Antimicrobial resistance is a rigorous health issue around the world. Because of the short turn-around-time and broad pathogen spectrum, culture-independent metagenomic next-generation sequencing (mNGS) is a powerful and highly efficient tool for clinical pathogen detection. The increasing question is whether mNGS is practical in the prediction of antimicrobial susceptibility. This review summarizes the current mNGS-based antimicrobial susceptibility testing technologies. The critical determinants of mNGS-based antibacterial resistance prediction have been comprehensively analyzed, including antimicrobial resistance databases, sequence alignment tools, detection tools for genomic antimicrobial resistance determinants, as well as resistance prediction models. The clinical challenges for mNGS-based antibacterial resistance prediction have also been reviewed and discussed.
The morbidity and mortality of pulmonary infection are high among infectious diseases worldwide. Rapid and accurate etiological diagnosis is the key to timely and effective treatment. Metagenomic next-generation sequencing (mNGS) technology has brokenthrough the limitations of traditional pathogenic microorganism detection methods and improved the detection rate of pathogens. In this paper, the application and advantages of mNGS technology in the diagnosis of bacteria, fungi, viruses and mixed infections in the lungs are analyzed, and the challenges and breakthroughs in RNA detection, wall breaking of firmicutes and host DNA clearance are described, in order to achieve targeted and accurate etiological diagnosis through mNGS, so as to effectively treat pulmonary infections.
ObjectiveTo improve the understanding of psittacosis, the clinical data of 8 cases are reviewed. The application of pathogen metagenomics next-generation sequencing (mNGS) in the diagnosis of nocardiosis is also investigated.MethodsThe clinical data of eight patients with psittacosis diagnosed by mNGS in Nanjing Drum Tower Hospital from January 2018 to May 2020 were reviewed. The clinical characteristics, laboratory examination characteristics and imaging changes were analyzed, and the treatment outcome was followed-up.ResultsAmong the eight cases, there were six males and two females, aged 43～83 years old, with an average age of 64±12 years old. Six of them had a clear history of poultry exposure. The major clinical manifestations were fever, cough, dyspnea, etc. Chest high-resolution computed tomography (HRCT) may have solid shadow, ground glass like shadow. Chlamydia psittaci was detected by mNGS in eight patients’ bronchoalveolar lavage fluid. Minocycline or moxifloxacin were administrated, six patients were discharged after their condition improved, and two patients died.ConclusionsThe incidence of psittacosis is low, and its clinical manifestations lack specificity. In the course of the disease, there may be different degrees of fever, cough, sputum, dyspnea and other symptoms. The lungs can be heard with wet rales, chest HRCT can be seen ground glass shadow, consolidation shadow, accompanied by air bronchogram. Chlamydia psittaci can be detected in alveolar lavage fluid by mNGS. The patients need to be treated for a long time, lasting at least 10 to 14 days. Tetracycline drugs should be the first choice, and can be combined with other antibiotics with activity against gram-positive and gram-negative bacteria in critical patients.
ObjectiveTo explore the application and clinical value of metagenomic next-generation sequencing (mNGS) combined with Omadacycline in the treatment of Refractory Mycoplasma pneumoniae pneumonia (RMPP).MethodsThe clinical data, relevant laboratory results, diagnosis and treatment process, and imaging outcomes of four patients diagnosed with Mycoplasma pneumoniae pneumonia through mNGS were analyzed. ResultsThe clinical symptoms at onset in all four patients were consistent with Mycoplasma pneumoniae pneumonia. After conventional treatment with macrolides, tetracyclines, or quinolone antibiotics, the symptoms showed no significant improvement, and there was a trend of radiological worsening. Following the confirmation of Mycoplasma pneumoniae infection through mNGS of bronchoalveolar lavage fluid, and due to various reasons preventing the use of the aforementioned drugs, omadacycline was ultimately chosen for treatment. Radiological improvements were observed in all cases, leading to a good prognosis and discharge. ConclusionsFor pneumonia cases where the infectious pathogen cannot be identified and conventional treatment has failed, mNGS can be utilized for early and accurate diagnosis. In cases of RMPP, Omadacycline can be employed as an alternative treatment to prevent delays in care and reduce the risk of complications.
