Distribution Of Yeast Species Research Articles

Species and antifungal susceptibility profile of agents causing vulvovaginal candidiasis in a military population: a cross-sectional study.

Military women on active duty are exposed to constant physical and mental demands, which may predispose them to some infection risks, including vulvovaginal candidiasis (VVC), a pathology considered a global public health problem. To monitor the prevalent and emerging pathogens in VVC, this study aimed to evaluate the distribution of yeast species and their in vitro antifungal susceptibility profile. We studied 104 vaginal yeast specimens obtained during routine clinical examinations. The population was attended at the Medical Centre of the Military Police, São Paulo, Brazil, and was divided into two groups: infected patients (VVC) and colonised patients. Species were identified by phenotypic and proteomic methods (MALDI-TOF MS) and susceptibility to eight antifungal drugs, including azoles, polyenes and echinocandins, was determined using microdilution broth. Candida albicans stricto sensu was found to be the most frequently isolated species (55%), but we observed a considerable rate of other Candida species isolates (30%), including Candida orthopsilosis stricto sensu only on the infected group. There were also other rare genera such as Rhodotorula, Yarrowia and Trichosporon (15%), of which Rhodotorula mucilaginosa was the most prevalent in both groups. Fluconazole and voriconazole had the highest activity against all species in both groups. Candida parapsilosis was the most susceptible species, except for amphotericin-B in the infected group. Of note, we observed unusual resistance in C. albicans. Our results have allowed us to compile an epidemiological database on the aetiology of VVC to support the empirical treatment and improve the health care of military women.

Species of Yeasts Identified from Different Clinical Samples Addis Ababa, Ethiopia

Background Currently, fungal diseases in humans are among the most problematic illnesses. This is the result of an increase in opportunistic fungal infections caused by a rise in the number of immune-compromised patients. Particularly, yeasts are the most common cause of fungal infections leading to a range of superficial types to life-threatening invasive infections. The aim of this study is to determine the species distribution of yeasts particularly of Candida species recovered from different clinical samples. Method A cross sectional study was conducted from January 2018 to September 2018 in Addis Ababa, Ethiopia. Specimen from Oropharyngeal, nail, eye’s cornea, and vaginal were collected from patients with signs and symptoms of infections. Identification was performed by using a YST card through VITEK 2 compact system. All data were coded, double-entered and analyzed using SPSS version 20. Result 174 yeasts were recovered of which 51.1% were Candida albicans, 43.1% were nonalbicans Candida species and 5.7% were yeasts other than Candida species. Eighteen (18) different types of yeast species were identified from different clinical samples. All recognized yeast is considered as a causative agent of fungal infection in previously reported data worldwide. Conclusion C. albicans remaining the predominant species, but the emergence of non-albicans Candida and other than candida species have increased. Thus, more studies on Candida prevalence are needed throughout country.

Genetic relatedness among azole-resistant Candida tropicalis clinical strains in Taiwan from 2014 to 2018

To monitor trends in the distribution of yeast species and the susceptibilities of these species to commonly prescribed antifungal drugs, we conduct the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) every 4 years. We found that 25 of 294 Candida tropicalis isolates from TSARY 2014 and 31 of 314 C. tropicalis isolates from TSARY 2018 were resistant to fluconazole. We determined the genetic relatedness among fluconazole-resistant C. tropicalis isolates by multilocus sequence typing (MLST). Among 174 C. tropicalis isolates, including all 56 fluconazole-resistant, all 26 susceptible-dose dependent and 92 selected fluconazole-susceptible isolates, 59 diploid sequence types (DSTs) were identified. We found that 22 of the 25 fluconazole-resistant C. tropicalis from TSARY 2014 and 29 of the 31 fluconazole-resistant C. tropicalis from TSARY 2018 were genetically related and belonged to the same cluster (clade 4). A combination of mutation and overexpression of ERG11, encoding the target of azole drugs, was the major mechanism contributing to drug resistance. Approximately two-thirds of reviewed patients infected or colonised by fluconazole-resistant C. tropicalis were azole-naïve. Furthermore, there was no evidence of patient-to-patient transmission. Because the clade 4 fluconazole-resistant C. tropicalis strain persists in Taiwan, it is important to identify the source of azole-resistant C. tropicalis to prevent the spread of this resistant strain.

Distribution of Yeast Species and Risk Factors of Oral Colonization after Oral-Care Education among the Residents of Nursing Homes.

