involvement of vasculitis in AAV patients. Fiberoptic bronchoscopy and bronchoalveolar lavage fluid (BALF) assays are useful diagnostic methods. In addition to conventional microbiological tests (CMTs), metagenomic next-generation sequencing (mNGS) facilitates rapid and sensitive detection of various pathogens. The current study aimed to evaluate the advantages of additional BALF mNGS in the management of pulmonary infection in AAV patients.

METHODS

27 patients with active AAV and suspected pulmonary infection whose BALF samples were tested by mNGS and CMTs and 17 active AAV patients whose BALF were tested by CMTs alone were retrospectively recruited. The results of microbiological tests, and adjustments of treatment following BALF mNGS, were described. The durations of antimicrobial treatment and in-hospital mortality in patients were compared.

RESULTS

Among the 27 patients whose BALF samples were tested by mNGS, 25.9% of patients did not have evidence of pathogenic microorganism in their BALF samples, 55.6% had polymicrobial infections, including bacteria, fungi and viruses. Of these 27 patients, 40.7% did not have evidence of pathogenic microorganism in their BALF or serum samples according to CMTs. Patients in the BALF mNGS/CMT group received a significantly shorter duration of antibacterial and total antimicrobial treatment than patients in the CMT alone group (17.3 ± 14.7 vs. 27.9 ± 19.0 days, P = 0.044; 18.9 ± 15.0 vs. 29.5 ± 17.7 days, P = 0.040, respectively). Fewer patients in the BALF mNGS/CMT group died than in the CMT alone group (4/27 vs. 7/17, P = 0.049).

CONCLUSION

Compared with CMT alone, additional mNGS tests may shorten the duration of antimicrobial treatment and possibly decrease death from severe infection by providing precise and quick diagnosis of infection.

Metagenomics in the Diagnosis of Pneumonia: Protocol for a Systematic Review

BACKGROUND

Causative pathogens are currently identified in only a minority of pneumonia cases, which affects antimicrobial stewardship. Metagenomic next-generation sequencing (mNGS) has potential to enhance pathogen detection due to its sensitivity and broad applicability. However, while studies have shown improved sensitivity compared with conventional microbiological methods for pneumonia diagnosis, it remains unclear whether this can translate into clinical benefit. Most existing studies focus on patients who are ventilated, readily allowing for analysis of bronchoalveolar lavage fluid (BALF). The impact of sample type on the use of metagenomic analysis remains poorly defined. Similarly, previous studies rarely differentiate between the types of pneumonia involved-community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), or ventilator-associated pneumonia (VAP)-which have different clinical profiles.

OBJECTIVE

This study aims to determine the clinical use of mNGS in CAP, HAP, and VAP, compared with traditional microbiological methods.

METHODS

We aim to review all studies (excluding case reports of a series of fewer than 10 people) of adult patients with suspected or confirmed pneumonia that compare metagenomic analysis with traditional microbiology techniques, including culture, antigen-based testing, and polymerase chain reaction-based assays. Relevant studies will be identified through systematic searches of the Embase, MEDLINE, Scopus, and Cochrane CENTRAL databases. Screening of titles, abstracts, and subsequent review of eligible full texts will be done by 2 separate reviewers (SQ and 1 of AL, CJ, or CH), with a third clinician (ES) providing adjudication in case of disagreement. Our focus is on the clinical use of metagenomics for patients with CAP, HAP, and VAP. Data extracted will focus on clinically important outcomes-pathogen positivity rate, laboratory turnaround time, impact on clinical decision-making, length of stay, and 30-day mortality. Subgroup analyses will be performed based on the type of pneumonia (CAP, HAP, or VAP) and sample type used. The risk of bias will be assessed using the QUADAS-2 tool for diagnostic accuracy studies. Outcome data will be combined in a random-effects meta-analysis, and where this is not possible, a narrative synthesis will be undertaken.

RESULTS

The searches were completed with the assistance of a medical librarian on January 13, 2024, returning 5750 records. Screening and data extraction are anticipated to be completed by September 2024.

CONCLUSIONS

Despite significant promise, the impact of metagenomic analysis on clinical pathways remains unclear. Furthermore, it is unclear whether the use of this technique will alter depending on whether the pneumonia is a CAP, HAP, or VAP or the sample type that is collected. This systematic review will assess the current evidence base to support the benefit of clinical outcomes for metagenomic analysis, depending on the setting of pneumonia diagnosis or specimen type used. It will identify areas where further research is needed to advance this methodology into routine care.

TRIAL REGISTRATION

PROSPERO CRD42023488096; https://tinyurl.com/3suy7cma.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/57334.

Comparison of targeted next-generation sequencing and metagenomic next-generation sequencing in the identification of pathogens in pneumonia after congenital heart surgery: a comparative diagnostic accuracy study

BACKGROUND

This study aimed to compare targeted next-generation sequencing (tNGS) with metagenomic next-generation sequencing (mNGS) for pathogen detection in infants with severe postoperative pneumonia after congenital heart surgery.

METHODS

We conducted a retrospective observational study using data from the electronic medical record system of infants who developed severe pneumonia after surgery for congenital heart disease from August 2021 to August 2022. Infants were divided into tNGS and mNGS groups based on the pathogen detection methods. The primary outcome was the efficiency of pathogen detection, and the secondary outcomes were the timeliness and cost of each method.

RESULTS

In the study, 91 infants were included, with tNGS detecting pathogens in 84.6% (77/91) and mNGS in 81.3% (74/91) of cases (P = 0.55). No significant differences were found in sensitivity, specificity, PPA, and NPA between the two methods (P > 0.05). tNGS identified five strains with resistance genes, while mNGS detected one strain. Furthermore, tNGS had a faster detection time (12 vs. 24 h) and lower cost ($150 vs. $500) compared to mNGS.

CONCLUSION

tNGS offers similar sensitivity to mNGS but with greater efficiency and cost-effectiveness, making it a promising approach for respiratory pathogen detection.

The Utility of Real-Time PCR, Metagenomic Next-Generation Sequencing, and Culture in Bronchoalveolar Lavage Fluid for Diagnosis of Pulmonary Aspergillosis

Timely detection of Aspergillus infection is crucial given the high mortality rate of pulmonary aspergillosis (PA). Here, the diagnostic performances for PA of mycological culture, Aspergillus real-time PCR, and metagenomic next-generation sequencing (mNGS) assay from bronchoalveolar lavage fluid, were evaluated. In total, 139 patients with suspected fungal pneumonia were enrolled between December 2021 and July 2023, collecting 139 bronchoalveolar lavage fluid samples for real-time PCR and culture, with 87 undergoing mNGS assay. The sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve with 95% CIs of these assays for PA were as follows: 35.3% (14.2%-61.7%), 100.0% (94.0%-100.0%), 100.0% (54.1%-100.0%), 84.5% (79.3%-88.6%), and 0.676 (0.560-0.779), respectively, for culture; 82.4% (56.6%-96.2%), 98.3% (91.1%-100.0%), 93.3% (66.4%-99.0%), 95.2% (87.6%-98.2%), and 0.903 (0.815-0.959), respectively, for same diagnostic performance of real-time PCR and mNGS; and 94.1% (71.3%-99.9%), 96.7% (88.5%-99.6%), 88.9% (67.1%-96.9%), 98.3% (89.6%-99.7%), and 0.954 (0.880-0.989), respectively, for real-time PCR combining mNGS; real-time PCR, mNGS, and their combination significantly improved in area under the curve values over culture (P < 0.001), but real-time PCR testing and mNGS had no significant difference with each other and their combination. Overall, the performance of culture was limited by low sensitivity; both real-time PCR and mNGS assays as single diagnostic tests are promising compared with culture and combined tests.

Metagenomic Next-Generation Sequencing in the Diagnosis of Pulmonary Infections after Allogeneic Hematopoietic Stem Cell Transplantation

Early and accurate identification of pathogens in pulmonary infections after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is critically important. The clinical usefulness of metagenomic next-generation sequencing (mNGS) in the diagnosis of pulmonary infections after allo-HSCT remains under discussion. This multicenter retrospective study was conducted to compare mNGS and conventional microbiological tests (CMTs) in identifying the pathogens of pulmonary infections in allo-HSCT recipients. One hundred forty allo-HSCT recipients with suspected pulmonary infections who underwent bronchoscopy were included. mNGS and CMTs performed on bronchoalveolar lavage fluid specimens showed 71.4% positivity on mNGS compared to 55.0% positivity on CMTs. mNGS identified 182 pathogens, including bacteria (n = 88), fungi (n = 35) and viruses (n = 59), compared to 106 pathogens detected by CMTs (bacteria, n = 31; fungi, n = 24; viruses, n = 51). Pulmonary infection was finally diagnosed in 98 patients, including 22 bacterial, 7 fungal, 18 viral, and 48 mixed infections and 3 infections with an unknown pathogen. Mixed infections were identified in 50.5% of the patients with pulmonary infection. The sensitivity of mNGS and CMTs for diagnosing pulmonary infections was 88.8% and 69.4%, respectively (P = .001), and the specificity were 81.0% and 85.7%, respectively (P = .688). Our findings suggest that mNGS may be a promising technology for diagnosing pulmonary infections in allo-HSCT recipients.

