Application of mNGS in the Etiological Diagnosis of Thoracic and Abdominal Infection in Patients With End-Stage Liver Disease

Tired of the confusion around pleural effusions: Adenosine deaminase detection sets the record straight!

Pleural effusion, characterized by the accumulation of fluid in the pleural space, poses significant challenges in clinical practice, especially in determining whether it belongs to the inflammatory exudates or non-inflammatory transudates. Adenosine deaminase (ADA), an enzyme primarily produced by immune cells, particularly lymphocytes, increase in response to inflammatory conditions, including tuberculosis and malignancies. Elevated ADA levels in pleural have been shown to correlate with inflammatory exudates, making it a valuable biomarker for differentiating between inflammatory and non-inflammatory effusions. Moreover, numerous studies have demonstrated the treatment function of ADA in inflammation- related pleural effusion syndrome. Recently, research has established the values for the implication of ADA in diagnosing and managing pleural disease. Based on these findings, ADA becomes a reliable, non-invasive marker for early diagnosis and the appropriate treatment for pleural inflammation, ultimately improving patient outcomes.

Clinical and metagenomic predicted antimicrobial resistance in pediatric critically ill patients with infectious diseases in a single center of Zhejiang

BACKGROUND

Antimicrobial resistance (AMR) poses a significant threat to pediatric health; therefore, precise identification of pathogens as well as AMR is imperative. This study aimed at comprehending antibiotic resistance patterns among critically ill children with infectious diseases admitted to pediatric intensive care unit (PICU) and to clarify the impact of drug-resistant bacteria on the prognosis of children.

METHODS

This study retrospectively collected clinical data, identified pathogens and AMR from 113 children's who performed metagenomic next-generation sequencing for pathogen and antibiotic resistance genes identification, and compared the clinical characteristic difference and prognostic effects between children with and without AMR detected.

RESULTS

Based on the presence or absence of AMR test results, the 113 patients were divided into Antimicrobial resistance test positive group (AMRT+, n = 44) and Antimicrobial resistance test negative group (AMRT-, n = 69). Immunocompromised patients (50% vs. 28.99%, P = 0.0242) and patients with underlying diseases (70.45% vs. 40.58%, P = 0.0019) were more likely to develop resistance to antibiotics. Children in the AMRT + group showed significantly increased C-reaction protein, score of pediatric sequential organ failure assessment and pediatric risk of mortality of children and longer hospital stay and ICU stay in the AMRT + group compared to the AMRT+- group (P < 0.05). Detection rate of Gram-negative bacteria was significantly higher in the AMRT + group rather than Gram-positive bacteria (n = 45 vs. 31), in contrast to the AMRT- group (n = 10 vs. 36). Cephalosporins, β-lactams/β-Lactamase inhibitors, carbapenems and sulfonamides emerged as the most common types of drug resistance in children. Resistance rates to these antibiotics exhibited considerable variation across common pathogens, including Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii.

CONCLUSIONS

The development of drug resistance in bacteria will significantly affect the prognosis of patients. The significant differences in drug resistance of common pathogenic bacteria indicate that identification of drug resistance is important for the rational use of antibiotics and patient prognosis.

Multiple skin abscesses due to Nocardia neocaledoniensis: a case report and literature review

N. neocaledoniensis is a very rare infectious pathogen that causes human disease, particularly in immunocompromised individuals. In this case report, we describe the successful diagnosis of N. neocaledoniensis in a patient confirmed by mNGS and the treatment of multiple skin abscesses due to N. neocaledoniensis infection. mNGS is an important diagnostic method complementary to routine bacterial culture and identification methods, especially for rare, novel, co-infected pathogens, and pathogens that are difficult to culture. This report may provide a reference for the clinical treatment and diagnosis of N. neocaledoniensis infection in humans.

Knowledge framework and emerging trends of invasive pulmonary fungal infection: A bibliometric analysis (2003-2023)

The rising number of immunocompromised people has increased concerns about fungal infections as a severe public health issue. Invasive pulmonary fungal infections (IPFIs) are prevalent and often fatal, particularly for those with weakened immune systems. Understanding IPFIs is crucial. The work aims to offer a concise overview of the field's characteristics, main research areas, development paths, and trends. This study searched the Web of Science Core Collection on June 5, 2024, collecting relevant academic works from 2003 to 2023. Analysis was conducted using CiteSpace, VOSviewer, Bibliometrix Package in R, Microsoft Excel 2019, and Scimago Graphica. The study indicated that the USA, the University of Manchester, and Denning DW led in productivity and impact, while the Journal of Fungi topped the list in terms of publication volume and citations. High-frequency terms include "fungal infection," "invasive," "diagnosis," and "epidemiology." Keyword and trend analysis identified "influenza," "COVID-19," "invasive pulmonary aspergillosis," and "metagenomic next-generation sequencing" as emerging research areas. Over the last 2 decades, research on IPFI has surged, with topics becoming more profound. These insights offer key guidance on current trends, gaps, and the trajectory of IPFI studies.

Pulmonary abscess caused by Streptococcus pseudopneumoniae in a child: A case report and review of literature

BACKGROUND

Lung abscess found on chest X-ray and computed tomography examinations is rare in infants and young children. Several pathogens can cause lung abscesses, with the most common pathogens being anaerobes, Streptococci and Staphylococcus aureus. Streptococcus pseudopneumoniae (S. pseudopneumoniae) is a member of the Streptococcaceae family, and is mainly isolated from respiratory tract specimens. There are currently no cases of lung abscess caused by S. pseudopneumoniae in the literature.

CASE SUMMARY

A 2-year-old boy was admitted to hospital due to persistent cough and fever. Lung computed tomography examination suggested the formation of a lung abscess. His diagnosis was not confirmed by testing for serum respiratory pathogens (6 items), respiratory pathogen nucleic acid (27 items), and laboratory culture. Finally, metagenomic next-generation sequencing of bronchoalveolar lavage fluid revealed the presence of S. pseudopneumoniae, confirming its role in causing the lung abscess. After receiving antibiotic treatment, reexamination with lung computed tomography showed that the abscess was resorbed and the patient's outcome was good.

