| Objective:To use a more accurate and rapid PCR detection method to detect pathogens in hospitalized children with community-acquired pneumonia in Chengde from 2021-2022,so as to improve the pathogen spectrum in this area and explore its epidemiological characteristics,so as to provide targeted prevention and treatment strategies for local children with community-acquired pneumonia and provide more reference information for clinicians.Methods:A total of 234 children who met the diagnostic criteria of communi ty-acquired pneumonia and were hospitalized in the Department of Pedia trics,Chengde Central Hospital from June 2021 to May 2022 were sele cted as the research objects.Throat swab specimens from 234 children were tested for 8 respiratory viruses by Polymerase Chain Reaction(PC R),including: Human metapneumovirus(h MPV),human bocavirus(HBo V),adenovirus(ADV),Respiratory syncytial virus A subgroups(RSV-A),Respiratory syncytial virus B subgroups(RSV-B),influenza A virus(FluA),influenza B virus(Flu-B),human rhinovirus(HRV).A total of 143 throat swabs were randomly selected from the 234 children.PCR was u sed to detect 8 kinds of respiratory bacteria and 3 kinds of atypical ath ogens,including: Staphylococcus aureus(S.aureus),Haemophilus influenza e(Hi),Streptococcus pneumoniae(SP),Group A Streptococcus(GAS),Kleb siella Pneumoniae(K.pneumoniae),Moraxella catarrhalis(MC),Pseudomon as aeruginosa(P.aeruginosa),Escherichia coli(E.coli),M.pneumoniae(MP),C.pneumoniae(CP),Legionella pneumophila(LP)。The PCR results were recorded.The detection rate,seasonal epidem ic characteristics and regional distribution characteristics of each pathoge n were analyzed.The children were grouped according to their age,sev erity of disease,and pathological type of pneumonia.The pathogen infe ction of children in each group was statistically analyzed.Results:1.The bacterial part1.1 Detection of bacteriaA total of 143 samples were detected by PCR for 8 kinds of bacteria,and123 samples were positive,the positive rate of bacteria was 87.4%.The positive rates of S.aureus,Hi,SP,GAS and MC were 37.8%,35%,22.4%,18.2% and 18.2%,respectively.The positive rate of K.pneumoniae was 15.4%,the positive rate of Escherichia coli was 11.2%,and the positive rate of P.aeruginosa was 7.7%.1.2 Seasonal distribution characteristicsBacteria had a high detection rate in each season,and the detection rate was more than 70% in each season.The detection rate in autumn and winter was the highest,and the detection rate was 95.2% and 96.4%,respectively.The detection rate of S.aureus was higher in winter and spring.Hi,SP and E.coli had high detection rates in autumn and winter.GAS was only detected in spring and summer.K.pneumoniae had the highest detection rate in autumn(28.6%),while MC was not detected in autumn.1.3 Regional distribution characteristicsBoth urban and rural children had a high bacterial detection rate,and the bacterial detection rate was more than 86%.There was no difference in the positive rate of bacterial infection between urban and rural children,and there was no difference in the single and mixed infection rates(P>0.05).1.4 Age distribution characteristicsBacteria had a high detection rate of more than 75% in children of all ages.The highest detection rate was found in the infant group.There was no significant difference in bacterial detection rate between children of different ages(P>0.05).There was no significant difference in bacterial mixed infection among children of different ages(P>0.05).1.5 Detection of bacteria with different diseasesThe positive rate of bacteria in severe group was 86.4%,and the positive rate of bacteria in mild group was 87.9%.There was no difference in the positive rate and distribution of bacteria between the two groups(P>0.05).In the severe group,the most common bacteria were Hi(36.4%)and S.aureus(36.4%),followed by SP(29.5%),and the detection rates of Escherichia coli,Streptococcus pyogenes,K.pneumoniae and MC were all more than 10%.The detection rate of P.aeruginosa was the lowest(9.1%).In the mild group,the highest detection rate of S.aureus was 38.4%,followed by Hi(34.3%).The detection rates of Streptococcus pyogenes,K.pneumoniae,SP and MC were all more than 16%.The detection rates of P.aeruginosa and Escherichia coli were 7.1% and 10.1%,respectively.1.6 Detection of different pathological types of bacteriaThe positive rate of bacteria was 80.4% in the lobar pneumonia group and90.4% in the bronchopneumonia group.There was no significant difference in the positive rate of bacteria and mixed bacterial infection between the two groups(P>0.05).The positive rate of MC in the lobar pneumonia group and the bronchopneumonia group was 8.7% and 23.4%,respectively.The detection rate of MC in the children with lobar pneumonia was significantly lower than that in the children with bronchopneumonia(P<0.05).1.7 Mixed infectionAmong the 143 specimens,75 cases were co-infected,and the co-infection rate was 52.4%.Among them,S.aureus combined with Hi was the most common,21 cases(28%),followed by S.aureus combined with SP,18 cases(24%).S.aureus combined with MC in 16 cases(21.3%);There were 13 cases(17.3%)of SP and Hi,and the number