Racial Distribution of
 Candida dubliniensis
 Colonization among South Africans

Blignaut, E; Pujol, Claude; Joly, Sophie; Soll, David R.

doi:10.1128/jcm.41.5.1838-1842.2003

Cited by 32 publications

(28 citation statements)

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“…In fact, a study by McCullough et al [23] reported that genotypic differences among C. dubliniensis may be related to ethnic or racial differences between Jews, Arabs and Druse, despite the fact that they inhabit the same geographic area. A racial preference of C. dubliniensis has also been suggested in another study from South Africa, where 16% of oral cavities of healthy white individuals were colonized with the species, whereas the isolation rate among healthy blacks was 0% [24] . Secondly, C. dubliniensis is closely related to C. albicans in evolutionary terms, sharing the latter's properties of commensalism and opportunistic infection with genomic similarities between these two species, with the vast majority of genes being approximately 90% homologous.…”

Section: Discussionmentioning

confidence: 90%

Prevalence of Candida dubliniensis among Oral Candida Isolates in Patients Attending the Kuwait University Dental Clinic

Ellepola¹,

Khan

Joseph³

et al. 2011

Med Princ Pract

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Objectives: The aim of this study was to determine the oral candidal carriage of patients seeking dental treatment at the Kuwait University Dental Clinic and to ascertain the Candida species composition among them. Methods: 370 oral rinse samples were collected from patients. The germ tube test, CHROMagar Candida medium and VITEK 2 yeast identification system were used for species identification. C. dubliniensis isolates were confirmed by the production of rough colonies with hyphal fringes and chlamydospores on simplified sunflower seed agar. Results: Of the 370 samples investigated, 160 (43.24%) showed Candida in culture. The isolation of Candida was significantly higher in individuals who were smokers or were under medication for either diabetics or asthma [99 (62%)] compared to healthy individuals [61 (38%)]. Of the 210 samples which did not yield Candida, 131 (62.38%) were healthy and 79 (37.62%) were associated with smoking or with usage of drugs for aforementioned conditions. Species isolated were C. albicans [102 (63.7%)], C. dubliniensis [23(14.3%)], C. krusei [13 (8.1%)], C. tropicalis [12 (7.5%)] and C. glabrata [10 (6.2%)]. Conclusions:Candida species were more prevalent in patients having predisposing factors implicated in oral candidosis, such as in smokers, diabetic patients and asthmatic patients using inhalation steroids. C. albicans was the most prevalent species isolated, followed by C. dubliniensis.

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Section: Discussionmentioning

confidence: 90%

Prevalence of Candida dubliniensis among Oral Candida Isolates in Patients Attending the Kuwait University Dental Clinic

Ellepola¹,

Khan

Joseph³

et al. 2011

Med Princ Pract

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“…Of the 82 tested isolates, 61 were members of the group I clade and 21 were members of group II ( Fig. 1) (7,11,20). EcoRI-digested DNA of all 82 isolates hybridized to either MTLa1 alone (a/a), the two MTL␣ probes alone (␣/␣), or all three probes (a/␣) (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The collection of 82 C. dubliniensis strains used in this study were DNA fingerprinted with the complex probe Cd25 (7,11,20). It included 61 from the group I clade and 21 from group II, a less closely related group of isolates than those of group I (see Fig.…”

Section: Methodsmentioning

confidence: 99%

The Closely Related Species Candida albicans and Candida dubliniensis Can Mate

et al. 2004

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Because Candida dubliniensis is closely related to Candida albicans, we tested whether it underwent whiteopaque switching and mating and whether white-opaque switching depended on MTL homozygosity and mating depended on switching, as they do in C. albicans. We also tested whether C. dubliniensis could mate with C. albicans. Sequencing revealed that the MTL␣ locus of C. dubliniensis was highly similar to that of C. albicans. Hybridization with the MTLa1, MTLa2, MTL␣1, and MTL␣2 open reading frames of C. albicans further revealed that, as in C. albicans, natural strains of C. dubliniensis exist as a/␣, a/a, and ␣/␣, but the proportion of MTL homozygotes is 33%, 10 times the frequency of natural C. albicans strains. C. dubliniensis underwent white-opaque switching, and, as in C. albicans, the switching was dependent on MTL homozygosis. C. dubliniensis a/a and ␣/␣ cells also mated, and, as in C. albicans, mating was dependent on a switch from white to opaque. However, white-opaque switching occurred at unusually high frequencies, opaque cell growth was frequently aberrant, and white-opaque switching in many strains was camouflaged by an additional switching system. Mating of C. dubliniensis was far less frequent in suspension cultures, due to the absence of matingdependent clumping. Mating did occur, however, at higher frequencies on agar or on the skin of newborn mice. The increases in MTL homozygosity, the increase in switching frequencies, the decrease in the quality of switching, and the decrease in mating efficiency all reflected a general deterioration in the regulation of developmental processes, very probably due to the very high frequency of recombination and genomic reorganization characteristic of C. dubliniensis. Finally, interspecies mating readily occurred between opaque C. dubliniensis and C. albicans strains of opposite mating type in suspension, on agar, and on mouse skin. Remarkably, the efficiency of interspecies mating was higher than intraspecies C. dubliniensis mating, and interspecies karyogamy occurred readily with apparently the same sequence of nuclear migration, fusion, and division steps observed during intraspecies C. albicans and C. dubliniensis mating and Saccharomyces cerevisiae mating.Beginning in 1990, a number of studies of the genetic relatedness of Candida albicans isolates derived from human immunodeficiency virus (HIV)-positive individuals identified atypical strains (9,29,31,33,49). These strains were subsequently grouped into the separate species C. dubliniensis in 1995 by Coleman, Sullivan, and coworkers (52). This new species shared a number of phenotypic characteristics with C. albicans, including two that in the past had been used to distinguish C. albicans from other species, namely, chlamydospore and true hypha formation (52). Like C. albicans, C. dubliniensis was diploid, contained a homolog to the dispersed complex repeat sequence RPS, and underwent the bud-hypha transition and colony-based 3153A-like phenotypic switching (10,17,19,37,50,51). The basic phenotypic char...

