Abstract:

Objective To understand the serotype，multilocus sequence typing（MLST） typing，drug resistance and virulence gene carriage of Klebsiella pneumoniae in respiratory syndrome in Chengde City in 2024，so as to provide a reference for the prevention，control，and treatment of Klebsiella pneumoniae in Chengde City. Methods A total of 166 respiratory syndrome specimens were collected from Chengde Medical University Affiliated Hospital，Chengde Central Hospital，Chengde Maternal and Child Health Hospital and Chengde County Hospital in 2024. Klebsiella pneumoniae was isolated，cultured and identified. The serotype of the isolated pure bacteria was determined by polymerase chain reaction（PCR），the drug resistance phenotype was determined by drug sensitivity test，the MLST typing and the carriage of drug resistance genes and virulence genes were determined by whole genome sequencing. Results The isolation rate of Klebsiella pneumoniaein respiratory syndrome in Chengde in 2024 was 4.8%. A total of 8 strains of Klebsiella pneumoniae were isolated in this study，among which 4 strains（50%） were K1 serotype，and the other 4 strains were other serotypes. A total of 7 sequence type（ST） types were detected（11，6 908，1 266，23，4 081，152，116），and ST11 was the relatively dominant type. A total of 11 drug resistance genes were carried，among which the carriage rate of sulbactam-hydrolyzing gene 11（SHV-11） was the highest（75%）. It was worth noting that 2 strains carried the Klebsiella pneumoniae carbapenemase gene 2（KPC-2） gene. The drug sensitivity test showed that the resistance rate to ampicillin（62.5%） was the highest，followed by cefotaxime，ceftazidime and ciprofloxacin. All were sensitive to polymyxin E，ceftazidime/avibactam and tigecycline. The carriage rate of the Yersiniabactin（ybt）iron carrier gene was the highest（62.5%），and strain No. 4 carried all 4 detected virulence genes simultaneously，namely regulator of mucoidy protein A2（rmpA2），ybt，Aerobactin，Salmochelin. Conclusion The detection rate and drug resistance of Klebsiella pneumoniae in respiratory syndrome in Chengde in 2024 are relatively low，but there are diverse ST types and drug resistance genes and virulence genes that are easy to spread. In the future monitoring process，more attention should be paid to Klebsiella pneumoniae，while continuing to strengthen the monitoring of rational use of antibiotics and hospital infection control work，in order to reduce the generation and clonal spread of drug-resistant and highly virulent strains，and avoid the outbreak and spread of large-scale epidemics.

Key words: Klebsiella pneumoniae, Serotyping, Multilocus sequence typing, Drug resistance, Virulence gene, Whole genome sequencing