Yeasts, like other microorganisms, create numerous types of multicellular communities, which differ in their complexity, cell differentiation and in the occupation of different niches. Some of the communities, such as colonies and some types of biofilms, develop by division and subsequent differentiation of cells growing on semisolid or solid surfaces to which they are attached or which they can penetrate. Aggregation of individual cells is important for formation of other community types, such as multicellular flocs, which sediment to the bottom or float to the surface of liquid cultures forming flor biofilms, organized at the border between liquid and air under specific circumstances. These examples together with the existence of more obscure communities, such as stalks, demonstrate that multicellularity is widespread in yeast. Despite this fact, identification of mechanisms and regulations involved in complex multicellular behavior still remains one of the challenges of microbiology. Here, we briefly discuss metabolic differences between particular yeast communities as well as the presence and functions of various differentiated cells and provide examples of the ability of these cells to develop different ways to cope with stress during community development and aging.
Candida bracarensis is an emerging cryptic species within the Candida glabrata clade. To date, little is known about its epidemiology, virulence, and antifungal susceptibility. This study documents the occurrence of C. bracarensis for the first time in Mexico and focuses on its in vitro production of hydrolytic enzymes, as well as antifungal susceptibility to echinocandins. This strain was isolated from a vaginal swab of a female with vulvovaginal candidosis; exhibited a very strong activity of aspartyl proteinase, phospholipase, and hemolysin; and was susceptible to caspofungin, anidulafungin, and micafungin (MIC = 0.031 μg/mL). Data obtained could contribute to the knowledge of the epidemiology and virulence attributes of this yeast as a fungal opportunistic human pathogen.
- MeSH
- antifungální látky farmakologie MeSH
- Candida klasifikace účinky léků enzymologie fyziologie MeSH
- DNA fungální genetika MeSH
- genom fungální MeSH
- hydrolasy metabolismus MeSH
- kandidóza vulvovaginální mikrobiologie MeSH
- lidé MeSH
- mezerníky ribozomální DNA genetika MeSH
- mikrobiální testy citlivosti MeSH
- mikrobiální viabilita účinky léků MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
- Geografické názvy
- Mexiko MeSH
Hemolytic factor production by pathogenic Candida species is considered an important attribute in promoting survival within the mammal host through the ability to assimilate iron from the hemoglobin-heme group. Hemolytic capability has been evaluated for Candida species based on hemolysis zones on plate assay, analysis of hemolytic activity in liquid culture medium, and hemolysis from cell-free culture broth. The production of hemolytic factor is variable among Candida species, where C. parapsilosis is the less hemolytic species. In general, no intraspecies differences in beta-hemolytic activities are found among isolates belonging to C. albicans, C. glabrata, C. krusei, C. tropicalis, and C. parapsilosis. The production of hemolytic factor by Candida species is affected by several factors such as glucose supplementation in the culture medium, blood source, presence of erythrocytes and hemoglobin, and presence of electrolytes. On the basis of existing achievements, more researches are still needed in order to extend our knowledge about the biochemical nature of hemolytic molecules produced by distinct Candida species, the mechanism of hemolysis, and the molecular basis of the hemolytic factor expression.
- MeSH
- Candida klasifikace metabolismus fyziologie MeSH
- druhová specificita MeSH
- faktory virulence biosyntéza chemie MeSH
- hemolýza * MeSH
- kandidemie mikrobiologie patologie MeSH
- kultivační média chemie metabolismus MeSH
- lidé MeSH
- membránové glykoproteiny metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Candida dubliniensis was reported as a new species in 1995. This species is often misidentified as Candida albicans. The aims of this work were to determine the occurrence of C. dubliniensis in various clinical materials, to evaluate several ways to identify it and to examine the genetic variability of isolates. Among 7706 isolates originally identified as C. albicans, 237 were identified as C. dubliniensis (3.1%). Most of the C. dubliniensis isolates were obtained from the upper and lower respiratory tract (61.4 and 22.9%). Five phenotypic methods including latex agglutination were used (cultivation on CHROMagar Candida, on Staib agar, at 42 °C and in medium with 6.5% NaCl), but only cultivation on the medium with an increased concentration of NaCl and latex agglutination gave reliable results. Species-specific polymerase chain reaction was used as the confirmation method. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry provided less reliable results. In fact, 78.9% of C. dubliniensis isolates had scores above 1.7. However, the rest of them (21.1%) were also identified as C. dubliniensis even when the scores were lower than 1.7. Divergences among C. dubliniensis strains were evaluated by means of pulsed-field gel electrophoresis. Eighty-six selected C. dubliniensis isolates showed a 69.6% level of similarity. The results of this study expand the knowledge of the incidence, means of identification and genotypic divergence of C. dubliniensis isolates.