CONCLUSION

This is the first report of a lung abscess in a child caused by S. pseudopneumoniae infection. Metagenomic next-generation sequencing of bronchoalveolar lavage fluid is helpful in achieving rapid and accurate pathogen identification.

Utility of Metagenomic Next-Generation Sequencing for Diagnosis of Infectious Diseases in Critically Ill Immunocompromised Pediatric Patients

Purpose

Infections cause high rates of illness and death in children worldwide. However, studies on the clinical value of metagenomic next-generation sequencing (mNGS) for immunocompromised children are still limited.

Patients and Methods

From June 2021 to December 2023, 119 samples were collected at Pediatric Intensive Care Unit (PICU) of a single-center pediatric hospital and classified into two groups based on their immune states. We compared the diagnostic performance of mNGS and conventional microbiological test (CMT) for pathogen identification, and assessed the clinical impacts of mNGS.

Results

Among the 119 samples, 48 (40.34%) belonged to the immunocompromised children. mNGS had a higher positivity rate than CMT (76.47% vs 55.46%, P = 0.0006). The positive percent agreement (PPA) of mNGS for immunocompromised children was higher compared to immunocompetent children (95.24% vs 77.78%). The most common pathogens for immunocompromised patients were gram-negative bacteria and herpesvirus. However, immunocompetent children showed a higher detection rate for gram-positive bacteria and respiratory viruses. Furthermore, the proportions of the positive impact of mNGS results were significantly higher in immunocompromised patients compared to immunocompetent patients for both diagnosis (91.67% vs 57.75%) and treatment (95.83% vs 64.79%) (P < 0.0001). Immunocompromised state, length of hospital stays, times stay in ICU, Pediatric Risk of Mortality (PRISM) score, neutrophil percentage (NEUT%) and the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2) were considered independent factors for poor prognosis in critically ill pediatric patients.

Conclusion

In patients from PICU, mNGS had a greater clinical significance in immunocompromised children compared to immunocompetent children. mNGS technology is an important auxiliary method for achieving accurate diagnosis and treatment of critically ill pediatric patients.

Spinal Infections? mNGS Combined with Microculture and Pathology for Answers

Introduction

This study evaluates the efficacy of metagenomic next-generation sequencing (mNGS) in diagnosing spinal infections and developing therapeutic regimens that combine mNGS, microbiological cultures, and pathological investigations.

Methods

Data were collected from 108 patients with suspected spinal infections between January 2022 and December 2023. Lesion tissues were obtained via C-arm assisted puncture or open surgery for mNGS, conventional microbiological culture, and pathological analysis. Personalized antimicrobial therapies were tailored based on these findings, with follow-up evaluations 7 days postoperatively. The sensitivity and specificity of mNGS were assessed, along with its impact on treatment and prognosis.

Results

mNGS showed a significantly higher positive detection rate (61.20%) compared to conventional microbiological culture (30.80%) and PCT (28%). mNGS demonstrated greater sensitivity (79.41%) and negative predictive value (63.16%) than cultures (25% and 22.58%, respectively), with no significant difference in specificity and positive predictive value. Seven days post-surgery, a significant reduction in neutrophil percentage (NEUT%) was observed, though decreases in white blood cell count (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were not statistically significant. At the last follow-up, significant improved in Visual Analogue Scale (VAS) scores, Oswestry Disability Index (ODI), and Japanese Orthopaedic Association (JOA) scores were noted.

Conclusion

mNGS outperforms traditional microbiological culture in pathogen detection, especially for rare and critical pathogens. Treatment protocols combining mNGS, microbiological cultures, and pathological examinations are effective and provide valuable clinical insights for treating spinal infections.

Metagenomic Next-Generation Sequencing-Based Fine-Needle Aspiration in Patients With Suspected Infected Pancreatic Necrosis

INTRODUCTION

Fine-needle aspiration (FNA) is no longer recommended for diagnosing infected pancreatic necrosis (IPN) due to a high false-negative rate. Metagenomic next-generation sequencing (mNGS) is a valuable tool for identifying potential pathogens. We hypothesized that adding mNGS to the standard FNA procedure may increase diagnostic accuracy.

METHODS

This is a prospective, single-arm feasibility study enrolling patients with acute necrotizing pancreatitis complicated by suspected IPN. Computed tomography-guided FNA was performed immediately after enrollment, and the drainage samples were subjected to culture and mNGS assays simultaneously. Confirmatory IPN within the following week of the index FNA procedure was the reference standard. The diagnostic performance of FNA-mNGS and the impact of mNGS results on treatment were evaluated. Historical controls were used for comparison of clinical outcomes.

RESULTS

There was no significant difference between mNGS and culture in the positive rate (75% vs 70%, P = 0.723). The accuracy of FNA-mNGS was 80.0%, with a sensitivity of 82.35%, specificity of 66.67%, positive predictive value of 93.3%, and negative predictive value of 40.0%. The results of the mNGS led to treatment change in 16 of 20 patients (80%), including implementing percutaneous catheter drainage (n = 7), expanding antibiotic coverage (n = 2), percutaneous catheter drainage and expanding coverage (n = 4), narrowing antibiotic coverage (n = 1), and discontinuation of antibiotics (n = 2). The FNA-mNGS approach was not associated with improved clinical outcomes compared with the historical control group.

DISCUSSION

The addition of mNGS to standard FNA has comparable diagnostic accuracy with culture-based FNA and may not be associated with improved clinical outcomes.

Application of metagenomic next-generation sequencing in optimizing the diagnosis of ascitic infection in patients with liver cirrhosis

BACKGROUND

Metagenomic next-generation sequencing (mNGS) is an emerging technique for the clinical diagnosis of infectious disease that has rarely been used for the diagnosis of ascites infection in patients with cirrhosis. This study compared mNGS detection with conventional culture methods for the on etiological diagnosis of cirrhotic ascites and evaluated the clinical effect of mNGS.

METHODS

A total of 109 patients with ascites due to cirrhosis were included in the study. We compared mNGS with conventional culture detection by analyzing the diagnostic results, pathogen species and clinical effects. The influence of mNGS on the diagnosis and management of ascites infection in patients with cirrhosis was also evaluated.