Nanopore Sequencing Technology: A Reliable Method for Pathogen Diagnosis in Elderly Patients with Community-Acquired Pneumonia

Purpose

Next-generation sequencing of the metagenome (mNGS) is gaining traction as a valuable tool for diagnosing infectious diseases. Compared to mNGS, pathogen detection based on Oxford Nanopore Technology further shortens the detection time. This study seeks to assess the efficacy of Nanopore sequencing in identifying pathogens associated with community-acquired pneumonia (CAP) among elderly individuals in China.

Patients and Methods

From January 2023 to June 2023, elderly patients with CAP were prospectively recruited from Hangzhou First People's Hospital. A comprehensive set of clinical data was gathered, and bronchoalveolar lavage (BAL) fluid samples were collected. Concurrently, pathogen identification was performed using conventional microbiological diagnostic methods, Illumina sequencing, and Nanopore sequencing, and the diagnostic efficacy of pathogen detection was compared.

Results

The study included a total of 29 patients. The diagnostic positivity rates of traditional microbiological detection, Illumina sequencing, and Nanopore sequencing were 24.1%, 51.7%, and 48.3%, respectively. Their diagnostic specificities were 91.7%, 50%, and 75%, respectively. Compared to traditional microbiological detection, both Nanopore and Illumina sequencing showed significantly increased sensitivity. However, Nanopore sequencing exhibited relatively better consistency with the final clinical comprehensive diagnosis, with a Kappa value of 0.574. This outperformed traditional microbiological detection and Illumina sequencing, which had a Kappa value of 0.296 and 0.402, respectively. In addition, Nanopore sequencing required the shortest turnaround time.

Conclusion

Nanopore sequencing technology demonstrates as a reliable and rapid method for detecting pathogens in elderly patients with CAP.

Diagnostic performance of pancreatic fluid aspiration through metagenomic next-generation sequencing for suspected infected pancreatic necrosis

AIMS

This study aimed to evaluate the diagnostic performance of metagenomic next-generation sequencing (mNGS) with pancreatic fluid aspiration for the detection of infected pancreatic necrosis (IPN).

METHODS

This retrospective observational study included 66 patients with suspected IPN. The participants simultaneously underwent pancreatic fluid aspiration mNGS, and microbial and blood culture. We compared the diagnostic performance of mNGS with that of culture in the detection of pathogens associated with IPN.

RESULTS

Of the 66 patients, 45 (68.2 %) were confirmed to have IPN. Pancreatic fluid aspiration mNGS yielded positive results in 32 of these patients (71.1 %), significantly outperforming microbial culture results (25 patients, 55.6 %; P = 0.039); however, both methods exhibited similar specificity (95.2% vs. 100 %). The results of pancreatic fluid aspiration mNGS and microbial culture matched in 73.3 % (33/45) of patients with IPN. The turnaround time for the mNGS results was significantly shorter than that for the microbial culture method (P < 0.001). In addition, survival analysis demonstrated that a positive mNGS result was not associated with increased mortality (hazard ratio, 0.652; 95 % confidence interval 0.157-2.699, P = 0.555).

CONCLUSIONS

Our study highlights the potential of mNGS for diagnosing IPN, with implications for improving patient care by facilitating early and accurate diagnosis, guiding appropriate interventions, and possibly improving patient outcomes.

Microbial signatures predictive of short-term prognosis in severe pneumonia

Objective

This retrospective cohort study aimed to investigate the composition and diversity of lung microbiota in patients with severe pneumonia and explore its association with short-term prognosis.

Methods

A total of 301 patients diagnosed with severe pneumonia underwent bronchoalveolar lavage fluid metagenomic next-generation sequencing (mNGS) testing from February 2022 to January 2024. After applying exclusion criteria, 236 patients were included in the study. Baseline demographic and clinical characteristics were compared between survival and non-survival groups. Microbial composition and diversity were analyzed using alpha and beta diversity metrics. Additionally, LEfSe analysis and machine learning methods were employed to identify key pathogenic microorganism associated with short-term mortality. Microbial interaction modes were assessed through network co-occurrence analysis.

Results

The overall 28-day mortality rate was 37.7% in severe pneumonia. Non-survival patients had a higher prevalence of hypertension and exhibited higher APACHE II and SOFA scores, higher procalcitonin (PCT), and shorter hospitalization duration. Microbial α and β diversity analysis showed no significant differences between the two groups. However, distinct species diversity patterns were observed, with the non-survival group showing a higher abundance of Acinetobacter baumannii, Klebsiella pneumoniae, and Enterococcus faecium, while the survival group had a higher prevalence of Corynebacterium striatum and Enterobacter. LEfSe analysis identified 29 distinct terms, with 10 potential markers in the non-survival group, including Pseudomonas sp. and Enterococcus durans. Machine learning models selected 16 key pathogenic bacteria, such as Klebsiella pneumoniae, significantly contributing to predicting short-term mortality. Network co-occurrence analysis revealed greater complexity in the non-survival group compared to the survival group, with differences in central genera.

Conclusion

Our study highlights the potential significance of lung microbiota composition in predicting short-term prognosis in severe pneumonia patients. Differences in microbial diversity and composition, along with distinct microbial interaction modes, may contribute to variations in short-term outcomes. Further research is warranted to elucidate the clinical implications and underlying mechanisms of these findings.

An umbrella review of the diagnostic value of next-generation sequencing in infectious diseases

BACKGROUND

An increasing number of systematic reviews (SRs) have evaluated the diagnostic values of next-generation sequencing (NGS) in infectious diseases (IDs).

AIM

This umbrella analysis aimed to assess the potential risk of bias in existing SRs and to summarize the published diagnostic values of NGS in different IDs.

METHOD

We searched PubMed, Embase, and the Cochrane Library until September 2023 for SRs assessing the diagnostic validity of NGS for IDs. Two investigators independently determined review eligibility, extracted data, and evaluated reporting quality, risk of bias, methodological quality, and evidence certainty in the included SRs.

RESULTS

Eleven SRs were analyzed. Most SRs exhibited a moderate level of reporting quality, while a serious risk of bias was observed in all SRs. The diagnostic performance of NGS in detecting pneumocystis pneumonia and periprosthetic/prosthetic joint infection was notably robust, showing excellent sensitivity (pneumocystis pneumonia: 0.96, 95% CI 0.90-0.99, very low certainty; periprosthetic/prosthetic joint infection: 0.93, 95% CI 0.83-0.97, very low certainty) and specificity (pneumocystis pneumonia: 0.96, 95% CI 0.92-0.98, very low certainty; periprosthetic/prosthetic joint infection: 0.95, 95% CI 0.92-0.97, very low certainty). NGS exhibited high specificity for central nervous system infection, bacterial meningoencephalitis, and tuberculous meningitis. The sensitivity to these infectious diseases was moderate. NGS demonstrated moderate sensitivity and specificity for multiple infections and pulmonary infections.

CONCLUSION

This umbrella analysis indicates that NGS is a promising technique for diagnosing pneumocystis pneumonia and periprosthetic/prosthetic joint infection with excellent sensitivity and specificity. More high-quality original research and SRs are needed to verify the current findings.

Clinical efficacy of macrolide antibiotics in mycoplasma pneumoniae pneumonia carrying a macrolide-resistant mutation in the 23 S rRNA gene in pediatric patients

BACKGROUND

The global prospective surveillance data showed the re-emergence of mycoplasma pneumoniae pneumonia (MPP) in Europe and Asia after the coronavirus disease 2019 pandemic. We sought to observe the effect of macrolide antibiotics in the treatment of MPP carrying a macrolide-resistant mutation gene and the potential of targeted next-generation sequencing (tNGS) as a front-line diagnostic in MPP patients.

METHODS

The baseline characteristics of 91 children with MPP hospitalized from January to October 2023 were retrospectively analyzed. They were divided into two groups according to whether carrying the macrolide-resistant mutation or not. The logistic and linear regression analyses were used to determine whether the mutation was a standalone predictive predictor of the duration of fever and hospital length of stay.

