Metagenomic Next-generation Sequencing Research Articles

The diagnostic value of metagenomic next-generation sequencing in critically ill patients with sepsis: A retrospective cohort study.

Metagenomic next-generation sequencing (mNGS) is a new high-throughput sequencing method that may have great importance in early diagnosis and clinical management of sepsis. This study aimed to detect the difference between mNGS and comprehensive routine microbiological test (CMT), and to explore the diagnostic efficacy of mNGS in septic patients. This study retrospectively analyzed 150 sepsis patients who were admitted to the intensive care units of 4 hospitals in Southwest China from October 1, 2018, to October 1, 2021, and underwent both blood mNGS and CMT. The demographic and clinical characteristics of the patients were recorded, and the distribution of pathogens was analyzed. Additionally, the diagnostic performance and concordance between mNGS and CMT were compared to evaluate the etiological diagnostic value of mNGS in sepsis patients. In this study of 150 sepsis patients, bacterial infections were identified in 126 (84.0%), viral in 15 (10.0%), and fungal in 9 (6.0%). Among the sample types, sputum was most common, representing 62% of the total cases. Bronchoalveolar lavage fluid constituted 58.7%, blood 56.0%, with other specimens including pleural fluid at 29.3%, pus at 19.3%, swabs at 9.3%, cerebrospinal fluid at 8.7%, tissue at 6.0%, and bone marrow at 5.3%. mNGS demonstrated a diagnostic accuracy of 56.0% for sepsis, with a sensitivity of 84.4%, specificity of 26.0%, a positive predictive value of 54.6%, a negative predictive value of 61.3%. Metagenomic testing enables the rapid and early identification of infectious pathogens in sepsis patients, especially fungi and viruses. The study found that mNGS has high sensitivity in diagnosing sepsis patients, particularly for fungal and viral infections. mNGS technology is beneficial for critically ill sepsis patients.

Metagenomic next-generation sequencing in diagnosing perinephric abscess infection caused by Trichomonas vaginalis.

Metagenomic next-generation sequencing in diagnosing perinephric abscess infection caused by Trichomonas vaginalis.

Plasma Cell-free DNA Metagenomic Next-Generation Sequencing in Immunocompromised Children

Abstract Background Plasma cell-free DNA metagenomic next-generation sequencing (mNGS) is a novel diagnostic tool for infectious diseases [1]. Data suggests that plasma mNGS may be useful in immunocompromised adults, changing management in up to 60% of the patients [2]. A prospective study evaluating utility of plasma mNGS for pneumonia in immunocompromised adults concluded that mNGS provided an additive diagnostic value of 12.1% [3]. A similar study in adults with febrile neutropenia reported a sensitivity and specificity of 85 and 100%, respectively [4]. However, there is limited data evaluating the utility of mNGS in immunocompromised children. Methods We retrospectively reviewed all pediatric immunocompromised patients who had plasma mNGS testing performed from December 2018 to July 2023 at St. Jude Children’s Research Hospital. Electronic medical records were reviewed to extract relevant clinical data and microbiologic data including results of mNGS, contemporaneous cultures, and related antimicrobial treatment. Descriptive statistics are presented as frequencies and medians (interquartile range, IQR). Comparisons were performed using Fisher’s exact test or Wilcoxon rank-sum test, as appropriate, using R version 3.6.3. Results A total of 18 immunocompromised children underwent plasma mNGS testing. Acute lymphoblastic leukemia was the most common malignancy (33.3%), followed by acute myeloid leukemia (22.2%). Two patients (11.1%) had undergone hematopoietic cell transplant, both allogeneic. At the time of testing, 16 patients (88.9%) had fever and 10 (55.6%) had an absolute neutrophil count of <500/mm3. All except one were on antimicrobial therapy at the time of testing, with a median duration of 8 days (IQR=12.25). Only 9 (50%) patients had a positive mNGS result. A positive mNGS resulted in broadening or extending antibiotics course in 4 patients (22.2%); negative mNGS results did not lead to changes in management in any of the cases. There were no significant differences in age, sex, days of fever, neutropenia, gastrointestinal (GI) symptoms, and days of fever before testing between those with positive versus negative results. However, a higher frequency of GI symptoms at the time of testing among those with positive results was observed. Clinical characteristics and impact on management in patients with positive and negative results are summarized in Table 1. Conclusion Plasma mNGS had a limited impact on the management of immunocompromised children at our institution. Negative results did not lead to de-escalation of therapy, and positive results led to additional exposure to antibiotics. Further research is needed to determine the role of mNGS in this population, and the interpretation of positive testing in the setting of gastrointestinal disease.

