Hypervirulence of Klebsiella Pneumoniae Strains Producing Carbapenemase and Extended-Spectrum Beta-Lactamase (ESBLs) Isolated from Hospitals of Rasht, Iran

New hypervirulent strains of Klebsiella pneumoniae have emerged in recent years and have led to life-threatening infections in young and healthy people. The aim of the present study was to determine the hypervirulence of Klebsiella Pneumoniae strains producing carbapenemase and Extended-Spectrum Beta-Lactamase (ESBLs) isolated from hospitals of Rasht, Iran.

This cross-sectional study was conducted on clinical samples isolated from inpatients in Razi, Poursina, Rasoul Akram, Golsar and Al-Zahra hospitals in Rasht. Standard microbiology and molecular methods were used to confirm the identity of Klebsiella pneumoniae isolates. String test was used to identify hypervirulent strains. CDT test was used to phenotypically determine ESBL producing strains. Then, determining the presence of the gene encoding carbapenemase (NDM-1) as well as typing of hypervirulent strains was done by PCR method.

In this study, 158 Klebsiella pneumoniae strains isolated from different samples were collected and analyzed. In total, 55 isolates (34.8%) had positive string test and were identified as hypervirulent. Among 55 Klebsiella pneumoniae isolated strains, 16 (29.1%) were determined phenotypically as ESBL producers. The results showed that only 2 isolates (3.6%) had NDM-1 gene. Also, the frequency of common sequence types in hypervirulent isolates were 9.1% for ST258, 9.1% for ST86 and 3.6% for ST23; ST65 was observed in none of the isolates.

The present study showed significantly high prevalence of hypervirulent Klebsiella pneumonia strains with the ability to produce ESBLs and carbapenemase. Undoubtedly, the emergence of high-risk strains in the region in the future is a serious threat to the health system.