Objective: To explore the infection characteristics and antibiotic resistance of Moraxella catarrhalis in lower respiratory tract infection specimens from children in Chengdu

and to provide a reference for clinical diagnosis and rational use of antibiotics. Methods: The sputum samples of 15

891 children aged 0-14 with lower respiratory tract infection admitted to the Department of Pediatrics of Sichuan Provincical Orthopedic Hospital and Chengdu Women’s and Children’s Central Hospital of Sichuan Province from February 2018 and January 2020 were collected

and the identification of Moraxella catarrhalis and their drug susceptibility were determined. Results: A total of 3

333 strains of Moraxella catarrhalis were detected in 15

891 children’s sputum samples

and the isolating rate was 20. 97%. The gender of children infected with Moraxella catarrhalis was not statistically significant (P > 0. 05); the isolating rate was the highest in children aged >1 to 3

and the lowest was in the age group ≤28 d. The isolating rate of Moraxella catarrhalis in different seasons had statistically significant differences (P<0. 05)

with the highest isolating rate in winter and the lowest in summer. The beta-lactamase positive rate of Moraxella catarrhalis was 98. 47%

and the susceptibility to amoxicillin/ clavulanic acid

cefotaxime

ofloxacin

tetracycline

chloramphenicol

and rifampicin were all more than 90%. Conclusion: Children aged 1 to 6 are susceptible to Moraxella catarrhalis in winter

and the detection rate of pneumonia is usually highest

and the beta-lactamase positive rate of Moraxella catarrhalis reaches 98. 47%. Amoxicillin/ clavulanic acid and cefotaxime can be used as the first choice for treatment. In order to control the infection better

clinicians can refer to the characteristics and antibiotic resistance when taking the diagnosis and treatment for patients.