Abstract: OBJECTIVE To study the capsular serotypes and virulence genes of hypermucoviscous Klebsiella pneumoniae(HMVKP) and classical K.pneumoniae(CKP), and to further analyze the drug sensitivity and drug resistance phenotype of HMVKP and CKP.HT5"HMETHODSHT5"SSA total of 185 strains of K.pneumoniae by bloodstream infections were collected from January 2013 to December 2016.HMVKP was determined by string-test.PCR method was used to amplify capsular serotypes and virulence genes, and the detection rates of HMVKP and CKP were analyzed.Meanwhile, antimicrobial susceptibility was also detected and analyzed; extended-spectrum β-lactamase was measured by in vitro disk method; in addition, carbapenem phenotype was detected by modified Hodge test and EDTA test.HT5"HRESULTSHT5"SSHypermucoviscous K.pneumoniae accounted for 23.2% (43/185) of the total strain.All six high virulent capsular serotypes were detected, including K1 (9.2%), K2 (11.4%), K5 (1.6%), K20 (2.2%), K54 (1.6%) and K57 (6.5%), with 32.4%(60/185) in total. The detection rate of virulence genes of HMVKP was higher than that of CKP, the toxicity (P50) of HMVKP and CKP were 7 and 4, respectively, showing difference ( P＜0.05).Furthermore, drug sensitivity of HMVKP was significantly better than that of CKP ( P＜0.05).There were 3 strains (7.0%) of HMVKP producing extended-spectrum β-lactamase, 1 strain (2.3%) of HMVKP indicated positive by modified Hodge test.HT5"HCONCLUSIONHT5"SSHypermucoviscous K.pneumoniaeare common in K1, K2 and K57 serotypes, and may carry more virulence factors, most of which are non-ESBL producing sensitive strains.However, the emergence of drug-resistant strains can't be ignored.