Candidal urinary tract infections caused by non-<Emphasis Type="Italic">albicans Candida</Emphasis> species

The incidence of non-albicans Candida and non-Candida species isolated from the urine of patients admitted to various departments of theFaculty Hospital of the Medical Faculty of Šafárik University in Košice was examined. From a total of 94 samples of analyzed urine 58 strains ofC. 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) andCryptococcus 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.     

Evaluation of Antifungal Susceptibility Testing with Microdilution and Etest Methods of <Emphasis Type="Italic">Candida</Emphasis> Blood Isolates

Candida species that show an increasing number of clinical and/or microbiological resistance to several antifungals and are the most common agents of invasive fungal infections. The aim of this study was to investigate the in vitro susceptibility of Candida blood isolates to antifungal agents (amphotericin B, fluconazole, itraconazole, and voriconazole) by comparative use of the CLSI reference microdilution method and Etest. Four hundred Candida blood isolates (215 Candida albicans, 185 non-albicans Candida strains) were included in the study. The broth microdilution test was performed according to the CLSI M27 A2 document. Etest was carried out according to the manufacturer’s instructions. The MIC results obtained with reference microdilution were compared with those obtained with the Etest by using percent and categorical agreements. According to MIK₉₀ values, voriconazole was the most active and itraconazole was the least active drug in vitro against all Candida species. Other than voriconazole, statistically significant differences were found when the susceptibility of Candida albicans and non-albicans Candida spp. to amphotericin B, fluconazole, and itraconazole were compared. These antifungal agents were found to be more active to C. albicans. Among the non-albicans Candida species, the lowest MIC values were obtained for Candida parapsilosis isolates. When the standard method was compared with Etest, the total agreement was higher for C. albicans than for non-albicans species, especially for fluconazole and voriconazole. In view of the findings, it was concluded that itraconazole showed the lowest activity against all Candida species. Etest could be an alternative method in assessing the in vitro antifungal susceptibility of Candida spp., but it is more convenient to use the microdilution method for studying in vitro susceptibility of non-albicans species, in particular for those possessing high MIC values against azoles.     

Identification of Candida isolated from the cutaneous candidiasis by the combined use of confirmatory medium and slide agglutination with monofactorial antibodies

Forty strains ofCandida and one ofTorulopsis were isolated from patients with cutaneous candidiasis. The isolates comprised 29 strains ofC. albicans, 7 strains ofC. tropicalis, 2 strains ofC. guilliermondii, and one each ofC. parakrusei, C. lipolytica, andT. famata were identified by the ordinary method. Besides the common pathogenC. albicans, a few other species ofCandida may be etiologic organisms of cutaneous candidiasis. These strains were re-examined by combined use of sucrose agar slants and slide agglutination tests with IgG monofactorial antibodies as a rapid identification method, especially for determining serotypes ofC. albicans. The new method was useful and reliable for rapid identification ofC. albicans and related species. All strains ofC. albicans isolated from skin lesions proved to be standard serotypes ofC. albicans.

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Zusammenfassung Vierzig Stämme vonCandida und eins vonTorulopsis wurden aus Kranken mit kutanen Candidamykosen isoliert. Neunundzwanzig Stämme vonC. albicans, 7 vonC. tropicalis, 2 vonC. guilliermondii, und je einer vonC. parakrusei, C. lipolytica undT. famata wurden mit dem ordinären Methode identifiziert. Außer dem gewohnlichen Erreger,C. albicans, konnten auch ein Paar andere Spezies vonCandida als den Erreger betrachtet werden. Sechsunddreißig Stämme vonC. albicans undC. tropicalis wurden mit der von uns verbesserten kombinierten serologischen und biologischen Methode untersucht, besonders um den Serotypus vonC. albicans festzusetzen. Die neue Methode war gut und zuverlässig als die rapide Identification vonC. albicans und verwandten Spezies. Alle aus der Hautläsion isoliertenC. albicans waren der in Japan allgemeine Serotypus vonC. albicans.

