Abstract: Background: Chinese ISPED (Infectious Disease Surveillance of Pediatrics) was established in 2015. The data of antibiotics resistance were collected from each member hospital and summarized every year to monitor the bacterial drug resistance among Chinese children. Objective: This study aimed to investigate the antimicrobial resistance profiles of pathogens in Chinese children and guide the reasonable use of antibiotics. Design: This is a crosssectional survey. Every member hospital was required to perform the standard procedure of bacterial culture, identification and antimicrobial susceptibility test and to report the isolated strains and drugresistant bacteria. All data were analyzed to reflect the current bacterial infection and drug resistance among children in mainland China. Methods: Clinical isolates were collected from 11 tertiary children's hospitals in China from January 1st to December 31st in 2020. Antimicrobial susceptibility testing was carried out according to a unified protocol using KirbyBauer method or automated systems. Penicillin susceptibility of streptococcus pneumonia was detected by Etest. All of the antimicrobial susceptibility testing results were interpreted according to the criteria of Clinical and Laboratory Standards Institute(2020). Main outcome measures: The distribution of bacteria strains and the changes of bacteria drug resistance in pediatrics, especially the multidrugresistant organisms(MDRO) among pediatric patients. Results: A total of 42,786 isolates were collected, of which 38.5% was grampositive organisms and 61.5% was gramnegative organisms. Top five pathogens were Escherichia coli (16.4%), Straphylococcus aureus(12.6%), Streptococcus pneumonia (9.8%), Coagulase negative staphylococci (7.3%) and Klebsiella pneunoniae (7.0%). Top three pathogens in the neonatal group were Staphylococcus aureus (19.3%), Escherichia coli (18.6%) and Klebsiella pneumoniae (13.2%) and top three pathogens in the nonneonatal group were Escherichia coli (16.2%), Staphylococcus aureus (11.7%) and Streptococcus pneumoniae (11.2%). The proportion of respiratory specimens decreased from 53.9% in 2019 to 45.2% in 2020. Most MDROs presented highlevel drug resistance to various antibiotics. The prevalence of Carbapenen Resistant Enterobacteriaceae (CRE) , Pseudomonas aeruginosa (CRPA) , and Acinetobacter baumannii (CRAB) was 4.9%, 9.5% and 33.5% respectively. The prevalence of CRPA was higher in the neonatal group than that in the nonneonatal group (19.4% vs 9.2%) and CRAB was just the opposite (14.8% vs 37.1%). The detection rates of MethicillinResistant Staphylococcus aureus (MRSA) and Coagulase negative staphylococci (MRCNS) were 31.5% and 75.9% respectively. Conclusion: Both the detection rates of MDROs and their antimicrobial resistance in children were decreased in 2020.

Key words: Bacteria, Antimicrobial resistance, Children, Infectious Disease Surveillance of Pediatrics, 2020