Most yeasts causing infections in humans are part of commensal microflora and etiological agents of different infections when hosts become susceptible, usually due to becoming immunocompromised. The colonization of potentially pathogenic microbes in the oral cavity is increased by poor oral hygiene. This follow-up survey was conducted approximately two months after providing information on proper oral care at 10 nursing homes in Taiwan. Among the 117 of 165 residents colonized by yeasts, 67 were colonized by more than one yeast species. A total of 231 isolates comprising eight fungal genera and 25 species were identified. Candida albicans (44.6%) was the dominant species, followed by Candida glabrata (17.7%), Candida parapsilosis (8.7%), Candida tropicalis (7.8%), and Candida pararugosa (7.3%). Residents having a yeast colony-forming unit >10 (OR, 8.897; 95% CI 2.972–26.634; p < 0.001) or using a wheelchair (OR, 4.682; 95% CI 1.599–13.705; p = 0.005) were more likely to be colonized by multiple species. By comparing before and after oral-care education, dry mouth (OR, 3.199; 95% CI 1.448–7.068; p = 0.011) and having heart disease (OR, 2.681; 95% CI 1.068–6.732; p = 0.036) emerged as two independent risk factors for increased density of colonizing yeast.

Candida gut colonization, yeast species distribution, and biofilm production in Clostridioides difficile infected patients: a comparison between three populations in two different time periods

Candida gut colonization and yeast biofilm production capacity were investigated, by means of XTT reduction assay, in Clostridioides difficile infected (CDI) patients, in non-CDI diarrheic patients, and in healthy donors in two different time periods (2013–2015 and 2018–2019 respectively). Candida gut colonization was significantly (p < 0.001) associated to C. difficile infection, and to patients infected with hypervirulent C. difficile strains bearing the tcdC deletion at nucleotide 117 (p = 0.0003). Although there was not a prevalent yeast species in CDI patients, C. albicans was the species significantly (p < 0.001) associated to both the infections sustained by the non-hypervirulent C. difficile strains and those caused by the hypervirulent strain (p = 0.001). The biofilm production by the yeasts isolated from the CDI patients and from non-CDI diarrheic patients did not differ significantly. However, a significantly (p = 0.007) higher biofilm production was observed in the Candida strains, particularly C. albicans, isolated from healthy donors compared to that of the yeasts cultured from CDI patients. Seasonal occurrence was observed in the isolation rate of CDI and non-CDI diarrheic cases (p = 0.0019), peaking in winter for CDI patients and in spring for non-CDI diarrheic patients. Furthermore, seasonality emerged in the gut colonization by Candida of CDI patients in the winter. It seems, therefore, that the reduced capacity of biofilm production by Candida strains isolated from CDI patients might have a role in the development of C. difficile infection, probably facilitating the spread of the bacteria into the gut thus amplifying their pathogenic action.

No Impact of Fluconazole to Echinocandins Replacement as First-Line Therapy on the Epidemiology of Yeast Fungemia (Hospital-Driven Active Surveillance, 2004-2017, Paris, France).

Replacement of fluconazole by echinocandins as the first-line therapy for yeast-related fungemia could have an impact on both the mortality rate and the epidemiology of yeast species responsible for candidemia. We analyzed the individual clinical and microbiological data collected through the active surveillance program on yeast fungemia (YEASTS program, 2004–2016, Paris area, France) within 14 University Hospitals. The cohort included 3,092 patients [male:female ratio: 1.56; median age 61.0 years (IQR: 23.8)]. The mean mortality rate within 30 days was 38.5% (1,103/2,868) and significantly higher in intensive care units (690/1,358, 50.8%) than outside (413/1,510, 27.4%, p < 0.0001) without significant change over time. The yeast species distribution [Candida albicans (n = 1,614, 48.0%), Candida glabrata (n = 607, 18.1%), Candida parapsilosis (n = 390, 11.6%), Candida tropicalis (n = 299, 8.9%), Candida krusei (n = 96, 2.9%), rare species (n = 357, 10.6%)], minimal inhibitory concentration distribution, and the distribution between the patient populations (hematological malignancies, solid tumors, without malignancy) did not change either while the proportion of patients ≥60-years increased from 48.7% (91/187) in 2004 to 56.8% (133/234) in 2017 (p = 0.0002). Fluconazole as first-line therapy dramatically decreased (64.4% in 2004 to 27.7% in 2017, p < 0.0001) with a corresponding increase in echinocandins (11.6% in 2004 to 57.8% in 2017, p < 0.0001). Survival rates did not differ according to the first antifungal therapy. The progressive replacement of fluconazole by echinocandins as the first-line antifungal therapy was not associated with change in global mortality, regardless of species involved and antifungal susceptibility profiles. Other factors remain to be uncovered to improve the prognosis of yeast fungemia.

