Mycology
Antifungal susceptibility of South African oral yeast isolates from HIV/AIDS patients and healthy individuals

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Abstract

The in vitro antifungal susceptibility profile of 589 oral yeast isolates from HIV/AIDS patients and healthy South Africans was determined against amphotericin B, nystatin, 5-fluorocytosine (5-FC), clotrimazole, miconazole, ketoconazole, itraconazole and fluconazole. The broth microdilution method of the National Committee on Clinical Laboratory Standards was used and MIC50 and MIC90 determined. A 100% susceptibility to fluconazole was observed among the 466 isolates of Candida albicans. Among C. krusei, the second most common isolate, only 2.6% of isolates were susceptible to fluconazole and itraconazole. Despite the lack of previous exposure to antifungal agents, very little difference was observed in the antifungal profile between the South African isolates and isolates from the United States (U.S.), Canada and South America. South Africa has a particularly high incidence of HIV-infection and oral candidiasis is the most common oral complication in these patients. This study provides important baseline data as the isolates were collected prior to fluconazole being made freely available to HIV/AIDS patients attending government health clinics.

Introduction

An estimated 4 to 5 million South Africans are presently infected with the Human Immunodeficiency Virus (HIV) Coetzer et al 2000, Joint United Nations programme on HIV/AIDS 2000 and it is expected that 7 million will be infected by 2005 (Wood et al., 2000). The vast majority of HIV infected patients are dependent on government health services. Similar to elsewhere in the world, oropharyngeal candidiasis (OPC) is the most prevalent oral complication in HIV/AIDS patients Glick et al 1994, Greenspan et al 1990, Teanpaisan and Nittayananta 1998 with a reported prevalence of 30–37% in patients from two different geographic regions in South Africa Arendorf et al 1998, Blignaut et al 1999. Access to antifungal therapy has been limited and fluconazole was not available to HIV/AIDS patients until recently due to the high cost. Recently this drug has been donated by the manufacturer to South African government institutions, for the treatment of opportunistic fungal infections in such patients.

Most clinical laboratories operated by government hospitals do not routinely perform antifungal testing, as is the case with bacteria isolated from clinical specimens. Little is known about the antifungal susceptibility profiles among South Africa clinical yeast isolates. This study represents the first information on the antifungal susceptibility of oral yeast isolates, collected over a four year period, from confirmed HIV positive cases in Gauteng, South Africa. It is generally accepted that Candida albicans is the most commonly isolated species from clinical specimens (Pfaller, 1994). However, it has been observed that Candida albicans was not the most frequently isolated oral yeast species in healthy individuals living in remote rural areas of South Africa Blignaut et al 1995, Blignaut et al 1996. Because many patients attending the urban and semi-urban HIV/AIDS clinics are from rural communities, it was decided to include oral yeast isolates from healthy individuals from both urban and rural settings in this study.

Section snippets

Test organisms

Five hundred and eighty nine oral isolates of yeast species (554 Candida spp. and 35 non-Candida yeasts) were tested. Isolates were obtained from confirmed HIV/AIDS patients attending three different comprehensive care AIDS clinics in Pretoria and GaRankuwa, Gauteng (339 isolates), and from healthy individuals in urban Pretoria and a rural region in the Northern Province, South Africa (250 isolates). Healthy volunteers were selected from staff and patients seeking dental care at the Oral and

Results and discussion

Among the 554 isolates of Candida spp. in the study, 330 were from HIV infected individuals (302 C. albicans, 17 C. krusei, 4 C. tropicalis, 3 C. parapsilosis, 2 C. glabrata, 2 C. dubliniensis) and 224 were from non-HIV infected individuals (164 C. albicans, 21 C. krusei, 8 C. dubliniensis, 8 C. lusitaniae, 6 C. parapsilosis, 7 C. glabrata, 5 C. tropicalis, 2 C. rugosa, 2 C. guilliermondii, and 1 C. kefyr). The 35 non-Candida yeasts were largely (83%) isolated from the oral cavities of non-HIV

Acknowledgements

This project was supported by a Fogarty International Research Fellowship from the NIH (TW05473). We thank Linda Elliott for excellent assistance in the preparation of this manuscript.

References (26)

  • J.D. Cartledge et al.

    Clinically significant azole cross-resistance in Candida isolates from HIV-positive patients with oral candidosis

    AIDS

    (1997)
  • P.W.W. Coetzer et al.

    Public health in South Africa

    Public Health Medicine

    (2000)
  • D.J. Diekema et al.

    In vitro activities of BMS-207147 against over 600 contemporary clinical bloodstream isolates of Candid species from the SENTRY antimicrobial surveillance program in North America and Latin America

    Antimicrobial Agents and Chemotherapy

    (1999)
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    1

    Dr. Blignaut was a visiting Fogarty Scholar from the Department of Stomatological Studies, Medical University of Southern Africa, MEDUNSA, South Africa.

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