Recovery and studies on chlamydospore-negative Candida albicans isolated from clinical specimens

Al-Hedaithy, Saleh S. A.; Fotedar, R.

doi:10.1080/714031115

Cited by 10 publications

(23 citation statements)

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“…The difference between these two codes is because of the variable assimilation of α‐methyl‐ d ‐glucoside shown by C. africana. 3,7 Moreover, our profile represents the most recurrent profile found among the chlamydospore‐negative C. albicans strains studied by Al‐Hedaithy & Fotedar [6] indicating that those strains probably belong to C. africana . Interestingly, the majority of the C. africana isolates were obtained from vaginal swabs suggesting, according to Al‐Hedaithy & Fotedar [6], an enhanced ability of these atypical strains to cause vaginitis.…”

Section: Resultsmentioning

confidence: 63%

Morphological, biochemical and molecular characterisation of the first Italian Candida africana isolate

Romeo

Criseo

2009

Mycoses

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One atypical isolate of the pathogenic yeast Candida albicans was isolated from an Italian patient with vulvovaginitis. The strain, germ tube positive and chlamydospore-negative showed white-thin turquoise colonies on Candida ID 2 medium. The yeast was identified as Candida africana by using morphological and biochemical tests. On the basis of the molecular results obtained in this study as well as in other studies, C. africana cannot be yet considered as a new species of Candida. It is possible that C. africana represents a new variant of C. albicans like the well-known Candida stellatoidea. To our knowledge, this is the first isolation of C. africana in Italy.

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Section: Resultsmentioning

confidence: 63%

Morphological, biochemical and molecular characterisation of the first Italian Candida africana isolate

Romeo

Criseo

2009

Mycoses

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“…They were identified as C. albicans on the basis of a positive germ tube test result, production of chlamydospores in cornmeal agar, and resistance to cycloheximide when they were grown on cycloheximide (500 g/ml)-containing medium (1). These isolates were reexamined to explore if any of them were actually C. dubliniensis and not C. albicans.…”

Section: Methodsmentioning

confidence: 99%

Candida dubliniensis at a University Hospital in Saudi Arabia

Fotedar

Hedaithy

2003

J Clin Microbiol

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Candida dubliniensis is a newly described yeast species that is a close phylogenetic relative of C. albicans. Although it has been reported from different parts of the world, no detailed investigation of this species has been done in Saudi Arabia. The purpose of the present study was to identify C. dubliniensis isolates recovered from clinical specimens at a tertiary-care hospital in Riyadh, Saudi Arabia, and to determine the drug susceptibility profiles of those isolates. Over a period of 8 months, 823 germ tube-and chlamydospore-positive yeasts identified as C. albicans and recovered from different clinical specimens were screened for their ability to grow at 45°C on Sabouraud dextrose agar. Isolates which failed to grow at 45°C were presumptively identified as C. dubliniensis. The species identities were further confirmed by the production of pseudohyphae and chlamydospores on Staib agar and their inability to assimilate D-xylose and ␣-methyl-D-glucoside by using the API 20C AUX system. A total of 27 (3.3%) isolates were identified as C. dubliniensis. They were all recovered from 23 human immunodeficiency virus-negative patients. The prevalence of C. dublinensis in bronchoalveolar lavage (33.3%), oral (16.7%), and blood (16.7%) specimens was high. In addition, 33 isolates previously identified as C. albicans and preserved among our stock blood culture isolates were also recruited for the study. Of these, 5 isolates were found to be C. dubliniensis, thus making the total number of isolates identified as this species 32. Antifungal susceptibility testing of the C. dubliniensis isolates showed 100% sensitivity to amphotericin B, 97% sensitivity to each of fluconazole and ketoconazole, and 87.5% sensitivity to itraconazole. However, in contrast to other studies, the majority of the isolates (65.6%) showed high levels of resistance to flucytosine (MIC > 64 g/ml). Further studies are warranted to investigate the cause of this unusually high rate of resistance to flucytosine of the C. dubliniensis isolates in this region.

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“…However, a potential role is suggested by the fact that the only Candida species that characteristically form chlamydospores, C. albicans and Candida dubliniensis, are two of the most prevalent human fungal pathogens. In fact, chlamydospore formation is an important diagnostic tool for distinguishing between different Candida species since the majority of C. albicans clinical isolates retain the ability to form chlamydospores (2,3). These observations raise the possibility that this conserved process contributes an advantage for growth as either a commensal or a pathogen in human hosts.…”

mentioning

confidence: 98%

Cell Cycle Dynamics and Quorum Sensing inCandida albicansChlamydospores Are Distinct from Budding and Hyphal Growth

Martin¹,

Douglas

Konopka

2005

Eukaryot Cell

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The regulation of morphogenesis in the human fungal pathogen Candida albicans is under investigation to better understand how the switch between budding and hyphal growth is linked to virulence. Therefore, in this study we examined the ability of C. albicans to undergo a distinct type of morphogenesis to form large thick-walled chlamydospores whose role in infection is unclear, but they act as a resting form in other species. During chlamydospore morphogenesis, cells switch to filamentous growth and then develop elongated suspensor cells that give rise to chlamydospores. These filamentous cells were distinct from true hyphae in that they were wider and were not inhibited by the quorum-sensing factor farnesol. Instead, farnesol increased chlamydospore production, indicating that quorum sensing can also have a positive role. Nuclear division did not occur across the necks of chlamydospores, as it does in budding. Interestingly, nuclei divided within the suspensor cells, and then one daughter nucleus subsequently migrated into the chlamydospore. Septins were not detected near mitotic nuclei but were localized at chlamydospore necks. At later stages, septins localized throughout the chlamydospore plasma membrane and appeared to form long filamentous structures. Deletion of the CDC10 or CDC11 septins caused greater curvature of cells growing in a filamentous manner and morphological defects in suspensor cells and chlamydospores. These studies identify aspects of chlamydospore morphogenesis that are distinct from bud and hyphal morphogenesis.

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Recovery and studies on chlamydospore-negative Candida albicans isolated from clinical specimens

Cited by 10 publications

References 0 publications

Morphological, biochemical and molecular characterisation of the first Italian Candida africana isolate

Morphological, biochemical and molecular characterisation of the first Italian Candida africana isolate

Candida dubliniensis at a University Hospital in Saudi Arabia

Cell Cycle Dynamics and Quorum Sensing inCandida albicansChlamydospores Are Distinct from Budding and Hyphal Growth

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