Emergence and Rapid Diagnosis of Talaromyces marneffei Infections in Renal Transplant Recipients by Next-Generation Sequencing

In the last few years, next-generation sequencing (NGS) has emerged as a technology for laboratory diagnosis of many culture-negative infections and slow-growing microorganisms. In this study, we describe the use of metagenomic NGS (mNGS) for rapid diagnosis of T. marneffei infection in a 37-year-old renal transplant recipient who presented with chronic pneumonia syndrome. Bronchoalveolar lavage for mNGS was positive for T. marneffei sequence reads. Prolonged incubation of the bronchoalveolar lavage revealed T. marneffei colonies after 6 days of incubation. Analysis of 23 cases of T. marneffei infections in renal transplant recipients from the literature revealed that the number of cases ranged from 1 to 4 cases per five years from 1990 to 2020; but increased rapidly to 9 cases from 2021 to 2023, with 7 of them diagnosed by NGS. Twenty of the 23 cases were from T. marneffei-endemic areas [southern part of mainland China (n = 9); Hong Kong (n = 4); northeastern India (n = 2); Indonesia (n = 1) and Taiwan (n = 4)]. For the 3 patients from non-T. marneffei-endemic areas [United Kingdom (n = 2) and Australia (n = 1)], they had travel histories to China and Vietnam respectively. The time taken for diagnosis by mNGS [median 1 (range 1 to 2) day] was significantly shorter than that for fungal culture [median 6 (range 3 to 15) days] (P = 0.002). mNGS is useful for picking up more cases of T. marneffei infections in renal transplant recipients as well as providing a rapid diagnosis. Talaromycosis is an emerging fungal infection in renal transplant recipients.

Usefulness of next-generation sequencing for laboratory diagnosis of rickettsiosis.

Rickettsiosis includes a diversity of culture-negative non-specific systemic infections. Laboratory diagnosis of rickettsiosis is often not easy. In this 12-month study, six patients with a variety of rickettsia infections of the spotted fever group, typhus group and scrub typhus were diagnosed directly or indirectly by metagenomic next-generation sequencing (mNGS). The patient with Japanese spotted fever was rapidly made when mNGS analysis of the patient's blood revealed Rickettsia japonica sequences. For the two patients with Rickettsia felis chest infections, the bacterium was detected in the bronchoalveolar lavage of one case and lung biopsy of the other. Both patients had underlying malignancies, carcinoma of the breast and carcinoma of the lung respectively, and were on chemotherapy with immunosuppressive effect. For the remaining three patients who presented over a period of 13 weeks, all had fever, headache and the typical eschar. They also had increased serum transaminases and responded promptly to doxycycline. However, the Weil-Felix test results of all three patients were negative. Since we considered the three cases typical of rickettsiosis, we submitted their serum samples for mNGS analysis. Results showed that Orientia tsutsugamushi sequences were present in the serum of one case. In view of the positive mNGS results, we repeated the Weil-Felix test for the residual sera of all three patients and it revealed that those of the other two cases showed OX-19 titers of 1:640 and 1:160 respectively, inferring that these two patients probably had rickettsiosis of the typhus group. As for the patient positive for O. tsutsugamushi sequences, we also detected IgM for O. tsutsugamushi in the serum, which double confirmed that it was a case of scrub typhus. mNGS is an important molecular tool and can complement serology for laboratory diagnosis of rickettsiosis.

The clinical application of metagenomic next-generation sequencing in immunocompromised patients with severe respiratory infections in the ICU.

