Virulence Factors and Molecular Epidemiology of Pyogenic Liver Abscess Causing Multidrug Resistant Klebsiella pneumoniae in Wenzhou, China
Abstract Background: To date, little is known about virulence characteristics of pyogenic liver abscess (PLA) causing multidrug resistant (MDR) Klebsiella pneumoniae (K. pneumoniae). It may be that these strains are rare. The aim of this study was to analyze the virulence characteristics and molecular epidemiology of 12 MDR strains from 163 PLA cases in a tertiary teaching hospital from the perspective of clinical characteristics, virulence phenotypes and genotypes.Results: The virulence phenotypes of the 12 PLA-causing MDR K. pneumoniae were similar or even more obvious than those of typical hypervirulent Klebsiella pneumoniae control strains according to the results of growth curves, string test, capsular quantification, serum killing test, biofilm formation assay, and infection model. These MDR strains were mainly non-K1/K2 serotypes and carried multiple virulence genes. Multilocus sequence typing (MLST) illustrated that the MDR strains were categorized into nine sequence types.Conclusions: This study is the first analysis of the virulence factors in PLA-causing MDR strains. Our data exhibited the coexistence of hypervirulence and multidrug resistance in PLA-causing MDR K. pneumoniae strains, and the clones of those PLA-causing MDR strains were diverse and scattered. The study was firstly found one ST11 carbapenem-resistant hypervirulent strain in PLA.