Environmental Isolation of Cryptococcus species and Tricosporon asahii in Southern Taiwan

• Main Authors: Chih-kung Lee, 李至恭
• Other Authors: Hsueh-wen Chang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/79470311040798804529

碩士 === 國立中山大學 === 生物科學系研究所 === 100 === The increasing infection of Cryptococcus species and Tricosporon asahii emerged in clinical patients who were immunocompromised. They usually induce lung, skin, brain and systemic infection. Morbidity and mortality of immunocompromised patients are higher than normal healthy people. Cryptococcus neoformans var. grubii （serotype A） infections were reported in clinical cases predominantly and they were isolated from birds’ droppings in large amount. Cryptococcus neoformans var. gattii （serotype B, C） had a natural life in plants, especially Eucalypticus trees. Isolations from other trees were reported increasingly in the tropical and subtropical areas. Comparing to Cryptococcus species, Tricosporon asahii is the normal mycoses of soil. In this study, we performed an environmental investigation concerning Cryptococcus species and Tricosporon asahii in Southern Taiwan. 120 droppings of racing pigeons and 114 samples from Eucalypticus trees were obtained. The results revealed that 30 Cryptococcus neoformans were isolated from racing pigeons’ droppings （25%）, as well as 4 Cryptococcus laurentii （3.3%） and 2 Cryptococcus albidus （1.7%）. In addition, 25 Tricosporon asahii ( 20.8% ) were isolated from droppings of racing pigeons. But, none of Cryptococcus species or Tricosporon asahii is isolated from Eucalypticus trees （0%）. All of Cryptococcus neoformans isolated from pigeons’ droppings were var. grubii （serotype A） and their drug susceptibility tests showed sensitive to Amphotericin B （minimal inhibitory concentration ≦0.25μg/ml） and Fluconazole （minimal inhibitory concentration 2μg/ml） and Flucytosine （minimal inhibitory concentration ≦1μg/ml）. To sum up, both Cryptococcus species and Tricosporon asahii were isolated from droppings of racing pigeons in our study, especially Tricosporon asahii in large amount. Opportunistic infection caused by these species should be given more attention to racing pigeons which have close contact with human . Intensive investigation and surveillance should be carried out in the future to provide an information for the control and prevention of diseases.