Antifungal drug susceptibility of fungal isolates in patients with human immunodeficiency virus receiving highly active antiretroviral therapy

<h3>Objectives</h3> Given the evolving drug therapy options and consequent opportunistic infections, antifungal drug resistance is a major concern in patients with human immunodeficiency virus (HIV) undergoing highly active antiretroviral therapy (HAART), prompting the need for clinically relevant antifungal susceptibility testing. The goals of the present study were to determine the asymptomatic oral fungal carriage and species distribution in patients with HIV infection receiving HAART in Kerala State, India, and to evaluate the antifungal susceptibility/resistance profile of these oral fungal isolates. We also sought to identify any correlation between antifungal susceptibility/resistance with respect to the duration of HAART therapy and if there was an association between oral fungal colonization, CD4 counts, and risk factors. <h3>Methods</h3> Thirty HIV-positive patients receiving HAART were divided into 2 groups based on duration of HAART (group 1, <2 years; group 2, >2 years). A detailed history, including demographic characteristics, treatment details, and presence of any risk factors for candidiasis, was taken before saliva sample collection by the oral rinse method. Candidal growth and colonies were evaluated on the Sabouraud slope. Germ tube, sugar assimilation, and fermentation tests were used for identification of species. When conventional methods failed to identify any fungal isolates, they were verified using the automated VITEK-2 YST system (bioMérieux, Marcy l'Etoile, France). The Wilcoxon signed-rank test was used to compare the CD4⁺ lymphocyte count before and after initiation of HAART. The association of risk factors with candidiasis was analyzed using the chi-square test. <h3>Results</h3> Overall culture positivity was 83.3%. <i>Candida albicans</i> was the most prevalent species (57.7%), followed by <i>Candida tropicalis</i> (26.9%). All except for 1 patient had a single fungal isolate. In vitro antifungal susceptibility testing of the isolates revealed that all candidal species were sensitive to amphotericin B. <i>Candida krusei</i> showed 100% resistance to fluconazole. All candidal species except <i>Geotrichum klebahnii</i> showed increased resistance to itraconazole. Comparison between initial and recent CD4⁺ counts revealed improvement in the CD4⁺ count after HAART, but no change in fungal population. Of the study sample, 63.3% had risk factors for candidiasis other than being immunocompromised, and colonization was increased in those with risk factors compared with those without risk factors. <h3>Conclusions</h3> The present study showed the distribution of yeast species and the antifungal drug susceptibility of fungal isolates in patients with receiving HAART.

Phylogenetic Analysis and Extracellular Enzyme Profiles of Yeast Strains Isolated from Raspberry Fruits

Raspberry fruit contains phenolic compounds, flavones, flavonoids, vitamins, and antioxidant substances that are important properties for health and pharmacological sciences. Edible berries provide also a suitable habitat for the growth of various microorganisms. In this study, yeast biota associated with raspberry fruits was determined by molecular identification techniques. Raspberry fruits were collected from Çanakkale, Gelibolu (Gallipoli). Yeast strains were isolated and then identified by using the analysis of ITS1-5.8S-ITS2 rDNA gene sequences. The phylo-genetic analysis of all yeast strains was carried out by using the MEGA–X phylogenetic analysis tool. The extracel-lular enzyme profiles of identified yeast species were determined by the API-ZYM kit system. The distribution of yeast species on the raspberry fruits was determined as Hanseniaspora uvarum, Metschnikowia viticola, Aureo-basidium pullulans, and Metschnikowia pulcherrima. It was observed that yeast strains belong to Metschnikowia genus were dominant on raspberry fruits. All yeast strains in Metschnikowia genus showed different enzyme pro-files against seven extracellular enzymes. These enzymes may be the discriminatory enzymes for the yeast strains in the Metschnikowia genus. When the phylogenetic relationships among all yeast strains were investigated, all strains were divided into two main clades. While the first clade consists of only Metschnikowia genus, second clade includes H. uvarum and A. pullulans yeast species. Our results indicated that restriction patterns and also extracel-lular enzyme profiles could be utilized for differentiation of yeast strains within the genus. M. pulcherrima, H. uvarum, and A. pullulans can be used for industrial applications for future researches.

