RESUMEN
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 AND 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.
Asunto(s)
Antibacterianos , Carbapenémicos , Infecciones por Klebsiella , Klebsiella pneumoniae , Pruebas de Sensibilidad Microbiana , Centros de Atención Terciaria , China/epidemiología , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/aislamiento & purificación , Humanos , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/microbiología , Antibacterianos/farmacología , Carbapenémicos/farmacología , Prevalencia , Integrones/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , beta-Lactamasas/genética , beta-Lactamasas/metabolismo , Farmacorresistencia Bacteriana/genética , Enterobacteriaceae Resistentes a los Carbapenémicos/genética , Enterobacteriaceae Resistentes a los Carbapenémicos/aislamiento & purificación , Enterobacteriaceae Resistentes a los Carbapenémicos/efectos de los fármacosRESUMEN
Background: In recent years, Klebsiella pneumoniae has attracted attention because of its increasing drug resistance. At the same time, the migration and pathogenicity caused by its virulence genes also bring many difficulties to the diagnosis and treatment of clinical infections. However, it is currently unclear whether there are differences in virulence and pathogenicity with changes in drug resistance. Objective: To understand the differences in molecular characteristics and expression of virulence genes in carbapenem-resistant Klebsiella pneumoniae (CRKP) and carbapenem-sensitive Klebsiella pneumoniae (CSKP). Methods: Using polymerase chain reaction (PCR), we examined capsule polysaccharide-related genes and virulence genes in 150 clinical isolates of CRKP and 213 isolates of CSKP from the local area in Ningbo, China. Multilocus sequence typing (MLST) was used to analyze the phylogenetic relationships of clinical Klebsiella pneumoniae isolates. Furthermore, real-time quantitative PCR (RT-qPCR) was used to analyze the expression differences of common virulence genes in CSKP and CRKP, and the virulence was further verified by the larval model of Galleria mellonella. Results: The study found that the detection rates of genes rmpA, iroB, peg-344, magA, aerobactin, alls, kfu, and entB were significantly higher in CSKP compared to CRKP. The capsule gene types K1 and K2 were more common in CSKP, while K5 was more common in CRKP. Hypervirulent Klebsiella pneumoniae (hvKP) was predominantly from CSKP. CRKP strains exhibited noticeable homogeneity, with ST11 being the predominant sequence type among the strains. CSKP strains showed greater diversity in ST types, but ST23 was still the predominant sequence type. Carbapenem-sensitive hypervirulent Klebsiella pneumoniae (CS-hvKP) had higher expression of rmpA and rmpA2 genes compared to carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP). In the wax moth virulence model, the survival rate of CS-hvKP was significantly lower than that of CR-hvKP. Conclusion: There is a significant difference in the distribution of virulence genes between CSKP and CRKP, with CSKP carrying a significantly greater number of virulence genes. Furthermore, compared to CSKP, CRKP strains exhibit noticeable homogeneity, with ST11 being the predominant sequence type among the strains. Additionally, in terms of virulence gene expression efficiency and virulence, CSKP is significantly higher than CRKP.