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Hypervirulent Klebsiella pneumoniae (hvKp) raised concern worldwide. We studied 22 hvKp clinical invasive isolates referred to the Belgian national reference laboratory between 2014 and 2020. Sixty-four percent of the isolates expressed K2 capsular serotype and belonged to 7 different MLST lineages, while 32% expressed K1 (all belonging to ST23) and were associated with liver abscesses. Primary extra-hepatic infections were reported in 36% and sepsis for 95% of the patients with 30% of deaths. Improved clinical and microbiological diagnostics are required as hvKp may represent an underestimated cause of community-acquired invasive infections in Belgium.

As the presence of hypervirulent Klebsiella pneumoniae (hvKP) has not been studied in the United Arab Emirates (UAE), the aim was to determine its rate among bloodstream isolates collected in a tertiary care hospital during two years. K. pneumoniae blood isolates of 125 individual patients from Tawam Hospital, Al Ain in 2014-2015 were investigated. Clinical data on patients’ demographics and underlying medical conditions were collected. Speciation was carried out by VITEK 2, antimicrobial susceptibility was determined by disc diffusion, and for colistin by microdilution. Hypermucoviscosity was assessed by string test. Genetic markers of hypervirulence (iucA, rmpA, rmpA2), K1 and K2 serotype-specific alleles, and carbapenemase genes were detected by PCR. HvKP isolates were compared by PFGE and by MLST and the localization of rmpA was confirmed by hybridization. Fischer’s exact test was used to calculate correlations between categorical variables. Of the 125 isolates 13 (10.4%) iucA and rmpA/rmpA2 positive strains were identified and were considered hvKP. Eight of them were string test positive. They were distributed among CC23 - serotype K1 (6, PFGE similarity >80%), ST65 – K2 (1), ST380 – K2 (2), ST86 – K2 (1), ST36 (1), and ST714 (2), respectively. While the majority of them were susceptible to most antibiotics tested, one K. pneumoniae ST23 was multi-drug resistant and produced a new allele of VIM carbapenemase. hvKP strains were more likely to be isolated from diabetic than from non-diabetic patients (P=0.001) and from patients who have not received prior antimicrobial therapy (P=0.0208). A further 11 iucA positive isolates were rmpA/rmpA2 and string test negative. Ten of these strains produced OXA-232 carbapenemase and were extremely drug-resistant (XDR). These isolates belonged to K. pneumoniae ST231. The results surmise that while members of this latter, the carbapenem-resistan