Rare non-albicans Candida species detected in different clinical diagnoses

Candida massiliensis sp. nov. Isolated from a Clinical Sample

The majority of Candida species are known as non-pathogenic yeasts and rarely involved in human diseases. However, recently case reports of human infections caused by non-albicans Candida species have increased, mostly in immunocompromised hosts. Our study aimed to describe and characterize as thoroughly as possible, a new species of the Metschnikowia clade, named here Candida massiliensis (PMML0037), isolated from a clinical sample of human sputum. We targeted four discriminant genetic regions: "Internal Transcribed Spacers" of rRNA, D1/D2 domains (28S large subunit rRNA) and part of the genes encoding Translation Elongation Factor 1-α and β-tubulin2. The genetic data were compared to morphological characters, from scanning electron microscopy (TM 4000 Plus, SU5000), physiological, including the results of oxidation and assimilation tests of different carbon sources by the Biolog system, and chemical mapping by Energy-Dispersive X-ray Spectroscopy. Lastly, the in vitro antifungal susceptibility profile was performed using the E-test™ exponential gradient method. The multilocus analysis supported the genetic position of Candida massiliensis (PMML0037) as a new species of the Metschnikowia clade, and the phenotypic analysis highlighted its unique morphological and chemical profile when compared to the other Candida/Metschnikowia species included in the study.

The Intricate Connection between Bacterial α-Diversity and Fungal Engraftment in the Human Gut of Healthy and Impaired Individuals as Studied Using the In Vitro SHIME® Model

From the estimated 2.2 to 3.8 million fungal species existing on Earth, only a minor fraction actively colonizes the human gastrointestinal tract. In fact, these fungi only represent 0.1% of the gastrointestinal biosphere. Despite their low abundance, fungi play dual roles in human health-both beneficial and detrimental. Fungal infections are often associated with bacterial dysbiosis following antibiotic use, yet our understanding of gut fungi-bacteria interactions remains limited. Here, we used the SHIME® gut model to explore the colonization of human fecal-derived fungi across gastrointestinal compartments. We accounted for the high inter-individual microbial diversity by using fecal samples from healthy adults, healthy babies, and Crohn's disease patients. Using quantitative Polymerase Chain Reaction and targeted next-generation sequencing, we demonstrated that SHIME®-colonized mycobiomes change upon loss of transient colonizers. In addition, SHIME® reactors from Crohn's disease patients contained comparable bacterial levels as healthy adults but higher fungal concentrations, indicating unpredictable correlations between fungal levels and total bacterial counts. Our findings rather link higher bacterial α-diversity to limited fungal growth, tied to colonization resistance. Hence, while healthy individuals had fewer fungi engrafting the colonic reactors, low α-diversity in impaired (Crohn's disease patients) or immature (babies) microbiota was associated with greater fungal abundance. To validate, antibiotic-treated healthy colonic microbiomes demonstrated increased fungal colonization susceptibility, and bacterial taxa that were negatively correlated with fungal expansion were identified. In summary, fungal colonization varied individually and transiently, and bacterial resistance to fungal overgrowth was more related with specific bacterial genera than total bacterial load. This study sheds light on fungal-bacterial dynamics in the human gut.

The life and times of yeasts in traditional food fermentations

Yeasts are eukaryotic microorganisms which have a long history in the biotechnology of food production, as they have been used since centuries in bread-making or in the production of alcoholic beverages such as wines or beers. Relative to this importance, a lot of research has been devoted to the study of yeasts involved in making these important products. The role of yeasts in other fermentations in association with other microorganisms - mainly lactic acid bacteria - has been relatively less studied, and often it is not clear if yeasts occurring in such fermentations are contaminants with no role in the fermentation, spoilage microorganisms or whether they actually serve a technological or functional purpose. Some knowledge is available for yeasts used as starter cultures in fermented raw sausages or in the production of acid curd cheeses. This review aimed to summarize the current knowledge on the taxonomy, the presence and potential functional or technological roles of yeasts in traditional fermented plant, dairy, fish and meat fermentations.