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“…Associations between certain Candida species and particular geographical regions and racial groups have been reported previously. A recent study (5) suggested that in South Africa, C. dubliniensis colonization is influenced more by race than by HIV infection status. However, no South Africa-specific clade was identified.…”

Section: Discussionmentioning

confidence: 99%

“…An S AB of 1.00 represents identical patterns, and S AB s ranging from 0.01 to 0.99 represent patterns with increasing proportions of bands at the same positions. A selection of Cd25-generated fingerprint patterns from EcoRI-digested DNA from an international collection of C. dubliniensis isolates from the study of Gee et al (18) from this laboratory were used with DENDRON to generate mixed dendrograms with the fingerprint pattern data generated with the Saudi Arabian, Egyptian, and Israeli isolates as described previously (5,43).…”

Section: Methodsmentioning

confidence: 99%

Novel 5-Flucytosine-Resistant Clade of Candida dubliniensis from Saudi Arabia and Egypt Identified by Cd25 Fingerprinting

et al. 2005

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DNA fingerprinting of Candida dubliniensis isolates using the species-specific probe Cd25 previously showed that this species consists of two distinct groups, termed Cd25 group I and Cd25 group II. The present study investigated the population structure of 30 C. dubliniensis oral isolates from Saudi Arabia and Egypt using Cd25 fingerprinting and rRNA gene internal transcribed spacer region-based genotyping. Cd25 fingerprinting analysis of these isolates revealed two distinct populations, the first of which consisted of 10 closely related genotype 1 isolates (average similarity coefficient [S AB ] value, 0.86). The second population of 20 isolates was much more heterogeneous (average S AB value, 0.35) and consisted of two distinct subpopulations, one of which consisted of genotype 3 isolates (n ‫؍‬ 13) and the other of genotype 4 isolates (n ‫؍‬ 7). A mixed dendrogram generated from the fingerprint data from the 30 Saudi Arabian and Egyptian isolates, 5 Israeli isolates, and 51 previously characterized international isolates (32 of Cd25 group I and 19 of Cd25 group II) revealed the presence of three distinct main clades. The first corresponded to the previously described Cd25 group I and contained all the Saudi Arabian, Egyptian, and Israeli genotype 1 isolates mixed with international isolates. The second clade corresponded to the previously described Cd25 group II and contained three Israeli isolates, one genotype 2 isolate, one genotype 3 isolate, and a genotype 4 variant isolate, which were mixed with international isolates. The third clade has not been described before and consisted solely of the 20 Saudi Arabian and Egyptian genotype 3 and 4 isolates identified in this study and a previously described genotype 4 Israeli isolate. All 20 Cd25 group III isolates exhibited high-level resistance to 5-flucytosine (MIC > 128 g/ml), whereas all Cd25 group I and Cd25 group II isolates tested (10 Saudi Arabian and Egyptian, 16 Israeli, and 24 international) were susceptible to 5-flucytosine (MIC < 0.125 g/ml). The results of this study show for the first time the presence of a novel 5-flucytosine-resistant clade of C. dubliniensis (Cd25 group III) that is predominant among isolates from Saudi Arabia and Egypt and absent from a previously characterized international collection of 98 isolates from 15 countries.

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Racial Distribution of Candida dubliniensis Colonization among South Africans

Abstract: Candida dubliniensis is a yeast species that has only recently been differentiated from

Cited by 32 publications

References 28 publications

Prevalence of <i>Candida dubliniensis</i> among Oral <i>Candida</i> Isolates in Patients Attending the Kuwait University Dental Clinic

Prevalence of <i>Candida dubliniensis</i> among Oral <i>Candida</i> Isolates in Patients Attending the Kuwait University Dental Clinic

The Closely Related Species Candida albicans and Candida dubliniensis Can Mate

Novel 5-Flucytosine-Resistant Clade of Candida dubliniensis from Saudi Arabia and Egypt Identified by Cd25 Fingerprinting

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