Antigenicity ofCandida tropicalisstrain cells cultured at 27 and 37°C

Tracking the fecal mycobiome through the lifespan of production pigs and a comparison to the feral pig

IMPORTANCE

This work provides evidence that early-life fungal community composition, or host genetics, influences long-term mycobiome composition. In addition, this work provides the first comparison of the feral pig mycobiome to the mycobiome of intensively raised pigs.

Similarities and Differences among Species Closely Related to Candida albicans: C. tropicalis, C. dubliniensis, and C. auris

Although Candida species are widespread commensals of the microflora of healthy individuals, they are also among the most important human fungal pathogens that under certain conditions can cause diseases (candidiases) of varying severity ranging from mild superficial infections of the mucous membranes to life-threatening systemic infections. So far, the vast majority of research aimed at understanding the molecular basis of pathogenesis has been focused on the most common species—Candida albicans. Meanwhile, other closely related species belonging to the CTG clade, namely, Candida tropicalis and Candida dubliniensis, are becoming more important in clinical practice, as well as a relatively newly identified species, Candida auris. Despite the close relationship of these microorganisms, it seems that in the course of evolution, they have developed distinct biochemical, metabolic, and physiological adaptations, which they use to fit to commensal niches and achieve full virulence. Therefore, in this review, we describe the current knowledge on C. tropicalis, C. dubliniensis, and C. auris virulence factors, the formation of a mixed species biofilm and mutual communication, the environmental stress response and related changes in fungal cell metabolism, and the effect of pathogens on host defense response and susceptibility to antifungal agents used, highlighting differences with respect to C. albicans. Special attention is paid to common diagnostic problems resulting from similarities between these species and the emergence of drug resistance mechanisms. Understanding the different strategies to achieve virulence, used by important opportunistic pathogens of the genus Candida, is essential for proper diagnosis and treatment.

The Flo Adhesin Family

The first step in the infection of fungal pathogens in humans is the adhesion of the pathogen to host tissue cells or abiotic surfaces such as catheters and implants. One of the main players involved in this are the expressed cell wall adhesins. Here, we review the Flo adhesin family and their involvement in the adhesion of these yeasts during human infections. Firstly, we redefined the Flo adhesin family based on the domain architectures that are present in the Flo adhesins and their functions, and set up a new classification of Flo adhesins. Next, the structure, function, and adhesion mechanisms of the Flo adhesins whose structure has been solved are discussed in detail. Finally, we identified from Pfam database datamining yeasts that could express Flo adhesins and are encountered in human infections and their adhesin architectures. These yeasts are discussed in relation to their adhesion characteristics and involvement in infections.

Coronary Vasculitis Induced in Mice by Cell Wall Mannoprotein Fractions of Clinically Isolated Candida Species

Kawasaki disease (KD) is an inflammatory disease that was identified by Professor Tomisaku Kawasaki in 1961. Candida albicans-derived substances (CADS) such as the hot water extract of C. albicans and Candida water-soluble fractions (CAWS) induce coronary vasculitis similar to KD in mice. An increasing proportion of deep-seated candidiasis cases are caused by non-albicans Candida and are often resistant to antifungal drugs. We herein investigated whether the mannoprotein fractions (MN fractions) of clinically isolated Candida species induce vasculitis in mice. We prepared MN fractions from 26 strains of Candida species by conventional hot water extraction and compared vasculitis in DBA/2 mice. The results obtained revealed that the induction of vasculitis and resulting heart failure were significantly dependent on the species; namely, death rates on day 200 were as follows: Candida krusei (100%), Candida albicans (84%), Candida dubliniensis (47%), Candida parapsilosis (44%), Candida glabrata (32%), Candida guilliermondii (20%), and Candida tropicalis (20%). Even for C. albicans, some strains did not induce vasculitis. The present results suggest that MN-induced vasculitis is strongly dependent on the species and strains of Candida, and also that the MN fractions of some non-albicans Candida induce similar toxicity to those of C. albicans.

Candida Endocarditis: A Review of the Pathogenesis, Morphology, Risk Factors, and Management of an Emerging and Serious Condition

Infective endocarditis is a significant healthcare burden due to the associated high mortality and complications. Endocarditis caused by both Candida albicans (C. albicans) and non-Candida albicans Candida (NCAC) species has been associated with a substantial rise in in-hospital morbidity and mortality. We used the Pubmed database to identify 47 out of 101 articles that had met our inclusion and exclusion criteria. We had put in place a broad inclusion criterion with no age or gender restrictions. These 47 articles included abstracts, 11 review articles, 13 case reports, 10 research articles, 1 clinical trial report, 1 meta-analysis, and other research articles. And they comprehensively cover the pathogenesis, risk factors, and management of infections caused by C. albicans and NCAC species in the past 26 years. The articles we scanned provided us with information on different associations in correlation to multiple types of Candida species. Here, we discuss the association between Candida and endocarditis, a major cause of morbidity and mortality in both C. albicans and NCAC. We also present our understanding regarding this interesting association and attempt to address some of the recurring questions.

