Browsing by Author "Rosa, Alcira Cristina"

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Candida parapsilosis sensu stricto can act as a pathobiont in conditions of oral dysbiosis
(2019) Rodriguez Coyago, Maria De lourdes; Rosa, Alcira Cristina; Jewtuchowicz, Virginia Marta
Recent publications have reported high prevalence of Candida parapsilosis Sensu Stricto in oral cavity niches. Our research group performed a pilot study in 2017 which showed that of the psilosis complex, Candida parapsilosis Sensu Stricto is the species most frequently isolated from oral cavity niches. Under inflammatory conditions, the probability of recovering it is almost four times higher, and it displays high- er biofilm-forming capacity in-vitro, differing significantly from isolates of the same species obtained in conditions of eubiosis. This led us to hypothesize that an oral environment in dysbiosis overregulates vir- ulent genes, promoting a more pathogenic phenotype. Accordingly, we decided to re-evaluate the in-vitro biofilm formation assay using a larger sample, under two nutritional conditions, using colorimetric meth- ods for quantification. In addition, the results obtained were validated by imaging techniques. For both clinical conditions (eubiosis and dysbiosis), high biofilm forming phenotype predominated with both reading methods, and for both nutritional conditions tested. XTT showed significant difference between absorbance values for isolates from buccal dysbiosis and eubiosis (P=0.0025). Candida parapsilosis Sensu Stricto cells that colonize oral cavity niches are basically strong biofilm formers, regardless of in vitro growing conditions. However, the oral cavity in dysbiosis probably promotes virulence in this species due to inheritable epigenetic modifications.
Ecological imbalance of the oral cavity improves the virulence of candida parapsilosis sensu stricto
(SciTech Central Conferences, 2020) Rodriguez Coyago, Maria De lourdes; Rosa, Alcira Cristina; Jewtuchowicz, Virginia Marta
Candida parapsilosis sensu stricto is the second to third most frequent cause of candidemia. Studies place this yeast as a frequent colonizer of niches of the oral cavity, predominantly in pathological conditions. We hypothesize that a buccal environment in dysbiosis enhances the virulence of C. parapsilosis sensu stricto. Objective: To evaluate at the phenotype and molecular level the production of biofilm in oral isolates of Candida parapsilosis sensu stricto, and correlate the results with the clinical origin (dysbiosis versus eubiosis). Material and methods: The biofilm-forming ability was compared in 50 oral isolates of Candida parapsilosis sensu stricto obtained from patients with and without oral dysbiosis; by quantification of biofilm biomass and metabolic activity. The results were corroborated by optical and confocal fluorescence microscopy, and correlated with the transcriptional activity of CPH2, by RT-qPCR. The data were analyzed by Excel 2010, and InfoStat 2018, with a 95% confidence interval. Results: The metabolic activity in biofilm was significantly higher in oral dysbiosis relative to control (p = 0.0025). Basal expression of CPH2 increased 2.8 times more in oral dysbiosis related to the control condition, and showed no significant differences with pathogenic isolates of this same yeast, derived from onychomycosis lesions. Conclusion: The oral cavity in dysbiosis increases the virulence of C. parapsilosis sensu stricto due to possible changes in epigenetic marks. This finding suggests that the oral cavity in dysbiosis may be an alternative route to the skin in the epidemiology of nosocomial candidemia.
Optimización de RT-PCR para la evaluación de RNA de la levadura cándida parapsilosis sensu stricto por dos métodos comerciales basados en sistema de purificación por columnas de sílice
(Asociación Argentina de Microbiología, Sociedad Argentina de Bacteriología, 2018) Rosa, Alcira Cristina; Rodriguez Coyago, Maria De lourdes
Oral dysbiosis exacerbates candida parapsilosis sensu stricto biofilm production via up-regulation of the CPH2 biofilm master gene
(2021) Nastri, María Lorena
Introduction: Candida parapsilosis sensu stricto is the second to third most frequent cause of candidemia. Studies place this yeast as a frequent colonizer of niches of the oral cavity, predominantly in pathological conditions. We hypothesize that a buccal environment in dysbiosis enhances the virulence of C. parapsilosis sensu stricto. Objective: To evaluate the phenotype and molecular level of the production of biofilm in oral isolates of Candida parapsilosis sensu stricto and correlate the results with the clinical origin (dysbiosis versus eubiosis). Materials and Methods: The biofilm-forming ability was compared in 50 oral isolates of Candida parapsilosis sensu stricto obtained from patients with and without oral dysbiosis; by quantification of metabolic activity. The results were corroborated by confocal fluorescence microscopy, and correlated with the transcriptional activity of CPH2, by RT-qPCR. The data were analysed by Excel 2010, and InfoStat 2018, with a 95% confidence interval. Results: The metabolic activity in biofilm was significantly higher in oral dysbiosis relative to control (p = 0.0025). Basal expression of CPH2 increased 2.8 times more in oral dysbiosis related to the control condition and showed no significant differences with pathogenic isolates of this same yeast, derived from onychomycosis lesions. Conclusion: The oral cavity in dysbiosis increases the virulence of C. parapsilosis sensu stricto due to possible changes in epigenetic marks. This finding suggests that the oral cavity in dysbiosis may be an alternative route to the skin in the epidemiology of nosocomial candidemia.