RESULTS

Ascites cases were classified into three types: spontaneous bacterial peritonitis (SBP) (16/109, 14.7%), bacterascites (21/109, 19.3%) and sterile ascites (72/109, 66.1%). In addition, 109 patients were assigned to the ascites mNGS-positive group (80/109, 73.4%) or ascites mNGS-negative group (29/109, 26.6%). The percentage of positive mNGS results was significantly greater than that of traditional methods (73.4% vs. 28.4%, P < 0.001). mNGS detected 43 strains of bacteria, 9 strains of fungi and 8 strains of viruses. Fourteen bacterial strains and 3 fungal strains were detected via culture methods. Mycobacteria, viruses, and pneumocystis were detected only by the mNGS method. The mNGS assay produced a greater polymicrobial infection rate than the culture method (55% vs. 16%). Considering the polymorphonuclear neutrophil (PMN) counts, the overall percentage of pathogens detected by the two methods was comparable, with 87.5% (14/16) in the PMN ≥ 250/mm3 group and 72.0% (67/93) in the PMN < 250/mm3 group (P > 0.05). Based on the ascites PMN counts combined with the mNGS assay, 72 patients (66.1%) were diagnosed with ascitic fluid infection (AFI) (including SBP and bacterascites), whereas based on the ascites PMN counts combined with the culture assay, 37 patients (33.9%) were diagnosed with AFI (P < 0.05). In 60 (55.0%) patients, the mNGS assay produced positive clinical effects; 40 (85.7%) patients had their treatment regimen adjusted, and 48 patients were improved. The coincidence rate of the mNGS results and clinical findings was 75.0% (60/80).

CONCLUSIONS

Compared with conventional culture methods, mNGS can improve the detection rate of ascites pathogens, including bacteria, viruses, and fungi, and has significant advantages in the diagnosis of rare pathogens and pathogens that are difficult to culture; moreover, mNGS may be an effective method for improving the diagnosis of ascites infection in patients with cirrhosis, guiding early antibiotic therapy, and for reducing complications related to abdominal infection. In addition, explaining mNGS results will be challenging, especially for guiding the treatment of infectious diseases.

Application of metagenomic next-generation sequencing technology in the etiological diagnosis of peritoneal dialysis-associated peritonitis

Pathogens detected by metagenomic next-generation sequencing (mNGS) and the laboratory blood culture flask method were compared to understand the advantages and clinical significance of mNGS assays in the etiological diagnosis of peritoneal dialysis-associated peritonitis (PDAP). The study involved a total of 37 patients from the hospital's peritoneal dialysis centre, six of whom were patients with non-peritoneal dialysis-associated peritonitis. Peritoneal dialysis samples were collected from the 37 patients, who were divided into two groups. One group's samples were cultured using conventional blood culture flasks, and the other samples underwent pathogen testing using mNGS. The results showed that the positive rate of mNGS was 96.77%, while that of the blood culture flask method was 70.97% (p < 0.05). A total of 29 pathogens were detected by mNGS, namely 24 bacteria, one fungus, and four viruses. A total of 10 pathogens were detected using the bacterial blood culture method, namely nine bacteria and one fungus. The final judgment of the PDAP's causative pathogenic microorganism was made by combining the clinical condition, response to therapy, and the whole-genome sequencing findings. For mNGS, the sensitivity was 96.77%, the specificity was 83.33%, the positive predictive value was 96.77%, and the negative predictive value was 83.33%. For the blood culture flask method, the sensitivity was 70.97%, the specificity was 100%, the positive predictive value was 100%, and the negative predictive value was 0%. In conclusion, mNGS had a shorter detection time for diagnosing peritoneal dialysis-related peritonitis pathogens, with a higher positive rate than traditional bacterial cultures, providing significant advantages in diagnosing rare pathogens.

Clinical performance of metagenomic next-generation sequencing for diagnosis of pulmonary Aspergillus infection and colonization

Background

Investigations assessing the value of metagenomic next-generation sequencing (mNGS) for distinguish Aspergillus infection from colonization are currently insufficient.

Methods

The performance of mNGS in distinguishing Aspergillus infection from colonization, along with the differences in patients' characteristics, antibiotic adjustment, and lung microbiota, were analyzed.

Results

The abundance of Aspergillus significantly differed between patients with Aspergillus infection (n=36) and colonization (n=32) (P < 0.0001). Receiver operating characteristic (ROC) curve result for bronchoalveolar lavage fluid (BALF) mNGS indicated an area under the curve of 0.894 (95%CI: 0.811-0.976), with an optimal threshold value of 23 for discriminating between Aspergillus infection and colonization. The infection group exhibited a higher proportion of antibiotic adjustments in comparison to the colonization group (50% vs. 12.5%, P = 0.001), with antibiotic escalation being more dominant. Age, length of hospital stay, hemoglobin, cough and chest distress were significantly positively correlated with Aspergillus infection. The abundance of A. fumigatus and Epstein-Barr virus (EBV) significantly increased in the infection group, whereas the colonization group exhibited higher abundance of A. niger.

Conclusion

BALF mNGS is a valuable tool for differentiating between colonization and infection of Aspergillus. Variations in patients' age, length of hospital stay, hemoglobin, cough and chest distress are observable between patients with Aspergillus infection and colonization.

Metagenomic next-generation sequencing of plasma cell-free DNA improves the early diagnosis of suspected infections

BACKGROUND

Metagenomic next-generation sequencing (mNGS) could improve the diagnosed efficiency of pathogens in bloodstream infections or sepsis. Little is known about the clinical impact of mNGS test when used for the early diagnosis of suspected infections. Herein, our main objective was to assess the clinical efficacy of utilizing blood samples to perform mNGS for early diagnosis of suspected infections, as well as to evaluate its potential in guiding antimicrobial therapy decisions.

METHODS

In this study, 212 adult hospitalized patients who underwent blood mNGS test in the early stage of suspected infections were enrolled. Diagnostic efficacy of mNGS test and blood culture was compared, and the clinical impact of mNGS on clinical care was analyzed.