RESULTS

First, no patients had a fever for ≥ 7 days after macrolide treatment. But length of stay and hormone concentration were significantly different between the two groups (P < 0.05). There were also no statistical association between the mutation and the duration of fever and hospital length of stay.

CONCLUSION

Macrolides can be administered to MPP children carrying a macrolide-resistant mutation. tNGS can be seen as a front-line diagnostic in MPP.

Bronchial lavage tNGS in the diagnosis of pulmonary tuberculosis

BACKGROUND

Tuberculosis (TB), primarily caused by Mycobacterium tuberculosis, remains a significant global health concern. Targeted Next-Generation Sequencing (tNGS) has emerged as a rapid and comprehensive diagnostic tool for tuberculosis, offering advantages over traditional methods and serving as an effective alternative for drug susceptibility testing and the detection of drug-resistant tuberculosis.

OBJECTIVE

This study aimed to retrospectively analyze the clinical characteristics of pulmonary tuberculosis patients. After explore the application value of targeted next-generation sequencing technology in this patient population, providing valuable insights for clinical diagnosis and treatment.

METHODS

In this retrospective study, we analyzed data from 65 patients with laboratory-confirmed tuberculosis admitted to Tianjin Baodi Hospital from November 14, 2020, to February 1, 2023. Patients underwent bronchoalveolar lavage fluid (BALF) testing, including acid-fast staining, culture, and tNGS. Biopsies and histopathological examinations were performed on some patients, along with comprehensive radiological assessments for all.

RESULTS

Among the 65 pulmonary tuberculosis patients, targeted next-generation sequencing detected pathogens in bronchoalveolar lavage fluid with a positivity rate of 93.8%, significantly higher than traditional methods such as acid-fast staining, culture, and pathology. Compared to bronchoalveolar lavage fluid smear, targeted next-generation sequencing demonstrated significantly higher diagnostic sensitivity (98.46% vs. 26.15%) and accuracy (98.46% vs. 26.15%).

CONCLUSION

Targeted next-generation sequencing, with its high sensitivity and specificity compared to traditional methods, provides unique advantages in detecting pathogens among these patients, highlighting its importance in disease management.

Metagenomic Next-Generation Sequencing as an Effective Diagnostic Tool for Talaromycosis in HIV-Negative Patients

The diagnosis of Talaromyces marneffei infection in HIV-negative patients remains challenging. There is an urgent need for rapid and convenient methods to diagnose this complicated disease. The aim of this study was to evaluate the diagnostic efficiency of metagenomic next-generation sequencing (mNGS) for talaromycosis in non-HIV-infected patients by comparing mNGS with traditional microbial culture. In total, 66 samples from 57 patients were analyzed via both mNGS and microbial culture. The ROC curve showed a sensitivity for mNGS of 97.22%, which was greater than that of microbial culture (61.11%). Samples from the respiratory tract, infectious skin lesions, and lymph nodes are recommended as routine samples for talaromycosis detection via mNGS. Furthermore, mNGS significantly reduced the diagnostic time compared to microbial culture. Overall, our study demonstrated that mNGS is a promising tool for rapid and accurate pathogenic detection in HIV-negative patients with talaromycosis.

Torquetenovirus from bronchoalveolar lavage fluid as a biomarker for lung infection among immunocompromised hosts

Aim: Torquetenovirus (TTV) was a promising biomarker for immunity, while lung regional TTV for evaluating the opportunistic infection among immunocompromised hosts (ICH) was unclear.Materials & methods: In the ICH and non-ICH populations, we compared the susceptibility to opportunistic infections, clinical severity and the prognosis between subgroups, respectively.Results: ICH with detectable bronchoalveolar lavage fluid (BALF)-TTV were more susceptible to lung aspergillosis and Mycobacterium infections. Furthermore, our data demonstrated that the ICH cohort with detectable BALF-TTV represented a higher clinical severity and a worse prognosis, while the above findings were not found in the non-ICH population.Conclusion: Our findings demonstrated that the BALF-TTV could act as an effective predictor for opportunistic infection for ICH that complemented the CD4+ T cell counts.

Clinical challenge of diagnosing non-ventilator hospital-acquired pneumonia and identifying causative pathogens: a narrative review

Non-ventilated hospital-acquired pneumonia (NV-HAP) is associated with a significant healthcare burden, arising from high incidence and associated morbidity and mortality. However, accurate identification of cases remains challenging. At present, there is no gold-standard test for the diagnosis of NV-HAP, requiring instead the blending of non-specific signs and investigations. Causative organisms are only identified in a minority of cases. This has significant implications for surveillance, patient outcomes and antimicrobial stewardship. Much of the existing research in HAP has been conducted among ventilated patients. The paucity of dedicated NV-HAP research means that conclusions regarding diagnostic methods, pathology and interventions must largely be extrapolated from work in other settings. Progress is also limited by the lack of a widely agreed definition for NV-HAP. The diagnosis of NV-HAP has large scope for improvement. Consensus regarding a case definition will allow meaningful research to improve understanding of its aetiology and the heterogeneity of outcomes experienced by patients. There is potential to optimize the role of imaging and to incorporate novel techniques to identify likely causative pathogens. This would facilitate both antimicrobial stewardship and surveillance of an important healthcare-associated infection. This narrative review considers the utility of existing methods to diagnose NV-HAP, with a focus on the significance and challenge of identifying pathogens. It discusses the limitations in current techniques, and explores the potential of emergent molecular techniques to improve microbiological diagnosis and outcomes for patients.

Comparison of plasma and blood cell samples in metagenomic next-generation sequencing for identification of the causative pathogens of fever

Background

Metagenomic next-generation sequencing (mNGS) of plasma DNA has become an attractive diagnostic method for infectious diseases; however, the rate of false-positive results is high. This study aims to evaluate the diagnostic accuracy of mNGS in plasma versus blood cell samples for immunocompromised children with febrile diseases.

Methods

The results of conventional microbiological test (CMT) and mNGS using plasma and blood cells in 106 patients with 128 episodes of febrile diseases from the Department of Hematology/Oncology were analyzed and described.

Results

The positivity rates for CMT and mNGS of plasma and blood cells were 35.9 %, 84.4 % and 46.9 %, respectively (P < 0.001). Notably, mNGS identified multiple pathogens in a single specimen in 68.5 % of plasma samples and 38.3 % of blood cell samples (P < 0.001). Furthermore, plasma and blood cell mNGS identified causative pathogens in 58 and 46 cases, accounting for 53.7 % and 76.7 % of the mNGS-positive cases for each sample type, respectively (P = 0.002). By integrating results from both plasma and blood cell samples, causative pathogens were identified in 77 cases (60.2 %), enhancing sensitivity to 87.5 % but reducing specificity to 15.0 %, compared to plasma (65.9 % sensitivity and 20.0 % specificity) and blood cell samples (52.3 % sensitivity and 80.0 % specificity).

Conclusions

mNGS of plasma is sensitive but has a high false-positive rate, while mNGS of blood cells has low sensitivity but higher specificity.

Exploring the pathogen diagnosis and prognostic factors of severe COVID-19 using metagenomic next-generation sequencing: A retrospective study

Background

This study aimed to identify pathogens and factors that predict the outcome of severe COVID-19 by utilizing metagenomic next-generation sequencing (mNGS) technology.

Methods

We retrospectively analyzed data from 56 severe COVID-19 patients admitted to our hospital between December 2022 and March 2023. We analyzed the pathogen types and strains detected through mNGS and conventional microbiological testing and collected general patient information.

Results

In this study, 42 pathogens were detected using mNGS and conventional microbiological testing. mNGS had a significantly higher detection rate of 90.48% compared to 71.43% for conventional testing (P=0.026). A total of 196 strains were detected using both methods, with a significantly higher detection rate of 70.92% for mNGS compared to 49.49% for conventional testing (P=0.000). The 56 patients were divided into a survival group (33 cases) and a death group (23 cases) based on clinical outcomes. The survival group had significantly lower age, number of pathogens detected by mNGS, number of pathogens detected by conventional testing, APACHE-II score, SOFA score, high-sensitivity troponin, creatine kinase-MB subtype, and lactate dehydrogenase compared to the death group (P<0.05). Multivariate logistic regression analysis showed that these factors were risk factors for mortality in severe COVID-19 patients (P<0.05). In contrast, ROC curve analysis revealed that these factors had diagnostic values for mortality, with AUC values ranging from 0.657 to 0.963. The combined diagnosis of these indicators had an AUC of 0.924.

Conclusions

The use of mNGS technology can significantly enhance the detection of pathogens in severe cases of COVID-19 and also has a solid ability to predict clinical outcomes.

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.

