Isolation of Candida dubliniensis in an Aboriginal Community in Ontario, Canada

Abstract

This study reports the first isolation of Candida dubliniensis from North American Indians. Of 39 healthy human hosts sampled, two had C. dubliniensis. Genotypic analysis identified polymorphisms in these strains and differences from two reference strains. Our results suggest that yeast populations from indigenous communities in North America may be unique.Candida dubliniensis is a newly described species with a close genetic similarity to the more common Candida albicans (9). Though C. dubliniensis has been recovered from several body sites in many human populations, it is most often recovered from the oral cavities of patients infected with human immunodeficiency virus (2,3,9). One hypothesis for the current global distribution of C. dubliniensis is the recent massive migrations of the human hosts, especially during the last century. If this hypothesis is correct, we expect that healthy human populations living in relative isolation should have no or very low percentages of C. dubliniensis. Furthermore, if such strains exist, their genotypes might be different from the genotypes found in other communities. Many aboriginal communities in North America are ideal populations to study to test this hypothesis.We sampled yeast populations from healthy human hosts in the Six Nations and New Credit reserves in southern Ontario, Canada. These reserves were established in 1847 by the British government and currently occupy an area of about 20,000 ha with a population of about 17,000. The ancestors of the residents of these reserves were living in the Great Lakes region for thousands of years, long before the discovery of the New World about 500 years ago (5). These populations have remained relatively isolated, in human population genetics terms, from new immigrants and from surrounding nonnative communities, before and after the establishment of these reserves about 150 years ago (5). Participation in our survey was voluntary (parents gave consent for their children) and based on their availability from April to June in 2002. A total of 39 healthy individuals were recruited and agreed to participate. Their ages ranged from 4 to 75 years. Most individuals spent almost all their time on the reserves. Each individual was sampled three times in 2002: mid-April, mid-May, and midJune. All hosts were healthy during the time of sampling, and none had human immunodeficiency virus infection before or during our sampling period. Sampling was done as described previously (4). A total of 351 samples were collected (three samples from three body sites from each of 39 hosts).Swabs and nail samples were directly deposited into microcentrifuge tubes containing 0.5 ml of sterile water. Each sample was vigorously vortexed, and liquid suspension was spread plated onto CHROMAgar Candida (CHROMAgar Company, Paris, France). Morphologically distinct green colonies from CHROMAgar plates were identified as either C. dubliniensis or C. albicans on the basis of carbohydrate metabolic profiles on API 20C strips (profiles typical of those for C. al...

Candida dubliniensis: Ten years on

“…There is also a lack of agreement in the literature concerning the prevalence of C. dubliniensis in the oral cavities of non-HIV-infected normal healthy individuals. In most studies published to date, C. dubliniensis has been absent or present at very low levels in this group [3,8,9]. However, oral infections caused by C. dubliniensis have been observed in healthy individuals [10] and relatively high prevalence rates of C. dubliniensis have been found in patients suffering from diabetes [11].…”

Prevalência de Candida spp e xerostomia em pacientes com líquen plano oral. Um estudo grupo-controle

“…A identificação de espécie C. dubliniensis constitui achado pouco comum, dado que esta espécie é mais encontrada em pacientes imunossuprimidos (Campanha et al, 2002) . A este respeito, ou seja, a identificação de C. dubliniensis em indivíduos imunocompetentes, deve-se salientar os resultados do estudo de Montour et al (2003), no qual C. dubliniensis foi isolada e identificada em população aborígene do Canadá (em 1,1% das amostras coletadas), sugerindo que esta levedura possa estar presente na microbiota oral endógena.…”

“…A espécie considerada mais patogênica e freqüentemente associada com a candidose oral é a C. albicans, mas outras espécies menos patogênicas podem estar envolvidas como C.glabrata, C. tropicalis, C. parapsilosis, C. krusei (Kleinegger et al, 1996;Oliveira et al, 2007). Cabe lembrar que uma nova espécie de Candida a C. dubliniensis também foi associada à candidose oral principalmente em pacientes imunodeprimidos, entretanto pode também ser encontrada na cavidade oral de indivíduos imunocompetentes (Montour et al, 2003 Pacientes LPO possuem a mucosa inflamada apresentando textura diferente da mucosa não-afetada, o que pode contribuir para a sensação de boca seca, mesmo que a mensuração do fluxo salivar total não esteja relacionada com a queixa.…”

Características sociodemográficas, alterações orais e prevalência da Candida spp em pacientes com transtornos alimentares

“…Em um estudo com uma população aborígene do Canadá (Montour et al, 2003), verificou que a C. dubliniensis foi isolada e identificada em 1,1% das amostras coletadas, sugerindo que esta levedura possa estar presente na microbiota oral endógena. Pacientes que sofrem de TAs purgativos tem um alto risco para a erosão dental (Schlueter et al, 2012 (Frydrych et al, 2005).…”