     

Species diversity of yeast in oral colonization of insulin-treated diabetes mellitus patients

The aim of this study was to investigate oral yeast colonization, antifungal susceptibility and strain diversity in insulin-dependent diabetes mellitus patients (175), as well as to evaluate the influence of dental prostheses. Oral rinse samples were cultured on selective media, in order to isolate, count and identify the yeasts recovered. More than half of the diabetic subjects (53%) carried significant amounts of Candida cells in the buccal cavity and these organisms were recovered at higher densities in diabetics wearing dentures. A total of 93 yeast strains were isolated from these patients, including: Candida spp. (n = 89); Pichia (n = 02); Trichosporon (n = 1), and Geotrichum (n = 1). C. albicans represented 56% of these strains, non-albicans Candida 39.8%, and other genera of yeast 4.3%. C. albicans was prevalent, followed by C. parapsilosis, C. tropicalis, C. glabrata, C. krusei, C. rugosa and C. guilliermondii. Agar disk-diffusion tests of the susceptibility of non-albicans Candida and other genera of yeast to fluconazole showed resistance in 21.9%, mainly in C. rugosa (100%), C. glabrata (57%) and C. krusei (50%). Local oral factors, such as the presence of dentures, in association with diabetes, seemed to have the effect of increasing the amount and variety of Candida species in the oral cavities, mainly those with lower drug susceptibilities.     

Composition of lipids produced by some strains ofCandida species. Production of single-cell oil in a chemostat culture

Fatty acid composition of the lipids produced by four strains ofCandida species was studied. Oleic acid was the principal fatty acid. Cellular lipids ofCandida sp. andC. pulcherima were rich in palmitic acid. Lipids fromC. lipolytica contained a significant amount of palmitoleic acid, whereasC. farinosa produced oil rich in stearis and α-linolenic acid. Analysis of cellular lipids ofCandida sp. andC. pulcherima during growth on a nitrogen-limited medium showed that oils accumulated in the exponential growth phase were more unsaturated than those accumulated in the decelerating and stationary phases. In a chemostat culture,Candida sp. accumulated about 40% of lipid. The specific rate of lipid formation, at a dilution rate ofD=0.09/h, was 35 mg of lipid per g of biomass per h and the yield of lipid on glucose was 11.4%.     

Interactions ofCandida albicans with bacteria and salivary molecules in oral biofilms

The yeastCandida albicans coaggregates with a variety of streptococcal species, an interaction that may promote oral colonization by yeast cells.C. albicans andCandida tropicalis are the yeasts most frequently isolated from the human oral cavity and our data demonstrate that both these species bind toStreptococcus gordonii NCTC 7869 while two otherCandida species (Candida krusei andCandida kefyr) do not. Adherence ofC. albicans was greatest when the yeast had been grown at 30° C to mid-exponential growth phase. For 21 strains ofC. albicans there was a positive correlation between the ability to adhere toS. gordonii and adherence to experimental salivary pellicle. Whole saliva either stimulated or slightly inhibited adherence ofC. albicans toS. gordonii depending on the streptococcal growth conditions. The results suggest that the major salivary adhesins and coaggregation adhesins ofC. albicans are co-expressed.     

Three new species of anamorphic yeasts phenotypically and phylogenetically related toCandida mesenterica: The description ofCandida fungicola sp. nov.,Candida sagamina sp. nov., andCandida fukazawae sp. nov. isolated from fruit bodies of mushrooms

Four strains of anamorphic yeasts isolated from fruit bodies of mushrooms collected in Japan were found to represent three new species of the genusCandida. These species resembleCandida mesenterica in characteristics commonly employed in the classification of yeasts. On the basis of DNA-DNA reassociation, however, they were clearly distinguished fromC. mesenterica and from one another. Three new species,Candida fungicola, Candida sagamina, andCandida fukazawae, are proposed for these yeasts. The analysis of SSU rDNA sequences suggested that these three species were closely related to each other and toC. mesenterica andC. suecica.     

