Pan-genome analysis and phylogenetic characterization of <i>Klebsiella pneumoniae</i> from global isolates

<h4>Aims</h4>This study aimed to investigate the global genetic diversity, evolutionary relationships, and antimicrobial resistance (AMR) profiles of <i>Klebsiella pneumoniae</i> by performing a comprehensive pan-genome and phylogenetic analysis across worldwide isolates.<h4>Materials and methods</h4>A total of 72,057 <i>K. pneumoniae</i> genomes were retrieved from the NCBI database, from which 91 high-quality representative genomes each from a unique country were selected based on completeness, metadata availability, and sequence quality. Genomic assemblies were assessed using QUAST, annotated with PROKKA, and analyzed for pan-genomic composition and phylogenetic relatedness using standard bioinformatics pipelines.<h4>Results</h4>The pan-genome revealed a large accessory component, reflecting extensive genomic plasticity and adaptability. QUAST analysis indicated significant variability in genome size and contig number, while PROKKA annotation identified diverse coding sequences, tRNA, rRNA, and AMR genes. Phylogenetic clustering demonstrated both geographically localized and globally disseminated lineages, suggesting regional adaptation and intercontinental transmission.<h4>Conclusions</h4>This study provides a global perspective on the genomic diversity and evolutionary patterns of <i>K. pneumoniae</i>. The widespread presence of AMR determinants underscores the urgent need for continuous genomic surveillance and integration of metagenomic approaches to improve monitoring, infection control, and therapeutic strategies against multidrug-resistant strains.