Temporal Shifts in Etiological Agents and Trends in Antimicrobial Resistance of Bloodstream Infection in Southwest China from 2016 to 2023

Shanshan Long,* Min Zhong,* Xiangning Huang, Jie Zhang, Xin Liu, Hua Yu Department of Laboratory Medicine, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 610072, People’s Republic of China*These authors contributed equally to this workCorrespondence: Hua Yu, Department of Laboratory Medicine, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Department of Clinical Laboratory, No. 32, West Second Section, 1st Ring Road, Chengdu, Sichuan, 610072, People’s Republic of China, Email [email protected]: The purpose of this study was to assess the frequency distribution of bacterial pathogens causing bloodstream infections (BSIs) as well as the characteristics of antibiotic susceptibility and resistance to gain a deeper understanding of the drug resistance situation in the southwest China.Methods: Non-duplicate pathogenic bacteria according to the American Clinical and Laboratory Standards Institute (CLSI) M100 and analyzed using WHONET 5.6 software.Results: A total of 170,246 non-duplicated pathogenic bacteria were isolated from blood from 2016 to 2023. Gram-negative bacteria accounted for 59.5% and Gram-positive bacteria accounted for 40.5%. The top five detection rates were Escherichia coli (33.9%), coagulase-negative staphylococci (21.7%), Klebsiella pneumoniae (11.5%), Staphylococcus aureus (7.0%), and Enterococcus spp (5.4%). Streptococcus pneumoniae, Salmonella spp and β-Hemolytic Streptococcus were significantly more frequently isolated in pediatric patients than in adult patients. The rate of resistance to carbapenems was less than 1.2% in the Escherichia coli over the 8-year period, with a significant upward trend in the Klebsiella pneumoniae. The overall resistance rate of Pseudomonas aeruginosa to imipenem and meropenem had a slow decreasing trend. The resistance rate of Acinetobacter baumannii to imipenem and meropenem has been maintained at a high level, which is greater than 50%. The detection rate of MRSA was 27.70% and vancomycin- and linezolid-resistant strains were not found. The resistance rates of Enterococcus faecium and Enterococcus faecalis to vancomycin, linezolid and teicoplanin were less than 2.1%.Conclusion: The pathogenic bacteria of bloodstream infection in southwest China were diversified, and the multi-drug resistant bacteria, especially Carbapenem-resistant Klebsiella pneumoniae (CRKP), had increased significantly, posing a serious challenge to clinical treatment. Additionally, the situation of Methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant Enterococcus (VRE) also required close attention.Keywords: bloodstream infections, bacterial resistance surveillance, multidrug-resistant bacteria, change of drug-resistant rate