Early targeted antibiotic therapy is crucial for improving the prognosis of immunocompromised patients with severe respiratory infections (SRIs) in the intensive care unit (ICU). Metagenomic next-generation sequencing (mNGS) has shown significant value in pathogen detection, but research on lower respiratory tract microorganisms remains limited. This study enrolled 234 patients with SRIs in the ICU, and individuals were categorized into immunocompromised and immunocompetent groups. We compared the diagnostic performance of mNGS using bronchoalveolar lavage fluid (BALF) with conventional microbiological tests (CMTs) and analyzed the value of mNGS in immunocompromised patients with SRIs in the ICU. Among all patients, the pathogenic microorganism detection rate of mNGS was higher than that of CMTs (94.02% vs 66.67%, P < 0.05), both in the immunocompromised group (95.0% vs 58.75%, P < 0.05) and the immunocompetent group (93.51% vs 71.43%, P < 0.05). mNGS detected more pathogens than CMTs did (167 vs 51), identifying 116 organisms that were missed by CMTs. The proportion of antibiotic regimen adjustments based on mNGS results was significantly higher compared to CMTs in both the immunocompromised (70.00% vs 17.50%, P < 0.05) and immunocompetent groups (48.70% vs 15.58%, P < 0.05). In the immunocompromised group, patients who had their antibiotic treatment adjusted on mNGS results had improved prognosis, with significantly lower ICU mortality (8.93% vs 50%, P < 0.05) and 28-day mortality rates (30.36% vs 68.75%, P < 0.05) than CMTs. In the immunocompetent group, no statistically significant differences were observed in ICU mortality or 28-day mortality (20.00% vs 33.33%, P > 0.05; 42.67% vs 45.83%, P > 0.05). mNGS shows significant value in detecting pathogens in immunocompromised patients with SRIs in ICU. For immunocompromised patients who respond poorly to empirical treatment, mNGS can provide an etiological basis, helping adjust antibiotic regimens more precisely and thereby improving patient prognosis.

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

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

Augmented pathogen detection in brain abscess using metagenomic next-generation sequencing: a retrospective cohort study.

Brain abscess is a severe infection characterized by the accumulation of pus within the brain parenchyma. Accurate identification of the causative pathogens is crucial for effective treatment and improved patient outcomes. This 10-year retrospective, single-center study aimed to compare the detection performance of conventional culture methods and metagenomic next-generation sequencing (mNGS) in brain abscess. We reviewed 612 patients diagnosed with brain abscess and identified 174 cases with confirmed etiology. The median age was 52 years, with 69.5% males. Culture tests predominately identified gram-positive bacteria, particularly Streptococcus spp. Gram-negative bacteria, including Klebsiella spp., were also detected. However, mNGS revealed a more diverse pathogen spectrum, focusing on anaerobes (e.g., Fusobacterium spp., Parvimonas spp., Porphyromonas spp., Prevotella spp., and Tannerella spp.). mNGS exhibited significantly higher overall pathogen-positive rates in pus samples (85.0% vs 50.0%, P = 0.0181) and CSF samples (84.2% vs 7.9%, P < 0.0001) compared to culture. Furthermore, the detection rates for anaerobes displayed a notable disparity, with mNGS yielding significantly higher positive detections in both pus samples (50.0% vs 10%, P = 0.0058) and CSF samples (18.4% vs 0%, P = 0.0115) when compared to culture methods. The assistance of mNGS in pathogen detection, particularly anaerobes in brain abscess, was evident in our findings. mNGS demonstrated the ability to identify rare and fastidious pathogens, even in culture-negative cases. These results emphasize the clinical value of mNGS as a supplement for brain abscess, enabling more comprehensive and accurate pathogen identification.IMPORTANCEThe accurate identification of pathogens causing brain abscess is crucial for effective treatment and improved patient outcomes. In this 10-year retrospective study, the detection performance of conventional culture methods and metagenomic next-generation sequencing (mNGS) was compared. The study analyzed 612 patients with brain abscess and confirmed etiology in 174 cases. The results showed that culture tests predominantly identified gram-positive bacteria, while mNGS unveiled a broader diverse pathogen spectrum, particularly anaerobes. The mNGS method exhibited significantly higher overall rates of pathogen positivity both in pus and cerebrospinal fluid (CSF) samples, surpassing the culture methods. Notably, mNGS detected a significantly higher number of anaerobes in both pus and CSF samples compared to culture methods. These findings underscore the clinical value of mNGS as a supplement for brain abscess diagnosis, enabling more comprehensive and accurate pathogen identification, particularly for rare and fastidious pathogens that evade detection by conventional culture methods.

