Quintero Elizabeth, Castañeda Elizabeth, Ruiz Alejandro
Universidad de Puerto Rico, Recinto Universitario de Mayaguez, Puerto Rico.
Rev Iberoam Micol. 2005 Jun;22(2):93-8. doi: 10.1016/s1130-1406(05)70015-2.
Cryptococcus neoformans is an opportunistic fungal pathogen that could cause infection in patients with immunodeficiency and healthy patients. The AIDS epidemic has shown the importance of studying the ecology and epidemiology of this fungus. The aim of this investigation was to determine if there was a relationship between the environmental distribution of the different varieties of C. neoformans and the climate zones in two transects located in department of Cundinamarca, in Colombia. For the isolation and identification of the yeast, conventional phenotypic methods were used and it was determined the population density (CFU/g of sample) and which was the variety of greater prevalence in each altitudinal rank. A total of 765 samples, from 26 municipalities were collected; of these 146 corresponded to pigeon droppings (Columba livia), 437 to Eucalyptus detritus (Eucalyptus camaldulensis and related species) and 182 to detritus of almond trees (Terminalia cattapa). C. neoformans was isolated from 46% of the studied municipalities, in both transects and the climate zones: warm, temperate and cold. The results indicated that the greater frequency of positive isolations came from the last climate zone (cold). The population density in pigeon excrements oscillated between 50 and 9.2 x 1,000,000, in eucalyptus between 500 and 10 x 1,000,000 and in almond trees was 50 CFU/g. Of 100,000 positive isolations 31% were serotype A, 59% serotype B and 10% serotype C; 96% of the isolates grew to 37 degrees C and all showed capsule. In conclusion, C. neoformans prevails in the three habitats studied but it showed a predilection for the cold thermal floor; the population densities did not allow defining a standard pattern of occurrence.
新型隐球菌是一种机会性真菌病原体，可导致免疫缺陷患者和健康患者感染。艾滋病的流行凸显了研究这种真菌的生态学和流行病学的重要性。本研究的目的是确定位于哥伦比亚昆迪纳马卡省的两个样带中，新型隐球菌不同变种的环境分布与气候带之间是否存在关系。对于酵母的分离和鉴定，采用了传统的表型方法，并确定了种群密度（每克样品的菌落形成单位）以及每个海拔等级中最普遍的变种。共收集了来自26个市的765个样本；其中146个对应鸽粪（家鸽），437个对应桉树叶屑（赤桉及相关物种），182个对应扁桃树（榄仁树）叶屑。在两个样带以及温暖、温带和寒冷气候带的46%的研究市中分离出了新型隐球菌。结果表明，阳性分离的频率最高来自最后一个气候带（寒冷）。鸽粪中的种群密度在50至9.2×1,000,000之间波动，桉树叶屑中的种群密度在500至10×1,000,000之间，扁桃树叶屑中的种群密度为50 CFU/g。在100,000个阳性分离株中，31%为A型血清型，59%为B型血清型，10%为C型血清型；96%的分离株在37℃下生长，且均显示有荚膜。总之，新型隐球菌在研究的三种栖息地中均占优势，但它表现出对寒冷温度层的偏好；种群密度不允许定义一个标准的发生模式。