The emergence of non-albicans Candida species as causes of invasive candidiasis and candidemia

The last three decades have seen an expanding pool of high-risk patients susceptible to the opportunistic pathogen Candida. Accordingly, a dramatic increase in nosocomial blood stream infections (BSIs) due to Candida spp has been reported throughout the world, starting in tertiary care centers and spreading to community hospitals. This absolute increase in Candida BSIs was accompanied by both an absolute and then a proportional increase in invasive infection caused by reduced fluconazole-susceptible non-albicans Candida spp. Currently, the incidence trend of BSI has stabilized, and Candida albicans remains the most common species causing fungal BSI. Clinicians must be aware of the importance and implications of non-albicans Candida spp when selecting antifungal drugs, although most studies have not shown significant outcome differences with use of the various antifungal classes.     

Numerical taxonomy ofKlebsiella pneumoniae strains isolated from clinical and nonclinical sources

A total of 180 clinical and nonclinical isolates ofKlebsiella pneumoniae, for which 99 characteristics were recorded, were subjected to numerical taxonomy analysis. Of these strains, 172 clustered into five major groups, with an overall similarity of 64%. Intragroup similarities ranged from 77 to 82%, with the subgroups corresponding to the speciesK. pneumoniae sensu stricto, K. oxytoca, andKlebsiella spp. 1, 2, and 3. Biochemical tests useful in distinguishing the species included production of indole, degradation of pectate, growth at 10°C, fecal coliform response, production of urease, fermentation of inulin andd-tartrate, utilization ofl-arginine and gentisate andm-hydroxybenzoate, and pigment formation ond-gluconate ferric citrate agar.     

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 ofCandida albicans, 2 strains ofC. krusei and one strain each ofC. guilliermondii, C. parapsilosis, C. tropicalis andCryptococcus 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.     

Role ofCandida in indirect pathogenesis of antibiotic associated diarrhoea in infants

One hundred and thirty seven isolates ofCandida species were isolated from antiobiotic associated diarrhoea cases and were examined to study the role ofCandida in the pathogenesis of diarrhoea in infants. The quantitative estimation of yeast population by simple gram stain smear revealed more than 70% of the cases had 3+ score. The isolates further screened for detection of-lactamases. Among the isolatedCandida sp,-lactamases was secreted byC. albicans, C. tropicalis, C. krusei andC. parapsilosis. Further, 46% of theCandida isolates were found to be produced 741–1110 mU/ml of-lactamases, suggesting that these enzyme would inactivate penicillin group of drugs and cause failure in the therapy directed against other diarrhoegenic bacteria.Abbreviation AAD antibiotic associated diarrhoea     

A method for taxonomic determination ofCandida albicans with DNA probes

Determination ofCandida species represents an important problem derived from the clinical implications of the species belonging to this genus. DNA probes have already been used for the epidemiology ofCandida albicans, as well as for taxonomic analysis ofCandida and other genera, although these probes are based on non-species-specific DNA sequences. In this work we carried out a 48-h assay, allowing the identification ofC. albicans from clinical isolates, using DNA probes based onC. albicans LEU2 andURA3 genes. Another probe related toC. albicans SEC18 gene was shown not to beC. albicans specific.     

Systemic Candida infection in University Hospital 1997–1999: the distribution of Candida biotypes and antifungal susceptibility patterns

A total of 102 Candida species were isolated from blood cultures from January 1997 to October 1999. Using assimilation of carbohydrate test, 52 (51.0%) of the Candida sp. were identified as C. parapsilosis, 25.5% (26) were C. tropicalis. C. albicans made up 11.8% (12), 6.9% (7) were C. rugosa, 3.8% (4) C. glabrata and 1% (1) C. guilliermondii. No C. dubliniensis was found in the study. In vitro antifungal susceptibility tests showed that all Candida species were sensitive to nystatin, amphotericin B and ketoconazole. Although all isolates remained sensitive to fluconazole, intermediate susceptibility was found in 3 C. rugosa isolates. Antifungal agents with high frequency of resistance were econazole, clotrimazole, miconazole and 5-fluorocytosine. Candida species found to have resistance to these antifungal agents were non-C. albicans. This revised version was published online in June 2006 with corrections to the Cover Date.     