RESULTS

In our study, the total detection rate of blood mNGS was significantly higher than that of culture method (74.4% vs. 12.1%, P < 0.001) in the paired mNGS test and blood culture. Blood stream infection (107, 67.3%) comprised the largest component of all the diseases in our patients, and the detection rate of single blood sample subgroup was similar with that of multiple type of samples subgroup. Among the 187 patients complained with fever, there was no difference in the diagnostic efficacy of mNGS when blood specimens or additional other specimens were used in cases presenting only with fever. While, when patients had other symptoms except fever, the performance of mNGS was superior in cases with specimens of suspected infected sites and blood collected at the same time. Guided by mNGS results, therapeutic regimens for 70.3% cases (149/212) were changed, and the average hospitalized days were significantly shortened in cases with the earlier sampling time of admission.

CONCLUSION

In this study, we emphasized the importance of blood mNGS in early infectious patients with mild and non-specific symptoms. Blood mNGS can be used as a supplement to conventional laboratory examination, and should be performed as soon as possible to guide clinicians to perform appropriate anti-infection treatment timely and effectively. Additionally, combining the contemporaneous samples from suspected infection sites could improve disease diagnosis and prognoses. Further research needs to be better validated in large-scale clinical trials to optimize diagnostic protocol, and the cost-utility analysis should be performed.

Diagnostic performance of metagenomic next-generation sequencing for the detection of pathogens in cerebrospinal fluid in pediatric patients with central nervous system infection: a systematic review and meta-analysis

BACKGROUND

Detecting pathogens in pediatric central nervous system infection (CNSI) is still a major challenge in medicine. In addition to conventional diagnostic patterns, metagenomic next-generation sequencing (mNGS) shows great potential in pathogen detection. Therefore, we systematically evaluated the diagnostic performance of mNGS in cerebrospinal fluid (CSF) in pediatric patients with CNSI.

METHODS

Related literature was searched in the Web of Science, PubMed, Embase, and Cochrane Library. We screened the literature and extracted the data according to the selection criteria. The quality of included studies was assessed by the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool and the certainty of the evidence was measured by the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) score system. Then, the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odd's ratio (DOR), and area under the curve (AUC) of the summary receiver operating characteristic curve (sROC) were estimated in Stata Software and MetaDisc. Subgroup analyses were performed to investigate the potential factors that influence the diagnostic performance.

RESULTS

A total of 10 studies were included in the meta-analysis. The combined sensitivity was 0.68 (95% confidence interval [CI]: 0.59 to 0.76, I2 = 66.77%, p < 0.001), and the combined specificity was 0.89 (95% CI: 0.80 to 0.95, I2 = 83.37%, p < 0.001). The AUC of sROC was 0.85 (95% CI, 0.81 to 0.87). The quality level of evidence elevated by the GRADE score system was low.

CONCLUSIONS

Current evidence shows that mNGS presents a good diagnostic performance in pediatric CNSI. Due to the limited quality and quantity of the included studies, more high-quality studies are needed to verify the above conclusion.

Diagnostic accuracy and microbial profiles of tuberculous pleurisy: a comparative study of metagenomic next generation sequencing and GeneXpert Mycobacterium tuberculosis

Introduction

There is a clinical challenge in diagnosing tuberculous pleurisy accurately and promptly, highlighting the urgent need for a rapid and sensitive diagnostic method. This study aimed to evaluate the diagnostic accuracy of metagenomic next-generation sequencing (mNGS) and GeneXpert Mycobacterium tuberculosis (MTB) for identifying tuberculous pleurisy and analyzing the microbial profiles of both tuberculous and non-tuberculous pleural effusions.

Methods

The study enrolled 31 patients with suspected tuberculous pleurisy, of which 15 were confirmed to have tuberculous pleurisy and subsequently allocated to the tuberculous pleurisy group (TP group), while the remaining 16 individuals were assigned to the non-tuberculous pleurisy group (NTP group). mNGS and GeneXpert MTB were performed on pleural effusion samples, and the diagnostic accuracy of both tests was compared. We employed established formulas to compute crucial indicators, including sensitivity, specificity, missed diagnosis rate, misdiagnosed rate, positive predictive value (PPV), and negative predictive value (NPV).

Results

The results showed that both tests had high specificity (100%) and positive predictive value (100%) for detecting tuberculous pleurisy, along with comparable sensitivity (46.67% for mNGS and 40.0% for GeneXpert MTB). Further analysis of the combined efficacy of mNGS and GeneXpert MTB showed that the combined test had a sensitivity of 66.67% and a specificity of 100%. mNGS analysis revealed that MTB was detected in 7 out of 15 patients with tuberculous pleural effusions, while non-tuberculous pleural effusions were associated with a diverse range of microbial genera and species. The most frequently detected genera at the microbial genus level in the NTP group were Microbacterium spp. (6/16), Prevotella spp. (5/16), and Campylobacter spp. (5/16).

Discussion

These findings suggest that mNGS and GeneXpert MTB are useful diagnostic tools for identifying patients with tuberculous pleurisy, and mNGS can provide valuable insights into the microbial profiles of both tuberculous and non-tuberculous pleural effusions.

Distribution Patterns of Pathogens Causing Lower Respiratory Tract Infection Based on Metagenomic Next-Generation Sequencing

Purpose

Lower Respiratory Tract Infection (LRTI) is a leading cause of morbidity and mortality worldwide. In this study, the distribution patterns of causative pathogens in LRTI were evaluated within a city-level hospital by combining conventional microbiological tests (CMT) with metagenomic next-generation sequencing (mNGS).

Patients and Methods

This retrospective cohort study involved 160 patients suspected of having LRTI in a single center. Specimens, including bronchoalveolar lavage fluid (BALF), blood, tissue, sputum, and pus were utilized to identify pathogens. The seasonal prevalence of pathogens and co-pathogens involved in multiple infections was analyzed.

