Distribution of virulence genes and capsule types in Klebsiella pneumoniae among bloodstream isolates from patients with hematological malignancies

The hypervirulent Klebsiella pneumoniae (hv-K. pneumoniae) pathotype has been spreading over during the last years. We evaluated the distribution of virulence genes (iucA, rmpA or rmpA2) and capsule types in K. pneumoniae isolates. A total of 572 K. pneumoniae were evaluated; of those 114 (20%) were carbapenemase-producing K. pneumoniae (CP-K.pneumoniae); 285 (49.8%) - extended-spectrum β-lactamase-producing K. pneumoniae (ESBL-K. pneumoniae); and 173 (30.2%) - non-CP- and non-ESBL. Among CP-K. pneumoniae the prevalent sequence type was ST395 (37.7%), followed by ST23 (16.7%). A total of 138 (24.1%) hv-K. pneumoniae were detected. The rate of hv-K. pneumoniae (55.3%) was higher among CP-K. pneumoniae compared to ESBL-K. pneumoniae (17.3%) and non-CP- and non-ESBL (15.8%).The iucA and rmpA2 genes were detected in 89.5% of ST23 and 58.1% of ST395. The K57 capsule type was detected in all ST23; K2 was found in 55.8% of ST395. The hv-K. pneumoniae were common in bloodstream isolates, with a significantly higher rate among CP-K. pneumoniae. Most of them belonged to ST23/K57 and ST395/K2.