Metagenomic Next-generation Sequencing for Pathogen Identification in Bronchoalveolar Lavage Fluid From Neonates Receiving Extracorporeal Membrane Oxygenation

BACKGROUND

Neonates on extracorporeal membrane oxygenation (ECMO) are at high risk of infection. Rapid and accurate identification of pathogens is essential to improve the prognosis of children on ECMO. Metagenome next-generation sequencing (mNGS) has been used in recent years to detect pathogenic bacteria, but evidence for its use in neonates on ECMO is lacking.

METHODS

This retrospective study was conducted using an electronic medical record system. We analyzed the results of mNGS and conventional microbiological tests (CMTs) in bronchoalveolar lavage fluid of neonates receiving ECMO support with pulmonary infections in our hospital from July 2021 to January 2023.

RESULTS

We screened 18 ECMO-supported neonates with pneumonia for inclusion in the study. The median age of the included children was 2 (1-4) days, the median gestational age was 38.3 (33-40 +4 ) weeks, and the median weight was 3.3 (2.2-4.8) kg. The detection rate of mNGS was 77.8% (14/18), higher than the 44.4% (8/18) of CMT ( P = 0.04). A total of 20 pathogens were detected in mNGS, with the top 3 most common pathogens being Klebsiella pneumoniae , Acinetobacter baumannii and Escherichia coli . Mixed infections were found in 14 cases (77.8%), including 13 cases (72.2%) with mixed infections detected by mNGS and 7 cases (27.8%) with mixed infections detected by CMT. A total of 9 children underwent treatment changes based on mNGS results and all of them experienced relief of symptoms.

CONCLUSION

Compared with CMT, mNGS can detect pathogens earlier and more sensitively, and may play an important role in ECMO-supported neonatal pneumonia pathogen detection and optimization of antibiotic therapy.

DIAGNOSTIC PERFORMANCE OF CENTRAL NERVOUS SYSTEM INFECTIONS IN PATIENTS WITH NEUROSURGICAL INTENSIVE CARE USING METAGENOMIC NEXT-GENERATION SEQUENCING: A PROSPECTIVE OBSERVATIONAL STUDY

ABSTRACT

Background. Identifying the causative pathogens of central nervous system infections (CNSIs) is crucial, but the low detection rate of traditional culture methods in cerebrospinal fluid (CSF) has made the pathogenic diagnosis of CNSIs a longstanding challenge. Patients with CNSIs after neurosurgery often overlap with inflammatory and bleeding. Metagenomic next-generation sequencing (mNGS) has shown some benefits in pathogen detection. This study aimed to investigate the diagnostic performance of mNGS in the etiological diagnosis of CNSIs in patients after neurosurgery. Methods. In this prospective observational study, we enrolled patients with suspected CNSIs after neurosurgical operations who were admitted to the intensive care unit of Beijing Tiantan Hospital. All enrolled patients' CSF was tested using mNGS and pathogen culture. According to comprehensive clinical diagnosis, the enrolled patients were divided into CNSIs group and non-CNSIs group to compare the diagnostic efficiency of mNGS and pathogen culture. Results. From December 2021 to March 2023, 139 patients were enrolled while 66 in CNSIs group and 73 in non-CNSIs. The mNGS exceeded culture in the variety and quantity of pathogens detected. The mNGS outperformed traditional pathogen culture in terms of positive percent agreement (63.63%), accuracy (82.01%), and negative predictive value (75.00%), with statistically significant differences ( P < 0.05) for traditional pathogen culture. The mNGS also detected bacterial spectrum and antimicrobial resistance genes. Conclusions. Metagenomics has the potential to assist in the diagnosis of patients with CNSIs who have a negative culture.

Clinical application of bronchoalveolar lavage fluid metagenomics next-generation sequencing in cancer patients with severe pneumonia

OBJECTIVE

Metagenomic next-generation sequencing (mNGS), as an emerging technique for pathogen detection, has been widely used in clinic. However, reports on the application of mNGS in cancer patients with severe pneumonia remain limited. This study aims to evaluate the diagnostic performance of bronchoalveolar lavage fluid (BALF) mNGS in cancer patients complicated with severe pneumonia.

METHODS

A total of 62 cancer patients with severe pneumonia simultaneously received culture and mNGS of BALF were enrolled in this study. We systematically analyzed the diagnostic significance of BALF mNGS. Subsequently, optimization of anti-infective therapy based on the distribution of pathogens obtained from BALF mNGS was also assessed.

RESULTS

For bacteria and fungi, the positive detection rate of mNGS was significantly higher than culture method (91.94% versus 51.61%, P < 0.001), especially for poly-microbial infections (70.97% versus 12.90%, P < 0.001). Compared with the culture method, mNGS exhibited a diagnostic sensitivity of 100% and a specificity of 16.67%, with the positive predictive value (PPV) and negative predictive value (NPV) being 56.14% and 100%, respectively. The agreement rate between these two methods was 59.68%, whereas kappa consensus analysis indicated a poor concordance (kappa = 0.171). After receipt of BALF mNGS results, anti-infective treatment strategies in 39 out of 62 cases (62.90%) were optimized. Moreover, anti-tumor therapy was a high-risk factor for mixed infections (87.18% versus 65.22%, P = 0.04).

CONCLUSIONS

The present study showed that cancer patients with severe pneumonia, especially those received anti-tumor therapy, were more likely to have poly-microbial infections. BALF mNGS can provide a rapid and comprehensive pathogen distribution of pulmonary infection, making it a promising technique in clinical practice, especially for optimizing therapeutic strategies for cancer patients.

Comparison of different criteria of metagenomic next-generation sequencing for the diagnosis of invasive pulmonary aspergillosis in critically ill patients

OBJECTIVE

To compare different criteria of Metagenomic Next-Generation Sequencing (mNGS) in bronchoalveolar lavage fluid (BALF) for diagnosing invasive pulmonary aspergillosis (IPA).

METHODS

We compared the diagnostic agreement and performances of six BALF mNGS-derived criteria (SDSMRN>1, SDSMRN≥3, SMRN≥10, SMRN≥50, RPM ratio≥10, and relative abundance of genus>30 %) in pneumonia patients.

RESULTS

A total of 115 patients were analyzed, with 28 identified with IPA. Diagnostic agreement among the six mNGS-derived criteria was moderate, with a Cohen's kappa of 0.577(P < 0.001). mNGS-derived criteria had low sensitivity ranging from 21.4 % to 57.1 % and high specificity from 88 % to 92 %. The optimal threshold of SDSMRN, SMRN, RPM ratio, and relative abundance of genus for diagnosing IPA were 5, 0.25, 8, and 20 %, respectively. Although using the optimal threshold, the sensitivity of mNGS is lower than 50 %.

CONCLUSIONS

All mNGS-derived criteria had low sensitivity for diagnosing IPA. A combination of mNGS and conventional mycological tests may be the best diagnostic strategy.

Diagnostic strategy of metagenomic next-generation sequencing for gram negative bacteria in respiratory infections

OBJECTIVE

This study aims to identify the most effective diagnostic method for distinguishing pathogenic and non-pathogenic Gram-negative bacteria (GNB) in suspected pneumonia cases using metagenomic next-generation sequencing (mNGS) on bronchoalveolar lavage fluid (BALF) samples.

METHODS

The effectiveness of mNGS was assessed on BALF samples collected from 583 patients, and the results were compared with those from microbiological culture and final clinical diagnosis. Three interpretational approaches were evaluated for diagnostic accuracy.

RESULTS

mNGS outperformed culture significantly. Among the interpretational approaches, Clinical Interpretation (CI) demonstrated the best diagnostic performance with a sensitivity of 87.3%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 98.3%. CI's specificity was significantly higher than Simple Interpretation (SI) at 37.9%. Additionally, CI excluded some microorganisms identified as putative pathogens by SI, including Haemophilus parainfluenzae, Haemophilus parahaemolyticus, and Klebsiella aerogenes.

CONCLUSION

Proper interpretation of mNGS data is crucial for accurately diagnosing respiratory infections caused by GNB. CI is recommended for this purpose.

A novel synthetic nucleic acid mixture for quantification of microbes by mNGS

Metagenomic next-generation sequencing (mNGS) provides considerable advantages in identifying emerging and re-emerging, difficult-to-detect and co-infected pathogens; however, the clinical application of mNGS remains limited primarily due to the lack of quantitative capabilities. This study introduces a novel approach, KingCreate-Quantification (KCQ) system, for quantitative analysis of microbes in clinical specimens by mNGS, which co-sequence the target DNA extracted from the specimens along with a set of synthetic dsDNA molecules used as Internal-Standard (IS). The assay facilitates the conversion of microbial reads into their copy numbers based on IS reads utilizing a mathematical model proposed in this study. The performance of KCQ was systemically evaluated using commercial mock microbes with varying IS input amounts, different proportions of human genomic DNA, and at varying amounts of sequence analysis data. Subsequently, KCQ was applied in microbial quantitation in 36 clinical specimens including blood, bronchoalveolar lavage fluid, cerebrospinal fluid and oropharyngeal swabs. A total of 477 microbe genetic fragments were screened using the bioinformatic system. Of these 83 fragments were quantitatively compared with digital droplet PCR (ddPCR), revealing a correlation coefficient of 0.97 between the quantitative results of KCQ and ddPCR. Our study demonstrated that KCQ presents a practical approach for the quantitative analysis of microbes by mNGS in clinical samples.

