Hypervirulent Klebsiella pneumoniae Infections in Vancouver, Canada: A Clinical, Microbiological, and Genetic Retrospective Investigation.

BACKGROUND

Hypervirulent Klebsiella pneumoniae (hvKp) is poorly characterized in North America and likely underrecognized. We evaluated a molecular screening approach for hvKp and described the clinical, microbiological, and genomic characteristics of hvKp isolates in Vancouver, Canada.

METHOD: We conducted a retrospective study of sterile-site Kp isolates recovered at a tertiary care center (2018-2024). Archived isolates were screened using polymerase chain reaction (PCR) targeting peg-344 and iucA. Whole-genome sequencing was then performed, with hvKp defined as a Kleborate virulence score of ≥3. Clinical data were obtained through chart review. Genomic relatedness was assessed using reference-based multilocus sequence typing.

RESULTS

Among 449 isolates, 43 were PCR positive for peg-344 and/or iucA, and 38 met criteria for hvKp. Only 5 (13%) cases were suspected at the time of isolation. The molecular screen demonstrated 100% sensitivity and 98.8% specificity for hvKp detection. Compared with classical Kp, hvKp infection was independently associated with travel history (adjusted odds ratio [aOR], 9.73; 95% CI, 2.06-46.04) and residence in Vancouver's Downtown Eastside (DTES; aOR, 3.69; 95% CI, 1.05-12.97), but not with Indo-Pacific country of origin (aOR, 1.77; 95% CI, .49-6.37). Genomic analysis suggested possible local transmission between 2 DTES patients. K1/K2 were the most common capsular serotypes. One ST15 hvKp isolate carried bla NDM, representing a convergent hypervirulent and carbapenem-resistant strain.

CONCLUSIONS

Routine molecular screening improved detection of hvKp and revealed evolving epidemiology, including possible clonal transmission. Implementing laboratory-based molecular screening can enhance clinical recognition, guide evaluation for metastatic complications, and monitor the emergence of high-risk strains.