Isolation and Characterization of an Atypical Metschnikowia sp. Strain from the Skin Scraping of a Dermatitis Patient

A yeast-like organism was isolated from the skin scraping sample of a stasis dermatitis patient in the Mycology Unit Department of Medical Microbiology, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia. The isolate produced no pigment and was not identifiable using chromogenic agar and API 20C AUX. The fungus was identified as Metschnikowia sp. strain UM 1034, which is close to that of Metschnikowia drosophilae based on ITS- and D1/D2 domain-based phylogenetic analysis. However, the physiology of the strain was not associated to M. drosophilae. This pathogen exhibited low sensitivity to all tested azoles, echinocandins, 5-flucytosine and amphotericin B. This study provided insight into Metschnikowia sp. strain UM 1034 phenotype profiles using a Biolog phenotypic microarray (PM). The isolate utilized 373 nutrients of 760 nutrient sources and could adapt to a broad range of osmotic and pH environments. To our knowledge, this is the first report of the isolation of Metschnikowia non-pulcherrima sp. from skin scraping, revealing this rare yeast species as a potential human pathogen that may be misidentified as Candida sp. using conventional methods. Metschnikowia sp. strain UM 1034 can survive in flexible and diverse environments with a generalist lifestyle.

An atypical, pigment-producing Metschnikowia strain from a leukaemia patient

A yeast strain was isolated from the sputum sample of a leukaemia patient in the Spirito Santo Hospital of Pescara, Italy. The fungus produced a pigment that formed a reddish halo around colonies, and was identified and deposited as a Metschnikowia spp. (accession number IHEM 25107-GenBank accession number JQ921016) in the BCCM/IHEM collection of biomedical fungi and yeasts (Bruxelles, Belgium). Although the physiology of the strain was close to that of Metschnikowia sinensis, the D1/D2 sequence did not correspond to any previously described Metschnikowia species. Phylogeny of the genus Metschnikowia is complex and requires far more analysis. We present the first non-M. pulcherrima Metschnikowia spp. isolate recovered from a human, and emphasize the role of man as a transient carrier of environmental yeasts, the pathogenicity of which still needs to be defined.

Control of postharvest Botrytis fruit rot of strawberry by volatile organic compounds of Candida intermedia

A study was conducted to identify volatile organic compounds or volatiles produced by Candida intermedia strain C410 using gas chromatography-mass spectrometry, and to determine efficacy of the volatiles of C. intermedia in suppression of conidial germination and mycelial growth of Botrytis cinerea and control of Botrytis fruit rot of strawberry. Results showed that, among 49 volatiles (esters, alcohols, alkenes, alkanes, alkynes, organic acids, ketones, and aldehydes) identified from C. intermedia cultures on yeast extract peptone dextrose agar, two compounds, 1,3,5,7-cyclooctatetraene and 3-methyl-1-butanol, were the most abundant. Synthetic chemicals of 1,3,5,7-cyclooctatetraene; 3-methyl-1-butanol; 2-nonanone; pentanoic acid, 4-methyl-, ethyl ester; 3-methyl-1-butanol, acetate; acetic acid, pentyl ester; and hexanoic acid, ethyl ester were highly inhibitory to conidial germination and mycelial growth of B. cinerea. Inhibition of conidial germination and mycelial growth of B. cinerea by volatiles of C. intermedia was also observed. Meanwhile, results showed that incidence and severity of Botrytis fruit rot of strawberry was significantly (P < 0.01) reduced by exposure of the strawberry fruit to the volatiles from C. intermedia cultures or C. intermedia-infested strawberry fruit. These results suggest that the volatiles of C. intermedia C410 are promising biofumigants for control of Botrytis fruit rot of strawberry.

Catheter-related fungemia caused by Candida intermedia

Candida intermedia is rarely reported as a human pathogen. We report two cases of catheter-related fungemia caused by C. intermedia which were treated successfully with intravenous fluconazole and catheter removal. The isolates were identified by commercial biochemical methods, oligonucleotide array, and partial sequencing analysis of rRNA genes.

