Investigation of clonal relationship in Klebsiella pneumoniae strains grown in invasive specimens obtained from intensive care units

Abstract

Introduction: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a bacterium in "critical" category on the World Health Organization's list of "priority pathogens". The aim of our study is to identify the carbapenem resistance genes of K. pneumoniae isolates obtained from blood and cerebrospinal fluid samples sent from the intensive care units of our hospital and to investigate the clonal relationship among them.

Methodology: K. pneumoniae strains isolated from blood and CSF samples routinely collected from the intensive care units of our hospital over a two-year period were included in the study. Carbapenemase screening of CRKP strains was performed using Carba NP and CIM tests. Additionally, carbapenemase resistance genes (bla_KPC, bla_NDM, bla_VIM, bla_IMP, and bla_OXA-48) and clone analysis were performed using AP-PCR on these strains.

Results: A total of 186 strains with reduced susceptibility to at least one carbapenem were detected. In carbapenemase screening, the sensitivity of the CIM test was 98.3% (169/172), specificity was 7.1% (1/14); the sensitivity of Carba NP was 90.7% (156/172), specificity was 78.6% (11/14). 83.9% of the strains were bla_OXA-48, 4.8% bla_NDM, and 3.8% bla_KPC positive. bla_IMP and bla_VIM resistance genes were not detected. One hundred and eighty-six K. pneumoniae isolates were identified with 62 different genotypes, and isolates showing clustering were grouped into 30 different clusters. The clustering rate of these isolates was 82.8%.

Conclusions: Resistant bacteria can cause small outbreaks in ICUs. Therefore, to identify high-risk clones and prevent further spread, there is a need to increase capacity to support outbreak investigations and surveillance with real-time whole genome sequencing.