Risk factors and predicting nomogram for the clinical deterioration of non-severe community-acquired pneumonia

BACKGROUND

Currently, there remains insufficient focus on non-severe community-acquired pneumonia (CAP) patients who are at risk of clinical deterioration, and there is also a dearth of research on the related risk factors. Early recognition of hospitalized patients at risk of clinical deterioration will be beneficial for their clinical management.

METHOD

A retrospective study was conducted in The First Affiliated Hospital of Wenzhou Medical University, China, spanning from January 1, 2018 to April 30, 2022, and involving a total of 1,632 non-severe CAP patients. Based on whether their condition worsened within 72 h of admission, patients were divided into a clinical deterioration group and a non-clinical deterioration group. Additionally, all patients were randomly assigned to a training set containing 75% of patients and a validation set containing 25% of patients. In the training set, risk factors for clinical deterioration in patients with non-severe CAP were identified by using LASSO regression analysis and multivariate logistic regression analysis. A nomogram was developed based on identified risk factors. The effectiveness of the nomogram in both the training and validation sets was assessed using Receiver Operating Characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

RESULTS

Age, body mass index (BMI), body temperature, cardiovascular comorbidity, respiratory rate, LDH level, lymphocyte count and D-dimer level were identified as risk factors associated with the clinical deterioration of non-severe CAP within 72 h of admission. The area under curve (AUC) value of the nomogram was 0.78 (95% CI: 0.74-0.82) in the training set and 0.75 (95% CI: 0.67-0.83) in the validation set. Furthermore, the calibration curves for both the training and validation sets indicated that the predicted probability of clinical deterioration aligned with the actual probability. Additionally, DCA revealed clinical utility for the nomogram at a specific threshold probability.

CONCLUSION

The study successfully identified the risk factors linked to the clinical deterioration of non-severe CAP and constructed a nomogram for predicting the probability of deterioration. The nomogram demonstrated favorable predictive performance and has the potential to aid in the early identification and management of non-severe CAP patients at elevated risk of deterioration.

Metagenomic next generation sequencing of bronchoalveolar lavage samples for the diagnosis of lower respiratory tract infections: A systematic review and meta-analysis

Background

Lower respiratory tract infections (LRTI)are known to be diagnosed late or inaccurately. This has fueled the unscrupulous use of antibiotics, as they are often used empirically and clinically, leading to antibiotic abuse and multidrug resistance in patients. Metagenomic next-generation sequencing (mNGS), now widely used in clinical studies, could be a potential intervention to revolutionize microbiology by rapidly identifying unknown species.

Methods

This review and meta-analysis were conducted on eligible studies with respect to metagenomic sequencing on clinical LRTI diagnostics up to May 01, 2022. QUADAS-2 was employed to assess the methodological bias as well as applicability. After that, a meta-analysis was conducted to analyze the accuracy of mNGS, compared with the composite reference standard (CRS), among the enrolled studies.

Results

This work collected 1248 samples in 13/21 qualified articles to factor in the accuracy of the diagnostic test. Typically, methods like molecular testing, culture, composite measures, and clinical decision-making were adopted as the reference criteria. With regard to Bronchoalveolar Lavage Samples, their sensitivity was 89% (82-93%) while their specificity was 90% (66-98%), with obvious heterogeneities in these two factors as demonstrated by different studies. The summary receiver operating characteristic (SROC) curve was plotted for mNGS as a function of LRTI, and the area under the curve (AUC) was 0.94. A Funnel plot with a p-value greater than 0.05 indicated the absence of publication bias. Positive and negative likelihood ratios (PLR and NLR) were >10 and > 0.1, respectively. In this pre-test probability-post-probability-likelihood ratio relationship graph, the values were Prior prob (%) = 20, Post-prob-Pos (%) = 77 and Post-prob-Neg (%) = 4.

Conclusion

The AUC value of SROC suggested a high accuracy of mNGS in diagnosis, with no publication bias and high reliability. The application of mNGS exhibits notable diagnostic efficacy in discerning pathogens present in bronchoalveolar lavage fluid (BALF) among patients afflicted with LRTI. However, mNGS is more meaningful for the definitive diagnosis of the disease rather than the exclusion of the disease. This post-test probability is significantly higher than the pre-test probability.

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.

Joint application of metagenomic next-generation sequencing and histopathological examination for the diagnosis of pulmonary infectious disease

IMPORTANCE

The diagnosis of some pulmonary infectious diseases and their pathogens is very difficult. A more precise diagnosis of pulmonary infectious diseases can help clinicians use proper antibiotics as well as reduce the development of drug-resistant bacteria. In this study, we performed both mNGS and pathology on lung puncture biopsy tissue from patients and found that combined mNGS and histopathology testing was significantly more effective than histopathology testing alone in detecting infectious diseases and identifying infectious diseases. In addition, the combined approach improves the detection rate of pathogenic microorganisms in infectious diseases and can be used to guide precision clinical treatment.

Determination of Ideal Factors for Early Adoption and Standardization of Metagenomic Next-generation Sequencing for Respiratory System Infections

BACKGROUND

Metagenomic next-generation sequencing (mNGS) demonstrates great promise as a diagnostic tool for determining the cause of pathogenic infections. The standard diagnostic procedures (SDP) include smears and cultures and are typically viewed as less sensitive and more time-consuming when compared to mNGS. There are concerns about the logistics and ease of transition from SDP to mNGS. mNGS lacks standardization of collection processes, databases, and sequencing. Additionally, there is the burden of training clinicians on interpreting mNGS results.

OBJECTIVE

Until now, few studies have explored factors that could be used as early adoption candidates to ease the transition between SDP and mNGS. This study evaluated 123 patients who had received both SDP and mNGS and compared several variables across a diagnostic test evaluation.

METHODS

The diagnostic test evaluation observed metrics such as sensitivity, specificity, positive and negative likelihood ratios (PLR, NLR), positive and negative predictive values (PPV, NPV), and accuracy. Factors included various sample sources such as bronchoalveolar lavage fluid (BALF), lung tissue, and cerebral spinal fluid (CSF). An additional factor observed was the patient's immune status.

RESULTS

Pathogen detection was found to be significantly greater for mNGS for total patients, BALF sample source, CSF sample source, and non-immunocompromised patients (p<0.05). Pathogen detection was found to be insignificant for lung tissue sample sources and immunocompromised patients. Sensitivity, PLR, NLR, PPV, NPV, and accuracy appeared to be higher with mNGS for the total patients, BALF sample source, and non-immunocompromised patients when compared with SDP (p<0.05).

CONCLUSION

With higher metrics in sensitivity, specificity, PLR, NLR, PPV, NPV, and accuracy for overall patients, mNGS may prove a better diagnostic tool than SDP. When addressing sample sources, mNGS for BALF-collected samples appeared to have higher scores than SDP for the same metrics. When patients were in a non-immunocompromised state, mNGS also demonstrated greater diagnostic benefits to BALF and overall patients compared to SDP. This study demonstrates that using BALF as a sample source and selecting non-immunocompromised patients may prove beneficial as early adoption factors for mNGS standard protocol. Such a study may pave the road for mNGS as a routine clinical method for determining the exact pathogenic etiology of lung infections.

Targeted next-generation sequencing for pulmonary infection diagnosis in patients unsuitable for bronchoalveolar lavage

Background

Targeted next-generation sequencing (tNGS) has emerged as a rapid diagnostic technology for identifying a wide spectrum of pathogens responsible for pulmonary infections.

Methods

Sputum samples were collected from patients unable or unwilling to undergo bronchoalveolar lavage. These samples underwent tNGS analysis to diagnose pulmonary infections. Retrospective analysis was performed on clinical data, and the clinical efficacy of tNGS was compared to conventional microbiological tests (CMTs).

