Etiological Study Of Community-acquired Pneumonia In Hospitalized Infants Aged From 28 Days To 3 Months

Objective: This aim of the study was to review the clinical medical records of hospitalized infants aged from 28 days to three months with community acquired pneumonia(CAP)from January 2017 to December 2017 in Shenzhen Children's Hospital.To understand the distribution of respiratory pathogens and their characteristics of CAP in the age group so as to improve provide a basis for early rational use of antibiotics.Methods: The data of in-patients CAP confirmed by chest imaging in infants from 28 days to 3 months old were collected in Shenzhen Children's Hospital from January 2017 to December 2017 and were excluded from hospital acquired pneumonia and CAP with underlying diseases.To develop a collection form,transfer medical records,collect symptoms and signs of hospitalization,laboratory and auxiliary examination and summarize the basic distribution of various pathogens.The clinical characteristics of the top two pathogen cases were analyzed.A group control study was conducted among the top two pathogens related singly-detected infection cases and co-infection cases.To conduct a group control study of the top four pathogens and analyze clinical characteristics and laboratory data of the four pathogens.Results:449 cases(54.4%)detected in 825 babies,and 376 cases(45.6%)were not detected.Chlamydia trachomatis(CT)23.6%(106/449),Respiratory syncytial virus(RSV)23.4%(105/449),Haemophilus influenzae 20.7%(93/449),Moraxella catarrhalis 16.7%(75/449),Staphylococcus aureus 13.8%(62/449),Streptococcus pneumoniae 10.0%(45/449),Influenza virus 6.5%(29/449),Mycoplasma pneumoniae 6.2%(28/449)and Bordetella pertussis 3.8%(17/449)were the top nine pathogens.In the 449 cases with detected pathogens,131 cases(29.2%,131/449)were detected more than two pathogens,with a maximum of co-detected of bacteria and virus in 40 cases(40/131),followed by co-detected of bacteria and bacteria in 34 cases(34/131).Among the 131 babies,thepositive rate of bacteria was 90.8%(119 cases),followed RSV(33.6%),CT(29.8%).The fever rate of CT singly-detected pneumonia was 7.5%(5/67),which was significantly lower than that of RSV singly-detected infection(29.5%),Haemophilus influenzae infection(35.2%)and Moraxella catarrhalis infection(18.9%).There was no significant difference in the proportion of fever,the proportion of WBC,and the number of hospital stays and so on in patients with CT singly-detected pneumonia group(67 cases)and CT with bacteria co-detected pneumonia group(32 cases).There was no significant difference in the proportion of the proportion of fever,the proportion of WBC and so on in patients with RSV singly-detected pneumonia group(61 cases)and RSV with bacteria co-detected pneumonia group(38 cases).The length of hospital stay in RSV with bacteria co-detected pneumonia group was longer than that in RSV singly-detected pneumonia group(6d vs 5d).Conclusion:1.The detection rate of respiratory tract pathogens in CAP between infants from 28 days to 3 months in Shenzhen is 54.4%,the pathogens are CT,RSV,Haemophilus influenzae,Moraxella catarrhalis,Staphylococcus aureus,Streptococcus pneumoniae and so on.2.CT and RSV are the main pathogens of CAP in infants from 28 days to 3 months in Shenzhen.The positive detection of co-infection of bacteria may be colonization or carrying rather than infectious pathogens.There is sufficient basis for the early empirical use of macrolide antibiotics in infants of CAP in this age group.