Acute infections of the central nervous system in children and adults: diagnosis and management.

Central nervous system infections are due to different microorganisms such as viruses, bacteria, mycobacteria, fungi, amoebas, and other parasites. The etiology depends on multiple risk factors, and it defines the infection location because some microorganisms prefer meninges, brain tissue, cerebellum, brain stem or spinal cord. The microorganisms induce diseases in the nervous system through direct invasion, neurotoxin production, and the triggered immune response. To determine the infection etiology, there are several diagnostic tests which may be conducted with cerebrospinal fluid, blood, respiratory and stool samples. These tests include but are not limited to direct microscopic examination of the sample, stains, cultures, antigenic tests, nucleic acid amplification tests, metagenomic next-generation sequencing, immunologic biomarker and neuroimaging, especially contrast-enhanced magnetic resonance imaging. The treatment may consist of specific antimicrobial treatment and supportive standard care. Since viruses have no specific antiviral treatment, antimicrobial treatment is mainly targeted at non-viral infections. This article will focus on diagnosis and treatment of acute acquired infections of the central nervous system beyond the neonatal period. The discussion defines the disease, provides the clinical presentation, explains the etiology and risk factors, and briefly mentions potential complications. This updated review aims to provide the reader with all the elements needed to adequately approach a patient with a central nervous system infection. Mycobacterium tuberculosis infection, Cryptococcus spp. infection and vaccines are not within the scope of this article.

Epidemiological characteristics of severe community-acquired pneumonia in children admitted to two tertiary hospitals in Shihezi, Xinjiang Region, China in 2023: a cross-sectional analysis.

Severe community-acquired pneumonia (SCAP) in children is associated with high morbidity and mortality, and the data of epidemiological characteristics of SCAP in Shihezi area were inadequate. The main pathogens responsible for SCAP may vary dramatically according to the geographical area. We identified two tertiary hospitals with better medical level and the largest number of hospitalized children in Shihezi as sentinel hospitals. The primary purpose of the study is to cross-sectionally summarize the epidemiological characteristics of SCAP in children admitted to hospitals in Shihezi, Xinjiang, China in 2023. SCAP was defined as involving the respiratory and other systems, accompanied by significant systemic toxic symptoms. We prospectively included all patients <15 years old who diagnosed with SCAP according to the SCAP diagnostic criteria. We enrolled all patients <15 years who were diagnosed with SCAP during the study period (January to December 2023), a total of 309 cases were included from two sentinel hospitals in Shihezi, Xinjiang, from January to December 2023. Basic information and clinical data were collected on a standardized questionnaire, and respiratory samples were obtained for the detection of 27 respiratory pathogens using a panel, targeted next-generation sequencing (t-NGS), and metagenomic next-generation sequencing (mNGS). We enrolled 309 patients aged 1-14 years: 157 males (50.8%) and 152 females (49.2%). There were 45 infants (1 month to 1 year, 14.6%), 33 toddlers (>1-3 years, 10.7%), 121 preschool children (>3-7 years, 39.2%), and 110 school-age children (>7-14 years, 35.6%). Overall, the number of SCAP cases in spring was 39 (12.6%), in summer was 44 (14.2%), in autumn was 137 (44.3%), and in winter was 89 (28.8%). A total of 572 pathogens were detected in this study, primarily Mycoplasma pneumoniae (MP) (n=120, 21.0%), respiratory syncytial virus (RSV) (n=82 strains, 14.3%), and Streptococcus pneumoniae (SP) (n=67, 11.7%). MP was prevalent mainly during the cold season of autumn, with its detection starting from July and reaching a peak detection rate in November. By studying the interaction among 22 common respiratory pathogens, we found a strong negative correlation between MP and SP, yet the highest number of co-infected cases involved MP and SP. Seventy-six (63.3% of all MP) SCAP were identified as macrolide-resistant (all with mutations at the A2063G site). MP SCAP was associated with prolonged illness duration and fever spikes. We observed incidence of pediatric SCAP showed an inverse trend with PM2.5 level changes. The most common pathogens responsible for SCAP in the Shihezi region in 2023 were MP, RSV, and SP. MP was the primary cause of SCAP in children, and increased risk of co-infections, and high prevalence of macrolides resistance-all related to mutations at the A2063G site. Early identification of SCAP pathogen epidemiological characteristics can reduce severe case occurrence.