of cases of mixed infection between other bacteria was less than 10 cases.2.The viral part2.1 Detection of virusA total of 87 out of 234 samples were positive for 8 kinds of viruses by PCR,and the positive rate of virus was 37.2%.The positive rates of Ad V,FluB,RSV-A,HBo V and h MPV were 18.8%,9.4%,8.5%,8.1% and 3.0%,respectively.The positive rate of HRV was 3.0%,the positive rate of RSV-B was 1.3%,and no Flu-A was detected.The positive rate of Ad V was the highest,which was twice as high as that of Flu-B.2.2 Seasonal distribution characteristicsAd V was detected more frequently in spring(21.3%)and summer(33.3%).The detection rates of Flu-B in spring,summer and autumn were 16%,12.5%and 14.6%,respectively,and none was detected in winter.RSV-A was detected in 1.3% of the children in spring and more than 10% in the other seasons.The highest detection rate of HBo V was in autumn(20.8%),and Hbov was detected in the other seasons.HRV was detected in all seasons,and the detection rate was less than 10%.h MPV was only detected in 7 cases,and all of them were detected in winter,with a detection rate of 8.0%.2.3 Regional distribution characteristicsThe positive rate of virus infection was 36.5% in urban children and 41.9%in rural children.There was no significant difference in the positive rate of virus infection between urban and rural children(P>0.05).The mixed infection rate of urban children was 13.3%,while there was no mixed infection in rural children.The mixed infection rate of virus in urban area was higher than that in rural area,and the difference was statistically significant(P<0.05).2.4 Age distribution characteristicsIn the 1-3 months old group,Ad V(20.4%),RSV-A(12.6%),and Flu-B(8.7%)were the most common viruses.Ad V(22.9%),Flu-B(11.5%)and HBo V(11.5%)were the most common viruses detected in children aged 3-6 years.Among children aged 6-14 years,Ad V(12.8%),Flu-B(8.6%)and HBo V(7.1%)were the most common viruses.There was no significant difference in virus coinfection among children of different ages(P>0.05).2.5 Detection of viruses in patients with different diseasesThe positive rate of virus was 31.7% in the severe group and 39.2% in the mild group.There was no significant difference in the positive rate of virus between the two groups(P<0.05).In the severe group,Ad V(12.7%)was the most common pathogen,followed by HBo V(9.5%),h MPV(6.3%),RSV-A(4.8%)and Flu-B(3.2%).FluA,HRV and RSV-B were not detected in the severe group.In the mild group,the most common pathogen was Ad V(21.1%),followed by Flu-B(11.7%),RSV-A(9.9%),HBo V(7.6%),HRV(4.1%),RSV-B(1.8%),and Flu-A was not detected in the mild group.Ad V was detected in 12.7% of the patients in the severe group and 21.1% of the patients in the mild group.There was no significant difference in the distribution of Ad V between the two groups(P>0.05).The positive rate of Flu-B in the severe group and the mild group was 3.2% and 11.7%,respectively.The positive rate of Flu-B in the mild group was significantly higher than that in the severe group(P<0.05).There was no significant difference in the distribution of other viruses between the two groups(P>0.05).There was no difference in mixed infection between the severe and mild groups(P<0.05).2.6 Detection of different pathological types of virusesThe positive rate of virus was 29.9% in lobar pneumonia group and 42.5%(57/134)in bronchopneumonia group.There was no significant difference in the positive rate of virus between the two groups(P>0.05).Ad V(10.3%),FluB(10.4%)and HBo V(6.9%)were the most common viruses in lobar pneumonia.Ad V(24.6%),Flu-B(10.0%)and RSV-A(10.4)were the most common viruses in bronchopneumonia.The Ad V positive rate in lobar pneumonia group and bronchopneumonia group was 10.3% and 24.6%,respectively.The Ad V positive rate in lobar pneumonia group was lower than that in bronchopneumonia group,and the difference was statistically significant(P<0.05).There was no significant difference in the distribution of other viruses between the two groups(P>0.05).There was no difference in mixed infection between lobar pneumonia group and bronchopneumonia group(P>0.05).2.7 Mixed infectionAmong the 234 children with community-acquired pneumonia,27(11.5%)had mixed infections,of which Ad V and Flu-B mixed infections were the most common(10 cases,37.0%),followed by Ad V and RSV-A mixed infections(8cases,29.6%).Seven cases(25.9%)were co-infected with Ad V and HBo V,while the co-infection with other viruses was rare.3.Atypical pathogens section3.1 Detection of atypical pathogensOf 143 samples tested by PCR for three atypical pathogens,93 samples were positive,and the positive rate was 65%.The positive rate of MP was 57.3%.The positive rate of CP was 10.5%.The positive rate of LP was 9.1%.MP infection plays an important role in atypical pathogen infections.3.2 Seasonal distribution characteristicsThe atypical pathogen detection rate was high in all seasons,and the detection rate was higher than 60% in all seasons.The detection rate of MP was 60% in spring,57.9% in summer,52.4% in autumn and 53.6% in winter.The detection rate of MP was higher than that of CP and LP in each season.3.3 Regional distribution characteristicsThe