Fungemia in the French department of Mayotte, Indian Ocean: A 10 years survey

ObjectiveThis study aimed at providing original data on fungemia in the Centre Hospitalier de Mayotte in terms of prevalence, epidemiological characteristics of infected patients, yeast species distribution and profile of in vitro antifungals susceptibility. MethodsA total of 223 positive blood cultures for yeasts were retrospectively reported during the period April 2010–April 2020. ResultsNinety-five episodes were identified corresponding to an incidence rate of 3.7 cases/100,000 inhabitants. The average age of patients was 33.5 years, and 63.3% patients were hospitalized in intensive care unit. The main co-morbidities were surgery in the 30 days prior to fungemia (27.8%), neoplasia (22.8%), parenteral nutrition (17.7%), diabetes (16.5%) and immunosuppressive medications (31.6%). Candida spp accounted for the majority of isolates (92.4%) with a predominance of non-albicans species (55.8% vs 33.7%), including C. albicans (33.7%), C. tropicalis (30.5%) and C. parapsilosis (20%). The antifungal susceptibility profiles did not differ from expected results for each species and did not change significantly over time. DiscussionFungemia remain frequent hospital infections associated with high mortality in Mayotte. The vast majority of fungemia was due to Candida spp. Non-albicansCandida species reach half of the Candida isolates with a high percentage of C. tropicalis. Surprisingly, no case of candidemia due to C. glabrata were identified. The management of candidemia remains satisfactory and the treatment was adapted according to the international recommendations. However, the high susceptibility of Candida spp. isolates to fluconazole may invite to reconsider the use of this molecule as empirical and first-line treatment of candidemia in Mayotte.

Distribution of Yeast Species Isolated from Blood Cultures for a Six Year Period in Turkey: a Multicentre Study

Bloodstream infections due to yeast species especially Candida spp. have been reported to be important healthcare associated infections with high mortality and morbidity rates. Candidemia causes prolonged hospital stays as well as increased cost. In order to prevent or treat these life-threatening bloodstream infections successfully, nationwide epidemiological data should be available about the etiological agents of these infections. Multi-centre national epidemiological data on yeast bloodstream infections in Turkey is lacking. A retrospective study was designed and data from six different centres in Turkey between 2011 and 2016 years were gathered and analysed for the distribution and frequency of yeast species in order to assist clinicians in their choice of early and appropriate antifungal therapy. All laboratories used automated blood culture systems for the isolation of blood strains. All the participating centres performed the identification of their own isolates by conventional methods using germ tube test, morphology on corn meal agar with tween 80 and chromogenic media and the identification was confirmed by API 20C AUX, API ID 32C or matrix-assisted laser desorption/ionization time of flight mass spectrophotometry (MALDI-TOF MS) systems. The analysis of the results was performed on the basis of intensive care units (ICUs), other inpatient clinics (OICs) and totally all clinics (ACs). Totally 2547 yeast isolates were determined from six participating centres during six years. According to the total ACs results, Candida albicans was the most prevalent species (43.1%), followed by Candida parapsilosis complex (29.1%), Candida glabrata (10.1%), Candida tropicalis (7.5%), Candida krusei (2.4%) and Candida kefyr (1.6%) and the remaining (6.2%) of them consisted of other yeast species. The distribution of the Candida species did not show statistically significant difference between the years, however the increase of C.parapsilosis complex in 2016 was statistically significant, (p= 0.02). During the study period, totally 1054 yeast isolates were obtained from the ICUs of the centres. C.albicans predominated with 476 (45.2%) isolates and C.parapsilosis complex (28.7%), C.glabrata (10.7%) and C.tropicalis (7.3%) were the other leading species in ICUs. Among 1493 isolates of the OICs of six centres participated in the study, C.albicans was the most prevalent species with 622 (41.7%) isolates. The other frequent species of OICs were C.parapsilosis complex (29.5%), C.glabrata (9.6%) and C.tropicalis (7.6%) resembling ICU results. It can be concluded that C.albicans is still the leading cause of bloodstream infections in the six different centres located in various geographical areas of Turkey.

