Molecular and Clinical Characterization of Multidrug-Resistant and Hypervirulent Klebsiella pneumoniae Strains from Liver Abscess in Taiwan

• Published in: Antimicrobial agents and chemotherapy 2020-04, Vol.64 (5)
• Main Authors: Lin, Yi-Tsung, Cheng, Yi-Hsiang, Chuang, Chien, Chou, Sheng-Hua, Liu, Wan-Hsin, Huang, Chi-Han, Yang, Tsuey-Ching, Kreiswirth, Barry N, Chen, Liang
• Format: Article
• Language: English
• Subjects: Aged; Community-Acquired Infections - microbiology; Drug Resistance, Multiple, Bacterial - genetics; Epidemiology and Surveillance; Female; Genome, Bacterial - genetics; Humans; Klebsiella Infections - drug therapy; Klebsiella pneumoniae - drug effects; Klebsiella pneumoniae - genetics; Klebsiella pneumoniae - isolation & purification; Liver Abscess - microbiology; Male; Microbial Sensitivity Tests; Middle Aged; Plasmids - genetics; Taiwan; Virulence - genetics; Whole Genome Sequencing
• ISSN: 0066-4804; 1098-6596
• DOI: 10.1128/aac.00174-20

Hypervirulent strains are the major cause of liver abscesses throughout East Asia, and these strains are usually antibiotic susceptible. Recently, multidrug-resistant and hypervirulent (MDR-HV) strains have emerged due to hypervirulent strains acquiring antimicrobial resistance determinants or the transfer of a virulence plasmid into a classic MDR strain. In this study, we characterized the clinical and microbiological properties of liver abscess (KPLA) caused by MDR-HV strains in Taiwan. Patients with community onset KPLA were retrospectively identified at Taipei Veterans General Hospital during January 2013 to May 2018. Antimicrobial resistance mechanisms, capsular types, and sequence types were determined. MDR-HV strains and their parental antimicrobial-susceptible strains further underwent whole-genome sequencing (WGS) and mice lethality tests. Thirteen MDR-HV strains were identified from a total of 218 KPLA episodes. MDR-HV strains resulted in similar outcomes to antimicrobial-susceptible strains. All MDR-HV strains were traditional hypervirulent clones carrying virulence capsular types. The major resistance mechanisms were the overexpression of efflux pumps and/or the acquisition of ESBL or AmpC β-lactamase genes. WGS revealed that two hypervirulent strains had evolved to an MDR phenotype due to mutation in the gene and the acquisition of an SHV-12-bearing plasmid, respectively. Both these MDR-HV strains retained high virulence compared to their parental strains. The spread of MDR-HV strains in the community raises significant public concerns, and measures should be taken to prevent the further acquisition of carbapenemase and other resistance genes among these strains in order to avoid the occurrence of untreatable KPLA.