- MeSH
- Candida klasifikace genetika izolace a purifikace fyziologie MeSH
- chlorid sodný metabolismus MeSH
- genetická variace MeSH
- genotyp MeSH
- kandidóza mikrobiologie MeSH
- latex fixační testy MeSH
- lidé MeSH
- mikrobiologické techniky metody MeSH
- polymerázová řetězová reakce MeSH
- pulzní gelová elektroforéza MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
- teplota MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Pathogenicity of Candida albicans is associated with its capacity switch from yeast-like to hyphal growth. The hyphal form is capable to penetrate the epithelial surfaces and to damage the host tissues. Therefore, many investigations have focused on mechanisms that control the morphological transitions of C. albicans. Recently, certain studies have showed that non-albicans Candida species can reduce the capacity of C. albicans to form biofilms and to develop candidiasis in animal models. Then, the objective of this study was to evaluate the effects of Candida krusei and Candida glabrata on the morphogenesis of C. albicans. Firstly, the capacity of reference and clinical strains of C. albicans in forming hyphae was tested in vitro. After that, the expression of HWP1 (hyphal wall protein 1) gene was determined by quantitative real-time PCR (polymerase chain reaction) assay. For both reference and clinical strains, a significant inhibition of the hyphae formation was observed when C. albicans was incubated in the presence of C. krusei or C. glabrata compared to the control group composed only by C. albicans. In addition, the culture mixed of C. albicans-C. krusei or C. albicans-C. glabrata reduced significantly the expression of HWP1 gene of C. albicans in relation to single cultures of this specie. In both filamentation and gene expression assays, C. krusei showed the higher inhibitory activity on the morphogenesis of C. albicans compared to C. glabrata. C. krusei and C. glabrata are capable to reduce the filamentation of C. albicans and consequently decrease the expression of the HWP1 gene.
- MeSH
- Candida albicans genetika růst a vývoj metabolismus MeSH
- Candida glabrata fyziologie MeSH
- Candida fyziologie MeSH
- down regulace MeSH
- fungální proteiny genetika metabolismus MeSH
- hyfy genetika růst a vývoj metabolismus MeSH
- lidé MeSH
- membránové glykoproteiny genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is, currently, used as a rapid and reliable tool in microbial diagnostics. The discriminatory power of the method extends its applicability also beyond species level. This study examined the possibility to use MALDI-TOF MS to differentiate between Candida parapsilosis sensu stricto biofilm-positive (n = 12) and biofilm-negative (n = 9) strains. The results indicated a grouping trend within MALDI-TOF mass spectra belonging to each of the tested groups. However, these trends were eclipsed by mass spectral variations resulting from limited repeatability of the method, making its application for the selected purpose impossible. Improvement in the discriminatory power of the method was not obtained neither by using different matrices (α-cyano-4-hydroxycinnamic acid, ferulic acid, 5-chloro-2-mercaptobenzothionazole) for MALDI-TOF MS analysis nor by testing different culture conditions (cultivation length, culture media).
Biofilms are often the cause of chronic human infections and contaminate industrial or medical equipment. The traditional approach has been to use increasing concentrations of antibiotics, but microorganisms rapidly develop multiresistance to them. Therefore, we investigated the use of natural substances as an alternative solution. The quantification of the biofilms based on the colonized areas was measured using a Cellavista automatic microscope equipped with image analysis software. Using the Cellavista device brings new possibilities for qualification and quantification of sessile cells. In our study, this feature was documented by exploring the antifungal/anti-biofilm activity of amphotericin B, baicalein, chitosan and usnic acid against yeast biofilm formation. The influence of these substances on the formation and eradication of opportunistic pathogenic yeasts Candida parapsilosis and Candida krusei biofilms was studied in 96-well polystyrene microtiter plates. While amphotericin B was not very efficient, the use of baicalein and chitosan, even in minimum inhibitory concentrations, was found to rapidly decrease the colonized areas in the wells. The usnic acid did not display any significant antibiofilm properties even at concentration 300μgml(-1). Our results propose that Cellavista is a promising tool for the study of yeast biofilm formation and the effects of antimicrobial agents.