Diversity and distribution of yeasts in indigenous fermented foods and beverages of Ethiopia

As one of the origin centers of domesticated plants in the world, Ethiopia is rich in diversified fermented foods and beverages, in which yeasts are usually among the essential functional microorganisms. This study aims to investigate yeast species diversity and distribution in indigenous fermented products in Ethiopia using conventional isolation and molecular identification methods. Yeast cell counts in 221 samples of various Ethiopian traditional fermented products, including fermented staple foods, alcoholic beverages, dairy products, and condiments, were compared using the typical dilution plating method. A total of 475 yeast isolates were recovered from these samples and 41 yeast species belonging to 25 genera were identified from yeast isolates using the sequence analysis of the D1/D2 domain of the large subunit of rRNA gene. Candida humilis, Wickerhamomyces anomalus, Meyerozyma guilliermondii, Pichia kudriavzevii, and Saccharomyces cerevisiae were the most dominant species that were widely distributed among the majority of the fermented products analyzed in the current study. Significant variations were encountered both in yeast cell counts, diversity, and distribution of yeast species among different types of fermented products and even among different samples of the same types of fermented products. It calls for a more extensive and systematic microbiological study of Ethiopian indigenous fermented foods, beverages and other related products that can be helpful for standardization and large-scale production of these foods in Ethiopia. © 2020 Society of Chemical Industry.

Distribution of Yeast Species and Risk Factors of Oral Colonization among the Residents at Nursing Homes in Taiwan

Distribution of Yeast Species and Risk Factors of Oral Colonization among the Residents at Nursing Homes in Taiwan

Species distribution and susceptibility profiles of Candida species isolated from vulvovaginal candidiasis, emergence of C. lusitaniae.

Background and Purpose:The aim of the current study was to investigate the epidemiology of vulvovaginal candidiasis (VVC) and recurrent VVC (RVVC), as well as the antifungal susceptibility patterns of Candida species isolates.Materials and Methods:A cross-sectional study was carried out on 260 women suspected of VVC from February 2017 to January 2018. In order to identify Candida species isolated from the genital tracts, the isolates were subjected to polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) using enzymes Msp I and sequencing. Moreover, antifungal susceptibility testing was performed according to the Clinical and Laboratory Standards Institute guidelines (M27-A3).Results:Out of 250 subjects, 75 (28.8%) patients were affected by VVC, out of whom 15 (20%) cases had RVVC. Among the Candida species, C. albicans was the most common species (42/95; 44.21%), followed by C. lusitaniae (18/95; 18.95%), C. parapsilosis (13/95; 13.69%), C. glabrata (8/95; 8.42%), C. kefyr (6/95; 6.31%), C. famata (5/95; 5.26%), C. africana (2/95; 2.11%), and C. orthopsilosis (1/95; 1.05%), respectively. Multiple Candida species were observed in 28% (21/75) of the patients. Nystatin showed the narrowest range of minimum inhibitory concentration (MIC) (0.25-16 μg/ml) against all Candida strains, whereas fluconazole (0.063-64 μg/ml) demonstrated the widest MIC range. In the current study, C. lusitaniae, as the second most common causative agent of VVC, was susceptible to all antifungal agents. Furthermore, 61.1% of C. lusitaniae isolates were inhibited at a concentration of ≤ 2 μg/ml, while 38.9% (n=7) of them exhibited fluconazole MICs above the epidemiologic cutoff values (ECV). Candida species showed the highest overall resistance against fluconazole (61.3%), followed by itraconazole (45.2%) and caspofungin (23.7%). All of C. albicans strains were resistant to itraconazole with a MIC value of ≥ 1 μg/ml; in addition, 87.5% of them were resistant to fluconazole. Moreover, 100% and 87.5% of C. glabrata strains were resistant to caspofungin and fluconazole, respectively.Conclusion:As the findings revealed, the majority of VVC cases were caused by non-albicans Candida species which were often more resistant to antifungal agents. Candida lusitaniae generally had fluconazole MICs above the ECV. Given the propensity of C. lusitaniae to develop resistance under drug pressure, antifungals should be administered with caution. The emergence of these species justify the epidemiological surveillance surveys to watch out the distribution of yeast species.