Otomycoses of candidal origin in eastern Slovakia

Mycological analysis of swabs and scraping samples from the external ear canals of 40 patients with clinically diagnosed otomycosis (10 neonates, 30 adults) revealed the presence of fungi as etiological agents. They were investigated microscopically using 20 % potassium hydroxide, and by cultivation on Sabouraud's glucose agar. The Candida species were identified using the germ-tube test, micromorphology observations of colonies on rice agar, and particularly by the commercial kit AUXAcolor. The following Candida species were identified in the aural material examined: C. albicans (n = 21; 52.5 %), C. parapsilosis (11; 27.5), C. tropicalis (3; 7.5), C. krusei (3; 7.5), C. guilliermondii (2; 5.0). The above yeasts were present in samples together with Staphylococcus epidermidis (31), S. aureus (16), alpha-hemolytic streptococci (14), Neisseria spp. (14), Proteus mirabilis (3), Pseudomonas aeruginosa (3), Escherichia coli (1) and Haemophilus influenzae (1). The most frequent predisposing factors for otomycosis were swimming in public pools and/or bath, spa and diabetes mellitus.

Candida--agent of the diaper dermatitis?

Occurrence of Candida spp. was determined in a population of 60 infants, 1-15-month-old, with diaper dermatitis, admitted to a neonatal intensive care unit in Hospital Saca (Kosice, Slovakia). Specimens were obtained from the perianal, pubic, inguinal, or gluteal areas that showed signs of secondary infection as manifested by erythema, oozing, vesiculopustular lesions, and pus formation. The most frequently isolated species was C. albicans (41), followed by C. parapsilosis (8), C. tropicalis (4), C. pulcherrima (4), C. guilliermondii (2), and C. zeylanoides (1). Other organisms present in the mixed culture from the diaper area were Staphylococcus aureus (6), Escherichia coli (3), and 2 strains of each group B and D streptococci, and Proteus mirabilis. Infants diapered exclusively in disposable diapers showed less rash than those diapered exclusively or sometimes in cloth diapers.

Primers ITS1, ITS2 and ITS4 detect the intraspecies variability in the internal transcribed spacers and 5.8S rRNA gene region in clinical isolates of fungi

Restriction fragment length polymorphism analysis of the 5.8S rRNA gene and the internal transcribed spacers (ITS1 and ITS2) was used for examination of 66 isolates belonging to 19 species. Intraspecies variability was found in the examined region of 11 species (Candida albicans, C. catenulata, C. colliculosa, C. glabrata, C. kefyr, C. melinii, C. parapsilosis, C. guillermondii, C. solanii, C. tropicalis, Saccharomyces cerevisiae). Region of ITS-5.8S rDNA was amplified using the primers ITS1 and ITS4. The amplicons were digested by HaeIII, HinfI and CfoI. The recognized intraspecies variability was confirmed in the second step, in which the shorter fragments of this region were amplified using primers ITS1 and ITS2 and analyzed by capillary electrophoresis. Considerable intraspecific variability renders this method unsuitable for species identification, whereas it can be useful for epidemiological tracing of isolates.

Candidal urinary tract infections caused by non-albicans Candida species

The incidence of non-albicans Candida and non-Candida species isolated from the urine of patients admitted to various departments of the Faculty Hospital of the Medical Faculty of Safárik University in Kosice was examined. From a total of 94 samples of analyzed urine 58 strains of C. albicans and 36 strains of yeasts belonging to 6 species of non-albicans Candida and non-Candida spp. were detected: C. parapsilosis (n = 23), C. tropicalis (6), C. krusei (3), C. robusta (2), C. catenulata (1) and Cryptococcus neoformans (1). In relation to the diagnosis, the yeasts were isolated from patients suffering from a kidneys disease, epididymitis, diabetes, neoplastic diseases, urogenital anomalies, obstructive uropathy, cystitis, prostatitis, hemolytic-uremic syndrome, and others.

Causative agents of nosocomial mycoses

In the last few years mycoses have been caused by fungi formerly considered to be harmless for humans. They cause diseases of plants and insects; some of them are also used in the industry. They are now usually called "emerging fungi". We investigated this flora with respect to their potential to cause infections in hospitals. These fungi are present in the air, on medical objects and instrumentation, in the respiratory tract and on the hands of hospital staff; other sources have been identified in the use of iatrogenic methods. Mycotic diseases, their risk factors, their clinical pictures, and spectra of agents were analyzed in 1990-2000; the results were compared with data in the literature. Transplantations were the most frequent risk factors, fungemia and abscess the most frequent clinical picture and filamentous fungi (genera Absidia, Acremonium, Alternaria, Apophysomyces, Aspergillus, Bipolaris, Cladophialophora, Cunninghamella, Exserohilum, Fusarium, Chaetomium, Chrysosporium, Lecythophora, Ochroconis, Paecilomyces, Pythium, Rhizopus, Scedosporium, Scopulariopsis) were the most frequent agents of nosocomial infections. These filamentous fungi and also some yeasts (genera Candida, Cryptococcus, Trichosporon) bring about different clinical syndromes in both immunocompromised and immunocompetent patients.

