Abstract
M. Tech.
Yeast such as Candida albicans are the major cause of human diseases such as
genital thrush and oral thrush. Some of the genital isolates of C. albicans that
were studied by Shah et al. (1991 & 1995) were found to produce the medically
important immunosuppressing mycotoxin gliotoxin, which has potential important
medical consequences. The biosynthesis of this mycotoxin is regulated and
expressed by the presence of the gliP and gliZ genes, which were identified on
the putative gene cluster of A. fumigatus. Most Candidal infections are treated
using a single or a combination of antifungal agents such as amphotericin B
(AmB), fluconazole, flucytosine, voriconazole, caspofungin, itraconazole,
posaconazole and ketoconazole. The mode of action for these antifungal agents
differs in terms of what molecule or processes are inhibited. The details of each
antifungal agent and its mode of action are discussed in chapter 6 (page 54).
These antifungal agents are usually recommended for the treatment of
candidosis and currently the most common Candida spp. have developed
resistance to these antifungal agents.
The identification of Candida isolates was done using 2 different types of
identification methods i.e., the chromogenic medium CHROMagar Candida and
the biochemical test kit API 10 Candida. The chromogenic medium was
inoculated with the Candida spp. supplied and incubated for 3 days at 37oC. The
API 10C test strips were loaded with the culture suspension and incubated for 24
hours at 37oC. For the screening of gliotoxin, 2 supplemented mediums were
used to cultivate the isolates that is the yeast extract sucrose (YES) and Eagles
minimal essential medium (EMEM) and the isolates were grown at 37oC for 72
days. The methods that were used to identify the gliotoxin were thin layer
chromatography (TLC) and high performance liquid chromatography (HPLC) to
quantify the levels of gliotoxin.