Oral dysbiosis exacerbates candida parapsilosis sensu stricto biofilm production via up-regulation of the CPH2 biofilm master gene
(2021) Rodríguez Coyago, María de Lourdes; Rosa, Alcira Cristina; Nastri, María Lorena; Jewtuchowicz, Virginia Marta
Introduction: Candida parapsilosis sensu stricto is the second to third most frequent cause of candidemia. Studies place this yeast as a frequent colonizer of niches of the oral cavity, predominantly in pathological conditions. We hypothesize that a buccal environment in dysbiosis enhances the virulence of C. parapsilosis sensu stricto. Objective: To evaluate the phenotype and molecular level of the production of biofilm in oral isolates of Candida parapsilosis sensu stricto and correlate the results with the clinical origin (dysbiosis versus eubiosis). Materials and Methods: The biofilm-forming ability was compared in 50 oral isolates of Candida parapsilosis sensu stricto obtained from patients with and without oral dysbiosis; by quantification of metabolic activity. The results were corroborated by confocal fluorescence microscopy, and correlated with the transcriptional activity of CPH2, by RT-qPCR. The data were analysed by Excel 2010, and InfoStat 2018, with a 95% confidence interval. Results: The metabolic activity in biofilm was significantly higher in oral dysbiosis relative to control (p = 0.0025). Basal expression of CPH2 increased 2.8 times more in oral dysbiosis related to the control condition and showed no significant differences with pathogenic isolates of this same yeast, derived from onychomycosis lesions. Conclusion: The oral cavity in dysbiosis increases the virulence of C. parapsilosis sensu stricto due to possible changes in epigenetic marks. This finding suggests that the oral cavity in dysbiosis may be an alternative route to the skin in the epidemiology of nosocomial candidemia.
Oral mucosa as a potential source of candidemia by Candida parapsilosis sensu stricto, under pathological conditions
(2018) Jewtuchowicz, Virginia Marta
Over the past 10 years, there have been increasingly frequent reports of colonization of niches in the oral cavity by Non-Candida Albicans Candida (NCAC) species. Among these species, Candida parapsilosis sensu stricto plays a major part both locally and systemically. Evidence shows that it may be the second most frequent yeast isolate, after Candida albicans, as commensal in the oral cavity and as pathogen in blood cultures of patients diagnosed with fungemia. Recent reports suggest that both its distribution and its virulence may be affected by environmental conditions and may increase in situations of oral dysbiosis. Based on this background, we hypothesize that oral mucosa in pathological condition may be a source of candidemia by Candida parapsilosis sensu stricto, when promoted by the conditions in the host. We reviewed the scientific databases in search of evidence which may support such hypothesis.
RNA extraction from the yeast candida parapsilosis sensu stricto using two commercial methods based on purification by silica columns
(2018) Rodriguez Coyago, Maria De lourdes; Rosa, Alcira Cristina; Jewtuchowicz, Virginia Marta
Good quality RNA needs to be obtained in order to study gene expression. Different RNA extraction methods have been described, but RNA quality and yield may vary among the different techniques and biological study species. To date, there is no standardized method for extraction and purification of RNA from Candida genus yeasts. The few available papers on the subject apply mainly to filamentous fungi and have produced poor results for extraction techniques based on manual or in-house IVD methods. The aim of this study was therefore to compare two commercial RNA extraction and purification systems using silica columns (Qiagen and Zymo Research) with Candida parapsilosis sensu stricto as model organism. This yeast has been identified in recent papers as the second most frequently isolated Candida species in the oral cavity. In the past decade, it has been the object of increasing medical interest because it is one of the main causes of candidemia in both adults and preterm neonates. In view of this background, we consider the study of Candida parapsilosis sensu stricto transcriptome and its variations according to environmental changes to be a priority. In this experimental study, 19 fungal isolates were processed using Qiagen and 17 isolates using Zymo Research. The results suggest that Qiagen lysis buffer RLT is essential for obtaining better quality RNA product.
The oral cavity promotes virulence of candida parapsilosis sensu stricto via up- regulation of BCR1
(2020) Rodriguez Coyago, Maria De lourdes; Alcaraz, Eliana Sabrina; Rosa, Alcira Cristina; Jewtuchowicz, Virginia Marta
Candida parapsilosis sensu stricto behaves as a frequent colonizer of niches of the oral cavity, predominantly in pathological conditions. Studies have suggested the influence of the ecological niche in the virulence of C. parapsilosis. Given this background, we hypothesize that the conditions of the niche affect the virulence of C. parapsilosis sensu stricto due to inheritable epigenetic changes. Measure and compare the virulence, at the phenotype and molecular level, of clinical isolates of C. parapsilosis sensu stricto from different niches and clinical conditions. Biofilm-forming ability was compared in 20 clinical isolates of C. parapsilosis sensu stricto obtained from blood (candidemia), skin (onychomycosis), and oral cavity (eubiosis and dysbiosis); by quantification of biofilm biomass, and metabolic activity. The results were corroborated by optical microscopy and correlated with the basal expression of the global biofilm regulator BCR1 by RT-PCR. Biofilm production and baseline BCR1 expression were significantly different depending on the ecological niche and the clinical origin of the isolates. The oral cavity exerts a preponderant role in the modulation of the virulence of this yeast via regulation of BCR1. The biofilm-forming ability in C. parapsilosis sensu stricto is dependent on the strain, but can be modulated by environmental conditions or ecological niche via epigenetic regulation of global biofilm regulators such as BCR1.