Objective To summarize the clinical characteristics of pneumocystis pneumonia (PCP) secondary to interstitial lung disease (ILD) to improve the prophylaxis and management level of clinicians. Methods The clinical data of 50 patients with PCP secondary to ILD in the Department of Respiratory and Critical Care Medicine of Nanjing Drum Tower Hospital from January 2015 to December 2022 were collected. SPSS 26.0 software was used for statistical analysis. Results A total of 50 patients with PCP secondary to ILD were screened. Among the 50 patients, there were 23 males and 27 females, with a median age of 64 years old. Forty-eight cases (96%) had a history of glucocorticoid therapy with the median duration of 3 months; 31 (77.5%, 31/40) cases developed PCP in the first 6 months after glucocorticoid therapy; 34 cases had a history of glucocorticoid and immunosuppressants at the same time. None of the 50 ILD patients used drugs for PCP prophylaxis before developing PCP. The major clinical manifestations of PCP secondary to ILD were worse cough and shortness of breath or fever. Laboratory results showed 38 cases (76.0%) had peripheral blood total lymphocyte count <200/µL, 27 cases (54.0%) had CD4+ T cell count <200/µL, 34 cases (68.0%) had CD4+ T cell count <300/µL, 37 cases (74.0%) had CD3+ T cell count <750/µL, 34 cases (68.0%) had β-D-glucan test >200 pg/mL, 35 cases (70.0%) had lactic dehydrogenase > 350 U/L and 41 cases (82.0%) had type Ⅰ respiratory failure. High resolution computed tomography showed added ground-glass opacity and consolidation on the basis of the original ILD. Thirty-six cases were detected the Pneumocystis jirovecii by metagenomic next-generation sequencing with broncho-alveolar lavage fluid as the main source, and 2 cases by smear microscopy. All patients were treated with trimethoprim-sulfamethoxazole. After treatment, 29 cases were discharged with a better health condition, 10 cased died, and 11 cases left hospital voluntarily because of treatment failure or disease deterioration. Conclusions After the use of glucocorticoid and immunosuppressants, ILD patients are susceptible to life-threatening PCP. It is particularly important to make an early diagnosis. Attention should be paid to integrate the symptoms, levels of peripheral blood lymphocyte count, β-D-glucan test, lactic dehydrogenase and imaging findings to make an overall consideration. It is suggested to perform next-generation sequencing with broncho-alveolar lavage fluid at an early stage when patients can tolerate fiberoptic bronchoscopy to avoid misdiagnosis and missed diagnosis. ILD patients often develop PCP in the first 6 months after using glucocorticoid and immunosuppressants. During follow-up, peripheral blood CD4+ and CD3+ T cell count should regularly be monitored so as to timely prevent PCP.
Objective To investigate the clinical manifestations, diagnosis, treatment and prognosis of psittacosis patients. Methods The clinical features, treatment and prognosis of severe pneumonia caused by Chlamydia psittaci were analyzed and relevant literatures were reviewed. Results An 83-year-old male with a history of type 2 diabetes mellitus was admitted to the hospital for "fever, cough for 5 days and dyspnea for 3 days". Chest CT showed a large mass of increased density in the right lung; CD4+ T lymphocytes had an absolute value of 23 cells/μL; Blood gas analysis showed type Ⅰ respiratory failure; Chlamydia psittaci was detected by metagenomic next-generation sequencing. The patient was diagnosed of severe pneumonia (Chlamydia psittaci), type 2 diabetes mellitus, suspected central nervous system infection. This patient was treated with doxycycline and macrolides antibiotics and discharged from hospital after complete recovery. Literature review showed that patients got infected from contacting sick bird, manifested with multiple system involvement. Respiratory symptoms were common, while central nervous system infection seemed to be rare. The diagnosis of psittacosis depended on serology, nucleic acid detection, pathogen isolation and culture. Metagenomic next-generation sequencing had superiority in the diagnosis of psittacosis. Tetracyclines were the preferable treatment, such as doxycycline or tetracycline, with a duration of at least 10 to 14 days. The prognosis of psittacosis was well, and most of the severe and even life-threatening cases were caused by unclear diagnosis and delayed treatment, and the overall mortality rate was about 1%. Conclusions Psittacosis is one kind of zoonoses. History of poultry exposure is helpful in diagnosis, and metagenomic next-generation sequencing has advantages in diagnosing psittacosis. Tetracyclines are preferred with adequate course of treatment. The overall prognosis is good.
