The tea fungus 'Kombucha' is a symbiosis of Acetobacter, including Acetobacter xylinum as a characteristic species, and various yeasts. A characteristic yeast species or genus has not yet been identified. Kombucha is mainly cultivated in sugared black tea to produce a slightly acidulous effervescent beverage that is said to have several curative effects. In addition to sugar, the beverage contains small amounts of alcohol and various acids, including acetic acid, gluconic acid and lactic acid, as well as some antibiotic substances. To characterize the yeast spectrum with special consideration given to facultatively pathogenic yeasts, two commercially available specimens of tea fungus and 32 from private households in Germany were analysed by micromorphological and biochemical methods. Yeasts of the genera Brettanomyces, Zygosaccharomyces and Saccharomyces were identified in 56%, 29% and 26% respectively. The species Saccharomycodes ludwigii and Candida kefyr were only demonstrated in isolated cases. Furthermore, the tests revealed pellicle-forming yeasts such as Candida krusei or Issatchenkia orientalis/occidentalis as well as species of the apiculatus yeasts (Kloeckera, Hanseniaspora). Thus, the genus Brettanomyces may be a typical group of yeasts that are especially adapted to the environment of the tea fungus. However, to investigate further the beneficial effects of tea fungus, a spectrum of the other typical genera must be defined. Only three specimens showed definite contaminations. In one case, no yeasts could be isolated because of massive contamination with Penicillium spp. In the remaining two samples (from one household), Candida albicans was demonstrated. The low rate of contamination might be explained by protective mechanisms, such as formation of organic acids and antibiotic substances. Thus, subjects with a healthy metabolism do not need to be advised against cultivating Kombucha. However, those suffering from immunosuppression should preferably consume controlled commercial Kombucha beverages.
Phospholipases are important pathogenicity determinants in Candida albicans. They play a significant role in damaging cell membranes and invading host cells. High phospholipase production is correlated with an increased ability of adherence and a higher mortality rate in animal models. By means of an egg yolk-containing agar and the Pz (= phospholipase activity zone) value according to Price, the present study investigated phospholipase production in 170 strains of C. albicans. At an incubation temperature of 37 degrees C, Pz values ranged from 0.395 to 1; no clear relationship was found between clinical origin of the isolates and severity of the disease. In addition to C. albicans, a total of 110 strains of 16 other yeast species were investigated for possible phospholipase production. Only yeasts of the species Rhodotorula rubra showed phospholipase activity, with mean values exceeding those observed in C. albicans. This result was confirmed by an assay using sterile culture filtrates and phosphatidyl-[3H-methyl]-choline-dipalmitoyl as a substrate. Since Rh. rubra has only rarely been demonstrated as a pathogen in humans, we believe that factors such as reduced growth at 37 degrees C, absence of dimorphism and low ability of adherence lessen the importance of high phospholipase activity in Rh. rubra as a pathogenicity determinant. Therefore, potential virulence factors should always be considered in the context of the whole spectrum of pathogenic determinants.
Based on molecular data, the genus Trichosporon was recently reclassified. Six human pathogenic species, which are closely related to specific types of infections can be differentiated. By means of commercial test systems and simple key criteria according to Gueho et al. [15], 44 isolates that had been identified as Tr. cutaneum between 7/92 and 1/96, were reclassified. The evaluation of clinical data also included 66 isolates that had not been preserved, and 27 strains of Tr. inkin. Trichosporon species were found in 4.8% of all yeast isolates (3.8% Tr. cutaneum, 1% Tr. inkin). Nearly every other isolate of Tr. cutaneum was cultivated from nail material, while Tr. inkin was mainly isolated from skin in the anogenital region. In 38 cases, reclassification revealed Tr. mucoides; Tr. ovoides and Tr. asteroides were identified in 3 cases each, while Tr. asahii, an especially remarkable pathogen in systemic mycoses, was not found. Clinically, isolates of Tr. mucoides were predominant in toenail mycoses which might be considered in the therapy of onychomycosis. Furthermore, isolates from the skin should be evaluated with respect to the increasing incidence of systemic Trichopsoron mycoses.
Despite the availability of modern antimycotics, which produce high cure rates in early infections, the therapy of advanced chromoblastomycosis is still unsatisfactory. An initial chromoblastomycosis caused by a hitherto unidentified species of the genus Phialophora was diagnosed in a 46-year-old teacher. The organism was isolated twice at an interval of 6 weeks from a partly psoriasiform, partly verrucous lesion on the 4th toe. The infection was apparently acquired 4 years ago during a holiday at Cape Verde. Treatment with itraconazole (Sempera). 200 mg/day, and amphotericin B (Ampho-Moronal) cream for 6 weeks initially resulted in rapid regression. However, 4 weeks after cessation of therapy, the Phialophora species was cultured again from skin scrapings. Complete healing was achieved after re-treatment with itraconazole for 20 weeks at the same dosage in combination with topical amorolfine and local hyperthermia. Until now, no relapse has occurred. The present case demonstrates that this rare disease, which mainly occurs as a traumatic mycosis in the rural population of tropical regions, must be included in the differential diagnosis of psoriasiform or verrucous skin lesions and also included in the list of diseases which may be acquired while on vacation in exotic locations.
In vitro antifungal properties of polidocanol (Thesi), a hydroxypolyethoxydecan, were investigated against various yeasts at concentrations of 0.05-10% (w/w) by means of the agar diffusion test; in the case of lipophilic Malassezia furfur, polidocanol-containing olive oil was used additionally for sensitivity study. Six strains of M. furfur of different clinical origin were tested as well as strains of C. albicans (3), C. krusei (3), C. parapsilosis (2), C. robusta (2), Tr. cutaneum (2) and one strain each of C. guilliermondii, C. glabrata, C. tropicalis and M. pachydermatis. Both test systems revealed predominantly fungistatic activity against M. furfur, with a minimal inhibitory concentration (MIC) of 1% polidocanol (w/w), while yeasts of other genera (Candida species, Trichosporum species) showed no or only transitory (C. krusei) inhibition of growth. M. pachydermatis was also found to be sensitive with a MIC of 0.1%; this suggests a specific inhibitory effect against the genus Malassezia. Polidocanol, which has been used for decades as an antipruritic and analgesic in various topical preparations at concentrations between 3% and 5%, might therefore be suitable for prophylaxis of recurrent pityriasis versicolor or in veterinary medicine.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.