Candida species isolated from cerebrospinal fluid

In the period from November 1998 to June 2001 13 cases of nosocomial meningitis were reported. Candida albicans was isolated from 54% of the patients (7); C. parapsilosis from 23% (3); C. tropicalis from 15% (2) and C. krusei from 8% (1). C. albicans was isolated from the cerebrospinal fluid (CSF) of five children with the following diagnoses: nonspecified tumor of the central nervous system, Hodgkin's disease, meningitis, suspect neuroinfection, and sepsis. Examination of CSF allowed us to detect 2 strains of C. albicans from adult patients, one after neurosurgery because of a brain tumor and one with a vascular disease of the brain. C. parapsilosis was found in CSF from two premature children and one child with epilepsy. Two isolates of C. tropicalis were obtained from both blood and the CSF of a child from the neonatal intensive care unit and from a child from pediatric oncology with multiple malignant neoplasms. Only one strain of C. krusei was found in the oral cavity and CSF of a patient after neurosurgery performed after head trauma.

Characterization of Cryptococcus neoformans var. neoformans serotype A and A/D in samples from Egypt

The cryptococcal polysaccharide antigen was detected in 10 cerebrospinal fluid (CSF) and 23 serum samples from cryptococcal meningitis and intestinal cryptococcosis by the cryptococcal antigen latex agglutination system (CALAS). CALAS titers in CSF and serum samples of cryptococcal meningitis ranged over 8-2048 and 32-2048, respectively, while in cases of intestinal cryptococcosis, serum titers ranged over 8-2048. The isolates of yeast Cryptococcus neoformans were determined to be of serotype A or of the A/D pair. The total leukocyte count and biochemical parameters in CSF were significantly increased as indicators of microbial infection. Furthermore, the in vitro change of the teleomorph (sexual state) to the anamorph (asexual state) was also detected and the teleomorph state changed in vivo to the encapsulated anamoph state which is more virulent during infection in vivo than the yeast-like noncapsulated form. Two primers for internal transcribed spacer (ITS) regions of ribosomal DNA were used for molecular detection of C. neoformans. After PCR amplification, a DNA band of 415 bp, visualized on agarose gel, indicated the presence of C. neoformans cells in the tested CSF and serum samples. The primer sensitivity was also characterized using purified yeast chromosomal DNA as template; it was about 20 pg or more chromosomal DNA which represents about 10 cells of C. neoformans. The primers were also specific for ITS regions of C. neoformans and gave negative results with Candida albicans and E. coli chromosomal DNA templates.

Candida-associated denture stomatitis

Candida-associated denture stomatitis was demonstrated by its cultivation in 171 out of 240 patients examined with partial or total dentures. After taking smears from lesions of the oral mucosa (tongue, cheeks, palate) and the contiguous denture surface by cotton wool swabs and inoculating them onto Sabouraud glucose agar and CHROMagar Candida, individual yeast species were identified by a germ tube, filamentous, and assimilation tests employing the commercial kit AuxaColor. Seven Candida species were identified in smears from the oral mucosa lesions and the contiguous denture surface: C. albicans (95 patients), C. tropicalis (26), C. parapsilosis (20), C. krusei (14), C. guilliermondii (12), C. lusitaniae (1) and C. freyschusii (1). Diabetes mellitus, neoplastic diseases, chemotherapy, radiotherapy, and broad-spectrum antibiotic therapy were identified as some of the large number of factors predisposing patients to stomatitis prothetica.

The histopathological characterization of oral Candida leukoplakias

Sixty four biopsy specimens of oral Candida leukoplakias were examined. Histological sections were stained with periodic acid-Schiff (PAS) reagent and by Grocott's silver method. C. albicans isolates were cultivated from all the patients but fungal hyphae were proved histologically only in 23 of them. PAS-positive and Grocott-positive elements were exclusively observed in the superficial epithelial layers, e.g., the cornified layer and the stratum granulosum. The inflammatory reaction was characterized by an early phase during which polymorphonuclear cells predominated. The skeletal muscle fascicles immediately adjacent to the infected epithelium showed striking degeneration and atrophy associated with a marked infiltrate of chronic inflammatory cells.

