Isolation and Typing of Cryptococcus neoformans from Pigeon and Ohther Birds'' Dropping

• Main Authors: Shih-Hui Chiu, 邱詩惠
• Other Authors: Ming-Jeng Pan
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/34711519881953290913

碩士 === 國立臺灣大學 === 獸醫學研究所 === 88 === Cryptococcus neoformans is a ubiquitous and opportunistic pathogen, which causes life-threatening meningoencephalitis. There are three varieties of this organism: Cryptococcus neoformans var. grubii （serotype A）, Cryptococcus neoformans var. neoformans（serotype D）and Cryptococcus neoformans var. gattii（serotype B and C）. According to the specific immunologic properties of their capsular polysaccharide, they have been divided into four distinct serotypes. In Taiwan, the majority of human cryptococcal infections belonged to Cryptococcus neoformans var. grubii, but the prevalent variety among environmental isolates never been reported. Bases on the previous studies, pigeon droppings were the important reservoir of Cryptococcus neoformans var. grubii and Cryptococcus neoformans var. neoformans. To clarify the relationship between human clinical isolates and birds’ cryptococcal isolates in Taiwan, we investigated the prevalence, serotypes, in vivo susceptibility tests and electrophoretic karotypes of Cryptococcus neoformans from pigeon and other birds’ droppings. Fecal specimens were collected from pigeon houses, bird shops and fodder shops respectively, from Taipei, Changhua, Kaohsiung and Pingtun area during Aug to Sep in 1999. All birds'' isolates were isolated by using sunflower seed agar and Niger seed agar from 26 of 68 (38.2%) pigeon dropping specimens and 10 of 35 (28.6%) dropping specimens of other bird species, including budgerigar, lovebird, sunbird, canary, and siskia. A total of 209 strains of birds’ isolates with 23 human isolates provided by National Taiwan University Hospital were typing by Crypto Check agglutination test, by inoculating on canavanine-glycine-bromothymo agar. All expect one isolate isolated from pigeon dropping was grouped as serotype AD belongs to serotype A. This findings were similar to the surveys in other counties in Asia. However, the information from serotyping was not sufficient to revel the relationship between birds'' isolates and human infection, other additional methods were required. As for electrophoretic karyotyping, they were much more similar in strains collected from the same spot. It suggests that electrophoretic karyotyping is a useful tool for molecular epidemiological research. Avian cryptococcal isolates have lower susceptibility to Fluconazole, whereas human clinical isolates have a wide range in Fluconazole MIC tests.