Abstract: ObjectiveTo investigate the characteristics of antimicrobial resistance,biofilm-forming capacity,and the distribution of capsular serotype in hypermucoviscous Klebsiella pneumoniae(hmKP). MethodsA total of 40 strains of hmKP isolated from Guang-dong Provincial People's Hospital betweenJanuary and December 2024 were colected. Meanwhile，4O strains of classic Klebsiella pneumoniae (cKP) during the same period were randomly selected as controls. The antimicrobial susceptibility testing was performed using the Vitek 2 Compact system. The biofilm-forming capacity of the strains at 2 h, 4 h, and 6 h was assessed by the crystal violet staining method. The wzi gene was amplifed by PCR and sequenced for capsular genotyping. The differences in antimicrobial resistance,biofilm-forming capacity, and the distribution of capsular types between hmKP and cKP were compared. ResultsThe main sources of hmKP isolates were respiratory tract（16 strains，40.0%)，blood(10 strains，25.0%），and urine（8 strains,20.0%). hmKP isolates exhibited high susceptibility to commonly used antimicrobial agents, and no carbapenem-resistant isolates were detected. The biofilm-forming assay showed that the As4o/Aczo.mratios at 2 hours of cultivation in the hmKP group (O.18±O.10) was significantly lower than that in the cKP group （O.28±0.22,P=O.019). However, there was no statistically significant difference between the two groups at 4 and 6 hours(P>0.05).The capsular genotyping results showed that the main subtypes of hmKP were K2（14 isolates,35.0%） and K1 (12 isolates,30.0%),while the serotype distribution of cKP were relatively dispersed. The incidence of por prognosis in the hmKP group (24 cases,60.0%）was significantly higher than that in the cKP group(16 cases，40.0%，P=0.003).ConclusionhmKP remains high susceptibility to commonly used antimicrobial agents. Compared with cKP, hmKP exhibits distinct characteristics in the distribution of capsular types and early biofilm formation and is associated with a higher incidence of poor prognosis.