Pulmonary microbial spectrum in late-stage SARS-CoV-2 infection: a case series.

Coronavirus disease 2019 (COVID-19), a kind of respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), primarily spreads through the respiratory tract from human to human. Its extensive and rapid spread has led to a global pandemic, causing great harm to human health and economic development all over the world. Current known evidence indicates that SARS-CoV-2 has evolved accumulating multiple mutations, with altered infectivity and viral replication capacity. A better understanding of the complications of COVID-19 and its relationship with underlying diseases is crucial for the prevention and treatment of SARS-CoV-2. This case series reviewed case data of our 4 recent patients with severe or critical COVID-19, including treatment plan, status of pulmonary infection and their microbiology workup with metagenomic next-generation sequencing with bronchoalveolar lavage fluid. This report shed light on the significance of rapid and accurate clinical diagnosis and treatment on COVID-19.

Clinical Application of Metagenomic Next-Generation Sequencing in Sepsis Patients with Early Antibiotic Treatment.

This study aimed to evaluate the clinical utility of metagenomic next-generation sequencing (mNGS) in sepsis patients who received early empirical antibiotic treatment. A retrospective analysis was conducted on clinical data from sepsis patients diagnosed in the Emergency Intensive Care Unit (EICU) between April 2019 and May 2023. All patients underwent standard conventional microbiological testing. Patients were categorized into either the mNGS group or the control group based on whether they underwent mNGS tests. Baseline variables were matched using propensity scores. Out of 461 sepsis patients screened, 130 were included after propensity matching, with 65 patients in each group. Despite prior antibiotic treatment, 57 cases (87.69%) in the mNGS group had positive mNGS results, exceeding the culture detection rate (52.31%). Besides, a higher proportion of patients in the mNGS group experienced antibiotic adjustments compared to the control group (72.31% vs 53.85%). Mortality rates were also compared based on the duration of antibiotic exposure before mNGS sampling. Patients exposed to antibiotics for less than 24hours had a lower mortality rate compared to those exposed for over 8 days (22.22% vs 42.86%). COX multivariate analysis identified mNGS testing, underlying diseases, lymphocyte percentage, infection site (respiratory and bloodstream) as independent risk factors for mortality in sepsis patients. With increased antibiotic exposure time, the positive rate of culture testing significantly decreased (44.44% vs 59.52% vs 35.71%, P = 0.031), whereas the positive rate of mNGS remained stable (77.78% vs 88.10% vs 92.86%, P = 0.557). mNGS demonstrated less susceptibility to antibiotic exposure. Early mNGS detection positively impacted the prognosis of sepsis patients.

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

BackgroundAccurate 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.MethodsTo 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.ResultsIn 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.ConclusionIn 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.

A Fatal Co-infections of Aspergillus latus and Pneumocystis jirovecii in COVID-19 Pneumonia Patient: Case Report

