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Int J Mol Epidemiol Genet 2012;3(1):84-90

Original Article
Fluconazole susceptibility and ERG11 gene expression in vaginal candida
species isolated from Lagos Nigeria

Victoria K Pam, Juliet  U Akpan, Oyinlola O Oduyebo, Francisca O Nwaokorie, Muinah A Fowora, Rita O Oladele, Folasade T
Ogunsola, Stella I Smith

Department of Microbiology, University of Jos. Nigeria; Department of Medical Microbiology and Parasitology, Collage of
Medicine, University of Lagos. Nigeria; Molecular Biology and Biotechnology Division, Nigerian Institute of Medical Research
Yaba, Lagos. Nigeria

Received August 28, 2011; Accepted February 20, 2012; Epub February 25, 2012; Published March 15, 2012

Abstract: Fluconazole resistance is an important type of resistance in Candida because in most countries, fluconazole is the
drug of choice for vulvovaginal candidiasis. Candida species resist fluconazole by various mechanisms but there is paucity of
data on these in our environment. Such mechanisms include among others, over-expression of the ERG11 gene, which codes
for synthesis of the target enzymes in the fungus. The aim of this study was to screen Candida spp. resistant to fluconazole for
the expression of ERG11 gene. Fluconazole susceptibility test was performed on 28 clinical strains of Candida species
previously obtained from students of a School of Nursing in Lagos, Nigeria. They were identified by API Candida, CHROMagar
candida and germ tube test. Using 25 mcg discs, fluconazole susceptibility was determined by the disc diffusion method and
results were interpreted in accordance with the Clinical Laboratory Standard Institute (CLSI) criteria; sensitive (S), resistant (R)
and susceptible dose dependent (SDD). The R and SDD isolates were subsequently evaluated for the presence of ERG11
gene. Of the 28 clinical isolates, 14 were identified as C. albicans and six as C. tropicalis.  The remaining isolates were
identified as C. glabrata (2), C. famata (2) C. kefyr (2) one each of C. parapsilosis and C. guilliermondii respectively.  In this
study, 18 were susceptible (S) to fluconazole, eight were SDD and two were resistant to the antifungal agent. Out of the 14 C.
albicans isolates, 12 were susceptible, one showed high level resistance and similar number showed susceptible dose
dependence. ERG11 was detected in three susceptible dose dependent Candida species. This analysis demonstrates that
susceptible dose dependence should not be overlooked as it may be associated with the presence of ERG11 gene and
resistance to fluconazole. There is a need to consider routine antifungal susceptibility testing for Candida species causing
vulvovaginitis. (IJMEG1108004).

Key words: Fluconazole, ERG11 gene, candida species, antifungal susceptibility

Address all correspondence to:
Nwaokorie Francisca Obiageri, PhD
Molecular Biology and Biotechnology Division
Nigerian Institute of Medical Research
PMB 2013 Yaba
Lagos, Nigeria.
Phone: 234 1 08037173766
E-mail: franoby@yahoo.com