Results

A total of 137 patients with 156 samples were included in this study. Pseudomonas aeruginosa, Corynebacterium striatum, Klebsiella pneumoniae, Candida, and human herpesvirus were the top prevalent pathogens. We observed seasonal dynamic variation in the top prevalent bacteria (Pseudomonas aeruginosa and Klebsiella pneumoniae) and herpesvirus (Epstein-Barr virus and Human herpesvirus-7). The majority of patients had single bacterial infections, followed by instances of bacterial-viral co-infections, as well as mixed infections involving bacteria, fungi, and viruses. Notably, the spectrum of co-infecting pathogens was broader among the elderly population, and positive Spearman correlations were observed among these co-infecting pathogens.

Conclusion

Co-infections were prevalent among patients with LRTI, and the pathogens displayed distinct seasonal distribution patterns. The findings underscored the significance of comprehending pathogen distribution and epidemic patterns, which can serve as a basis for early etiological identification.

Use of metagenomic next-generation sequencing for diagnosis of peritonitis in end-stage liver disease

Background: Conventional methods are low in positive rates and time-consuming for ascites pathogen detection in patients with end-stage liver disease (ESLD). With many advantages, metagenomic next-generation sequencing (mNGS) may be a good alternative method. However, the related studies are still lacking. Methods: Ascites from 50 ESLD patients were sampled for pathogen detection using mNGS and conventional methods (culture and polymorphonuclear neutrophils detection) in this prospective observational study. Results: Forty-two samples were detected positive using mNGS. 29 strains of bacteria, 11 strains of fungi, and 9 strains of viruses were detected. 46% of patients were detected to be co-infected with 2 or more pathogens by mNGS. Moreover, mNGS showed similar and high positive rates in ESLD patients with different clinical characteristics. Compared to conventional methods, mNGS had higher positivity rates (84% vs. 20%, P<0.001), sensitivity (45.2% vs. 23.8%, P=0.039), broader pathogen spectrum, shorter detection time (24 hours vs. 3-7 days), but lower specificity (25% vs 100%, P = 0.010). Furthermore, compared to conventional methods, mNGS showed similar consistence with final diagnosis (42% vs. 36%, P=0.539). Conclusions: mNGS may be a good supplement for conventional methods and helpful to early etiological diagnosis of peritonitis, and thus improve ESLD patients' survival.

Application of metagenomic sequencing of drainage fluid in rapid and accurate diagnosis of postoperative intra-abdominal infection: a diagnostic study

BACKGROUND

Postoperative intra-abdominal infection (PIAI) is one of the most serious complications of abdominal surgery, increasing the risk of postoperative morbidity and mortality and prolonging hospital stay. Rapid diagnosis of PIAI is of great clinical value. Unfortunately, the current diagnostic methods of PIAI are not fast and accurate enough.

METHODS

The authors performed an exploratory study to establish a rapid and accurate diagnostic method of PIAI. The authors explored the turnaround time and accuracy of metagenomic next-generation sequencing (mNGS) in diagnosing PIAI. Patients who underwent elective abdominal surgery and routine abdominal drainage with suspected PIAI were enroled in the study. The fresh midstream abdominal drainage fluid was collected for mNGS and culturing.

RESULTS

The authors found that the median sample-to-answer turnaround time of mNGS was dramatically decreased than that of culture-based methods (<24 h vs. 59.5-111 h). The detection coverage of mNGS was much broader than culture-based methods. The authors found 26 species from 15 genera could only be detected by mNGS. The accuracy of mNGS was not inferior to culture-based methods in the 8 most common pathogens detected from abdominal drainage fluid (sensitivity ranged from 75 to 100%, specificity ranged from 83.3 to 100%, and kappa values were higher than 0.5). Moreover, the composition of the microbial spectrum established by mNGS varied between upper and lower gastrointestinal surgery, enhancing the understanding of PIAI pathogenesis.

CONCLUSION

This study preliminarily revealed the clinical value of mNGS in the rapid diagnosis of PIAI and provided a rationale for further research.

High specificity of metagenomic next-generation sequencing using protected bronchial brushing sample in diagnosing pneumonia in children

BACKGROUND

Lower respiratory tract infections are the leading cause of morbidity and mortality in children worldwide. Timely and accurate pathogen detection is crucial for proper clinical diagnosis and therapeutic strategies. The low detection efficiency of conventional methods and low specificity using respiratory samples seriously hindered the accurate detection of pathogens.

METHODS

In this study, we retrospectively enrolled 1,032 children to evaluate the performance of metagenomics next-generation sequencing (mNGS) using bronchoalveolar lavage fluid (BALF) sample and protected bronchial brushing (BB) sample in diagnosing pneumonia in children. In addition, conventional tests (CTs) were also performed.

RESULTS

The specificity of BB mNGS [67.3% (95% CI 58.6%-75.9%)] was significantly higher than that of BALF mNGS [38.5% (95% CI 12.0%-64.9%)]. The total coincidence rate of BB mNGS [77.6% (95% CI 74.8%-80.5%)] was slightly higher than that of BALF mNGS [76.5% (95% CI 68.8%-84.1%)] and CTs [38.5% (95% CI 35.2%-41.9%)]. During the epidemics of Mycoplasma pneumoniae, the detection rate of M. pneumoniae in the >6-year group (81.8%) was higher than that in the 3-6-year (78.9%) and <3-year groups (21.5%). The highest detection rates of bacteria, fungi, and viruses were found in the <3-year, >6-year, and 3-6-year groups, respectively. mNGS detection should be performed at the duration of 5-7 days after the start of continuous anti-microbial therapy or at the duration of 6-9 days from onset to mNGS test.

CONCLUSIONS

This is the first report to evaluate the performance of BB mNGS in diagnosing pulmonary infections in children on a large scale. Based on our findings, extensive application of BB mNGS could be expected.

Early application of metagenomics next-generation sequencing may significantly reduce unnecessary consumption of antibiotics in patients with fever of unknown origin

BACKGROUND

Metagenomic next-generation sequencing (mNGS) is a novel nucleic acid method for the detection of unknown and difficult pathogenic microorganisms, and its application in the etiological diagnosis of fever of unknown origin (FUO) is less reported. We aimed to comprehensively assess the value of mNGS in the etiologic diagnosis of FUO by the pathogen spectrum and diagnostic performance, and to investigate whether it is different in the time to diagnosis, length of hospitalization, antibiotic consumption and cost between FUO patients with and without early application of mNGS.

