rcsB enhances drug resistance of Klebsiella pneumoniae ATCC43816 by regulating the formation of its capsule

Objective To analyze the composition and drug resistance characteristics of clinical isolates from a tertiary general hospital of Lianyungang in 2021, and to explore the possible regulatory mechanism of drug resistance of Klebsiella pneumoniae. Methods The clinical samples submitted in 2021 were collected for bacterial culture, identification and drug sensitivity test, and the distribution and drug resistance of the isolated pathogens were analyzed. The biological characteristics of highly virulent Klebsiella pneumoniae ATCC43816 and its rcsB deletion strains were compared by growth curve test, viscosity semi quantitative test, uronic acid quantitative test and drug sensitivity test. Results A total of 1,077 strains of pathogenic bacteria were isolated, and the top 3 pathogens were Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa (23.96%, 17.46%, 11.23%). Klebsiella pneumoniae had high resistance rates to cefazolin, ampicillin/sulbactam and cefuroxime. Compared with the wild strain, the MIC values of imipenem, ampicillin/sulbactam and tegacyclin in ΔrcsB was decreased. Conclusion Klebsiella pneumoniae should be the focus of bacterial drug resistance monitoring in order to guide early anti-infection treatment. rcsB may indirectly regulate the drug resistance of Klebsiella pneumoniae by regulating the amount of capsule formation, which is of great significance for improving the drug resistance status of Klebsiella pneumoniae.