Villar L A, Restrepo A
Corporación para Investigaciones Biológicas, Hospital Pablo Tobón Uribe, Medellin, Colombia.
J Med Vet Mycol. 1989;27(3):141-8.
Paracoccidioides brasiliensis (ATCC 60885) produces conidia that, when plated in enriched media and incubated at 21-25 degrees C, give rise to a yeast-form variant (YRT) (ATCC 46678). The virulence of this variant for BALB/c mice has been compared with that of the yeast and conidia produced by the parent isolate. Adult female mice were inoculated intravenously with 10(7) viable cells of YRT or yeast, or 5 x 10(5) viable conidia. Mice were weighed weekly, and three mice were sacrificed at 1, 2, 3, 4 and 8 weeks post-inoculation and their organs weighed and prepared for determination of viable counts (colony forming units; c.f.u.). Animals infected with yeast cells or with conidia exhibited little weight loss in comparison with that seen in the YRT-infected mice which began to lose weight 1 week post-challenge. Organ weights increased in the YRT group, while the changes in the remaining two groups were minor. The c.f.u. from these organs also increased in the YRT-infected mice, whereas the infection in the yeast-and conidia-infected mice was self-limiting. A proportion (16.6%) of the YRT-infected animals died during the observation period. Conversely, no deaths occurred in the remaining groups. These results indicate that the YRT variant possesses increased virulence.
巴西副球孢子菌（ATCC 60885）产生分生孢子，将其接种于富集培养基并在21 - 25摄氏度下培养时，会产生酵母形态变体（YRT）（ATCC 46678）。已将该变体对BALB/c小鼠的毒力与亲本菌株产生的酵母和分生孢子的毒力进行了比较。成年雌性小鼠静脉注射10⁷个YRT或酵母的活细胞，或5×10⁵个活的分生孢子。每周称小鼠体重，在接种后1、2、3、4和8周处死三只小鼠，称量其器官重量并制备用于测定活菌数（菌落形成单位；c.f.u.）。与YRT感染的小鼠相比，感染酵母细胞或分生孢子的小鼠体重减轻很少，YRT感染的小鼠在攻击后1周开始体重减轻。YRT组的器官重量增加，而其余两组的变化较小。YRT感染小鼠这些器官中的c.f.u.也增加，而酵母和分生孢子感染小鼠的感染是自限性的。在观察期内，YRT感染的动物中有一部分（16.6%）死亡。相反，其余组未发生死亡。这些结果表明YRT变体具有增强的毒力。
