Fernandes Karla S S, Mathews Herbert L, Bezerra Leila M Lopes
Department of Microbiology and Immunology, Loyola University of Chicago, Maywood, IL, USA.
J Med Microbiol. 1999 Feb;48(2):195-203. doi: 10.1099/00222615-48-2-195.
A murine model was used to evaluate the virulence of Sporothrix schenckii conidia cultured for 4, 7, 10 or 12 days in Sabouraud's dextrose broth (SDB). A correlation was observed between length of culture and virulence. Mice infected intravenously with S. schenckii conidia cultured for 4 or 7 days showed 40-100% cumulative mortality. In contrast, mice infected with conidia from cultures grown for 10 or 12 days in SDB showed no mortality (100% survival). A much greater accumulation of fungal colony forming units (cfu) was observed in the lungs, livers and spleens of mice inoculated with conidia of S. schenckii cultured for 7 days than in mice infected with conidia cultured for 12 days. The livers of mice from the former group showed a widespread granulomatous reaction whereas mice inoculated with S. schenckii cultured for 12 days showed a more limited response with fewer granulomas. No difference in viability or replicative capacity was discerned for these S. schenckii cultured cells. However, the more virulent forms of the fungus showed differences in cell-wall sugar composition with rhamnose:mannose molar ratios of 1.7:1.0 for cells cultured for 4 days and 1.0:1.7 for conidia cultured for 12 days. These results suggest that the virulence of S. schenckii conidia may be determined by their cell-wall composition.
利用小鼠模型评估申克孢子丝菌分生孢子在沙氏葡萄糖肉汤（SDB）中培养4、7、10或12天后的毒力。观察到培养时间与毒力之间存在相关性。静脉注射培养4天或7天的申克孢子丝菌分生孢子的小鼠累积死亡率为40%-100%。相比之下，感染在SDB中培养10天或12天的分生孢子的小鼠没有死亡（100%存活）。接种培养7天的申克孢子丝菌分生孢子的小鼠的肺、肝和脾中观察到的真菌集落形成单位（cfu）积累比感染培养12天的分生孢子的小鼠多得多。前一组小鼠的肝脏出现广泛的肉芽肿反应，而接种培养12天的申克孢子丝菌的小鼠反应更有限，肉芽肿更少。这些培养的申克孢子丝菌细胞在活力或复制能力上没有差异。然而，毒力更强的真菌形式在细胞壁糖组成上存在差异，培养4天的细胞鼠李糖：甘露糖摩尔比为1.7:1.0，培养12天的分生孢子为1.0:1.7。这些结果表明，申克孢子丝菌分生孢子的毒力可能由其细胞壁组成决定。