METHODS

A total of 149 FUO inpatients underwent both mNGS and routine pathogen detection was retrospectively analyzed. The diagnostic performance of mNGS, culture and CMTs for the final clinical diagnosis was evaluated by using sensitivity, specificity, positive predictive value, negative predictive value and total conforming rate. Patients were furtherly divided into two groups: the earlier mNGS detection group (sampling time: 0 to 3 days of the admission) and the later mNGS detection group (sampling time: after 3 days of the admission). The length of hospital stay, time spent on diagnosis, cost and consumption of antibiotics were compared between the two groups.

RESULTS

Compared with the conventional microbiological methods, mNGS detected much more species and had the higher negative predictive (67.6%) and total conforming rate (65.1%). Patients with mNGS sampled earlier had a significantly shorter time to diagnosis (6.05+/-6.23 vs. 10.5+/-6.4 days, P < 0.001) and days of hospital stay (13.7+/-20.0 vs. 30.3 +/-26.9, P < 0.001), as well as a significantly less consumption (13.3+/-7.8 vs. 19.5+/-8.0, P < 0.001) and cost (4543+/-7326 vs. 9873 +/- 9958 China Yuan [CNY], P = 0.001) of antibiotics compared with the patients sampled later.

CONCLUSIONS

mNGS could significantly improve the detected pathogen spectrum, clinical conforming rate of pathogens while having good negative predictive value for ruling out infections. Early mNGS detection may shorten the diagnosis time and hospitalization days and reduce unnecessary consumption of antibiotics.

Donor-Derived Transmission of Scedosporiosis in Kidney Transplant Recipients from a Systemic lupus erythematosus donor

Donor-derived infection (DDI) associated with Scedosporium spp is extremely rare, and results in a very poor prognosis. The present study reports a probable DDI due to Scedosporium boydii (S. boydii) from a donor with neuropsychiatric systemic lupus erythematosus. Two recipients developed Scedosporiosis after kidney transplantation from the same donor. Recipient 1 died of central nervous system infection due to S. boydii based on the clinical presentations, and the positive metagenomic next-generation sequencing (mNGS) and culture results for the cerebrospinal fluid. The other recipient with urinary tract obstruction due to S. boydii, which was identified through the positive culture and mNGS results of the removed stents, was successfully treated by stent replacement and voriconazole administration. Undiagnosed disseminated donor infection and the transmission of S. boydii should be given attention, particularly when the donor and recipients have primary immunodeficiency disease. The screening of donors and recipients for S. boydii using mNGS may be helpful in guiding antifungal prophylaxis and treatment recipients, due to its higher sensitivity and shorter diagnostic time relative to other traditional techniques.

Short-term prognostic analysis of patients with systemic lupus erythematosus co-infection and comparison of mNGS and conventional microbiological test results

Objectives

Infection is one of the major causes of morbidity and mortality in patients with systemic lupus erythematosus (SLE), and as a new diagnostic technique, metagenomic next-generation sequencing (mNGS) is increasingly used for the pathogenetic detection of co-infected SLE patients. However, conventional microbiological testing (CMT) is still the gold standard for pathogenic diagnosis, and the specific diagnostic efficacy of mNGS versus CMT in such patients is not known. In addition, there are few studies on the short-term prognosis of co-infected SLE patients.

Methods

This study retrospectively included 58 SLE patients with co-infection admitted to the First Affiliated Hospital of Zhengzhou University from October 2020 to August 2022. Patients were divided into a survivors (n=27) and a non-survivors (n=31) according to their discharge status. Baseline characteristics and etiological data were collected and statistically analyzed for all patients during their hospitalization. The sequential organ failure assessment (SOFA) score, acute physiology and chronic health evaluation (APACHE) II and systemic lupus erythematosus disease activity index (SLEDAI) were calculated for each patient to assess the predictive ability of the 3 scores on the short-term prognosis of SLE patients. The mNGS and CMT culture results were also compared to clarify the flora characteristics of patients with SLE infection.

Results

More patients in the non-survivors had renal impairment, neurological manifestations, multiplasmatic cavity effusion and gastrointestinal manifestations compared to the survivors (p &lt; 0.05). The SOFA score, APACHE II and SLEDAI were significantly higher in the non-survivors than in the survivors (p &lt; 0.01). There were also significant differences between the two groups in several tests such as hemoglobin, platelets, albumin, total bilirubin, C-reactive protein (CRP), procalcitonin (PCT), and complement C3 (p &lt; 0.05). In addition, the absolute values of T lymphocytes, CD4+ T cells and CD8+ T cells were smaller in the non-survivors than in the survivors (p &lt; 0.05). The most common type of infection in this study was pulmonary infection, followed by bloodstream infection. mNGS and CMT positivity rates were not significantly different among patients in the non-survivors, but were significantly different among patients in the survivors (p=0.029). In-hospital survival of patients with SLE infection could be predicted based on the SOFA score in relation to 6. For patients with SOFA &lt;6, we recommend earlier mNGS testing to identify the pathogen and improve patient prognosis.

Conclusions

For SLE patients with co-infection, in-hospital survival can be predicted based on SOFA score. For patients with SOFA &lt;6, advising them to complete mNGS testing as early as possible may improve the prognosis to some extent.

