ABSTRACT
The aim of this paper is to study the changes in the resistance and distribution of pathogenic bacteria isolated from adult lower respiratory tract specimens from our hospital during the novel coronavirus (COVID-19) epidemic.Antimicrobial susceptibility testing is used for adult lower respiratory tract isolates from 2017 to 2022 using automated micro-broth dilution and Kirby-Bauer methods.The top six pathogens isolated in our hospital from 2017 to 2022 were A.baumannii, K.pneumoniae, P.aeruginosa and S.aureus,E.coli and S.maltophilia. The numbers of strains increased from 1041 in 2017 to 1799 in 2022, antibacterial drug resistance rates also changed. There is decline in the number of ESBLs-producing strains. The rate of isolation of carbapenem-resistant Acinetobacter baumannii (CRAB)decreased to75%、52.1%、61.5%、61.8%、36.8% and 51.6% respectively. Although the number of detected strains of K.pneumoniae increased, the isolation rate of carbapenem-resistant Klebsiella pneumoniae（CRKP）showed a decreasing trend with 12.6%、20.3%、28.3%、17.7%、9.8% and 13.8%, respectively. The Carbapenem-resistant Pseudomonas aeruginosa（CRPA）also increased from 32 strains in 2017 to 67 strains in 2022，but did not increase isolation rates, The separation rate for 2019 is 26.4% and 17.7% in 2020. The isolation rates of methicillin-resistant Staphylococcus aureus(MRSA) showed a decreasing trend during the COVID-19 epidemic, with 58.1%、41.3%、44.0%、34.1%、32.2% and 31.3%, respectively.During the COVID-19 epidemic, the spread of the pathogenic bacteria within the hospital was interrupted by measures such as reducing outings, wearing masks, nucleic acid testing , sanitary environment disinfection and blocking control. The detection rate of ESBLs, CRKP, CRAB and CRPA in adult lower respiratory tract specimens has been generally decreasing, and the detection rate of MRSA has been gradually decreasing.The rate of CRPA did not increase.