Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
Institute of Emergency and Critical Care Medicine, National Yang-Ming University, Taipei, Taiwan.
Antimicrob Agents Chemother. 2020 Apr 21;64(5). 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.
产毒能力超强的菌株是东亚地区肝脓肿的主要病因，此类菌株通常对抗生素敏感。最近，由于产毒能力超强的菌株获得了抗微生物药物耐药决定因子，或毒力质粒转移至经典的多重耐药（MDR）菌株，出现了多重耐药-产毒能力超强（MDR-HV）菌株。本研究对台湾产毒能力超强的 MDR-HV 菌株引起的肝脓肿（KPLA）的临床和微生物学特征进行了描述。我们回顾性地确定了 2013 年 1 月至 2018 年 5 月期间台北荣民总医院社区发病型 KPLA 患者。确定了抗微生物药物耐药机制、荚膜型和序列型。MDR-HV 菌株及其亲代抗菌敏感菌株进一步进行了全基因组测序（WGS）和小鼠致死性试验。从总共 218 例 KPLA 发作中鉴定出 13 株 MDR-HV 菌株。MDR-HV 菌株与抗菌敏感菌株的结果相似。所有 MDR-HV 菌株均为携带毒力荚膜型的传统产毒超强克隆。主要耐药机制为外排泵过度表达和/或获得 ESBL 或 AmpCβ-内酰胺酶基因。WGS 显示，由于 基因的突变和携带 SHV-12 的质粒的获得，两个产毒超强菌株分别进化为 MDR 表型。与亲代菌株相比，这两种 MDR-HV 菌株仍保持高毒力。MDR-HV 菌株在社区中的传播引起了公众的极大关注，应采取措施防止这些菌株进一步获得碳青霉烯酶和其他耐药基因，以避免发生无法治疗的 KPLA。