Clinical Evaluation of Metagenomic Next-Generation Sequencing Method for the Diagnosis of Suspected Ascitic Infection in Patients with Liver Cirrhosis in a Clinical Laboratory

Metagenomic next-generation sequencing (mNGS), mostly carried out in independent clinical laboratories, has been increasingly applied in clinical pathogen diagnosis. We aimed to explore the feasibility of mNGS in clinical laboratories and analyze its potential in the diagnosis of infectious ascites. Two reference panels composed of 12 strains commonly appearing in peritonitis were constructed to evaluate the performance metrics based on in-house mNGS protocols. The mNGS clinical detection value was analyzed in 211 ascitic samples and compared with culture and composite standards. Finally, eight patients with cirrhosis were prospectively enrolled to verify the clinical value of mNGS in peritoneal infection diagnosis. The mNGS analytical performance showed that the assay had great linearity, specificity, stability, interference, and limits of detection of 33 to 828 CFU/mL. The sensitivity and specificity of mNGS for bacterial or fungal detection using culture standards were 84.2% and 82.0%, respectively. After adjustment using digital PCR and clinical judgment, the sensitivity and specificity increased to 87.2% and 90.1%, respectively. Compared with culture, mNGS detected a broad range of pathogens and more polymicrobial infections (49% versus 9%, P < 0.05). The pathogen results were obtained within 24 h using mNGS in eight prospective cases, which effectively guided antibiotics therapy. mNGS testing in clinical laboratories affiliated with a hospital has certain advantages. It has unique superiority in pathogens detection, particularly in patients with polymicrobial infections. However, considering spectrum characteristics and test cost, pertinent pathogen panels should be developed in clinical practice. IMPORTANCE This study established and evaluated a complete metagenomics next-generation sequencing assay to improve the diagnosis of suspected ascitic infection in a clinical laboratory affiliated with a hospital. The assay is superior to traditional culture testing and will aid in the early and accurate identification of pathogens, particularly in patients with polymicrobial infections. This assay is also essential for precision therapy and can reduce the incidence of drug resistance stemming from irrational use of antibiotics.

Diagnosis of Neurological Infections in Pediatric Patients from Cell-Free DNA Specimens by Using Metagenomic Next-Generation Sequencing

Central nervous system (CNS) infections can cause significant morbidity and mortality, especially in children. Rapid and accurate pathogenic detection in suspected CNS infections is essential for disease control at the early stage of infection. To evaluate the performance of metagenomic next-generation sequencing (mNGS) of cell-free DNA (cfDNA) in cerebrospinal fluid (CSF) in pediatric patients, we retrospectively analyzed the efficiency of cfDNA mNGS in children with CNS infections (n = 257) or noninfectious neurological disorders (n = 81). The CSF samples of 124 random subjects were used to evaluate the accuracy between mNGS of cfDNA and whole-cell DNA (wcDNA). In total, cfDNA mNGS detected a wide range of microbes with a detection rate of 71.0%, and the sensitivity and total coincidence rate with clinical diagnosis reached 68.9% and 67.5%, respectively. Compared with wcDNA mNGS, cfDNA mNGS had a higher efficacy in detecting viruses (66 versus 13) and Mycobacterium (7 versus 1), with significantly higher reads per million. The dominant causative pathogens were bacteria and viruses in CNS infections, but these presented with different pathogen spectra in different age categories. The best timing for the mNGS test ranged from 1 to 6 days after the start of anti-infection therapy, and the earlier mNGS started, the better was identification of bacterial CNS infections. This study emphasized that cfDNA mNGS had overall superiority to conventional methods on causative pathogen detection in pediatric CNS infections, and it was even better than wcDNA mNGS. Furthermore, research needs to be better validated in large-scale clinical trials to improve the clinical applications of cfDNA mNGS. IMPORTANCE Our study emphasized that cfDNA mNGS had overall superiority to conventional methods on causative pathogen detection in CNS-infected children, and it was even better than wcDNA mNGS. cfDNA mNGS detected a wide range of pathogens with a high total coincidence rate (67.5%) against clinical diagnosis. The best timing for cfDNA mNGS detection ranged from 1 to 6 days, rather than 0 days, after the start of empirical anti-infection therapy. The earlier mNGS started, the better the identifications of bacterial CNS infections. To the best of our knowledge, this research is the first report evaluating the clinical utility of mNGS with different methods (cfDNA versus wcDNA) of extracting DNA from CSF specimens in diagnosing pediatric CNS infections. Meanwhile, this is the largest cohort study that has evaluated the performance of mNGS using cfDNA from CSF specimens in pediatric patients with CNS infections.

The Diagnostic Value of Blood Next-Generation Sequencing in Early Surgical Site Infection After Spine Surgery

Objective

To determine the diagnostic value of blood next-generation sequencing (NGS) in early surgical site infection after spine surgery. Because the blood is sterile in healthy individuals, it is expected that blood NGS is both sensitive and specific for the detection of infection.

Methods

A total of 28 patients with definitive spinal surgical site infections and controls (n=30) were retrospectively included. The postoperative results of NGS and culture on different samples, such as blood and drainage fluid, were obtained and compared to evaluate the diagnostic value of blood NGS. The diagnostic value parameters (sensitivity, specificity, etc.) were calculated.

Results

Among the four bacteriological exam methods, blood NGS was both sensitive and specific for the determination of infection after spine surgery. The sensitivities of blood and drainage fluid NGS were similar (0.82 vs 0.89, P=0.617). However, the specificities of the two assessments differed, which were 0.97 for blood NGS and 0.40 for drainage fluid NGS (P<0.001). The sensitivities of bacterial culture were lower than those of NGS (blood: 0.82 vs 0.25, P<0.001; drainage fluid: 0.89 vs 0.61, P<0.001), regardless of the sample type. However, the specificities of bacterial culture were equal to or higher than those of NGS (blood: 0.97 vs 0.97, P=1.000; drainage fluid: 0.40 vs 0.80, P=0.002).

Conclusion

This article emphasizes the superiority of blood NGS in infection detection and bacterial determination in patients undergoing spine surgery. Compared with traditional drainage fluid bacterial culture and NGS, blood NGS was more sensitive and specific, and its extensive application could be expected.

