| Objective: To investigate the pathogen composition of children hospitalized with pneumonia in Shijiazhuang,Hebei Province and the epidemic characteristics of each pathogen,and to analyze the genetic characteristics of ADV to provide basic information and scientific basis for prevention and control of respiratory infectious diseases such as pneumonia in Shijiazhuang,Hebei.Methods:1.Selected 444 hospitalized pneumonia patients under the age of 14 who were admitted to a children’s hospital in Hebei Province from April 2018 to March 2020 as the research subjects,registered the patient’s case information,collected their alveolar lavage fluid samples,and used multiple RT-PCR The technology detects 29 respiratory pathogens and analyzes the epidemiological characteristics of each pathogen.2 Virus isolation for ADV positive cases,the obtained ADV strains amplify their Hexon,Penton and Fiber genes,use MEGA and Bio Edit software to establish a kinship tree,and analyze its genetic characteristics.3Using SPSS21.0 and Excel2016 for data processing and statistical analysis.Results:1.Test sample collection A total of 444 specimens were collected from2018 to 2020,including 243 boys and 201 girls,with a male to female ratio of1.21:1.There were 44,128,139 and 133 cases in the infant group,toddler group,preschool group and school age group,respectively.2.Multiple RT-PCR test results A total of 388 positive cases were detected in 444 specimens,with a total detection rate of 87.4%.The detection rates of viral pathogens,bacterial pathogens,and atypical pathogens were39.2%,49.3%,and 44.4%,respectively.Among them,the viral pathogens HRV,PIV3,and ADV The detection rate of RSV,IFVA is 10.6%,8.3%,6.8%,6.5%,3.8%;the detection rate of HPMV,HBo V,PIV4 is 1.8%;the detection rate of Co V-OC43 is 1.4%;IFVB The detection rate of PIV2 is 0.9%,the detection rate of PIV1 and EV is 0.7%;the detection rate of Co V-229 E is0.5%;the detection rate of bacterial pathogen SP is 30.4%,and the detection rate of HI is 16.7 %;the detection rate of PA is 7.9%,the detection rate of MC is 6.5%,the detection rates of KP,AB,BP,TB,SA are 2.7%,2.0%,1.8%,1.6%,1.4%,respectively.The detection rate of atypical pathogen MP was the highest at 41.0%.Followed by LP and CP,2.7% and 1.8% respectively.1)In seasonal distribution,HRV among viral pathogens is mainly detected in spring,summer and autumn,and the detection rates are 6.9%,8.8%,and 8.0%respectively;PIV3 is mainly detected in spring,with a detection rate of 7.4%;ADV,IFVA is mainly detected in winter,with a detection rate of 7.9% and5.9% respectively;RSV is prevalent in autumn and winter,with a detection rate of 8.0% and 7.4%,respectively;among the bacterial pathogens,the detection rate of HI in spring is the highest(14.3%)The highest detection rate of PA in winter is 5.4%;MC has the highest detection rate in spring(8.5%),TB and SA have higher detection rates in spring of 2.6% and 2.1%,respectively;MP is detected in summer in atypical pathogens The detection rate was the highest(33.9%),while LP and CP had higher detection rates in spring of 4.2% and 3.7%,respectively.2)The gender distribution shows that the positive detection rate of each pathogen in different genders is not statistically significant.3)In the age distribution,among the viral pathogens,HRV and RSV have the highest detection rates in the infant group,with F being 19.0% and 11.1% respectively;PIV3 and HBo V have higher detection rates in the infant group(7.5%,2.5%);bacteria Among the pathogens,SP,MC,and KP have the highest detection rates in the infant group,24.1%,7.5%,and2.9%,respectively.Among the atypical pathogens,MP has a higher detection rate in the school-age group and the preschool group(31.8%,39.6 %).3.Mixed infection results A total of 214 cases of mixed infection were detected,and the mixed rate was 48.2%(214/444).The number of cases of double,triple,quadruple,fifth,and sixth infections were 129,63,17,7 and 1respectively.Among them,mixed infections are mainly SP,MP,HI and HRV,and the infection rates are 52.3%,46.7%,29.9%,21.5%,respectively.4.Virus isolation results Virus isolation was performed on specimens that were positive for ADV by PCR,and a total of 8 ADV strains were obtained.5.Sequence analysis Comparing the isolated virus strains,the Hexon gene results showed that the nucleotide and amino acid similarities of the ADV-3 reference strain were 99.48-100.00% and 99.45-100.00%,respectively;compared with the nucleosides of the reference strain ADV-7 reference strain The similarity of acid and amino acid is 97.32-97.34% and 96.72%,respectively.Nucleotide comparison results show that the 8 virus strains are closest to the ADV-3 Beijing,Guangzhou,and Shanghai virus strains,and the ADV-3 Korean virus strain The similarity is the lowest.The phylogenetic tree of Fiber gene and Penton gene is similar to the analysis result of hexon gene.8strains are all ADV-3 virus strains.Conclusions:1.The overall detection rate of the three major pathogens in hospitalized children with pneumonia in Shijiazhuang City,Hebei Province,from high to low,are bacterial pathogens,atypical pathogens and viral pathogens.The top seven pathogens with detection rates are MP,SP,HI,HRV,PIV3,PA,ADV.2.Among viral pathogens,ADV is prevalent in winter,HRV is prevalent in spring,summer and autumn,and PIV3 is prevalent in summer;HI and PA of bacterial pathogens are prevalent in winter and spring;MP in atypical pathogens is prevalent in summer and autumn.3.The pathogens are not gender-selective when infecting children.4.Each pathogen has a different age group that is susceptible to infection.HRV,PIV3,and SP are more likely to occur in the infant group;MP mainly infects the preschool and school age groups.5.Mixed infections are more common in double and triple infections,mainly SP,MP,HI and HRV combined with other pathogens.6.The predominant serotype of adenovirus in Shijiazhuang area is ADV-3.The analysis results of Fiber,Penton and hexogene are similar,and the genetic evolution analysis did not find any related mutations. |
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