Kwon-Chung K J, Wickes B L, Stockman L, Roberts G D, Ellis D, Howard D H
Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
Infect Immun. 1992 May;60(5):1869-74. doi: 10.1128/iai.60.5.1869-1874.1992.
Four strains of Cryptococcus neoformans var. gattii originating from Eucalyptus camaldulensis, three from Australia and one from San Francisco, were tested for their serotype, virulence for mice, and a number of genetic and molecular characteristics. All were found to be serotype B and showed significantly higher virulence for mice than did the type strains of C. neoformans var. gattii and Filobasidiella neoformans var. bacillispora, which were obtained from human cryptococcosis cases. Electrophoretic karyotypes of the strains from Australia were identical, although they were collected from sites at least 15 to 500 km apart. The electrophoretic karyotype of the strain from San Francisco was the same as that of the Australian isolates except for the mobility of one chromosome. On the contrary, no two isolates of serotype B (of a total of 11) from clinical sources were the same, regardless of their geographic origin. Furthermore, none of the clinical isolates showed a chromosomal banding pattern identical to that of Eucalyptus-originated strains. The Eucalyptus-originated strains failed to form dikaryons when crossed with the tester strains of the two varieties of F. neoformans. Hybridization analysis with a nucleic acid probe (AccuProbe C. neoformans Culture Confirmation Test; Gen-Probe Inc., San Diego, Calif.), however, showed signals of equal intensity for clinical strains and the Eucalyptus-originated strains. Various fungi phylogenetically related to C. neoformans, including a phenol oxidase-positive strain of Cryptococcus laurentii obtained from E. camaldulensis, were negative in the nucleic acid hybridization test. These observations confirm that, in spite of karyotypic differences and the lack of dikaryon formation with the tester strains of F. neoformans, Eucalyptus-originated C. neoformans var. gattii is the same organism as those isolated from cases of human infection. Furthermore, the C. neoformans culture confirmation test using a commercial nucleic acid probe is specific for C. neoformans.
对4株源自赤桉的新型隐球菌格特变种进行了检测，其中3株来自澳大利亚，1株来自旧金山，检测内容包括它们的血清型、对小鼠的毒力以及一些遗传和分子特征。结果发现，所有菌株均为B血清型，且对小鼠的毒力显著高于从人类隐球菌病病例中分离得到的新型隐球菌格特变种和新生隐球菌芽孢变种的模式菌株。来自澳大利亚的菌株的电泳核型相同，尽管它们是从相距至少15至500公里的地点采集的。来自旧金山的菌株的电泳核型与澳大利亚分离株相同，只是一条染色体的迁移率不同。相反，临床来源的11株B血清型分离株中，没有两株是相同的，无论其地理来源如何。此外，没有一株临床分离株的染色体条带模式与源自赤桉的菌株相同。源自赤桉的菌株与新生隐球菌两个变种的测试菌株杂交时未能形成双核体。然而，用核酸探针（AccuProbe新型隐球菌培养确认试验；Gen-Probe公司，加利福尼亚州圣地亚哥）进行杂交分析表明，临床菌株和源自赤桉的菌株的信号强度相同。与新型隐球菌系统发育相关的各种真菌，包括从赤桉中获得的一株酚氧化酶阳性的罗伦隐球菌，在核酸杂交试验中均为阴性。这些观察结果证实，尽管存在核型差异且与新生隐球菌测试菌株杂交时缺乏双核体形成，但源自赤桉的新型隐球菌格特变种与从人类感染病例中分离出的菌株是同一生物体。此外，使用商业核酸探针进行的新型隐球菌培养确认试验对新型隐球菌具有特异性。