Electrophoretic karyotyping of Candida albicans strains isolated from premature infants and hospital personnel in a neonatal intensive care unit

Electrophoretic karyotyping was used to compare DNA probes of yeasts isolated from blood of preterm neonates (n = 66) in a neonatal intensive care unit (NICU) and from the hands of healthy hospital personnel (n = 10). The yeasts were identified as Candida albicans using standard laboratory methods. DNA was extracted from yeasts and isolation of identical DNA strains from the pairs nurse-neonate suggested that one nurse transmitted one yeast strain by her hands to three neonates. Four neonates harbored two identical strains originating from two nurses, i.e. each nurse transmitted the same strain to two neonates. In the additional 7 cases transmission of 1 yeast strain by 1 nurse to 1 neonate was observed. Our data suggest that nonperinatal nosocomial transmission of C. albicans occurs in neonates, possibly via cross-contamination being transferred on hands of health care workers. The importance of careful hand washing of staff (health care workers) and other infection-control procedures (to prevent the nosocomial transmission of pathogens in the NICU environment) is emphasized.

Candidaemia in cancer patients and in children in a neonatal intensive care unit

The species most frequently found in the group of neonates was C. parapsilosis, its incidence reaching 48%. Other yeasts isolated from blood were C. albicans (41%), C. tropicalis (7%), C. krusei and C. pseudotropicalis (2% each). Six yeast species (C. albicans 44%, C. parapsilosis 28%, C. tropicalis 11%, C. krusei 8%, C. guilliermondii 6%, C. lusitaniae 3%) were detected in cancer patients. The presence of an intravenous catheter as a possible risk in the development of candidaemia was identified in all neonates and in 69% of cancer patients. C. krusei candidaemia was associated with prophylactic fluconazole therapy.

Yeast-like microorganisms in eye infections

The proportion of yeast species involved in eye infections in 11 patients was examined. The presence of yeast organisms as causative agents of endophthalmitis was found in corneal smears (n = 4), conjunctival swabs (4), and vitreous fluid (3). Altogether 5 strains of Candida albicans, 2 strains of C. krusei and one strain each of C. guilliermondii, C. parapsilosis, C. tropicalis and Cryptococcus neoformans were isolated from the clinical material. The hematogenic origin of endophthalmitis was proved in 7 cases on the basis of positive blood samples and in 2 cases by the isolation of yeasts from the tip of an intravenous catheter. Endophthalmitis-supporting risk factors such as indwelling intravenous catheters, prolonged use of broad-spectrum antibiotics and chemotherapy, surgical intervention, diabetes mellitus, and malignancy were observed in the patients.

Detection of anti-Candida antibodies in neonates from a Neonatal Intensive Care Unit

Anti-Candida antibodies were determined in a group of preterm neonates from a neonatal intensive care unit with serious diseases including candidemia. Antibodies to C. albicans blastospores, i.e. antibodies to C. albicans surface mannan and to C. albicans germ tubes were detected. Higher titers of antibodies to blastospores (1:320) occurred in all patients examined while antibodies to C. albicans germ tubes (with the highest titer of 1:160) were present in 32 out of 66 neonates examined. The highest titers of both anti-C. albicans blastospore antibodies and anti-C. albicans germ tube antibodies were detected in neonates with candidemia and disorders of saccharide metabolism.

Fungal diseases of the respiratory tract

The proportion of Candida and non-Candida species in the clinical material from patients with respiratory-tract diseases was determined. C. albicans was isolated in 102 cases. An additional 89 strains of yeasts, isolated in association with respiratory diseases, belonged to 10 non-albicans Candida spp. and Cryptococcus spp. The prevailing species, which occurred in 47 cases, was C. parapsilosis. C. tropicalis, C. glabrata, and C. guilliermondii were isolated in 12, 10, and 9 cases, respectively. Four strains of C. krusei and three strains of C. lusitaniae and one strain each of C. freyschussii, C. robusta, C. zeylanoides, and Cryptococcus neoformans were also isolated.