Results

This study included 209 pediatric and adult patients with confirmed pulmonary infections. tNGS detected 45 potential pathogens, whereas CMTs identified 23 pathogens. The overall microbial detection rate significantly differed between tNGS and CMTs (96.7% vs. 36.8%, p < 0.001). Among the 76 patients with concordant positive results from tNGS and CMTs, 86.8% (66/76) exhibited full or partial agreement. For highly pathogenic and rare/noncolonized microorganisms, tNGS, combined with comprehensive clinical review, directly guided pathogenic diagnosis and antibiotic treatment in 21 patients. This included infections caused by Mycobacterium tuberculosis complex, certain atypical pathogens, Aspergillus, and nontuberculous Mycobacteria. Among the enrolled population, 38.8% (81/209) of patients adjusted their treatment based on tNGS results. Furthermore, tNGS findings unveiled age-specific heterogeneity in pathogen distribution between children and adults.

Conclusion

CMTs often fall short in meeting the diagnostic needs of pulmonary infections. This study highlights how tNGS of sputum samples from patients who cannot or will not undergo bronchoalveolar lavage yield valuable insights into potential pathogens, thereby enhancing the diagnosis of pulmonary infections in specific cases.

Pneumocystis jirovecii with high probability detected in bronchoalveolar lavage fluid of chemotherapy-related interstitial pneumonia in patients with lymphoma using metagenomic next-generation sequencing technology

BACKGROUND

Previous studies achieved low microbial detection rates in lymphoma patients with interstitial pneumonia (IP) after chemotherapy. However, the metagenomic next-generation sequencing (mNGS) is a comprehensive approach that is expected to improve the pathogen identification rate. Thus far, reports on the use of mNGS in lymphoma patients with chemotherapy-related IP remain scarce. In this study, we summarized the microbial detection outcomes of lymphoma patients with chemotherapy-related IP through mNGS testing of bronchoalveolar lavage fluid (BALF).

METHODS

Fifteen lymphoma patients with chemotherapy-related IP were tested for traditional laboratory microbiology, along with the mNGS of BALF. Then, the results of mNGS and traditional laboratory microbiology were compared.

RESULTS

Of the 15 enrolled patients, 11 received rituximab and 8 were administered doxorubicin hydrochloride liposome. The overall microbial yield was 93.3% (14/15) for mNGS versus 13.3% (2/15) for traditional culture methods (P ≤ 0.05). The most frequently detected pathogens were Pneumocystis jirovecii (12/15, 80%), Cytomegalovirus (4/15, 26.7%), and Epstein-Barr virus (3/15, 20%). Mixed infections were detected in 10 cases. Five patients recovered after the treatment with antibiotics alone without glucocorticoids.

CONCLUSION

Our findings obtained through mNGS testing of BALF suggested a high microbial detection rate in lymphoma patients with IP after chemotherapy. Notably, there was an especially high detection rate of Pneumocystis jirovecii. The application of mNGS in patients with chemotherapy-related IP was more sensitive.

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.

Diagnostic Value and Clinical Application of Metagenomic Next-Generation Sequencing for Infections in Critically Ill Patients

Objective

To evaluate the diagnostic value and clinical application of metagenomic next-generation sequencing (mNGS) for infections in critically ill patients.

Methods

Comparison of diagnostic performance of mNGS and conventional microbiological testing for pathogens was analyzed in 234 patients. The differences between immunocompetent and immunocompromised individuals in mNGS-guided anti-infective treatment adjustment were also analyzed.

Results

The sensitivity and specificity of mNGS for bacterial and fungal detection were 96.6% (95% confidence interval [CI], 93.5%-99.6%) and 83.1% (95% CI, 75.2%-91.1%), and 85.7% (95% CI, 71.9%-99.5%) and 93.2% (95% CI, 89.7%-96.7%), respectively. Overall, 152 viruses were detected by mNGS, but in which 28 viruses were considered causative agents. The proportion of mNGS-guided beneficial anti-infective therapy adjustments in the immunocompromised group was greater than in the immunocompetent group (48.5% vs 30.1%; P=0.008). In addition, mNGS-guided anti-infective regimens with peripheral blood and BALF specimens had the highest proportion (39.0%; 40.0%), but the proportion of patients not helpful due to peripheral blood mNGS was also as high as 22.0%.

Conclusion

mNGS might be a promising technology to provide precision medicine for critically ill patients with infection.

Staphylococcus cohnii infection diagnosed by metagenomic next generation sequencing in a patient on hemodialysis with cirrhotic ascites: a case report

Background

Patients with spontaneous bacterial peritonitis (SBP) often just receive empirical antibiotic therapy, as pathogens can be identified in only few patients using the techniques of conventional culture. Metagenomic next generation sequencing (mNGS) is a useful tool for diagnosis of infectious diseases. However, clinical application of mNGS in diagnosis of infected ascites of cirrhotic patients is rarely reported.

Case presentation

A 53-year-old male with cirrhosis on regular hemodialysis presented with continuous abdominal pain. After treatment with empiric antibiotics, his inflammatory parameters decreased without significant relief of abdominal pain. Finally, based on ascites mNGS detection, he was diagnosed as infection of Staphylococcus cohnii (S.cohnii), a gram-positive opportunistic pathogen. With targeted antibiotic treatment, the bacterial peritonitis was greatly improved and the patient's abdominal pain was significantly alleviated.

Conclusions

When conventional laboratory diagnostic methods and empirical antibiotic therapy fail, proper application of mNGS can help identify pathogens and significantly improve prognosis and patients' symptoms.

The Diagnostic Accuracy of Metagenomic Next-Generation Sequencing in Diagnosing Pneumocystis Pneumonia: A Systemic Review and Meta-analysis

Background

Pneumocystis pneumonia (PCP) is a growing concern as the immunocompromised population expands. Current laboratory approaches are limited. This systematic review aimed to evaluate metagenomic next-generation sequencing (MNGS) tests' performance in detecting PCP.

Methods

Five databases were searched through December 19, 2022, to identify original studies comparing MNGS with clinically diagnosed PCP. To assess the accuracy, symmetric hierarchical summary receiver operating characteristic models were used.

Results

Eleven observational studies reporting 1442 patients (424 with PCP) were included. Six studies focused exclusively on recipients of biologic immunosuppression (none with HIV-associated immunosuppression). Six were exclusively on bronchoalveolar lavage, while 1 was on blood samples. The sensitivity of MGNS was 0.96 (95% CI, 0.90-0.99), and specificity was 0.96 (95% CI, 0.92-0.98), with negative and positive likelihood ratios of 0.02 (95% CI, 0.01-0.05) and 19.31 (95% CI, 10.26-36.36), respectively. A subgroup analysis of studies exclusively including bronchoalveolar lavage (BAL) and blood samples demonstrated a sensitivity of 0.94 (95% CI, 0.78-0.99) and 0.93 (95% CI, 0.80-0.98) and a specificity of 0.96 (95% CI, 0.88-0.99) and 0.98 (95% CI, 0.76-1.00), respectively. The sensitivity analysis on recipients of biologic immunosuppression showed a sensitivity and specificity of 0.96 (95% CI, 0.90-0.98) and 0.94 (95% CI, 0.84-0.98), respectively. The overall confidence in the estimates was low.

Conclusions

Despite the low certainty of evidence, MNGS detects PCP with high sensitivity and specificity. This also applies to recipients of biologic immunosuppression and tests performed exclusively on blood samples without the need for BAL. Further studies are required in individuals with HIV-associated immunosuppression.

Case Report: Four cases of SARS-CoV-2-associated Guillain-Barré Syndrome with SARS-CoV-2-positive cerebrospinal fluid detected by metagenomic next-generation sequencing: a retrospective case series from China

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is often absent or at low levels in the cerebrospinal fluid (CSF) of patients with previous SARS-CoV-2-associated Guillain-Barré syndrome (GBS). This has led to speculation that SARS-CoV-2-associated GBS is more likely mediated by post-infectious immunity or a parainfection. This understanding has influenced the development of treatment regimens for SARS-CoV-2-associated GBS. This paper reports our experience with four Chinese patients with SARS-CoV-2-associated GBS who tested positive for SARS-CoV-2 RNA in the CSF. They developed symptoms of peripheral nerve damage 4-15 days after fever and confirmed SARS-CoV-2 infection, all of whom presented with progressive weakness of both lower limbs; three with autonomic nerve function impairment such as constipation and urination disorder; and one with polycranial neuritis and Miller-Fisher syndrome. Three patients were tested for anti-ganglioside antibodies, and one tested positive for GD1a-IgG. Four patients recovered well after treatment with anti-viral drugs combined with intravenous immunoglobulin. The present results showed that SARS-CoV-2 RNA can be detected via mNGS in the CSF of some patients with SARS-CoV-2-associated GBS, suggesting that SARS-CoV-2-associated GBS may have multiple pathogeneses.