Objective To explore the clinical characteristics of Chlamydia psittaci pneumonia. Methods From January 2020 to March 2023, 21 cases of Psittacosis from the First Affiliated Hospital of Nanjing Medical University were diagnosed via metagenomic next-generation sequencing (mNGS). They were divided into a severe group (n=10) and a non-severe group (n=11) based on diagnostic criteria for severe pneumonia, and the clinical presentation, secondary examination, treatment, and prognosis of the two groups were analyzed retrospectively. Results Among the 21 patients, there were 11 males and 10 females, with a mean age of (51.7±11.6) years. All patients had an acute onset and 12 had a confirmed history of exposure to poultry. The onset of the disease occurred in the autumn and winter seasons in 18 patients. All the patients were suffering from high fevers. Other symptoms included coughing, phlegm, tightness in the chest and fatigue. Laboratory examinations showed that the levels of leukocytes, neutrophil counts, C-reactive protein, procalcitonin, aminotransferase, creatine kinase, lactic dehydrogenase, brain natriuretic peptide precursors and D-dimer were significantly higher in the severe group than those in the non-severe group. Chest CT scans revealed varying levels of consolidation and spot shadowing with peripheral exudate in all patients. The patients in the severe group were more likely to have bilateral lung involvement, bilateral pleural effusion, cavity and mediastinal lymph node enlargement. Eleven patients received tetracycline alone, three received laudanum alone, two received respiratory quinolones alone, and five received a combination of two drugs including tetracycline. Chest CT at clinical follow-up showed absorption of lung lesions. Conclusions Chlamydia psittaci pneumonia usually occurs in the fall and winter, and most patients have a history of contact with poultry. Clinical presentation and imaging are not specified. The technology of mNGS enables early diagnosis of the disease, and neutrophil lymphocyte ratio, neutrophil-lymphocyte ratio and lactic dehydrogenase levels help assess the risk of severe disease.
Objective To summarize and explore the clinical features, diagnosis and treatment of severe pulmonary tuberculosis (TB). Methods One death case of pulmonary TB in The First Affiliated Hospital of Soochow University was analyzed, related publications of case reports and articles relevant on the analysis and study of pulmonary tuberculosis deaths from Pubmed between January 2012 and March 2022 were also reviewed. Results A 25-year-old female patient was admitted for "intermittent cough with sputum for more than 1 year, aggravated with chest tightness and shortness of breath for 5 days". She had no underlying disease. Pulmonary TB was diagnosed by TB bacterium smear and next-generation sequencing of bronchoalveolar lavage fluid. The patient was in shock compensation period and developed acute respiratory distress syndrome immediately after admission. Through active anti-tuberculosis, invasive mechanical ventilation, intra-aortic balloon counterpulsation and continuous renal replacement therapy, the disease continued to deteriorate and she died on the third day after admission. A total of 269 pulmonary TB deaths were retrieved. An analysis of 244 patients' past medical history showed that human immunodeficiency virus co-infection was the most common among young people and chronic diseases were the most common among the elderly. All 269 patients died of septic shock, respiratory failure and multiple organ dysfunction syndrome (MODS), among which hyponatremia was also a significant complication. The shortest time from admission to death was 7 days, while the longest average time was only 35 days. Conclusions Pulmonary TB could develop into septic shock and MODS with poor prognosis and high mortality. Health education on TB should be strengthened.
