McCullough M J, Clemons K V, McCusker J H, Stevens D A
Division of Infectious Diseases, Department of Medicine, Santa Clara Valley Medical Center, San Jose, California 95128, USA.
J Clin Microbiol. 1998 Sep;36(9):2613-7. doi: 10.1128/JCM.36.9.2613-2617.1998.
Saccharomyces boulardii (nom. inval.) has been used for the treatment of several types of diarrhea. Recent studies have confirmed that S. boulardii is effective in the treatment of diarrhea, in particular chronic or recurrent diarrhea, and furthermore that it is a safe and well-tolerated treatment. The aim of the present study was to identify strains of S. boulardii to the species level and assess their virulence in established murine models. Three strains of S. boulardii were obtained from commercially available products in France and Italy. The three S. boulardii strains did not form spores upon repeated testing. Therefore, classical methods used for the identification of Saccharomyces spp. could not be undertaken. Typing by using the restriction fragment length polymorphisms (RFLPs) of the PCR-amplified intergenic transcribed spacer regions (including the 5. 8S ribosomal DNA) showed that the three isolates of S. boulardii were not separable from authentic isolates of Saccharomyces cerevisiae with any of the 10 restriction endonucleases assessed, whereas 9 of the 10 recognized species of Saccharomyces could be differentiated. RFLP analysis of cellular DNA with EcoRI showed that all three strains of S. boulardii had identical patterns and were similar to other authentic S. cerevisiae isolates tested. Therefore, the commercial strains of S. boulardii available to us cannot be genotypically distinguished from S. cerevisiae. Two S. boulardii strains were tested in CD-1 and DBA/2N mouse models of systemic disease and showed intermediate virulence compared with virulent and avirulent strains of S. cerevisiae. The results of the present study show that these S. boulardii strains are asporogenous strains of the species S. cerevisiae, not representatives of a distinct and separate species, and possess moderate virulence in murine models of systemic infection. Therefore, caution should be advised in the clinical use of these strains in immunocompromised patients until further study is undertaken.
布拉氏酵母菌（名称无效）已被用于治疗多种类型的腹泻。最近的研究证实，布拉氏酵母菌在治疗腹泻，尤其是慢性或复发性腹泻方面有效，而且它是一种安全且耐受性良好的治疗方法。本研究的目的是将布拉氏酵母菌菌株鉴定到种水平，并在已建立的小鼠模型中评估它们的毒力。从法国和意大利的市售产品中获得了三株布拉氏酵母菌。经过反复测试，这三株布拉氏酵母菌菌株均未形成孢子。因此，无法采用用于鉴定酿酒酵母属的经典方法。通过使用聚合酶链反应扩增的基因间转录间隔区（包括5.8S核糖体DNA）的限制性片段长度多态性（RFLP）进行分型，结果显示，在所评估的10种限制性内切酶中，这三株布拉氏酵母菌分离株与酿酒酵母的正宗分离株无法区分，而10种公认的酿酒酵母属物种中有9种可以区分。用EcoRI对细胞DNA进行RFLP分析表明，所有三株布拉氏酵母菌具有相同的图谱，并且与测试的其他正宗酿酒酵母分离株相似。因此，我们获得的布拉氏酵母菌商业菌株在基因型上无法与酿酒酵母区分开来。在CD-1和DBA/2N小鼠全身疾病模型中对两株布拉氏酵母菌进行了测试，与酿酒酵母的强毒株和无毒株相比，它们表现出中等毒力。本研究结果表明，这些布拉氏酵母菌菌株是酿酒酵母物种的无孢子菌株，而非一个独特且独立物种的代表，并且在全身感染的小鼠模型中具有中等毒力。因此，在对免疫功能低下的患者临床使用这些菌株时应谨慎，直至进行进一步研究。
