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Objective:To understand the etiology and clinical characteristics of hospitalized severe community-acquired pneumonia(SCAP) in Changchun, and provide scientific basis for its etiology diagnosis and targeted treatment.Methods:The study subjects included 618 children with clinical diagnosis of SCAP who were hospitalized from January 2016 to December 2019.We collected pharyngeal swabs and alveolar lavage fluid from children.Virus isolation, bacterial culture, time-of-flight mass spectrometry, PCR/RT-PCR, colloidal gold method and Optochin test were used to detect the antigen, nucleic acid and protein profiles in the specimen.Results:There were more boys than girls in hospitalized children with SCAP.The peak age of onset was 7 to 12 months.Most cases occurred in winter and spring.The highest detection rate of SCAP virus was 56.15%(347/618); 73.49%(255/347) were positive for one virus, among which the top five were respiratory syncytial virus (27.8%), influenza A virus (23.9%), influenza B virus (16.1%), rhinovirus (12.2%) and metapneumovirus (10.2%). Two viruses were positive for 19.88%(69/347); three viruses were positive for 4.32%(15/347); four viruses were positive for 2.31%(8/347). Atypical microbial infections were 29.77%(184/618), of which Mycoplasma pneumoniae accounted for 95.65%(176/184). Bacterial infections were 17.31%(107/618), mainly Streptococcus pneumoniae(39.25%, 42/107) and Staphylococcus aureus(24.30%, 26/107). The mixed infection of multiple pathogens was 7.61%(47/618), among which the mixed infection rates of Mycoplasma pneumonia with Streptococcus pneumoniae, virus were 40.43% and 34.04%, respectively.High fever, faster breathing, and perioral cyanosis were risk factors for SCAP, with OR and 95% CI of 7.71 and 4.56-13.04, 2.43 and 2.02-2.93, 3.53 and 2.56-4.86, respectively.Viral co-infection occurred in 36.96%(34/92) of complications such as heart failure, toxic encephalopathy, and myocardial damage; Mycoplasma pneumoniae and other pathogens co-infected 35.29% of children with pleural effusion. Conclusion:The pathogens of SCAP in Changchun are mainly viruses notably, respiratory syncytial virus is the dominant pathogen, followed by Mycoplasma pneumoniae.The bacterial pathogen is mainly Streptococcus pneumoniae.High fever, faster breathing, and cyanosis around the mouth are risk factors for severe pneumonia.Multi-pathogen mixed infection is prone to serious complications.
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Objective:To clarify the infection and epidemic characteristics of the human metapneumovirus (HMPV) in Chinese patients with febrile respiratory syndrome (FRS), and to provide important baseline data for clinical diagnosis, treatment, prevention and control of HMPV-induced respiratory tract diseases in China.Methods:FRS cases from January 2009 to June 2021 in 9 provinces in China, including Beijing, Hebei, Jilin, Shandong, Shaanxi, Xinjiang, Anhui, Guangdong, Hunan were retrospectively analyzed for their respiratory samples, clinical and epidemic data.The respiratory samples were detected for HMPV by quantitative real-time PCR.Results:A total of 11 660 cases were tested for HMPV, involving 296 (2.54%) HMPV-positive cases.Among 296 HMPV-positive cases, 218 were single HMPV infection, and 78/296 (26.35%) were co-infected with one or more respiratory viruses.HMPV mainly affected children under 5 years of age (3.10%), and in this population, the proportion of pneumonia in HMPV co-infection cases was significantly higher than that of single HMPV infection.HMPV could be detected all year round, which was more popular in winter and spring, with the peak of HMPV epidemic in March.Conclusions:HMPV is one of the important pathogens causing acute respiratory infection in children, showing a clear seasonal epidemic.HMPV can be infected alone or in combination with other respiratory viruses, which may increase the risk of pneumonia in children.
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Objective@#To investigate the effect of capillary electrophoresis-based multiplex PCR (CEMP) in detecting pathogens for children respiratory tract infection, and to provide scientific basis for clinical diagnosis and treatment rapidly and accurately.@*Methods@#The cases were defined according to the national monitoring program of febrile respiratory syndrome during the 12th Five-Year Plan, and the samples were collected from nasopharyngeal swabs, bronchoalveolar lavage fluid and sputum of children with respiratory tract infection hospitalized in Changchun Children′s Hospital from January 2017 to February 2018.Multiplex PCR amplification was performed by one-step method, then PCR products were separated by DNA length size with capillary electrophoresis and pathogens were analyzed by "Genemapper software" software.Detecting pathogens included Influenza A virus (InfA), Human Adenovirus (HADV), Boca virus (Boca), Human Rhinovirus (HRV), Novel InfA-09H1 (InfA-09H1) and Seasonal Influenza virus H3N2 (InfA-H3N2), Parainfluenza virus (HPIV), Human metapneumonia virus (HMPV), Influenza B virus (InfB), Mycoplasma pneumoniae (Mp), Chlamydia pneumoniae (CP), Human Coronavirus (HCOV), Human Respiratory Syncytial virus (HRSV).@*Results@#The effective detection rate of the CEMP assay was 95.71%.The positive detection rate of respiratory tract pathogens was 62.84% and the mixed infection rate was 9.61%.The mixed infection was mainly InfA and HRSV.The highest three positive rates were named InfA, HRSV and Mp.The positive rate of HRSV was significantly higher in the 0-3 age group than that in older group.Different pathogens were detected in different age groups, and the high-occurrence season of respiratory tract infection with virus was from December to March of the next year.InfA-09H1 was the main prevalent influenza virus in January, February and March 2017, InfA-H3N2 was the main prevalent influenza virus in November and December 2017, and the outbreak of InfB was happened in Changchun in late 2017 and early 2018.HRSV was detected only in the coldest season in Changchun from November to March of the next year.Different pathogens were detected in different respiratory infection.HRSV was the main pathogen detected in pneumonia; InfA-03H2 and HPIV were the main pathogens detected in acute bronchitis; HRV and InfA were the main pathogens detected in upper respiratory tract infection.@*Conclusion@#CEMP is an efficient, rapid and accurate method for the detection of pathogens in patients with respiratory tract infections, and it will have a broad application prospect to develop reagents suitable for clinical diagnosis.
