Whole‐Genome Sequencing and Functional Analysis of <i>Klebsiella</i> Strain mr‐1S Originating From <i>Macrobrachium rosenbergii</i>

Background: Klebsiella mr‐1S, a newly emerging pathogen that poses a substantial threat to public health by inducing severe infectious diseases, has been detected in Macrobrachium rosenbergii for the first time in our prior investigation. Given its potential for environmental adaptation and genomic evolution, this study aims to delve into these aspects to better understand its pathogenicity and evolutionary trajectory. Methods: In this study, the Klebsiella isolates were subjected to routine cultivation in a tryptic soya broth (TSB) medium. Subsequently, the genomic DNA of each isolate was individually extracted and analyzed. Prior to genomic sequencing, the integrity and concentration of the DNA samples were meticulously evaluated to ensure the accuracy and reliability of the subsequent sequencing process. Results: The genomic sequence of Klebsiella mr‐1S was deciphered, revealing a length of 5,143,806 base pairs with a GC content of 54.97%. Remarkably, the genome encompasses a multitude of putative mobile genetic elements (MGEs), including 43 genomic islands (GIs) and 2 prophages. These elements confer upon the bacterium crucial adaptive attributes such as resistance, virulence, and metabolic capabilities. Notably, the identification of prophage‐associated clusters originating from the genus Pseudomonas suggests a potential horizontal gene transfer (HGT) mechanism mediated by phages within Pseudomonas, highlighting the complex genetic interactions between different bacterial species. Conclusion: In addition, the presence of two genes encoding CRISPR‐Cas proteins within the Klebsiella mr‐1S genome indicates the existence of a functional CRISPR‐Cas system in this bacterium. This finding implies that during its evolutionary history, Klebsiella mr‐1S may have developed mechanisms to evade host immune recognition, thereby facilitating efficient HGT and enhancing its adaptability and survival capabilities in diverse environments. Overall, this study provides novel insights into the environmental adaptability and genomic plasticity of Klebsiella from Macrobrachium rosenbergii , underscoring its potential as an emerging pathogen in aquatic ecosystems and paving the way for future research on its pathogenic mechanisms and potential control strategies.