摘要
目的:比较四环素对自然生长条件下的新生隐球菌新生变种(CZYD7)胞外磷脂酶的抑制作用;观察四环素对CZYD7毒力的影响。方法:在37℃温度下,用蛋黄平板法培养并测量菌株产生的沉淀圈大小,用沉淀圈比值(PZ值)比较磷脂酶活力的变化;建立小鼠感染模型,用菌落形成单位(cfu)及生存期比较菌株毒性的变化。结果:体外实验中,对照组与四环素不同浓度组的PZ值分别为0.387±0.039、0.479±0.086、0.702±0.029、0.891±0.072、0.955±0.021;四环素0.36%、0.54%和0.72%浓度组与对照组的PZ值比较差异有显著性(P<0.001);体内实验中,对照组与四环素0.18%、0.36%和0.54%浓度组小鼠的平均生存期分别为18.90、19.20、26.39、25.94d;小鼠脑组织匀浆培养对照组与四环素不同浓度组(0.18%、0.36%、0.54%)的菌落形成单位分别为518.67±203.86、469.07±243.13、261.73±225.82、226.47±196.13,四环素0.36%组和0.54%组与对照组比较差异有显著性(P<0.01)。结论:体内、外实验中,四环素对CZYD7胞外磷脂酶具有抑制作用,并且与浓度相关,四环素降低了菌株的毒性。
Objectives: To compare the effect of tetracycline hydrochloride on inhibiting the activity of phospholipases secreted by Cryptococcus neoformans var. neoformans and on the pathogenicity to mice infected by the strains of high extracelluar phospholipase. Methods: The high phospholipase-producer Cryptococcus neoformans strain was selected as the subject after being incubated onto egg yolk agar at 37 ℃. Phospholipase activity of the strain was measured and compared by the ratio of the colony diameter to the diameter of the colony plus zone of precipitation(PZ). Infected mouse models were established for comparing the different virulence of the isolates by colony forming unit (cfu) and survival time of the mice. Results: In vitro, the PZs of control group and tetracycline hydrochloride groups in different concentration of 0.18%, 0.36%, 0.54% and 0.72% were 0.387±0.039, 0.479±0.086, 0.702±0.029, 0.891±0.072 and 0.955±0.021 respectively. There was significant difference in PZs between the tetracycline hydrochloride groups of 0.36%, 0.54%, 0.72% concentrations and control group (P < 0.001). In vivo, the mean survival time of control and tetracycline hydrochloride groups of different concentrations were 18.90 d, 19.92 d, 19.20 d, 26.39 d and 25.94 d respectively; the colony forming units in the brain tissues of the control and tetracycline hydrochloride groups of 0.18%, 0.36% and 0.54% were 518.67±203.86, 469.07±243.13, 261.73±225.82 and 226.47±196.13 respectively. There wasa significant difference between the tetracycline hydrochloride groups of 0.36%, 0.54% and control group (P < 0.01). Conclusions: Tetracycline hydrochloride can inhibit the isolate activity of extracelluar phospholipase and there was concentration-effect correlation both in vitro and in vivo tests. Tetracycline hydrochloride reduced the virulence of Cryptococcus neoformans var. neoformans.
出处
《临床皮肤科杂志》
CAS
CSCD
北大核心
2003年第7期379-381,共3页
Journal of Clinical Dermatology
基金
国家自然科学基金(项目编号:39870658)
关键词
四环素
新生隐球菌新生变种
磷脂酶
tetracycline hydrochloride
Cryptococcus neoformans var. neoformans
phospholipase
