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[Isolation, identification, and typing of yeasts from HIV-positive patients with oral candidiasis]
G Martínez Machín1, M Perurena Lancha, J Núñez Carvajal
1Instituto de Medicina Tropical Pedro Kourí, Ciudad de La Habana, Cuba.
Abstract:
A study of oral candidiasis was conducted among 25 HIV-positive and AIDS patients. The predominant clinical form of presentation was the pseudomembranous one, whereas the most frequently yeast species found in the isolations were: Candida albicans (54.1%), Candida tropicalis (8.1%), and Torulopsis glabrata (8.1%). It was demonstrated that patients with recurrent infections have colonization of the oral cavity by multiple strains and/or yeast species more often (30.8%) than those through their first episode of oral candiadisis (12.5%). Of the 3 culture media used for the initial isolation, the combination of the potatodextrose agar (PDA) with Sabouraud triphenytletrazolium agar (STA) allowed to obtain the maximum isolation and differentiation among strains. The Sabouraud agar (SA), the most used medium to these ends at the international level, proved to be less useful than the previous ones. The STA was very efficient in the studies of phenotypic typing of most of the isolated yeast species and specially of C. albicans, which will make possible to approach epidemiological studies.
Insights
This study on oral candidiasis in HIV/AIDS patients found Candida albicans is the most common cause. Recurrent infections are linked to multiple yeast strains, and a potato dextrose agar/Sabouraud triphenytletrazolium agar combination aids diagnosis.
Area of Science:
- Medical Mycology
- Infectious Diseases
- HIV/AIDS Research
Background:
- Oral candidiasis is a common opportunistic infection in individuals with HIV/AIDS.
- Pseudomembranous candidiasis is the predominant clinical presentation in this population.
- Understanding yeast species and strain diversity is crucial for managing recurrent infections.
Purpose of the Study:
- To investigate the prevalence and species of Candida causing oral candidiasis in HIV-positive and AIDS patients.
- To identify risk factors associated with recurrent oral candidiasis.
- To evaluate the efficacy of different culture media for yeast isolation and strain differentiation.
Main Methods:
- A cohort of 25 HIV-positive and AIDS patients with oral candidiasis was studied.
- Yeast species were isolated and identified using three different culture media: potato dextrose agar (PDA), Sabouraud triphenytletrazolium agar (STA), and Sabouraud agar (SA).
- Phenotypic typing was performed, particularly for Candida albicans.
Main Results:
- Candida albicans was the most frequently isolated yeast (54.1%), followed by Candida tropicalis and Torulopsis glabrata (8.1% each).
- Patients with recurrent oral candidiasis showed higher rates of oral colonization by multiple yeast strains/species (30.8%) compared to initial episodes (12.5%).
- The combination of PDA and STA yielded maximum isolation and differentiation, outperforming standard Sabouraud agar (SA). STA proved efficient for phenotypic typing.
Conclusions:
- Candida albicans is the primary agent of oral candidiasis in this HIV/AIDS cohort.
- Multiple yeast strains/species colonization is associated with recurrent oral candidiasis.
- The PDA/STA medium combination offers superior diagnostic utility for oral candidiasis in immunocompromised patients, facilitating epidemiological studies.