Comparison of metagenomic next-generation sequencing using cell-free DNA and whole-cell DNA for the diagnoses of pulmonary infections

Although the fast-growing metagenomic next-generation sequencing (mNGS) has been used in diagnosing infectious diseases, low detection rate of mNGS in detecting pathogens with low loads limits its extensive application. In this study, 130 patients with suspected pulmonary infections were enrolled, from whom bronchoalveolar lavage fluid (BALF) samples were collected. The conventional tests and mNGS of cell-free DNA (cfDNA) and whole-cell DNA (wcDNA) using BALF were simultaneously performed. mNGS of cfDNA showed higher detection rate (91.5%) and total coincidence rate (73.8%) than mNGS of wcDNA (83.1% and 63.9%) and conventional methods (26.9% and 30.8%). A total of 70 microbes were detected by mNGS of cfDNA, and most of them (60) were also identified by mNGS of wcDNA. The 31.8% (21/66) of fungi, 38.6% (27/70) of viruses, and 26.7% (8/30) of intracellular microbes can be only detected by mNGS of cfDNA, much higher than those [19.7% (13/66), 14.3% (10/70), and 6.7% (2/30)] only detected by mNGS of wcDNA. After in-depth analysis on these microbes with low loads set by reads per million (RPM), we found that more RPM and fungi/viruses/intracellular microbes were detected by mNGS of cfDNA than by mNGS of wcDNA. Besides, the abilities of mNGS using both cfDNA and wcDNA to detect microbes with high loads were similar. We highlighted the advantage of mNGS using cfDNA in detecting fungi, viruses, and intracellular microbes with low loads, and suggested that mNGS of cfDNA could be considered as the first choice for diagnosing pulmonary infections.

Application of Metagenomic Next-Generation Sequencing (mNGS) Using Bronchoalveolar Lavage Fluid (BALF) in Diagnosing Pneumonia of Children

Pneumonia is the leading cause of death in children; the pathogens are often difficult to diagnose. In this study, the performance of metagenomic next-generation sequencing (mNGS) using bronchoalveolar lavage fluid (BALF) samples from 112 children with confirmed pneumonia has been evaluated. mNGS performed a significantly higher positive detection rate (91.07%, 95% confidence interval [CI] 83.80% to 95.40%) and coincidence rate against the final diagnosis (72.32%, 95% CI 62.93% to 80.15%) than that of conventional methods (70.54%, 95% CI 61.06% to 78.58% and 56.25%, 95% CI 46.57% to 65.50%, respectively) (P < 0.01 and P < 0.05, respectively). Bacteria, viruses, and their mixed infections were common in children with pneumonia. Streptococcus pneumoniae was the most common bacterial pathogen in children with pneumonia, while Haemophilus parainfluenzae and Haemophilus influenzae seemed more likely to cause nonsevere pneumonia in children. In contrast, human cytomegalovirus (CMV) infection and the simultaneous bacterial infections could cause severe pneumonia, especially in children with underlying diseases. After adjustments of antibiotics based on mNGS and conventional methods, the conditions improved in 109 (97.32%) children. mNGS of BALF samples has shown great advantages in diagnosing the pathogenic etiology of pneumonia in children, especially when considering the limited volumes of BALF and the previous use of empirical antibiotics, contributing to the timely adjustment of antibiotic treatments, which can potentially improve the prognosis and decrease the mortality. IMPORTANCE Our study indicates high efficiency of mNGS using BALF for the detection of causative pathogens that cause pneumonia in children. mNGS can be a potential diagnostic tool to supplement conventional methods for children's pneumonia.

Empyema caused by Eikenella halliae diagnosed by metagenomic next-generation sequencing (mNGS) after pulmonary surgery: A case report

Background

Empyema is one of the complications of pulmonary surgery for lung cancer, the incidence of which is not very high, but in severe cases, it can even lead to death, and it is always difficult to diagnose the cause by conventional methods.

Case presentation

In this study, we report a clinical case of empyema caused by Eikenella halliae after pulmonary surgery in a 55-year-old man. He had a fever, cough, and expectoration for 3 days and was diagnosed with right hydropneumothorax and empyema, pneumonia, postoperative malignant tumor of the right lower lobe (adenocarcinoma), and hypertension. The microbiology laboratory reported Gram-negative bacteria in pleural effusion, which was preliminarily considered as Eikenella based on culture and 16S rRNA sequencing. Furthermore, metagenomic next-generation sequencing (mNGS) of sputum samples was performed two times and reported negative results and the presence of E. halliae, respectively. The pathogen was finally confirmed as E. halliae by whole genome sequencing, suggesting the high-resolution ability of mNGS in the clinical diagnosis of this case.

Conclusion

To our knowledge, this is the first case report of E. halliae infection in China, indicating increased pathogenicity of Eikenella sp. in immunocompromised patients, especially after invasive operations. Our findings emphasize that mNGS allows bacterial diagnosis of empyema and can significantly improve the accuracy of the diagnosis.

Plasma metagenomic next-generation sequencing of microbial cell-free DNA detects pathogens in patients with suspected infected pancreatic necrosis

Background

Infected pancreatic necrosis (IPN) is a life-threatening complication of acute pancreatitis (AP). Timely diagnosis of IPN could facilitate appropriate treatment, but there is a lack of reliable non-invasive screening tests. In this study, we aimed to evaluate the diagnostic value of plasma metagenomic next-generation sequencing (mNGS) based on circulating microbial cell-free DNA in patients with suspected IPN.

Methods

From October 2020 to October 2021, 44 suspected IPN patients who underwent plasma mNGS were reviewed. Confirmatory diagnosis of IPN within two weeks after the index blood sampling was considered the reference standard. The confirmation of IPN relied on the microbiological results of drains obtained from the necrotic collections. The distribution of the pathogens identified by plasma mNGS was analyzed. Positive percent agreement (PPA) and negative percent agreement (NPA) were evaluated based on the conformity between the overall mNGS results and culture results of IPN drains. In addition, the clinical outcomes were compared between mNGS positive and negative patients.

Results

Across all the study samples, thirteen species of bacteria and five species of fungi were detected by mNGS. The positivity rate of plasma mNGS was 54.55% (24/44). Of the 24 mNGS positive cases, twenty (83.33%, 95% CI, 68.42–98.24%) were consistent with the culture results of IPN drains. The PPA and NPA of plasma mNGS for IPN were 80.0% (20/25; 95% CI, 64.32–95.68%) and 89.47% (17/19; 95% CI, 75.67–100%), respectively. Compared with the mNGS negative group, patients in the positive group had more new-onset septic shock [12 (50.0%) vs. 4 (20.0%), p = 0.039].

Conclusion

IPN relevant pathogens can be identified by plasma mNGS, potentially facilitating appropriate treatment. The clinical application of mNGS in this cohort appears feasible.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07662-2.