Molecular Prevalence and Geographical Variations of Carbapenem-Resistant Klebsiella pneumoniae ST15 Isolates in a Tertiary Hospital in Ningbo, China

Background:In China, the most prevalent type of CRKP is ST11, but the high-risk clone ST15 has grown in popularity in recent years, posing a serious public health risk.Therefore, we investigated the molecular prevalence characteristics of ST15 CRKP detected in a tertiary hospital in Ningbo to understand the current potential regional risk of ST15 CRKP outbreak. Material/Methods:We collected and evaluated 18 non-duplicated CRKP strains of ST15 type for antibiotic resistance.Their integrons, virulence genes, and resistance genes were identified using polymerase chain reaction (PCR), and their homology was determined using MALDI-TOF MS. Results:The predominant serotype of 18 ST15 CRKP strains was K5.ST15 CRKP exhibited the lowest antimicrobial resistance to Cefoperazone/sulbactam (11.1%), followed by trimethoprim/sulfamethoxazole (22.2%).Resistance gene testing revealed that 14 out of 18 ST15 CRKP strains (77.8%) carried Klebsiella pneumoniae carbapenemase 2 (KPC-2), whereas all ST15 CRKP integrons were of the intI1 type.Furthermore, virulence gene testing revealed that all 18 ST15 CRKP strains carried ybtS, kfu, irp-1, and fyuA genes, followed by the irp-2 gene (17 strains) and entB (16 strains).The homology analysis report showed that 2 clusters had closer affinity, which was mainly concentrated in classes C and D. Conclusions:The ST15 CRKP antibiotic resistance rates demonstrate clear geographical differences in Ningbo.Additionally, some strains carried highly virulent genes, indicating a possible evolution towards carbapenem-resistant highly virulent strains.To reduce the spread of ST15 CRKP, we must rationalize the clinical use of antibiotics and strengthen resistance monitoring to control nosocomial infections.