新生隐球菌L型生物学性状研究

目的观察人工诱导的新生隐球菌L型生物学性状,并与其酵母型比较。方法制备新生隐球菌L型高渗培养基,依此进行生长特性、滤过性试验、同化试验、糖发酵试验、尿素试验等。结果新生隐球菌L型高渗培养基的基本成分为:葡萄糖4%、蛋白胨1%、氯化钠2.5%、氯化钙0.015%、灭活人血浆20%。新生隐球菌L型的特征为:革兰染色性改变、大小不一、能通过孔径0.8μm的滤器、电镜检查见细胞壁有不同程度的缺损。在高渗液体培养基中,新生隐球菌L型生长缓慢、不易回复;在高渗固体平板上则易回复。不稳定新生隐球菌L型与酵母型一样,均能同化葡萄糖、麦芽糖、甘露醇、蔗糖;但稳定L型的同化能力减弱。三者均不同化乳糖、硝酸钾,亦不发酵上述5种糖。不稳定、稳定L型对尿素的分解能力亦减弱。结论新生隐球菌形成L型后,其形态、培养特性及生化反应发生变化,这在菌种鉴定与临床检验时要注意。

Biological characteristics of the L-form of Cryptococcus neoformans

In the present report, the biological characteristic of the L-forms of Cryptococcus neiformans was compared with that of the yeast form, in which a hypertonic medium for the cultivation of C. neoformans L-form, containing 4 % glucose, 1% peptone, 2.5 % NaC1, 0. 015 % CaC12 and 20 % inactivated human plasma, was prepared, and the growth property, filtration, assimilation, fermentation and urea test were carried both in the L-form and the yeast form of this organism respectively. In comparison with the yeast form, the L-form showed alteration in Gram staining property, variation in cell size, the capacity to pass through bacterial filter of pore 0.8 btrn and different degree of cell membrane defects as demonstrated by electron microscopical examinations. The growth of L-form in liquid hypertonic medium was rather slow, and few of them could revert back to its yeast form, whereas, on the solid medium, they reverted easily to its yeast form. Meanwhile, the biochemical reactions of both the unstable L-form and the yeast form were quite similar, but the ability of the stable L-form to assimilate saccharides and to decompose urea was decreased. It is evident that the L-form of C. neoformans show definite changes in morphology, cultivation and biochemical reactions, suggesting its significance in the identification of this organism and the clinical diagnosis of infection with this pathogen.