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.
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.
In recent years, due to the extensive usage of immunosuppressant and the rise of patients with cancers and organ transplantation, the incidence rate of invasive fungal infection, especially invasive pulmonary fungal infection, has increased. Besides the clinical manifestations, medical history and imaging, the diagnosis of pulmonary mycosis mainly depends on pathogen detection methods in clinical microbiology laboratory. However, due to the difficulty in fungi culturing and the low sensitivity of smear microscopy, better molecular biology methods are needed. To date, the emergence of metagenomic next-generation sequencing (mNGS) has improved the identification rate of pulmonary fungal infections. mNGS is significantly superior to traditional detection methods in rapid, accurate, and comprehensive determination of fungi from various clinical specimens, especially atypical fungi. However, some problems in mNGS method have to be addressed including sample collection, report interpretation, and its combination with traditional microbiology methods. With the in-depth discussion and solution of the above problems, mNGS will be indispensable to the etiological diagnosis of pulmonary invasive fungal infection.
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.