Research Progress of Wine Yeast Diversity in Yunnan Wine Producing Regions and Characteristic Yeast Strains in Wine Making Application

The distribution of yeast species are closely related to geographical location and climatic conditions. In our country (China), most of wine producing regions are located in north latitude 35 to 40°N, only a little region located in north latitude 28 to 30°N in Yunnan province. This region has complex topography and diversity climate types, which provide superior conditions for the research and development of high quality wine yeast. In this review, the research progress of yeast biodiversity in Yunnan wine-producing regions and the application of these characteristic yeast strains in wine making application were described. It was expected to provide references for the development of local wine yeast resources and the production of characteristic wine.

Diversity and relationships among strains of culturable yeasts in agricultural soils in Cameroon

Yeasts are unicellular fungi; they are found in a diverse range of natural habitats, including soil, aquatic environments, the surface of plants, and the skin and mucosal surfaces of animal hosts. A variety of yeasts have been found in the soil environment. However, most studies of soil yeasts have come from developed countries, and there is a dearth of research on soil yeasts in Africa. In this study, we analyzed 493 soil samples from nine geographical locations in Cameroon for yeasts, using a culture - based method. A total of 110 yeast isolates were obtained. Based on their sequences at the fungal barcode locus, the Internal Transcribed Spacer (ITS) regions of the nuclear ribosomal RNA gene cluster, the 110 yeast isolates were putatively identified as belonging to 16 yeast species, including 15 Ascomycetes and one Basidiomycete. Differences in yeast species distribution were observed among the analyzed geographic regions. PCR fingerprinting analyses identified a large number of genotypes among strains within each of the obtained yeast species. Significantly, there was little evidence of geographic clustering among yeast strains from any of the yeast species. Our results suggest that Cameroon contains significant yeast diversity and that gene flow is common among local and regional soil yeast populations.

Six-Year Trend Analysis of Nosocomial Candidemia and Risk factors in Two Intensive Care Hospitals in Mato Grosso, Midwest Region of Brazil

We conducted this cross-sectional retrospective study using clinical and laboratory data from two tertiary hospitals in Cuiabá, Mato Grosso, Brazil, in order to explore the risk factors and estimate mortality, prevalence and lethality of candidemia between 2006 and 2011. A total of 130 episodes of candidemia were identified. The prevalence of candidemia was 1.8 per 1,000 admissions, the mortality rate was 0.9 per 1,000 admissions, and the lethality was 49.2%. The main agent in this population was Candida parapsilosis (n=50), followed by C. albicans (n=45). Comparison between the numbers of episodes in the two triennia revealed that the non-albicans group grew by 48.2%. The distribution of yeast species of Candida per hospital unit revealed that C. albicans was more prevalent than C. parapsilosis in the adult ICU and C. parapsilosis was more prevalent than C. albicans in the neonatal ICU. Patients remained hospitalized for an average of 53.5days. Central venous catheters, parenteral nutrition and age were the variables that proved to be independent in the multivariate analysis and that maintained a statistically significant association with the incidence of death in patients with candidemia. The annual prevalence of candidemia showed a significant increase in the second triennium (2009-2011) compared with the first (2006-2008) probably due to increased exposure to risk factors: central venous catheter, H2 blockers, nutrition parenteral corticosteroids and mean hospital duration.

Patterns of Human Oral Yeast Species Distribution on Hainan Island in China

Infections by yeast strains of the genus Candida are among the most prevalent fungal infections of humans. These yeasts are common residents of the oral mucosa and other body surfaces. Since most yeast infections are due to endogenous strains and that species of Candida differ in virulence properties and in intrinsic susceptibilities to antifungal drugs, understanding the human commensal yeast flora can help designing effective treatment and prevention strategies against yeast infections. Here, we report the patterns of yeast species distributions in the oral cavities of 1,799 people from Hainan Island in southern China. Based on sequence information at the fungal barcode locus ITS regions, 368 of the 415 obtained oral yeast strains were identified as belonging to 26 yeast species, while the remaining 47 strains all showed significant sequence divergence to the currently described species. The four most common yeast species were C. albicans (42%), C. tropicalis (20%), C. glabrata (5.5%), and C. parapsilosis (4.1%) and 10 of the 26 yeast species were represented by only one strain each. Our analyses identified that the gender of hosts and ethnical background showed no contribution to oral yeast species distributions. However, the health status, place of birth, current residency, and the age of hosts all showed significant contributions to the distributions of the four dominant yeast species. We compared our results with those reported previously and discussed the potential mechanisms for the observed differences in oral yeast species distributions.

