Abstract
This study aims to delineate the antimicrobial resistance profiles and virulence gene carriage of Klebsiella pneumoniae (KP) in Southwest Shandong region of China, investigate the differences in clinical infection characteristics between classical Klebsiella pneumoniae (cKP) and hypermucoviscous Klebsiella pneumoniae (hmKP), and explore the correlation between hmKP and hypervirulent Klebsiella pneumoniae (hvKP). This study collected Klebsiella pneumoniae-infected strains and clinical case data from the Affiliated Hospital of Jining Medical University in Shandong Province, performed isolation, culture, identification, antimicrobial susceptibility testing, serological typing, and virulence gene detection to analyze etiological characteristics, conducted a retrospective analysis of the epidemiological characteristics of infection cases, and analyzed their clinical features. No significant differences were observed between hvKP and cKP groups in age, gender, presence of underlying diseases, or infection categories. However, significant differences were identified in the types of underlying diseases and invasive procedures (P < 0.05). The hvKP group exhibited significantly lower resistance rates to 10 antibiotics (e.g., GEN, CSL) compared to the cKP group, while no differences were observed in resistance to 8 antimicrobial agents (e.g., AMK, IPM) (P < 0.05). In the hvKP group, the detection rates of K1 and K2 serotypes reached 25.00% (15/60) and 36.67% (22/60) respectively, significantly higher than those in the cKP group (12.00% [30/250] and 9.20% [23/250]) (P < 0.05). Additionally, the virulence gene carriage rate in the hvKP group (90.00%) was markedly higher than that in the cKP group (12.80%) (P < 0.05). In this region, KP infections predominantly affect elderly male patients. Patients comorbid with diabetes, hepatobiliary diseases, or those undergoing invasive procedures constitute a high-risk population for hmKP infections. The hmKP strains exhibited significantly lower resistance rates to most antimicrobial agents compared to cKP. hmKP isolates were predominantly of the K1 and K2 serotypes, with the hmKP group demonstrating widespread carriage of multiple virulence genes. An epidemiological correlation was observed between hmKP and hvKP. Clinically, the hypermucoviscosity phenotype may serve as a preliminary indicator for assessing bacterial virulence.