Background Only few pathogens that cause lower respiratory tract infections (LRTIs) can be identified due to limitations of traditional microbiological methods and the complexity of the oropharyngeal normal flora. Metagenomic next-generation sequencing (mNGS) has the potential to solve this problem. Methods This prospective observational study sequentially enrolled 93 patients with LRTI and 69 patients without LRTI who visited Peking University People’s Hospital in 2019. Pathogens in bronchoalveolar lavage fluid (BALF) specimens were detected using mNGS (DNA and RNA) and traditional microbiological assays. Human transcriptomes were compared between LRTI and non-LRTI, bacterial and viral LRTI, and tuberculosis and nontuberculosis groups. Results Among 93 patients with LRTI, 20%, 35%, and 65% of cases were detected as definite or probable pathogens by culture, all microbiological tests, and mNGS, respectively. Our in-house BALF mNGS platform had an approximately 2-working-day turnaround time and detected more viruses and fungi than the other methods. Taking the composite reference standard as a gold standard, it had a sensitivity of 66.7%, specificity of 75.4%, positive-predictive value of 78.5%, and negative-predictive value of 62.7%. LRTI-, viral LRTI–, and tuberculosis-related differentially expressed genes were respectively related to immunity responses to infection, viral transcription and response to interferon-γ pathways, and perforin 1 and T-cell receptor B variable 9. Conclusions Metagenomic DNA and RNA-seq can identify a wide range of LRTI pathogens, with improved sensitivity for viruses and fungi. Our in-host platform is likely feasible in the clinic. Host transcriptome data are expected to be useful for the diagnosis of LRTIs.

BackgroundDiagnosis of community-acquired pneumonia (CAP) caused by Mycoplasma pneumoniae (Mp) in children has been hampered by difficulty in obtaining convalescent serum and time constraints. In this study, the two diagnostic assays that targeted respectively on Mp-antibody and Mp-DNA were retrospectively investigated.MethodsA total of 3146 children were clinically diagnosed to have CAP and were confirmed by chest X-ray during March 2015 to February 2016 in Children’s hospital of Hebei Province (China). Both of the sera and sputum samples were collected in 24 h after their admission. The Mp-antibody was examined by the passive particle agglutination assay and a fourfold or greater increase of antibody titers of paired sera or≧1:160 titer of single serum was set as the serology positive. Mp-DNA in the sputum samples was tested by a multiplex-PCR method named GeXP assay (multiplex PCR combined with automated capillary electrophoresis). In order to eliminate the false positive results caused by the asymptomatic carriage after infected by M. pneumoniae, the inconsistent samples were tested by the real-time isothermal transcription-mediated RNA amplification assay (SAT).ResultsThe inter-rated agreement test was performed in 3146 CAP patients, with a highest kappa value in the school-age children as 0.783. There were 6.29% (198/3146) cases showed inconsistent results determined by GeXP and serology assay. All of the 19 GeXP(+)/Serology (−) samples and a randomly chosen 27 from 179 GeXP(−)/Serology (+) samples were tested by SAT assay, and a 97.8% diagnosis agreement was observed between SAT and GeXP assay, but not with the serology assay. In addition, patients who were detected only by serology or only by multiplex-PCR were significantly younger than those with both methods positive (3.0 and 1.5 years vs. 5.0 years, p < 0.01). The Viral-Mp coinfection accounted for 37.0% (97/262), which was more common in winter and spring (p < 0.05) and in the infantile group (p < 0.01), compared to the pure Mp positive ones.ConclusionIn some children CAP cases, the Mp laboratory diagnosis was inconsistent between serology and multiplex-PCR assay. Verified by the SAT assay, the GeXP showed a more sensitive and reliable performance compared with the serology assay. Furthermore, employing the multiplex-PCR could provide more information on the associated pathogens for clinical assessment of CAP.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-017-2614-3) contains supplementary material, which is available to authorized users.

No abstract

A B S T R A C TBackground: Human adenovirus (HAdV) is a common pathogen in children that can cause acute respiratory tract infection (ARTI), but the molecular epidemiological and clinical information relating to HAdV among hospitalized children with ARTI are few reported in China. Objectives: To evaluate the epidemiological, clinical, and molecular characteristics of HAdV infections among hospitalized children with ARTI in Hebei, Northern China from June 2017 to May 2018. Study design: A 12-month longitudinal, retrospective study on HAdV, typed by nested polymerase chain reaction targeting the hexon gene's hypervariable region (typing was merely performed by sequencing of the hexon neutralization epitope and thus genotypes could not be identified unequivocally), associated with ARTI was performed. The epidemiological and clinical data of different types of HAdV were analyzed using statistical product and service solutions (SPSS) 21.0 software. Results: HAdV was detected in 330 (3.71%) of the 8906 specimens, with most (88.48%, 292/330) HAdV-positives cases detected among children < 3 years old. HAdV were detected throughout the year with a higher prevalence in spring. 11 types were identified, with HAdV-2 (33.33%, 110/330) as the predominant type, followed by HAdV-3 (21.21%, 70/330) and HAdV-7 (13.94%, 46/330). Of the 330 HAdV-positive specimens, 247 (74.85%) were co-detected with other respiratory pathogens, most commonly rhinovirus (HRV) (58.7%, 145/ 247). Additionally, patients with HAdV-7 positive had longer duration of fever than HAdV-2 or -3 positive patients. Conclusions: During the study period, HAdV-2, HAdV-3 and HAdV-7 were the predominant types identified from children with ARTI in Hebei Province. Pediatric patients with HAdV-7 positive may not present more severe clinical outcome except a longer duration of fever.