The Vineyard Yeast Microbiome, a Mixed Model Microbial Map

Vineyards harbour a wide variety of microorganisms that play a pivotal role in pre- and post-harvest grape quality and will contribute significantly to the final aromatic properties of wine. The aim of the current study was to investigate the spatial distribution of microbial communities within and between individual vineyard management units. For the first time in such a study, we applied the Theory of Sampling (TOS) to sample gapes from adjacent and well established commercial vineyards within the same terroir unit and from several sampling points within each individual vineyard. Cultivation-based and molecular data sets were generated to capture the spatial heterogeneity in microbial populations within and between vineyards and analysed with novel mixed-model networks, which combine sample correlations and microbial community distribution probabilities. The data demonstrate that farming systems have a significant impact on fungal diversity but more importantly that there is significant species heterogeneity between samples in the same vineyard. Cultivation-based methods confirmed that while the same oxidative yeast species dominated in all vineyards, the least treated vineyard displayed significantly higher species richness, including many yeasts with biocontrol potential. The cultivatable yeast population was not fully representative of the more complex populations seen with molecular methods, and only the molecular data allowed discrimination amongst farming practices with multivariate and network analysis methods. Importantly, yeast species distribution is subject to significant intra-vineyard spatial fluctuations and the frequently reported heterogeneity of tank samples of grapes harvested from single vineyards at the same stage of ripeness might therefore, at least in part, be due to the differing microbiota in different sections of the vineyard.

Rare opportunistic (non- Candida, non- Cryptococcus) yeast bloodstream infections in patients with cancer

Rare opportunistic (non-Candida, non-Cryptococcus) yeast bloodstream infections (ROYBSIs) are rare, even in cancer patients. We retrospectively reviewed all episodes of ROYBSIs occurring from 1998 to 2010 in our cancer center. Of 2984 blood cultures positive for Candida and non-Candida yeasts, 94 (3.1%) were positive for non-Candida yeasts, representing 41 ROYBSIs (incidence, 2.1 cases/100,000 patient-days). Catheter-associated fungemia occurred in 21 (51%) patients. Breakthrough ROYBSIs occurred in 20 (49%) patients. The yeast species distribution was Rhodotorula in 21 (51%) patients, Trichosporon in 8 (20%) patients, Saccharomyces cerevisiae in 8 (20%) patients, Geotrichum in 2 (5%) patients, Pichia anomala, and Malassezia furfur in 1 patient each. All tested Trichosporon, Geotrichum, and Pichia isolates were azole-susceptible, whereas the Rhodotorula isolates were mostly azole-resistant. We noted echinocandin nonsusceptibility (minimal inhibitory concentration≥2mg/L) in all but the S. cerevisiae isolates. Most of the isolates (28/33 [85%]) were susceptible to amphotericin B. Themortality rate in all patients at 30 days after ROYBSIs diagnosis was 34%. Multivariate survival analysis revealed increased risk of death in patients with S. cerevisiae infections (hazard ratio, 3.7), Geotrichum infections (hazard ratio, 111.3), or disseminated infections (hazard ratio, 33.4) and reduced risk in patients who had catheter removal (hazard ratio,0.1). ROYBSIs are uncommon in patients with cancer, and catheters are common sources of them. Half of the ROYBSIs occurred as breakthrough infections, and invitro species-specific resistance to echinocandins and azoles was common. Disseminated infections resulted in the high mortality rate.

Distribution of yeast species associated with oral lesions in HIV-infected patients in Southwest Uganda

Oropharyngeal candidiasis remains a significant clinical problem in HIV-infected and AIDS patients in regions of Africa where anti-retroviral therapy isn't readily available. In this study we identified the yeast populations associated with oral lesions in HIV-infected patients in Southwest Uganda who were receiving treatment with nystatin and topical clotrimazole. Samples were taken from 605 patients and 316 (52%) of these yielded yeast growth following incubation on Sabouraud dextrose agar. Samples were subsequently re-plated on CHROMagar Candida medium to facilitate identification of the yeast species present. The majority (56%) of culture-positive samples yielded a mix of two or more species. Candida albicans was present in 87% (274/316) of patient samples and accounted for 87% (120/138) of single species samples. Candida glabrata, Candida tropicalis and Candida norvegensis were also found in cultures that yielded a single species. No Candida dubliniensis isolates were identified in this population.