Diagnostic efficacy of metagenomic next generation sequencing in bronchoalveolar lavage fluid for proven invasive pulmonary aspergillosis

Objective

To assess the diagnostic efficacy of metagenomic next generation sequencing (mNGS) for proven invasive pulmonary aspergillosis (IPA).

Methods

A total of 190 patients including 53 patients who had been diagnosed with proven IPA were retrospectively analyzed. Using the pathological results of tissue biopsy specimens as gold standard, we ploted the receiver operating characteristic (ROC) curve to determine the optimal cut-off value of mNGS species-specific read number (SSRN) of Aspergillus in bronchoalveolar lavage fluid (BALF)for IPA. Furthermore, we evaluated optimal cut-off value of mNGS SSRN in different populations.

Results

The optimal cut-off value of Aspergillus mNGS SSRN in BALF for IPA diagnosis was 2.5 for the whole suspected IPA population, and 1 and 4.5 for immunocompromised and diabetic patients, respectively. The accuracy of mNGS was 80.5%, 73.7% and 85.3% for the whole population, immunocompromised and diabetic patients, respectively.

Conclusions

The mNGS in BALF has a high diagnostic efficacy for proven IPA, superioring to Aspergillus culture in sputum and BALF and GM test in blood and BALF. However, the cut-off value of SSRN should be adjusted when in different population.

Utilizing metagenomic next-generation sequencing for diagnosis and lung microbiome probing of pediatric pneumonia through bronchoalveolar lavage fluid in pediatric intensive care unit: results from a large real-world cohort

Background

Metagenomic next-generation sequencing (mNGS) is a powerful method for pathogen detection in various infections. In this study, we assessed the value of mNGS in the pathogen diagnosis and microbiome analysis of pneumonia in pediatric intensive care units (PICU) using bronchoalveolar lavage fluid (BALF) samples.

Methods

A total of 104 pediatric patients with pneumonia who were admitted into PICU between June 2018 and February 2020 were retrospectively enrolled. Among them, 101 subjects who had intact clinical information were subject to parallel comparison of mNGS and conventional microbiological tests (CMTs) for pathogen detection. The performance was also evaluated and compared between BALF-mNGS and BALF-culture methods. Moreover, the diversity and structure of all 104 patients' lung BALF microbiomes were explored using the mNGS data.

Results

Combining the findings of mNGS and CMTs, 94.06% (95/101) pneumonia cases showed evidence of causative pathogenic infections, including 79.21% (80/101) mixed and 14.85% (15/101) single infections. Regarding the pathogenesis of pneumonia in the PICU, the fungal detection rates were significantly higher in patients with immunodeficiency (55.56% vs. 25.30%, P =0.025) and comorbidities (40.30% vs. 11.76%, P=0.007). There were no significant differences in the α-diversity either between patients with CAP and HAP or between patients with and without immunodeficiency. Regarding the diagnostic performance, the detection rate of DNA-based BALF-mNGS was slightly higher than that of the BALF-culture although statistically insignificant (81.82% vs.77.92%, P=0.677) and was comparable to CMTs (81.82% vs. 89.61%, P=0.211). The overall sensitivity of DNA-based mNGS was 85.14% (95% confidence interval [CI]: 74.96%-92.34%). The detection rate of RNA-based BALF-mNGS was the same with CMTs (80.00% vs 80.00%, P>0.999) and higher than BALF-culture (80.00% vs 52.00%, P=0.045), with a sensitivity of 90.91% (95%CI: 70.84%-98.88%).

Conclusions

mNGS is valuable in the etiological diagnosis of pneumonia, especially in fungal infections, and can reveal pulmonary microecological characteristics. For pneumonia patients in PICU, the mNGS should be implemented early and complementary to CMTs.

Metagenomic next-generation sequencing for rapid detection of pulmonary infection in patients with acquired immunodeficiency syndrome

BACKGROUND

Acquired immunodeficiency syndrome (AIDS) is associated with a high rate of pulmonary infections (bacteria, fungi, and viruses). To overcome the low sensitivity and long turnaround time of traditional laboratory-based diagnostic strategies, we adopted metagenomic next-generation sequencing (mNGS) technology to identify and classify pathogens.

RESULTS

This study enrolled 75 patients with AIDS and suspected pulmonary infections who were admitted to Nanning Fourth People's Hospital. Specimens were collected for traditional microbiological testing and mNGS-based diagnosis. The diagnostic yields of the two methods were compared to evaluate the diagnostic value (detection rate and turn around time) of mNGS for infections with unknown causative agent. Accordingly, 22 cases (29.3%) had a positive culture and 70 (93.3%) had positive valve mNGS results (P value < 0.0001, Chi-square test). Meanwhile, 15 patients with AIDS showed concordant results between the culture and mNGS, whereas only one 1 patient showed concordant results between Giemsa-stained smear screening and mNGS. In addition, mNGS identified multiple microbial infections (at least three pathogens) in almost 60.0% of patients with AIDS. More importantly, mNGS was able to detect a large variety of pathogens from patient tissue displaying potential infection and colonization, while culture results remained negative. There were 18 members of pathogens which were consistently detected in patients with and without AIDS.

CONCLUSIONS

In conclusion, mNGS analysis provides fast and precise pathogen detection and identification, contributing substantially to the accurate diagnosis, real-time monitoring, and treatment appropriateness of pulmonary infection in patients with AIDS.

Validation of metagenomic next-generation sequencing of bronchoalveolar lavage fluid for diagnosis of suspected pulmonary infections in patients with systemic autoimmune rheumatic diseases receiving immunosuppressant therapy

Background

The accuracy and sensitivity of conventional microbiological tests (CMTs) are insufficient to identify opportunistic pathogens in patients with systemic autoimmune rheumatic diseases (SARDs). The study aimed to assess the usefulness of metagenomic next-generation sequencing (mNGS) vs. CMTs for the diagnosis of pulmonary infections in patients with SARDs receiving immunosuppressant therapy.

Methods

The medical records of 40 patients with pulmonary infections and SARDs treated with immunosuppressants or corticosteroids were reviewed retrospectively. Bronchoalveolar lavage fluid (BALF) samples were collected from all patients and examined by mNGS and CMTs. Diagnostic values of the CMTs and mNGS were compared with the clinical composite diagnosis as the reference standard.

Results

Of the 40 patients included for analysis, 37 (92.5%) were diagnosed with pulmonary infections and 3 (7.5%) with non-infectious diseases, of which two were considered primary diseases and one an asthma attack. In total, 15 pathogens (7 bacteria, 5 fungi, and 3 viruses) were detected by CMTs as compared to 58 (36 bacteria, 12 fungi, and 10 viruses) by mNGS. Diagnostic accuracy of mNGS was superior to that of the CMTs for the detection of co-infections with bacteria and fungi (95 vs. 53%, respectively, p < 0.01), and for the detection of single infections with fungi (97.5 vs. 55%, respectively, p < 0.01). Of the 31 patients diagnosed with co-infections, 4 (12.9%) were positive for two pathogens and 27 (87.1%) for three or more. The detection rate of co-infection was significantly higher for mNGS than CMTs (95 vs. 16%, respectively, p < 0.01).

Conclusion

The accuracy of mNGS was superior to that of the CMTs for the diagnosis of pulmonary infections in patients with SARDs treated with immunosuppressants. The rapid diagnosis by mNGS can ensure timely adjustment of treatment regimens to improve diagnosis and outcomes.

BALF metagenomic next-generation sequencing analysis in hematological malignancy patients with suspected pulmonary infection: clinical significance of negative results

Purpose

Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) is gradually being used in hematological malignancy (HM) patients with suspected pulmonary infections. However, negative results are common and the clinical value and interpretation of such results in this patient population require further analysis.

Methods

Retrospective analysis of 112 HM patients with suspected pulmonary infection who underwent BALF mNGS and conventional microbiological tests. The final diagnosis, imaging findings, laboratory results and treatment regimen of 29 mNGS-negative patients were mainly analyzed.

Results

A total of 83 mNGS positive and 29 negative patients (15 true-negatives and 14 false-negatives) were included in the study. Compared to false-negative patients, true-negative patients showed more thickening of interlobular septa on imaging (p < 0.05); fewer true-negative patients had acute respiratory symptoms such as coughing or sputum production (p < 0.05) clinically; On the aspect of etiology, drug-related interstitial pneumonia (6/15, 40%) was the most common type of lung lesion in true-negative patients; on the aspect of pathogenesis, false-negative patients mainly missed atypical pathogens such as fungi and tuberculosis (8/14, 57.1%). Regarding treatment, delayed anti-infection treatment occurred after pathogen missing in mNGS false-negative patients, with the longest median time delay observed for anti-tuberculosis therapy (13 days), followed by antifungal therapy (7 days), and antibacterial therapy (1.5 days); the delay in anti-tuberculosis therapy was significantly longer than that in antibacterial therapy (p < 0.05).

