Analysis Of Clinical And Molecular Characteristics Of Hypervirulent Klebsiella Pneumoniae

Objective:To analyze the drug resistance of Hypervirulent Klebsiella pneumoniae and Classic Klebsiella pneumoniae.To explore the capsular serotyping,virulence gene and its distribution of Hypervirulent Klebsiella pneumoniae.To understand the epidemic characteristics,risk factors and types of infection of Hypervirulent Klebsiella pneumoniae.Methods:277 strains of Klebsiella pneumoniae isolated from inpatients in a Grade 3A hospital in Guizhou were collected.HvKP was screened by mucus drawing test and virulence gene test,and the proportion of HvKP and CKP strains from different sources and departments was analyzed.Case-control method was used to make a retrospective statistical analysis of patients in HvKP and CKP groups.The drug sensitivity of all strains was tested by Micro Scan Walk Away 96 plus automatic bacteria identification and drug sensitivity analysis system.Polymerase chain reaction(PCR)was used to detect 6 common capsular serotypes(K1,K2,K5,K20,K54,K57)and 9 virulence genes(rmp A,all S,kfu BC,Wca G,aerobaction,mrk D,ent B,ybt S,fim H)of Klebsiella pneumoniae.The technique of multi-locus gene sequence typing was used for molecular typing of the strains.ERIC-PCR method was used to analyze the homology of the strains.Results:A total of 227 strains of Klebsiella pneumoniae were isolated,mainly from respiratory tract(59.03%),urethra(13.65%)and blood samples(11.45%).The main departments of Klebsiella pneumoniae were found in intensive care unit(21.15%),neurosurgery(8.37%)and emergency neurology(7.49%).According to the wiredrawing test and virulence gene detection,77 strains of KP were identified as high virulent Klebsiella pneumoniae(HvKP),150 strains and Klebsiella pneumoniae CKP.Among the 77 strains of HvKP,63.64% were from respiratory tract,16.89% from blood,5.19% from hydrothorax and ascites,5.19%from hydrothorax and ascites,3.90% from urine,and 10.39% from other specimens.Retrospective analysis of the clinical data of 77 strains of HvKP and 150 strains of CKP showed that the patients with HvKP infection mainly came from hospital-acquired infection,which was significantly different from that of CKP(P <0.05).There were significant differences in diabetes mellitus,multi-site infection,lung disease,admission rate of ICU and patients with CKP in patients with HvKP infection(P < 0.05).From the laboratory WBC,CRP,neutrophils,hospitalization days,the highest body temperature,the presence of septic shock,mortality and other data.There was no difference between patients infected with HvKP and patients infected with CKP.There were significant differences in diabetes mellitus,liver abscess and invasive operation between HvKP from blood and aseptic body fluid and CKP infection(P < 0.05).The drug sensitivity test of 77 strains of HvKP and 150 strains of CKP showed that the resistance rate of HvKP to penicillins,carbapenems,cephalosporins and quinolones was significantly lower than that of CKP.HvKP-related capsular serotypes were detected.Type K1 accounted for 48.05%(37/76),type K2 24.68%(19/76),K57 type 14.29%(11/76),K20 3.90%(3/76),K545.19%(4/76),and K5 2.60%(2/76).The detection rates of virulence genes rmp A,aerobactin,ent B,ybt S,kfu BC,Wca G and all S genes were also higher than those of CKP,and almost all of all S genes existed in K1 strains.According to the multi-site sequence typing of HvKP,21 St types were found.ST23,ST65 and ST86 were the main St types.K1 mainly corresponds to ST23,K2 mainly corresponds to ST65,ST86,ST25 and ST218,K57 mainly corresponds to ST592 and ST413 HvKP,K54 mainly corresponds to ST29 HvKP.Homology analysis of HvKP showed that 18 strains belonged to type I,5 strains of II-V type,4 strains of VI-VIII type,3 strains of IX-XI type,2 strains of XII-XIV type,and the other 12 strains showed unique DNA maps.Among them,I/ST23 K1 is mainly found in ICU department.Conclusion:The detection rate of HvKP was 33.92%,mainly respiratory tract samples.The main capsular serotypes are K1,K2 and K57,and almost all of the all S gene exists in K1 strain.HvKP is easy to cause hospital-acquired infection.Diabetes,invasive operation and admission to ICU may be the risk factors of HvKP infection.HvKP can cause multi-site infection and has the ability of metastasis.HvKP is sensitive to commonly used antibiotics,and the MLST types of HvKP are mainly ST23,ST65 and ST86.By MLST typing and ERIC-PCR analysis of HvKP,it was found that I/ST23K1 was the main type of HvKP.