Nucleotide sequence analysis of a variable region of the large subunit rRNA for identification of marine-occurring yeasts

A 230-nucleotide region of the large subunit (LSU) ribosomal RNA was examined to determine whether signature nucleotide sequences could be used for species identifications of basidiomycetous yeasts. Multiple strains of genetically defined heterothallic species ofRhodosporidium, Leucosporidium, Cystofilobasidium, andSporidiobolus demonstrated that nucleotide sequences within these species are homologous and that differences between species range from 1 to 20 or more bases. Also included in this study were several homothallic species of these teleomorphic genera and some anamorphs assigned toRhodotorula andCandida. Those results indicated close relationships among certain homothallic species, particularly in the genusMrakia, and potential relationships of homothallic and anamorphic strains to several teleomorphs. The data suggest that LSU sequences can be used for yeast identifications with the possible exception of closely related homothallic species.     

Host range ofFrankia endophytes

Summary Cross-inoculation experiments with 10 pure cultured strains and 17 host species were carried out. The 10 strains were isolated from the root nodules on actinorhizal trees ranging in 9 species, 5 genera and 4 families. The host species belong to 5 genera. The pure cultured strains fromAlnus are of strong ability to infect different species of the same genus. The seedlings inoculated with these strains are able to nodulate normally. These strains can also infect and nodulate the seedlings ofMyrica californica, but not the seedlings of Elaeagnus, Casuarina andMyrica rubra. The pure cultured strains from Elaeagnus can infect and nodulate the host species in the same genus and family with an exception ofE. viridis vardelavayi, which can be only poorly nodulated by a few strains from Elaeagnus. The strains from Elaeagnus cannot infect the seedlings of Alnus andMyrica rubra. The results presented here suggest thatFrankia endophytes can be divided into two groups: Alnus group and Elaeagnus group.     

Comparative observations of ultrastructure of five species of Candida

An electron microscopic comparison was made of five species ofCandida, namely:C. guilliermondii, C. krusei, C. parapsilosis, C. stellatoidea andC. tropicalis. The cell wall, plasma membrane and the cytoplasm with its organelles were described. The cell wall ofC. tropicalis was twice as thick as the cell wall in the other species.C. krusei appeared with distinct, rather elaborate wall sculpturing, a feature not pronounced in the other four species. A single nucleus with nucleolus appeared only in micrographs ofC. guilliermondii andC. krusei. At the same time, large central electron-luscent area (vacuole) appeared in the cells ofC. guilliermondii, C. parapsilosis andC. stellatoidea. The cytoplasm ofC. tropicalis was characterized by a granular appearance. Budding cells and pseudohyphae appeared similar to single cells in their general organelles. Such organelles in species studied were similar to these reported for other yeasts. These include: mitochondria, lipid granules, endoplasmic reticulum, ribosomes and vacuoles.Southwest Foundation for Research and Education, San Antonio, Texas.In partial fulfillment of the requirement of course work for Master of Science, Incarnate Word College, San Antonio.     

Species Distribution and Virulence Factors of Candida spp. Isolated from the Oral Cavity of Kidney Transplant Recipients in Brazil

Although yeasts belonging to the genus Candida are frequently seen as commensals in the oral cavity, they possess virulence attributes that contribute for pathogenicity. The aims of the present study were to study the prevalence of Candida spp. isolated from the oral cavity of renal transplant recipients and to analyze strains virulence factors. We isolated a total of 70 Candida strains from 111 transplant recipients, and Candida albicans was the most prevalent species (82.86 %). Oral candidiasis was diagnosed in 14.4 % kidney transplant patients, while 11 isolates (15.7 %) corresponded to non-Candida albicans Candida (NCAC) species. C. albicans adhered to a higher extension than NCAC strains. Some isolates of Candida tropicalis were markedly adherent to human buccal epithelial cells and highly biofilm-forming strains. Regarding proteinase activity, Candida orthopsilosis was more proteolytic than Candida metapsilosis. Candida glabrata and Candida dubliniensis showed very low ability to form biofilm on polystyrene microtiter plates. We have demonstrated here diverse peculiarities of different Candida species regarding the ability to express virulence factors. This study will contribute for the understanding of the natural history and pathogenesis of yeasts belonging to the genus Candida in the oral cavity of patients who were submitted to kidney transplant and are under immunosuppressive therapies.     