Detection of anti-Candida antibodies by the indirect immunofluorescence assay in patients with cancer in the orofacial region

An indirect immunofluorescence assay was performed to detect antibodies to Candida albicans blastospores and germ tubes. Serum specimens were obtained from 82 patients with neoplastic diseases in the orofacial region and thrush of the oral mucosa. C. albicans was identified in the oral cavity of 63 patients investigated but serum anti-Candida antibodies were detected in only 23 of them. Serological examination showed that titers of antibodies to C. albicans blastospores ranged from 1:20 to 1:1280. High titers from 1:640 to 1:1280 were detected in patients without antibiotic, cytostatic, or radiotherapeutic treatment. The titers of antibodies to C. albicans germ tubes ranged from 1:20 to 1:640. Our results indicate that titers of antibodies to the C. albicans germ tubes were lower and were detected in a smaller number of patients.

The frequency of Candida species in onychomycosis

Mycological investigation of 108 nail specimens taken from a total of 41 patients examined over three years included direct microscopy and repeated cultures. A higher incidence of onychomycosis of the fingernails (75%) was observed in women while afflictions of the toenails (71%) prevailed in men. The highest prevalence of onychomycosis was found in patients between 50 and 70 years of age. Candida albicans was the dominant organism causing onychomycosis (prevalence rate 60.9%), followed by C. parapsilosis (19.6%), C. tropicalis (9.8), C. krusei (4.9), C. guilliermondii and C. zeylanoides (2.4% each).

Relative pathogenicity of Candida tropicalis in rat tongue mucosa

The potential of C. tropicalis to colonize and infect rat tongue mucosa was demonstrated. Thirty female Sprague-Dawley rats were infected orally with three different strains of C. tropicalis. The animals were killed one and three weeks following the inoculation and sections of their tongue were stained with hematoxylin-eosin and Grocott stain. Histological changes were observed in the group of animals killed one week after inoculation and infected with C. tropicalis strain isolated from the crural ulcer of a diabetic patient. The most important finding was acute purulent myositis with the formation of abscesses. The myositis was local without signs of spreading to the surrounding tissue. Epithelium-penetrating hyphae observed in the Grocott-stained sections were relatively fewer and more sparsely distributed.

Cutaneous candidosis in immunosuppressed patients

One-hundred patients with candidosis of the skin, mucous membranes and nail plates (confirmed by cultivation) were examined. Topical or systemic antimycotic treatment was successful in 58 patients. After a complete evaluation, 42 patients were found to suffer from factors supporting candidosis--diabetes mellitus (12), anemia (3) and various local factors (10 patients); 27 patients showed a deficiency in cell-mediated immunity. In addition to intensive antimycotic therapy, successful treatment is affected by the actual immunity level and can be ensured by efficient immunomodulation treatment of immunodeficiency.

Incidence of Candida species isolated from human skin and nails: a survey

Distribution of Candida species was investigated by examining 245 samples from skin lesions and nails. The isolates were identified using standard laboratory methods including germ tube test, micromorphology of colonies on rice agar, the commercial kit, saccharide assimilation and fermentation tests. Eight species of Candida were identified: C. albicans accounted for 56.4% of the isolates, C. parapsilosis 29.1, C. tropicalis 7.8, C. pulcherrima 2.9, C. guilliermondii 1.5, C. krusei and C. zeylanoides for 0.9% each, and C. robusta for 0.5%. The factors significantly associated with colonization were prolonged antibiotic therapy, parenteral nutrition, low birth body mass of infants, intubation, duration of stay in hospital, indwelling intravenous catheter, malignancies, diabetes, surgery, and obesity.

Prevalence of Cryptococcus neoformans in clinical specimens

Cryptococcus neoformans isolated from various clinical materials in 14 cases, was identified by (1) cultivation on Sabouraud glucose agar and CHROMagar Candida, (2) microscopic examination of Indian-ink-stained preparations and (3) determination of biochemical properties (assimilation and fermentation of saccharides, assimilation of KNO3, production of urease and phenol monooxygenase). C. neoformans was determined in five specimens from paediatric patients in the intensive care unit and in nine specimens from adult patients, most frequently from liquor at meningitis (n = 3).