Virulence,Antimicrobial Resistance,and Epidemiology Of Klebsiella Pneumoniae Isolated From Blood Cultures

Objective To evaluate the antibiotic resistance,virulence and epidemiology features of Klebsiella pneumoniae isolated from blood cultures.Provide reference for preventing and controlling bloodstream infection caused by Klebsiella pneumoniae.Methods 1.Klebsiella pneumoniae isolated from blood cultures in our hospital during October 2016 to March 2018 were collected continuously.The antimicrobial susceptibility test were carried out by VITEK-2 Compact automatic microbiological assay system and disk diffusion.2.The ability of biofilm formation was measured using crystal violet stain method.3.String tests were performed to determine HMKP.The capsular serotypes were confirmed by wzi sequencing.The virulence genes were identified by PCR and DNA sequencing.4.MLST was used to determine sequence type of these isolates,and the clinical records were collected to analyze the characteristics of molecular epidemiology of Klebsiella pneumoniae isolated from blood cultures.Results 1.A total of 80 strains isolated from blood cultures were collcted from October 2016 to March 2018,47 of these strains were CRKP.Among 33 non-CRKP strains,17 out of them were ESBL-producing strains.2.A total of 59 isolates had the ability to form biofilm.There are no correlation between antibiotic resistance and the ability of biofilm formation.3.9 HMKP were detected by string test.According to the criterion of hvKP,10 hvKP were screened.There were 6 capsular serotype K1,3 K2,and 1 K16 among 10 hvKP.4.The dominant capsular serotype of these isolates was K14.K64.Significant difference was found between hvKP and cKP in detection rate of magA?iucA?iutA?iroN?kfu?rmpA2?allS?wcaG?pLVPK?silS and terW genes.5.MLST revealed that ST11 was the major type,most of the K14.K64 belonged to ST11,K1 to ST23 and K2 to ST380.6.The Klebsiella pneumoniae was the most prevalence in pediatric intensive care unit.Hospital-acquired infection,antibiotics exposure and invasive procedures might be the risk factors for CRKP bacteremia.Conclusion 1.The resistance of Klebsiella pneumoniae isolated from blood cultures to clinical used antibiotics was serious.There are no correlation between antibiotic resistance and the ability of biofilm formation.2.The hvKP detected in blood cultures were associated with capsular serotypes,aerobactin,salmonellin and virulence plasmid pLVPK.3.Blooodstream infections caused by CRKP were mainly acquired from hospital.Rational use of antimicrobial agents,reducing invasive procedures might be helpful to prevent and control bloodstream infection caused by CRKP.