Molecular Characteristics and Phenotypical Analysis of Carbapenem-Resistant K. Pneumoniae in the Lüliang Region, Shanxi Province.

Introduction: To explore the resistance characteristics and molecular features of carbapenem-resistant K. pneumoniae (CRKP) isolates prevalent in the Lüliang region, 81 CRKP isolates were collected from three hospitals in the Lüliang region, Shanxi Province.

Methods: The resistance of these CRKP isolates to 11 antibiotics was determined using the disk diffusion method, and antimicrobial resistance encoding genes and virulence genes were detected by PCR. The mucoid phenotype of the CRKP isolates was examined via the string test, and bacterial biofilm formation ability was measured using the crystal violet staining method.

Results: The resistance rates of the 81 CRKP isolates to the 11 antibiotics ranged from 62.96% to 100%, with a multidrug resistance rate of 83.95%. The resistance genes bla_SHV, bla_TEM and bla_KPC were the most widely distributed, with a detection rate of 100%. Among the 81 CRKP isolates, 70 had the ability to form biofilms, and 58 presented highly mucoid phenotypes. The virulence genes rmpA2, peg-344, and fimH presented high carriage rates of 92.59%, 91.36%, and 88.89%, respectively. The carriage rate of IroB was low, at 20.99%. Among these genes, fimH, rmpA2, and iucA were associated with biofilm formation, while markD and fimH were associated with a highly mucoid phenotype, and the highly mucoid phenotype was strongly correlated with the biofilm formation ability.

Conclusion: This study revealed that the CRKP strains isolated in the Lüliang region of Shanxi Province were strongly resistant and that this resistance was related to virulence characteristics. Therefore, antibiotic management should be strengthened in clinical practice to control the prevalence of CRKP in this region.