Fusarium fractiflexum sp. nov. and two other species within theGibberella fujikuroi species complex recently discovered in Japan that form aerial conidia in false heads

Morphological and molecular phylogenetic analyses were conducted on 12 strains ofFusarium, deposited in MAFF asF. subglutinans (≡F. moniliforme var.subglutinans≡F. sacchari var.subglutinans) orFusarium sp. because they formed aerial conidia in false heads in the dark. These strains were resolved as three distinct species within theGibberella fujikuroi species complex. A new species,F. fractiflexum, and two species new to Japan,F. circinatum andF. concentricum, are described and illustrated and their morphological features are discussed.Fusarium fractiflexum, isolated from diseased yellow leaf spots ofCymbidium spp., is differentiated from other fusaria based on its yellowish colonies and aerial conidia formed in false heads in the dark and in zigzag-like conidial chains under black light. Japanese strains ofF. circinatum also formed elongate, coiled sterile hyphae. Phialidic aerial conidia with a pointed apex and a wedgeshaped base were found inF. concentricum cultured under black light and represent a new diagnostic character of the species, in addition to colonies with alternating concentric rings when cultured on PDA. Based on DNA sequences of the β-tubulin gene and two other loci, strains ofF. fractiflexum were resolved phylogenetically as members of the Asian clade of theG. fujikuroi species complex. In addition, Japanese strains ofF. circinatum andF. concentricum were phylogenetically identical to the ex-type strains.     

Candida albicans and Non-C. albicans Candida Species: Comparison of Biofilm Production and Metabolic Activity in Biofilms, and Putative Virulence Properties of Isolates from Hospital Environments and Infections

Candida albicans and, more recently, non-C. albicans Candida spp. are considered the most frequent fungi in hospitals. This study analyzed Candida spp. isolates and compared the frequency of different species, that is, C. albicans and non-C. albicans Candida spp., and the origins of isolates, that is, from hospital environments or infections. Yeast virulence factors were evaluated based on biofilm production and metabolic activity. Hemolysin production and the antifungal susceptibility profiles of isolates were also evaluated. Candida spp. were highly prevalent in samples collected from hospital environments, which may provide a reservoir for continuous infections with these yeasts. There were no differences in the biofilm productivity levels and metabolic activities of the environmental and clinical isolates, although the metabolic activities of non-C. albicans Candida spp. biofilms were greater than those of the C. albicans biofilms (p < 0.05). Clinical samples had higher hemolysin production (p < 0.05) and lower susceptibility to fluconazole (p < 0.05). Non-C. albicans Candida spp. predominated in samples collected from hospital environments and infections (p < 0.05). These species had a lower susceptibility to fluconazole and amphotericin B, and their biofilms had higher metabolic activities than those produced by C. albicans, which may explain the increased incidence of fungal infections with these yeasts during recent years.     

A comparative study of the extracellular and cell-wall polysaccharides of someCandida species

Candida bogoriensis, C.buffonii, C.diffluens, C.foliarum andC.javanica, produce an extracellular polysaccharide which contains galactose, glucose, mannose, fucose and rhamnose. These sugars were also found in cell-wall preparations of the same yeast species. The cell-wall preparations ofC.diffluens andC.foliarum included capsular material. The similarity in composition of the extracellular polysaccharides and components of the cell wall suggests that both are synthetized by the same enzymatic system. The fiveCandida species may be closely related.