Conclusion

For HMs patients with imaging showing thickening of interlobular septa and no obvious acute respiratory symptoms, lung lesions are more likely caused by drug treatment or the underlying disease, so caution should be exercised when performing BALF mNGS. If BALF mNGS is negative but infection is still suspected, atypical pathogenic infections should be considered.

Diagnostic Laboratory Features and Performance of an Aspergillus IgG Lateral Flow Assay in a Chronic Pulmonary Aspergillosis Cohort

Chronic pulmonary aspergillosis (CPA) is a chronic and progressive fungal disease with high morbidity and mortality. Avoiding diagnostic delay and misdiagnosis are concerns for CPA patients. However, diagnostic practice is poorly evaluated, especially in resource-constrained areas where Aspergillus antibody testing tools are lacking. This study aimed to investigate the diagnostic laboratory findings in a retrospective CPA cohort and to evaluate the performance of a novel Aspergillus IgG lateral flow assay (LFA; Era Biology, Tianjin, China). During January 2016 and December 2021, suspected CPA patients were screened at the Center for Infectious Diseases at Huashan Hospital. A total of 126 CPA patients were enrolled. Aspergillus IgG was positive in 72.1% with chronic cavitary pulmonary aspergillosis, 75.0% with chronic necrotizing pulmonary aspergillosis, 41.7% with simple aspergilloma, and 30.3% with Aspergillus nodule(s). The cavitary CPA subtypes had significantly higher levels of Aspergillus IgG. Aspergillus IgG was negative in 52 patients, who were finally diagnosed by histopathology, respiratory culture, and metagenomic next-generation sequencing (mNGS). Sputum culture was positive in 39.3% (42/107) of patients and Aspergillus fumigatus was the most common species (69.0%, 29/42). For CPA cohort versus controls, the sensitivity and specificity of the LFA were 55.6% and 92.7%, respectively. In a subgroup analysis, the LFA was highly sensitive for A. fumigatus-associated chronic cavitary pulmonary aspergillosis (CCPA; 96.2%, 26/27). Given the complexity of the disease, a combination of serological and non-serological tests should be considered to avoid misdiagnosis of CPA. The novel LFA has a satisfactory performance and allows earlier screening and diagnosis of CPA patients. IMPORTANCE There are concerns on avoiding diagnostic delay and misdiagnosis for chronic pulmonary aspergillosis due to its high morbidity and mortality. A proportion of CPA patients test negative for Aspergillus IgG. An optimal diagnostic strategy for CPA requires in-depth investigation based on real-world diagnostic practice, which has been rarely discussed. We summarized the clinical and diagnostic laboratory findings of 126 CPA patients with various CPA subtypes. Aspergillus IgG was the most sensitive test for diagnosing CPA. However, it was negative in 52 patients, who were finally diagnosed by non-serological tests, including biopsy, respiratory culture, and metagenomic next-generation sequencing. We also evaluated a novel Aspergillus IgG lateral flow assay, which showed a satisfactory performance in cavitary CPA patients and was highly specific to Aspergillus fumigatus. This study gives a full picture of the diagnostic practice for CPA patients in Chinese context and calls for early diagnosis of CPA with combined approaches.

Pathogen Diagnosis Value of Nanopore Sequencing in Severe Hospital-Acquired Pneumonia Patients

Background

Next-generation sequencing of the metagenome (mNGS) is increasingly used in pathogen diagnosis for infectious diseases due to its short detection time. The time for Oxford Nanopore Technologies (ONT) sequencing-based etiology detection is further shortened compared with that of mNGS, but only a few studies have verified the time advantage and accuracy of ONT sequencing for etiology diagnosis. In 2022, a study confirmed that there was no significant difference in sensitivity and specificity between ONT and mNGS in suspected community-acquired pneumonia patients, which there was no clinical study verified in patients with SHAP.

Methods

From October 24 to November 20, 2022, 10 patients with severe hospital-acquired pneumonia (SHAP) in the Nanfang Hospital intensive care unit (ICU) were prospectively enrolled. Bronchoalveolar lavage fluid (BALF) was collected for ONT sequencing, mNGS, and traditional culture. The differences in pathogen detection time and diagnostic agreement among ONT sequencing, mNGS, traditional culture method, and clinical composite diagnosis were compared.

Results

Compared with mNGS and the traditional culture method, ONT sequencing had a significant advantage in pathogen detection time (9.6±0.7 h versus 24.7±2.7 h versus 132±58 h, P <0.05). The agreement rate between ONT sequencing and the clinical composite diagnosis was 73.3% (kappa value=0.737, P <0.05).

Conclusion

ONT sequencing has a potential advantage for rapidly identifying pathogens.

Microbiological diagnostic performance of metagenomic next-generation sequencing compared with conventional culture for patients with community-acquired pneumonia

Background

Community-acquired pneumonia (CAP) is an extraordinarily heterogeneous illness, both in the range of responsible pathogens and the host response. Metagenomic next-generation sequencing (mNGS) is a promising technology for pathogen detection. However, the clinical application of mNGS for pathogen detection remains challenging.

Methods

A total of 205 patients with CAP admitted to the intensive care unit were recruited, and broncho alveolar lavage fluids (BALFs) from 83 patients, sputum samples from 33 cases, and blood from 89 cases were collected for pathogen detection by mNGS. At the same time, multiple samples of each patient were tested by culture. The diagnostic performance was compared between mNGS and culture for pathogen detection.

Results

The positive rate of pathogen detection by mNGS in BALF and sputum samples was 89.2% and 97.0%, which was significantly higher (P < 0.001) than that (67.4%) of blood samples. The positive rate of mNGS was significantly higher than that of culture (81.0% vs. 56.1%, P = 1.052e-07). A group of pathogens including Mycobacterium abscessus, Chlamydia psittaci, Pneumocystis jirovecii, Orientia tsutsugamushi, and all viruses were only detected by mNGS. Based on mNGS results, Escherichia coli was the most common pathogen (15/61, 24.59%) of non-severe patients with CAP, and Mycobacterium tuberculosis was the most common pathogen (21/144, 14.58%) leading to severe pneumonia. Pneumocystis jirovecii was the most common pathogen (26.09%) in severe CAP patients with an immunocompromised status, which was all detected by mNGS only.

Conclusion

mNGS has higher overall sensitivity for pathogen detection than culture, BALF, and sputum mNGS are more sensitive than blood mNGS. mNGS is a necessary supplement of conventional microbiological tests for the pathogen detection of pulmonary infection.

[Metagenomic next-generation sequencing of plasma for the identification of bloodstream infectious pathogens in severe aplastic anemia]

Objective: To analyze the diagnostic value of cell-free plasma metagenomic next-generation sequencing (mNGS) pathogen identification for severe aplastic anemia (SAA) bloodstream infection. Methods: From February 2021 to February 2022, mNGS and conventional detection methods (blood culture, etc.) were used to detect 33 samples from 29 consecutive AA patients admitted to the Anemia Diagnosis and Treatment Center of the Hematology Hospital of the Chinese Academy of Medical Sciences to assess the diagnostic consistency of mNGS and conventional detection, as well as the impact on clinical treatment benefits and clinical accuracy. Results: ①Among the 33 samples evaluated by mNGS and conventional detection methods, 25 cases (75.76%) carried potential pathogenic microorganisms. A total of 72 pathogenic microorganisms were identified from all cases, of which 65 (90.28%) were detected only by mNGS. ②All 33 cases were evaluated for diagnostic consistency, of which 2 cases (6.06%) were Composite, 18 cases (54.55%) were mNGS only, 2 cases (6.06%) were Conventional method only, 1 case (3.03%) was both common compliances (mNGS/Conventional testing) , and 10 cases (30.3%) were completely non-conforming (None) . ③All 33 cases were evaluated for clinical treatment benefit. Among them, 8 cases (24.24%) received Initiation of targeted treatment, 1 case (3.03%) received Treatment de-escalation, 13 cases (39.39%) received Confirmation, and the remaining 11 cases (33.33%) received No clinical benefit. ④ The sensitivity of 80.77%, specificity of 70.00%, positive predictive value of 63.64%, negative predictive value of 84.85%, positive likelihood ratio of 2.692, and negative likelihood ratio of 0.275 distinguished mNGS from conventional detection methods (21/12 vs 5/28, P<0.001) . Conclusion: mNGS can not only contribute to accurately diagnosing bloodstream infection in patients with aplastic anemia, but can also help to guide accurate anti-infection treatment, and the clinical accuracy is high.

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.