Abstract: Objective　To analyze the main pathogen types and clinical characteristics of lobar pneumonia in children. Methods　Clinical data of 149 hospitalized children of lobar pneumonia who performed bronchoalveolar lavage fluid (BALF) collecting in March 2015 to March 2019 were collected. Fluorescence quantitative PCR (FQ - PCR) is used to detect pathogens in BALF, and enzyme-linked immunosorbent (assay) was used to detect serum Mycoplasma pneumoniae (MP) antibody specificity (MP - IgM). Clinical pulmonary infection score (CPIS) difference between the two kinds of detection methods, different ages group, the MP pneumonia and non-MP pneumonia, mixed infection and single infection were compared. Results There were 129 cases with positive pathogen, among which 71 were male (55.0%), 58 were female (45.0%), 18 were 1-3 years old (14.0%), 40 were ~6 years old (31.0%), and 71 were ~14 years old (55.0%). There are 107 cases of MP, 18 cases of Streptococcus pneumoniae (SP), 12 cases of adenovirus (ADV), 6 cases of Haemophilus influenzae (HI), 3 cases of Klebsiella pneumoniae (KP), 3 cases of respiratory syncytial virus (RSV) and 2 cases of Chlamydia pneumoniae (CP).There were 23 cases of mixed infection, most of which were MP and SP. There were 10 cases of bacterial and viral infection in the 1-3 year old group, accounting for 55.6% of the positive cases in the same age group. There were 99 cases of MP infection above 3 years old, accounting for 92.5% of the MPpositive cases. In 107 cases of MP infection, the positive rate of MP in BALF detected by FQ-PCR was higher than that in the serum of MP-IgM, with significant difference (P< 0.05). Compared with non-MP pneumonia, MP pneumonia was more prone to pleural effusion, abnormal liver function and nervous system involvement (P< 0.05). The difference between mixed infection and single infection in CPIS ≥ 6 was significant (P< 0.05). Conclusions　The detection rate of MP in children with lobar pneumonia is the highest, followed by SP and ADV. The pathogens of infection are different in different age groups. Mixed infections are more likely to be severe or difficult to be treated.

Key words: Child;　lobar pneumonia;　Bronchoalveolar lavage fluid;　Pathogen