Objective To explore the clinical value of metagenomic next-generation sequencing (mNGS) in the diagnosis and treatment of severe and complex infection of malignant hematological disorder. Methods The mNGS test results, traditional etiology test results and general clinical data of inpatients with malignant hematological disorder in the Department of Hematology, the Affiliated Hospital of Southwest Medical University between June 2020 and February 2022 were retrospectively analyzed. To explore the clinical application value of mNGS in the diagnosis and treatment of severe complicated infection of hematological disorder. Results A total of 21 patients were included. The samples included 18 peripheral blood samples, 2 pleural fluid samples and 1 alveolar lavage fluid sample. In the included patients, through mNGS, pathogenic bacteria were directly detected in 17 patients, including 8 fungi, 9 bacteria and 10 viruses, of which 9 were mixed infections. The positive rate (81.0% vs. 33.3%, P=0.002), sensitivity (85.7% vs. 30.0%), granulocytopenia (9 vs. 3 cases, P=0.031) and the types of pathogen (Z=−3.416, P=0.001) detected by mNGS were all higher than those by traditional method. The infection control of 17 patients improved in varying degrees after adjusting the treatment plan according to the test results. ConclusionsmNGS has significantly higher detection rate and sensitivity for bacteria, fungi, viruses and mixed infections. Compared with the traditional method, mNGS has more efficient characteristics. Its clinical application can further improve the diagnosis and treatment efficiency of severe complicated infection of malignant hematological disorder, and thus improve the survival rate of patients.
Objective To analyze the differences in microbial communities in bronchoalveolar lavage fluid (BALF) from patients with simple pneumonia versus those with chronic obstructive pulmonary disease (COPD) combined with lower respiratory tract infection using metagenomic next-generation sequencing (mNGS). Methods Patients hospitalized for pulmonary infections at the First Affiliated Hospital of Xinjiang Medical University between December 2021 and March 2023 were included. Based on the presence of COPD, the patients were divided into two groups: those with simple pneumonia and those with COPD combined with lower respiratory tract infection. mNGS was employed to detect microbes in BALF, and the microbial community distribution characteristics of the two groups were analyzed. Results A total of 97 patients were included, of whom 80 (81.82%) had positive microbial detection results. The smoking index in COPD group with lower respiratory tract infection was significantly higher than that in the group with simple pneumonia (t= −3.62, P=0.001). Differences in microbial community distributions were observed between the groups. At the genus level, 19 species of microorganisms were detected in the simple pneumoniapulmonary infection group, including 8 bacteria (42.11%), 2 fungi (10.53%), 3 viruses (15.79%), and 6 other types of microorganisms (31.58%). In contrast, 22 types of microbes were detected in COPD group with lower respiratory tract infection, including 10 bacteria (47.62%), 3 fungi (14.29%), 4 viruses (19.05%), and 4 other types of microorganisms (19.05%). Differences were also noted in reads per million (RPM) values; bacterial RPM values at the genus level were significantly higher in the COPD group during non-severe pneumonia compared to the simple pneumonia group (Z=–2.706, P=0.007). In the patients with severe pneumonia, RPM values at the genus and species levels were significantly higher than those in non-severe pneumonia (Z=−2.202, P=0.028; Z=−2.141, P=0.032). In COPD combined with severe pneumonia, bacterial RPM values were significantly higher at the species level compared to non-severe pneumonia (Z=−2.367, P=0.017). ConclusionsThere are differences in the distribution of microbial communities at the genus and species levels in BALF from patients with COPD combined with lower respiratory tract infection compared to those with simple pulmonary pneumonia. Bacteria are the predominant microbial type in both groups, but the dominant bacterial species differ between them. Simple pneumonia are primarily associated with bacterial, viral, and other types of microbial infections, while COPD combined with lower respiratory tract infection is predominantly associated with fungal and bacterial infections. RPM values may serve as an indicator of the severity of pneumonia.