Introduction: For coronavirus disease 2019 (COVID-19) positive patients, co-infection with fungi has previously been reported. Owing to non-specific clinical manifestations and radiographic evidence, it is difficult to distinguish fungal infection from COVID-19 alone, resulting in delayed diagnosis and lack of appropriate treatment. Aspergillus latus infection, a newly rare species with life-threatening characteristics, requires rapid detection with accurate diagnosis to reduce mortality. However, there is little literature that provides a reference for a better understanding of this rare pathogen and guides medical practitioners in choosing the right diagnostics and therapies. Case Presentation: We reported a 67-year-old female complaining of fever, cough, and chest tightness, who had previously been hospitalized for a week due to initial COVID-19 pneumonia. On admission, clinical manifestations and radiological evidence were consistent with COVID-19 pneumonia, and there was no obvious improvement after anti-infective therapy. In terms of etiology for the patient, Galactomannan test was positive for Aspergillus genus, and Metagenomic next-generation sequencing further determined co-infections of A. latus and Pneumocystis jirovecii. Subsequently, isolation of A. latus was obtained through microbial culture. Despite targeted antifungal therapy, no clinical improvement was observed, possibly due to delayed diagnosis and treatment. Finally, the patient died of respiratory failure. Conclusions: This case report demonstrated that metagenomic next-generation sequencing is a fast, unbiased, culture-free approach that can increase the detection of rare pathogens, helping clinicians improve the accuracy of clinical diagnosis and take therapeutic action as quickly as possible. Clinicians should be aware of the risk of COVID-19-associated pulmonary Aspergillosis in COVID-19 patients, and we hope to optimize diagnosis and improve outcomes of COVID-19-associated pulmonary Aspergillosis.

Culture-Negative Native Vertebral Osteomyelitis: A Narrative Review of an Underdescribed Condition.

The incidence of culture-negative NVO (CN-NVO) cases is increasing, presenting significant diagnostic and therapeutic challenges due to the inability to isolate causative organisms with conventional microbiological methods. Factors influencing the diagnosis of CN-NVO include prior antimicrobial therapy, low pathogen burden, fastidious or intracellular organisms, technical issues, and non-infectious mimickers. Diagnosis often relies on imaging modalities like magnetic resonance imaging (MRI) and computed tomography (CT)-guided biopsy, though these methods can sometimes fail to yield positive microbiological results. Advanced diagnostic tools, such as polymerase chain reaction (PCR), metagenomic next-generation sequencing (mNGS), and cell-free DNA analysis, may be necessary to identify the pathogen. The causative pathogen cannot be isolated in some patients, among which an empirical antimicrobial therapy should be initiated. This narrative review discusses the management, monitoring, surgical indications, and outcomes for patients with CN-NVO.

Recurrent pulmonary nocardiosis due to Nocardia Otitidiscaviarum in a patient with isolated CD4 lymphocytopenia: a case report

BackgroundIdiopathic CD4 lymphocytopenia (ICL) is an underdiagnosed immunodeficiency syndrome characterised by persistent low CD4 counts in the absence of HIV and other causes of lymphocytopenia. ICL patients are susceptible to opportunistic infections, with human papillomavirus, cryptococcal, and tuberculosis being the most common infections reported. Nocardiosis is rarely reported in patient with ICL.Case PresentationWe herein discuss a 46-year-old female presented with complaints of weight loss, low grade fever and cough with expectoration from last four months. The patient was diagnosed with pulmonary nocardiosis and aspergillosis co-infection four years back; in addition she also had ICL. Subsequently, the patient was lost in follow-up and readmitted four years later. Bronchoalveolar lavage sample shows the presence of acid-fast bacilli in modified gram stain, which later identified as Nocardia otitidiscaviarum by metagenomic next-generation sequencing. Her CD4 counts were still found low (298 cells/mm3). After an initial improvement with trimethoprim-sulfamethoxazole (TMP-SMX), she was commenced on indefinite secondary prophylaxis.ConclusionsNocardiosis without usual risk factors should be evaluated for ICL. This case emphasize the importance of periodic follow-up with CD4 count monitoring and secondary prophylaxis therapy to prevent recurrence or the emergence of new infections in ICL.Clinical trial numberNot applicable.

