Antibiotic resistance characteristics and genetic determinants of hypervirulence in Klebsiella pneumoniae isolated from wounded individuals in Ukraine

INTRODUCTION: This study continues the surveillance of antimicrobial resistance and genetic determinants of hypervirulence in Klebsiella pneumoniae associated with combat injuries in Ukraine. AIM: To characterize the antibiotic resistance patterns and hypervirulence-associated genetic determinants of K. pneumoniae isolated from combat wound infections in Ukrainian soldiers during 2022-2023. METHODS: Fifty-six K. pneumoniae isolates were obtained from wound swabs of 171 injured soldiers treated at three military hospitals in central Ukraine. Bacterial identification and antimicrobial susceptibility testing, whole genome sequencing and core genome multi-locus sequence typing were conducted at the Walter Reed Army Institute of Research to determine clonal lineages and virulence gene profiles. FINDINGS: All isolates exhibited multi-drug resistance (MDR), with 78.6% (N=44) categorized as extensively drug-resistant (XDR). Carbapenem resistance was high (69.6% to imipenem, 82.1% to meropenem), while all isolates remained susceptible to colistin. Phylogenetic analysis revealed five main clonal groups, dominated by ST395 (35.7%) and ST307 (25%). Virulence determinants were variably present, including iuc (aerobactin), ybt (yersiniabactin) and rmpA. Notably, 100% of isolates carried carbapenemase genes (blaNDM-1, blaOXA-48) or extended-spectrum beta-lactamases (blaCTX-M-15), and several strains harboured 16S rRNA methyltransferases (armA, rmtF1), indicating a convergence of resistance and virulence traits. CONCLUSION: This study highlights a concerning prevalence of MDR and XDR K. pneumoniae in war-related wound infections in Ukraine, with high-risk international clones (ST307, ST395, ST147, ST23) predominating. These strains exhibit convergent antibiotic resistance and hypervirulence features, necessitating strengthened surveillance and infection control.