Determination of biofilm production by Candida tropicalis isolated from hospitalized patients and its relation to cellular surface hydrophobicity, plastic adherence and filamentation ability

Candida tropicalis is an emerging virulent species. The aim of this study is to determine the biofilm-forming ability of 29 strains of C. tropicalis isolated from inpatients, and to examine its relation with other virulence factors such as cellular surface hydrophobicity (CSH), immediate (15 min, IA) and late (24 h, LA) plastic adherence and filamentation ability. The study was performed in parallel using two incubation temperatures - 37 and 22 °C - to determine the effect of growth temperature variations on these pathogenic attributes of C. tropicalis. Biofilm formation (BF) was measured by optical density (OD) and by XTT reduction (XTT); Slime index (SI), which includes growth as a correction factor in BF, was calculated in both methods. All strains were hydrophobic and adherent - at 15 min and 24 h - at both temperatures, with higher values for 22 °C; the adhered basal yeast layer appears to be necessary to achieve subsequent development of biofilm. Filamentation ability varied from 76.2% of strains at 37 °C to 26.6% at 22 °C. All C. tropicalis strains were biofilm producers, with similar results obtained using OD determination and XTT measurement to evaluation methods; SI is useful when good growth is not presented. BF at 37 °C was similar at 24 h and 96 h incubation; conversely, at 22 °C, the highest number of biofilm-producing strains was detected at 96 h. CSH is an important pathogenic factor which is involved in adherence, is influenced by the filamentation of yeast, and plays a critical role in BF.

Insights into Candida tropicalis nosocomial infections and virulence factors

Candida tropicalis is considered the first or the second non-Candida albicans Candida (NCAC) species most frequently isolated from candidosis, mainly in patients admitted in intensive care units (ICUs), especially with cancer, requiring prolonged catheterization, or receiving broad-spectrum antibiotics. The proportion of candiduria and candidemia caused by C. tropicalis varies widely with geographical area and patient group. Actually, in certain countries, C. tropicalis is more prevalent, even compared with C. albicans or other NCAC species. Although prophylactic treatments with fluconazole cause a decrease in the frequency of candidosis caused by C. tropicalis, it is increasingly showing a moderate level of fluconazole resistance. The propensity of C. tropicalis for dissemination and the high mortality associated with its infections might be strongly related to the potential of virulence factors exhibited by this species, such as adhesion to different host surfaces, biofilm formation, infection and dissemination, and enzymes secretion. Therefore, the aim of this review is to outline the present knowledge on all the above-mentioned C. tropicalis virulence traits.

Adhesion of Candida albicans to HeLa cells: studies using polystyrene beads

The adherence to HeLa cells by the yeast-type cells of the Candida albicans NIH A-207 strain cultivated for 2 d at 27 degrees C in the yeast extract-added Sabouraud liquid medium (YSLM) and the 500 mM galactose-added yeast nitrogen base medium (YNB-Gal) was compared. The yeast cells cultured in the YNB-Gal clearly increased the adherence to the HeLa cells compared to the YSLM. The adherence drastically decreased by pronase treatment of the yeast cells. Next, to define the sugar receptors of the yeast cells, lactosylceramide (LC)-, the H type 1 antigen (HA)-, Lewis(a) antigen (Le(a))-, mannan- and BSA-coated polystyrene beads were used for the adherence to the yeast cells. Only the LC- and HA-beads were bound to the yeast cells. The adherence of the two beads to the yeast cells cultured in the YNB-Gal was higher than that to the yeast cells cultured in the YSLM. The yeast cell wall mannan-coated polystyrene beads did not adhere at all to the Hela cells. Based on these results, it is evident that the protein parts involving the LC and HA receptors on the surface of the yeast cells correlate with the adherence to the HeLa cells.

Antigenicity of Cell Wall Mannans of Candida albicans and Candida stellatoidea Cultured at High Temperatures in BACTEC Medium

The study of the antigenicity of pathogenic Candida albicans and Candida stellatoidea cells grown in BACTEC fungal medium (BFM) is useful for clinical analysis so as accurately to diagnose candidiasis. When C. albicans NIH A-207 was grown in BFM and fetal bovine serum-added BFM at the high temperatures of 36 and 40 degrees C, the cell density increased, with a mixture of yeast cells, pseudohyphae, and hyphae and with full hyphal development in the cultures compared with cultivation (mostly cells in yeast form) at 27 degrees C in both media. The mannans produced when cells were grown at these high temperatures were less reactive by enzyme-linked immunosorbent assay with factor sera 4, 5, and 6 in the commercially available kit 'Candida Check' than were the mannans obtained following growth at 27 degrees C. Based on 1H-nuclear magnetic resonance analysis, the mannans from cells grown at high temperatures had lost a phosphate group and a beta-1,2-linked mannopyranose unit, and had increased the number of non-reducing terminal alpha-1,3-linked mannopyranose units. We obtained similar results for mannans produced by C. albicans J-1012, C. albicans NIH B-792, C. albicans JCM 9061, C. stellatoidea ATCC 20408, and C. stellatoidea ATCC 36232 strains cultivated in BFM at 36 degrees C. These results suggest that both C. albicans and C. stellatoidea cells cultured at high temperatures, irrespective of the medium and shape of the cells, alter their antigenicity and chemical structure of cell wall mannans.