Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Virulence factors and molecular characteristics of hypermucoviscous Klebsiella pneumoniae strains isolated from patients with invasive infection.

Abstract

OBJECTIVE: To investigate the drug susceptibility rates, virulence factors and molecular characteristics of hypermucoviscous Klebsiella pneumoniae (HMKP) strains and non-hypermucoviscous K. pneumoniae strains causing invasive infections. METHODS: From Nov 2016 to May 2018, totally 112 strains of K. pneumoniae that were isolated from patients with invasive infection were chosen as the test strains, the HMKP strains were identified based on the positive string test, the phenotypes of extended-spectrumβ-lactamases (ESBLs) in the K. pneumoniae strains were confirmed by using disk method, the capsular serotypes and virulence genes were detected by means of polymerase-chain-reaction (PCR), Chromeazurol S (CAS) plat assay was conducted to determine whether the K. pneumoniae strains could produce siderophore, and the homology of the K. pneumoniae strains was analyzed by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). RESULTS: Of the 112 strains of repetitive K. pneumoniae, 47 were HMKP, with the isolation rate 41.96%; the isolation rate of the HMKP strains was 52.17% (12/23) in pus specimens. The drug resistance rate of the HMKP strains was lower than that of the nonHMKP strains, and there were 5 (10.64%) strains of ESBLs-producing HMKP.K1 was the predominant capsular serotype, the detection rate of virulence genes was higher in the HMKP strains than in the non-HMKP strains, and the siderophore was found to be consistent with the aerobaction gene. ERIC-PCR fingerprint showed that the HMKP was grouped into 27 genotypes. CONCLUSION: The isolation rate of HMKP strains is high among the patients with invasive infections, the strains carry with multiple virulence genes, the multidrug-resistant strains have emerged, and it is necessary for the hospital to attach great importance and take effective measures to curb the spread.