A case of NDM-carbapenemase-producing hypervirulent Klebsiella pneumoniae sequence type 23 from the UK.

Introduction: Hypervirulent capsular type K1 Klebsiella pneumoniae strains of clonal complex 23 (CC23) are associated with severe community-acquired pyogenic liver abscesses, often complicated by metastatic infections and significant mortality. The majority of hypervirulent strains reported are susceptible to most antibiotics except ampicillin. To the best of our knowledge, this is the first case of New Delhi metallo-β-lactamase ( bla NDM )-producing hypervirulent K. pneumoniae from the UK.

Case presentation: We present a case of pyogenic liver abscess in a 63-year-old female of Bangladeshi origin, with a recent diagnosis of pancreatic cancer. The patient was treated with piperacillin/tazobactam and blood cultures grew a fully susceptible Escherichia coli. Despite antimicrobial therapy and drainage of the abscess, the patient continued to deteriorate and died on day seven of admission. The fluid drained from the liver abscess grew a fully susceptible E. coli and a multi-drug-resistant K. pneumoniae . Two weeks prior to admission, a rectal screening swab grew a metallo-β-lactamase-producing K. pneumoniae . Molecular characterization revealed that both the K. pneumoniae isolates belonged to the hypervirulent K1 cluster of CC23, sequence type 23. The isolate from the rectal screen was positive for the bla NDM metallo-β-lactamase gene.

Conclusion: The emergence of carbapenemase-producing hypervirulent K. pneumoniae strains presents a new and significant threat to global public health. Management of these infections will be extremely challenging due to the limited treatment options available and they are likely to be associated with an even greater mortality.