The adaptive growth and mechanisms of Klebsiella pneumoniae under sucrose and glucose exposure.

Abstract

Klebsiella pneumoniae commonly colonizes the gastrointestinal (GI) mucosa of animals and healthy humans. Successful GI colonization by K. pneumoniae requires overcoming the colonization resistance (CR) exerted by the gut microbiota. Although previous studies have demonstrated the role of microbial carbohydrate metabolism in K. pneumoniae colonization, the specific effects of individual carbohydrates, such as glucose and sucrose, particularly across concentration gradients or under sustained induction on the adaptive growth of K. pneumoniae remain unknown. Herein, we demonstrate that 4% or 8% glucose and sucrose are favorable for promoting adaptive growth of sugar-induced strains. Additionally, the growth response to glucose exhibited strain-specific variability. Sustained sugar induction did not significantly alter the hypermucoviscosity (HMV) phenotype but did affect antibiotic resistance of K. pneumoniae. Knockout of the scrA and scrY genes impaired the adaptive growth under sucrose and glucose conditions, yet did not significantly influence antimicrobial susceptibility or the HMV phenotype. These findings provide insights into the metabolic regulation of K. pneumoniae colonization and offer potential guidance for clinical treatment strategies targeting K. pneumoniae-associated infections.

Importance: This work elucidates the impact of single-carbon source gradients and sustained sugar induction on the adaptive growth and drug resistance of Klebsiella pneumoniae and preliminarily reveals the roles of scrA and scrY in carbohydrate metabolism, suggesting a possible mechanism by which sucrose and glucose affect the adaptive growth of K. pneumoniae. These findings contribute to the theoretical understanding of CCR and provide insights that may inform clinical management of K. pneumoniae-related infections.