- MeSH
- amfotericin B farmakologie MeSH
- antiinfekční látky farmakologie MeSH
- benzofurany farmakologie MeSH
- biofilmy účinky léků MeSH
- Candida účinky léků fyziologie MeSH
- chitosan farmakologie MeSH
- flavanony farmakologie MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- mikroskopie metody MeSH
- počítačové zpracování obrazu MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Since biofilms are important in many clinical, industrial, and environmental settings, reliable methods to quantify these sessile microbial populations are crucial. Most of the currently available techniques do not allow the enumeration of the viable cell fraction within the biofilm and are often time consuming. This paper proposes flow cytometry (FCM) using the single-stain viability dye TO-PRO(®)-3 iodide as a fast and precise alternative. Mature biofilms of Candida albicans and Escherichia coli were used to optimize biofilm removal and dissociation, as a single-cell suspension is needed for accurate FCM enumeration. To assess the feasibility of FCM quantification of biofilms, E. coli and C. albicans biofilms were analyzed using FCM and crystal violet staining at different time points. A combination of scraping and rinsing proved to be the most efficient technique for biofilm removal. Sonicating for 10 min eliminated the remaining aggregates, resulting in a single-cell suspension. Repeated FCM measurements of biofilm samples revealed a good intraday precision of approximately 5 %. FCM quantification and the crystal violet assay yielded similar biofilm growth curves for both microorganisms, confirming the applicability of our technique. These results show that FCM using TO-PRO(®)-3 iodide as a single-stain viability dye is a valid fast alternative for the quantification of viable cells in a biofilm.
- MeSH
- barvení a značení metody MeSH
- biofilmy růst a vývoj MeSH
- Candida fyziologie MeSH
- Escherichia coli fyziologie MeSH
- karbocyaniny metabolismus MeSH
- mikrobiální viabilita * MeSH
- mikrobiologické techniky metody MeSH
- průtoková cytometrie metody MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
Kvasinky rodu Candida jsou jedním z nejčastějších původců nozokomiálních infekcí. Tyto infekce velmi často přerůstají do závažných onemocnění, jakými jsou například endokarditida, nebo meningitida. Jedním z důvodů, které činí tyto kvasinky tak nebezpečnými oportunními patogeny je jejich schopnost tvořit biofilm. Tato komunita mikroorganismů je schopná odolávat nepříznivým podmínkám prostředí a také vysokým dávkám antimikrobiálních látek. Na těchto vlastnostech má velký podíl specifická exprese genů v biofilmu a také fenotyp kvasinek.
Yeasts of the genus Candida are one of the most common causes of nosocomial infections. These infections can further evolve into serious conditions such as endocarditis or meningitis. One of the reasons, why these opportunistic pathogens are so dangerous is their ability to form biofilm. This community of microorganisms is able to withstand adverse effects of surrounding environment and is even immune to very high amounts of antimicrobial agents. These properties are present mainly due to specific gene expression in biofilm and phenotype of yeast.
- MeSH
- biofilmy * MeSH
- Candida albicans fyziologie patogenita účinky léků MeSH
- Candida * fyziologie účinky léků MeSH
- exprese genu MeSH
- kandidóza * MeSH
- lidé MeSH
- mykózy * klasifikace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
A group of 29 isolates of Candida parapsilosis sensu stricto, 29 of Candida orthopsilosis, and 4 of Candida metapsilosis were assayed for the presence of killer activity using Saccharomyces cerevisiae ATCC 26609 as a sensitive strain. All C. metapsilosis isolates showed killer activity at 25 °C while strains of C. parapsilosis sensu stricto or C. orthopsilosis did not exhibit this activity. Sensitivity to killer toxins was evaluated using a set of previously reported killer strains of clinical origin. Only 11 isolates of the C. parapsilosis complex were inhibited by at least one killer isolate without resulting in any clear pattern, except for C. parapsilosis sensu stricto ATCC 22019, which was inhibited by every killer strain with the exception of C. parapsilosis and Candida utilis. The lack of sensitivity to killer activity among isolates of the genus Candida suggests that their toxins belong to the same killer type. Differentiation of species within the C. parapsilosis complex using the killer system may be feasible if a more taxonomically diverse panel of killer strains is employed.
- MeSH
- antibióza * MeSH
- Candida klasifikace izolace a purifikace fyziologie MeSH
- kandidóza mikrobiologie MeSH
- lidé MeSH
- Saccharomyces cerevisiae růst a vývoj MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