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Objective To investigate the effect of capillary electrophoresis﹣based multiplex PCR ( CEMP) in detecting pathogens for children respiratory tract infection,and to provide scientific basis for clin﹣ical diagnosis and treatment rapidly and accurately. Methods The cases were defined according to the na﹣tional monitoring program of febrile respiratory syndrome during the 12th Five﹣Year Plan,and the samples were collected from nasopharyngeal swabs,bronchoalveolar lavage fluid and sputum of children with respira﹣tory tract infection hospitalized in Changchun Children′s Hospital from January 2017 to February 2018. Multi﹣plex PCR amplification was performed by one﹣step method, then PCR products were separated by DNA length size with capillary electrophoresis and pathogens were analyzed by"Genemapper software" software. Detecting pathogens included Influenza A virus (InfA),Human Adenovirus (HADV),Boca virus ( Boca), Human Rhinovirus ( HRV), Novel InfA﹣09H1 ( InfA﹣09H1 ) and Seasonal Influenza virus H3N2 ( InfA﹣H3N2),Parainfluenza virus ( HPIV),Human metapneumonia virus ( HMPV), Influenza B virus ( InfB), Mycoplasma pneumoniae (Mp),Chlamydia pneumoniae ( CP),Human Coronavirus ( HCOV),Human Re﹣spiratory Syncytial virus (HRSV). Results The effective detection rate of the CEMP assay was 95. 71%. The positive detection rate of respiratory tract pathogens was 62. 84% and the mixed infection rate was 9. 61%. The mixed infection was mainly InfA and HRSV. The highest three positive rates were named InfA, HRSV and Mp. The positive rate of HRSV was significantly higher in the 0﹣3 age group than that in older group. Different pathogens were detected in different age groups,and the high﹣occurrence season of respiratory tract infection with virus was from December to March of the next year. InfA﹣09H1 was the main prevalent influenza virus in January,February and March 2017,InfA﹣H3N2 was the main prevalent influenza virus in November and December 2017,and the outbreak of InfB was happened in Changchun in late 2017 and early 2018. HRSV was detected only in the coldest season in Changchun from November to March of the next year. Different pathogens were detected in different respiratory infection. HRSV was the main pathogen detec﹣ted in pneumonia; InfA﹣03H2 and HPIV were the main pathogens detected in acute bronchitis; HRV and InfA were the main pathogens detected in upper respiratory tract infection. Conclusion CEMP is an effi﹣cient,rapid and accurate method for the detection of pathogens in patients with respiratory tract infections,and it will have a broad application prospect to develop reagents suitable for clinical diagnosis.
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Objective To construct a chimeric infectious clone of the fatal virulent strain SDLY 107, containing the gene fragments encoding 2A and 3B proteins of the mild virulent strain SDLY 1, and to establish a reverse genetic system platform for further investigation on virulence of enterovirus 71 strains. Methods The overlap PCR analysis was performed to obtain the gene fragments encoding 2A and 3B pro-teins of the mild virulent strain SDLY 1.The obtained gene fragments were digested and then cloned into a plasmid pMD19-T containing the full-length gene of SDLY 107 strain by using gene replacement strategy. The recombinant RNA was transfected into Vero cells for the preparation of recombinant virus particles.Sev-eral assays including the PCR, indirect immunofluorescence ( IFA) , Western blot and sequencing were per-formed for virus identification.Virus titers were measured by 50%cell culture infective dose ( CCID50 ) and plaque assay.Results The infectious clones of SDLY 107-2A-1 and SDLY 107-3B-1 chimeric virus strains were constructed successfully.Typical cytopathic effect was observed in Vero cells after viral transfection. Identification of the rescued viruses by PCR, IFA, Western blot and sequencing further confirmed the suc-cessful construction of infectious virus strains.The virus titers of SDLY 107-2A-1 and SDLY 107-3B-1 strains detected by CCID50 and plaque assay were 1.25 ×105 PFU/ml and 0.7 ×105 PFU/ml, respectively. Conclusion The chimeric viruses SDLY 107-2A-1 and SDLY 107-3B-1 were rescued successfully, causing cytopathic effects similar to those by using the parental virus strain SDLY 107.This study might pave the way for further investigation on in vitro and in vivo virulence of enterovirus 71 strains.