RESUMEN
OBJECTIVES: The emergence and expansion of carbapenem-resistant Klebsiella pneumoniae infections is a concern due to the lack of 'first-line' antibiotic treatment options. The ceftazidime/avibactam is an important clinical treatment for carbapenem-resistant K. pneumoniae infections but there is an increasing number of cases of treatment failure and drug resistance. Therefore, a potential solution is combination therapies that result in synergistic activity against K. pneumoniae carbapenemase: producing K. pneumoniae (KPC-Kp) isolates and preventing the emergence of KPC mutants resistant to ceftazidime/avibactam are needed in lieu of novel antibiotics. METHODS: To evaluate their synergistic activity, antibiotic combinations were tested against 26 KPC-Kp strains. Antibiotic resistance profiles, molecular characteristics and virulence genes were investigated by susceptibility testing and whole-genome sequencing. Antibiotic synergy was evaluated by in vitro chequerboard experiments, time-killing curves and dose-response assays. The mouse thigh model was used to confirm antibiotic combination activities in vivo. Additionally, antibiotic combinations were evaluated for their ability to prevent the emergence of ceftazidime/avibactam resistant mutations of blaKPC. RESULTS: The combination of ceftazidime/avibactam plus meropenem showed remarkable synergistic activity against 26 strains and restored susceptibility to both the partnering antibiotics. The significant therapeutic effect of ceftazidime/avibactam combined with meropenem was also confirmed in the mouse model and bacterial loads in the thigh muscle of the combination groups were significantly reduced. Furthermore, ceftazidime/avibactam plus meropenem showed significant activity in preventing the occurrence of resistance mutations. CONCLUSIONS: Our results indicated that the combination of ceftazidime/avibactam plus meropenem offers viable therapeutic alternatives in treating serious infections due to KPC-Kp.
Asunto(s)
Antibacterianos , Compuestos de Azabiciclo , Proteínas Bacterianas , Ceftazidima , Modelos Animales de Enfermedad , Combinación de Medicamentos , Sinergismo Farmacológico , Infecciones por Klebsiella , Klebsiella pneumoniae , Meropenem , Pruebas de Sensibilidad Microbiana , beta-Lactamasas , Animales , Ceftazidima/farmacología , Ceftazidima/uso terapéutico , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/genética , Compuestos de Azabiciclo/farmacología , Compuestos de Azabiciclo/uso terapéutico , Meropenem/farmacología , Meropenem/administración & dosificación , Infecciones por Klebsiella/tratamiento farmacológico , Infecciones por Klebsiella/microbiología , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Ratones , beta-Lactamasas/genética , Proteínas Bacterianas/genética , Femenino , Secuenciación Completa del Genoma , Quimioterapia Combinada , Enterobacteriaceae Resistentes a los Carbapenémicos/efectos de los fármacos , Enterobacteriaceae Resistentes a los Carbapenémicos/genéticaRESUMEN
Tubulin polymerisation inhibitors exhibited an important role in the treatment of patients with prostate cancer. Herein, we reported the medicinal chemistry efforts leading to a new series of benzothiazoles by a bioisosterism approach. Biological testing revealed that compound 12a could significantly inhibit in vitro tubulin polymerisation of a concentration dependent manner, with an IC50 value of 2.87 µM. Immunofluorescence and EBI competition assay investigated that compound 12a effectively inhibited tubulin polymerisation and directly bound to the colchicine-binding site of ß-tubulin in PC3 cells. Docking analysis showed that 12a formed hydrogen bonds with residues Tyr357, Ala247 and Val353 of tubulin. Importantly, it displayed the promising antiproliferative ability against C42B, LNCAP, 22RV1 and PC3 cells with IC50 values of 2.81 µM, 4.31 µM, 2.13 µM and 2.04 µM, respectively. In summary, compound 12a was a novel colchicine site tubulin polymerisation inhibitor with potential to treat prostate cancer.