Clinical Study Of Mixed Infection In Hospitalized Children With Mycoplasma Pneumoniae Pneumonia

Objectives:To understand the mixed infection of children with Mycoplasma pneumoniae pneumonia(MPP)in Suzhou;To analyze the epidemiological characteristics,clinical characteristics and risk factors of mixed infection;To provide a clinical basis for the diagnosis and treatment of MPP mixed infection.Methods:We selected 815 inpatients from January 2015 to December 2016 in the department of respiration in Children's Hospital of Suzhou University,who are conformed to the diagnostic criteria for MPP.We test them for multiple pathogens,including the detection of sputum germiculture,sputum respiratory syncytial virus(RSV)? influenza virus A(INF-A)? influenza virus B(INF-B)? parainfluenza virus type 3~1(PIV1~3)? adenovirus(ADV)? human rhinovirus(HRV)? human bocavirus(HBo V)and human metapneumovirus(HMPV).We performed bronchoalveolar lavage for those with the indications for bronchoscopy,and carried out bacterial culture and virus detection in the lavage fluid.At the same time.We studied the clinical data of patients,such as age,sex,history and clinical symptoms,pulmonary signs,imaging findings and laboratory results.Results:(1)In 815 cases of MPP,350 cases(42.9%)had mixed infection,including 199 cases of mixed virus infection(24.4%),91 cases of mixed bacterial infection(11.2%),60 cases of mixed virus and bacterial infection(7.4%).In the formation of pathogenic factors,the most common virus infection was HRV(7.4%),HBo V(5.2%)and RSV(5.0%).The most common bacterial infection was Streptococcus pneumoniae(SP,6.5%)and Haemophilus influenzae(Hi,1.2%).(2)The MPP mixed infection was closely related to age,the younger the age is,the higher the mixed infection rate will be.And the difference was statistically significant(?2=30.01,P<0.01).In the mixed virus infection group,the rate of mixed virus infection in the group less than 3 years was significantly higher than that of those over 3 years old,and the difference was statistically significant(?2=23.897,P=0.000).(3)MPP in children of different ages have different mixed pathogens.0~1 year old group mainly mixed RSV(11.6%)?HRV(8.9%),1~3(8.4%)group mainly mixed HRV and HBo V(8.4%)? SP(7.3%),3~5(6.8%)group mainly mixed SP and RSV(5%)?HRV(4.6%),more than 5 year old group mainly mixed HRV(7.6%)?SP(5.7%).(4)MPP mixed infection is closely related to season.The mixed infection rate from high to low is autumn(48.8%)?spring(45.1%)?summer(40.5%)?winter(32.4%).The difference is statistically significant(?2=11.417,P=0.01).In the mixed virus infection group,the seasonal difference was obvious,and the mixed infection rate was the highest in autumn.The difference was statistically significant compared with the spring,summer and winter(?2=6.185,P=0.013;?2=4.687,P=0.033;?2=7.688,P=0.006).(5)815 cases of MPP were divided into single infection group(465cases),mixed virus infection group(199cases),mixed bacterial infection group(91cases)and simultaneous mixed virus and bacterial infection group(60cases).There were significant differences in age,fever time,wheezing,dyspnea,gastrointestinal symptoms,severe pneumonia and pulmonary positive signs in four groups(P < 0.05).There was no significant difference in the the course of disease before hospitalization,hospitalization time,fever proportion,heat peak and the number of high fever,whether or not combined basic disease or anaphylactic disease(P>0.05).Comparison between groups,mixed virus infection group?mixed bacterial infection group?mixed virus and bacterial infection group suggests that younger children are more likely to have dyspnea,and have more pulmonary positive signs than single infection group.The differences were statistically significant(P<0.05).The mixed virus infection group had a higher proportion of wheezing and gastrointestinal symptoms than the single infection group(?2=8.466,P=0.004;?2=12.093,P=0.001),and was more likely to have severe pneumonia(?2=7.267,P=0.007).The fever time of the mixed bacterial infection group was higher than that of the single infection group and the mixed virus infection group,and the difference was statistically significant(?2=4.944,P=0.026;?2=9.536,P=0.002).Compared with the single infection group,the fever time of the mixed virus and bacterial infection group was longer than that of the single infection group,and the proportion of wheezing was high,the difference was statistically significant(?2=5.647,P=0.017;?2=4.161,P=0.041).(6)The results of WBC?ALT and CKMB in the four groups were significantly different(P<0.05).Comparison between groups,the proportion of ALT and CKMB in the mixed viral infection group was higher than that of the single infection group,and the difference was statistically significant(?2=6.569,P=0.01;?2=6.258,P=0.012).WBC in the mixed bacterial infection group was higher than that in the single infection group,and CRP was higher than that of the mixed virus infection group.The difference was statistically significant(F=6.065,P=0.014;Z=-2.453,P=0.014).WBC and CRP values in the viral and bacterial infection group were higher than those of single infection group(F=11.035,P=0.001),and the proportion of lobar pneumonia,pleural effusion and atelectasis in chest radiograph was also higher than that of single infection group(?2=4.946,P=0.026;?2=5.382,P=0.02).(7)Multivariate logistic regression analysis showed that risk factors for MPP mixed virus infection were age and gastrointestinal symptoms.Risk factors for MPP mixed bacterial infection and simultaneous mixed virus and bacterial infection were age,fever> 10 days and the high WBC value.Conclusion:(1)There is a certain proportion of mixed infection among the MPP hospitalized children.(2)The rate of mixed infection in different age groups is different,the younger the age is,the higher the mixed infection rate will be.(3)The main mixed pathogens of MPP is the virus,followed by bacteria.The pathogens of mixed infection in children of different ages are different.The main pathogens of the mixture under 3 years of age are HRV?RSV?HBo V,and the main pathogens of the mixture over 3 years of age are SP?HRV.(4)The mixed infection of MPP has the seasonal difference.Autumn has the hingest mixed infection rate.(5)The clinical characteristics of mixed infection are related to the pathogen of mixed infection.Patients with mixed virus infection have a high proportion of wheezing and severe pneumonia.Attention should be paid to the mixed bacterial infection group with the fever more than ten days,and the WBC value was high.(6)Age,fever> 10 days,having gastrointestinal symptoms and the high WBC value are valuable in the diagnosis of early MPP mixed infection.