Table 1_Epidemiological features of hypermucoviscous Klebsiella pneumoniae infection in a coastal city of China: clinical and molecular perspectives.xlsx

PurposeThe present study aimed to investigate the overall clinical and molecular characteristics of hypermucoviscous Klebsiella pneumoniae (hmKP) infection in Yantai, China.
MethodsA retrospective study was conducted in Yantai Yuhuangding Hospital from October 2024 to December 2024. As the inclusion criterion, all clinical isolates of K. pneumoniae were analyzed by a string test, in which an inoculation loop was used to generate sticky strings of >5 mm length from a K. pneumoniae colony. The isolates showing a positive test result were designated as hmKP. The clinical characteristics of patients with hmKP infection were retrospectively reviewed. Antibiotic susceptibility tests were performed for all hmKP isolates, and whole-genome sequencing studies were conducted for these isolates to determine their epidemiological characteristics.
ResultsA total of 88 unique hmKP isolates were collected from 485 strains of K. pneumoniae, accounting for 18.1%. Patients with hmKP infection were distributed across different age groups, clinical departments, and specimen types. Whole-genome sequencing revealed the predominance of K1/ST23 and K2/ST65 clones in the hmKP group. Virulence determinants such as rmpA, rmpA2, iuc, iro, peg-344, and clb were commonly present in the hmKP isolates. All hmKP isolates carried multiple resistance genes; however, the antibiotic resistance phenotype did not fully match with the resistance genes. Additionally, two hypervirulent carbapenem-resistant Klebsiella pneumoniae(HCKP) strains were detected in this study.
ConclusionHmKP infection is prevalent in Yantai, China, with dominant K1/ST23 and K2/ST65 clones carrying prevalent virulence genes. Vigilance is required to prevent the spread of HCKP in clinical practice.