positive rate of atypical pathogens in urban children was 65.3%(83/127),and the positive rate of atypical pathogens in rural children was 68.75%(11/16).There was no difference in the positive rate of atypical pathogens between urban and rural children(P>0.05),and there was no difference in single and mixed infection rates(P>0.05).3.4 Age distribution characteristicsThirty-five cases of atypical pathogens were detected in children aged from1 month to 3 years,and the detection rate was 59.3%(35/59).9 cases(15.3%)had mixed infection.Atypical pathogens were detected in 25 children aged 3-6 years,with a detection rate of 59%(23/39),and 3 children(7.7%)had mixed infection.The detection rate of atypical pathogens in children aged 6-14 years was 77.8%(35/45),and 2 cases(4.4%)had mixed infection.There was no significant difference in the detection rate of atypical pathogens among children of different ages(P>0.05).There was no significant difference in the detection rate of atypical pathogens among children of different ages(P>0.05).There were differences in the mixed infection rate of atypical pathogens among different age groups(P<0.05),and the children aged 1 month to 3 years had a significantly higher mixed infection rate than the children aged 6-14 years(P<0.017).The positive rate of MP was 52.5%(31/59)in children aged 1-3 years,43.6%(17/39)in children aged 3-6 years,and 75.6%(34/45)in children aged6-14 years.There was a high detection rate of MP in all age groups,and there was a difference in the distribution of MP infection in different age groups(P<0.05).The positive rate of MP infection in the 3-6 years old group was lower than that in the 6-14 years old group(P< 0.017).There was no significant difference in the distribution of CP and LP among different age groups(P>0.05).3.5 Detection of atypical pathogens in patients with different conditions MP had a high detection rate in the severe and mild groups,and the detection rate was more than 50%.The positive rate of MP in the severe group and the mild group was 52.3% and 59.6%,respectively.There was no significant difference in the distribution of MP,CP and LP between the two groups(P>0.05).3.6 Detection of atypical pathogens of different pathological typesThe positive rate of atypical pathogens was 67.4%(31/46)in lobar pneumonia group and 63.8%(60/94)in bronchopneumonia group.There was no significant difference in the positive rate of atypical pathogens between the two groups(P>0.05).The positive rate of MP in lobar pneumonia and bronchopneumonia was 65.2% and 54.3%,respectively.There was no significant difference in the distribution of MP,CP and LP between the two groups(P>0.05).There was no significant difference in mixed infection between the lobar pneumonia group and the bronchopneumonia group(P>0.05).3.7 Mixed infectionAmong 143 children with community-acquired pneumonia,79 cases(55.2%)were infected with a single atypical pathogen,and 14 cases(9.8%)were infected with atypical pathogens.Among the 79 cases of single atypical pathogen infection,68 cases(86.1%)were MP,6.3% were CP 5,and 7.6% were LP 6.Among the 14 cases of atypical co-infection,the most common coinfection was 2 atypical pathogens(11 cases,7.7%),followed by 3 atypical pathogens(3 cases,2.1%).4.The overall part4.1 Among the 234 samples,143 samples were simultaneously detected by PCR for 8 kinds of bacteria,8 kinds of viruses and 3 kinds of atypical pathogens,and 138 cases were positive for at least one pathogen.There were 38 cases infected with only one type of pathogen(virus,bacteria,atypical pathogen),among which 31 cases were infected with bacteria alone,3 cases were infected with virus alone,and 4 cases were infected with atypical pathogen alone.One hundred children had at least two types of pathogens(virus,bacteria,atypical pathogens)infection,of which 11 children had virus and bacterial infection at the same time,and 6 children had virus and atypical pathogens infection at the same time.There were 60 children with bacterial and atypical pathogens,and23 children with three types of pathogens.4.2 There were 83 cases of atypical pathogen and bacterial infection,o f which 73 cases were mixed infection with MP and bacteria.There we re 30 cases of MP and Hi co-infection,27 cases of MP combined with S.aureus,18 cases of MP combined with K.pneumoniae,17 cases of MP combined with Streptococcus pyogenes,16 cases of MP combined with MC,and 11 cases of MP combined with P.aeruginosa.There wer e 8 cases of MP and Escherichia coli.Conclusions:1.In children with community-acquired pneumonia in Chengde area,bacteria and MP are the main pathogens,and there are often atypical p athogens and bacteria mixed infection.2.The pathogen spectrum of children with community-acquired pneu monia in Chengde has changed greatly,suggesting that we should conti nue to monitor it.The top three bacterial infections were S.aureus,Hi,and SP.Adenovirus was the most common viral infection,and MP was the main atypical pathogen.3.MP plays an important role in community acquired pneumonia in Chengde area.All age groups are susceptible to MP,and the detection rate is high in all seasons. |
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