Virulence gene detection and homology analysis of Klebsiella pneumoniae inducing liver abscess

Objective To investigate the serotype and virulence genes of Klebsiella pneumoniae capsule for in-hospital liver abscess, as well as the homology of these strains.Methods A total of 26 non-repetitive strains of Klebsiella pneumoniae isolated from the patients with liver abscess in The First Affiliated Hospital of Jiamusi University from October 2018 to October 2019 were collected. These strains were identified to be Klebsiella pneumonia by Vitek-2 Compact automatic microbiological analyzer. The string test was performed for these strains; PCR was used to determine the major capsular serotypes and related virulence genes; multi-locus sequence typing was used to analyze the homology of the strains. The Fisher's exact test was used for comparison of categorical data between groups.Results The positive rate of all 26 strains of Klebsiella pneumoniae was 100% in the string test, with 17 strains of K1 type,5 strains of K2 type,1 strain of K5 type,1 strain of K57 type,and 2 strains with unknown serotype. The virulence genes rmpA, aero, and ureA had a positive rate of 100%(26/26); uge and mrkD had a positive rate of 96.2%(25/26); fimH had a positive rate of 80.8%(21/26); iucB had a positive rate of 73.1%(19/26); wcaG, magA,and kfu had a positive rate of 65.4%(17/26); allS had a positive rate of 61.5%(16/26); kpn had a positive rate of 30.8%(8/26); iroNB had a positive rate of 7.7%(2/26). The cf29 a gene was not detected; wcaG, magA, and allS were only detected in K1 serotype; uge was not detected in K57 serotype. Multi-locus sequence typing found 17 trains with ST23 type, 3 strains with ST86 type, 2 strains with ST65 type, 2 strains with ST1934 type,1 strain with ST485 type, and 1 strain with ST592 type.Conclusion K1 and K2 serotypes are the main serotypes in the strains in this experiment, and ST23 type is the main sequence type for infection in our hospital.