Analysis Of Clinical And Molecular Characteristics Of Hypervirulent Klebsiella Pneumoniae

PURPOSE Clinic and molecular characteristics of hypervirulent Klebsiella pneumoniae(HvKP)were analyzed to provide references for clinical diagnosis and therapy on the associated infections.METHODS A total of 211 clinical KP strains were isolated and identified from Sichuan Province People Hospital from Oct 2014 to Oct 2015.Clinical information of the strains and patients was collected for statistical analysis,while the antibiotic susceptibility testing was carried out to evaluate the drug resistance.DNA of all strains was extracted for PCR amplification that can verify the capsular serotypes and the strains carrying regulator of mucoid phenotype gene A(rmpA)and aerobactin.HvKP strains were identified using the string test.Statistical analysis was performed using SPSS 23.0 software.RESULTS Sixty-six strains(31.3%)were identified as HvKP by string tests.Among these strains,the most common isolation sites were respiratory tract(82.2%)and abdominal digestive system(8.9%).The rate of community-acquired infections cause by HvKP was 60.6%(40/66),significantly higher than the rate of 50.3%(65/145)that caused by classical KP(cKP)(P<0.05).Leucocyte count from patients infected by HvKP was 10.00±5.67×109/L,and the ratio of neutrophile granulocyte was 0.81±0.40,higher than the 9.50±3.42×109/L of leucocyte count and 0.81±0.40 of neutrophile granulocyte ratio from the patients infected by cKP.Compared with the cKP,the 66 HvKP strains were sensitive to the most of antibiotics,but had the decreased sensitivity of piperacillin and cefazolin,with a ratio of 65.2% and 81.8%,respectively.Five HvKP strains produced ESBLs and one strain was resistant to carbapenems.In 66 Hv KP clinical isolates,the strain number of K1,K2,K5,K57,K20,K54 and unidentified type were 23,16,2,15,3,1 and 15 respectively.Among which K1 and K2 strain accounted for 74.24%.In 145 cKP strains,the number of K1,K2,K5,K57,K20,K54 and unidentified type were 8,2,5,3,1,2 and 124 respectively.The carry rates of virulence gene rmpA and aerobactin in HvKP strains were 68.18% and 71.21%.However,the rates in cKP strains were 4.13% and 25.52%.There was a significant difference between these two groups(P <0.05).Conclusions HvKP strain is prevalent in patients with community-acquired infections.The strains are sensitive to majoraity of antibiotics used commonly in clinic,however,the sensitivity of ESBL and KPC in HvKP are on the decline.Clinical isolates of HvKP are mainly K1 and K2 strains,which have a high carrier rate of virulence gene rmpA and aerobactin.The situation may be related to the virulence of the strains.