The epidemiological and infectious characteristics of novel types of Coxiella burnetii co-infected with Coxiella-like microorganisms from Xuyi County, Jiangsu province, China

Coxiella burnetii (C. burnetii) is the causative agent of Q fever, a type of zoonoses withwidespread distribution. In 2019, a case of Q fever was diagnosed by metagenomic next-generation sequencing (mNGS) method in Xuyi County (Jiangsu province, China). The seroprevalence of previous fever patients and the molecular epidemiology of Coxiella in wild hedgehogs and harbouring ticks around the confirmed patient were detected to reveal the genetic characteristics and pathogenicity of the Coxiella strains. Four of the 90 serum samples (4.44%) were positive for specific C. burnetii IgM antibody, suggesting that local humans are at risk of Q fever. The positive rates of C. burnetii in hedgehogs and ticks were 21.9% (7/32) and 70.5% (122/173), respectively. At least 3 strains of Coxiella were found prevalent in the investigated area, including one new genotype of pathogenic C. burnetii (XYHT29) and two non-pathogenic Coxiella-like organisms (XYHT19 and XYHT3). XYHT29 carried by ticks and wild hedgehogs successfully infected mice, imposing a potential threat to local humans. XYHT19, a novel Coxiella-like microorganism, was first discovered in the world to co-infect with C. burnetii in Haemaphysalis flava. The study provided significant epidemic information that could be used for prevention and control strategies against Q fever for local public health departments and medical institutions.

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

ObjectivePulmonary 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.Methods27 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.ResultsAmong 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).ConclusionCompared 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.

Diagnosis of Acute Q Fever in an Elderly Patient Using Metagenomic Next-Generation Sequencing: A Case Report

Query fever (Q fever) is a globally spread zoonotic disease caused by Coxiella burnetii, commonly found in natural foci but rarely seen in Hebei Province. The clinical manifestations of Q fever are diverse and nonspecific, which often leads to missed or incorrect diagnoses in clinical practice. This article reports a case of acute Q fever diagnosed in an elderly patient using metagenomic next-generation sequencing.

Characteristics of Endemic Mycoses Talaromyces marneffei Infection Associated with Inborn Errors of Immunity.

Talaromyces marneffei (T. marneffei) is an opportunistic pathogen that causes endemic mycoses, which could lead to multiple organ damage. Talaromycosis is frequently disregarded as an early cautionary sign of immune system disorders in non-HIV-infected children. We conduct a comprehensive review of the genotypes and clinical features of talaromycosis in patients with IEI to enhance clinical awareness regarding T. marneffei as a potential opportunistic pathogen in individuals with immune deficiencies. A systematic literature review was performed by searching PubMed, Cochrane Central Register of Controlled Trials, Web of Science, EMBASE, and Scopus. Data on IEI patients with talaromycosis, including genotypes and their immunological and clinical features, were collected. Fifty patients with talaromycosis and IEI were included: XHIM (30.0%), STAT3-LOF deficiency (20.0%), STAT1-GOF (20.0%), IL2RG (6.00%), IFNGR1 (6.0%), IL12RB1 (4.0%), CARD9 (4.0%), COPA (4.0%), ADA (2.0%), RELB deficiency (2.0%), and NFKB2 (2.0%). Common symptoms of respiratory (43/50, 86.0%), skin (17/50, 34.0%), lymph node (31/50, 62.0%), digestive (34/50, 68.0%), and hematologic (22/50, 44.0%) systems were involved. The CT findings of the lungs may include lymph node calcification (9/30), interstitial lesions (8/30), pulmonary cavities (8/30), or specific pathogens (4/30), which could be easily misdiagnosed as tuberculosis infection. Amphotericin B (26/43), Voriconazole (24/43) and Itraconazole (22/43) were used for induction therapy. Ten patients were treated with Itraconazole sequentially and prophylaxis. 68.0% (34/50) of patients were still alive, and 4.0% (2/50) of were lost to follow-up. The disseminated T. marneffei infection resulted in the deaths of 14 individuals. The XHIM, STAT1-GOF, and STAT3-LOF demonstrated the highest susceptibility to talaromycosis, indicating the potential involvement of cellular immunity, IL-17 signaling, and the IL-12/IFN-γ axis in T. marneffei defense. T. marneffei infection may serve as an early warning indicator of IEI. For IEI patients suspected of T. marneffei, metagenomic next-generation sequencing (mNGS) could rapidly and effectively identify the causative pathogen. Prompt initiation of antifungal therapy is crucial for optimizing patient outcomes.