Evaluation of the Experimental Inoculation of <Emphasis Type="Italic">Cryptococcus albidus</Emphasis> and <Emphasis Type="Italic">Cryptococcus laurentii</Emphasis> in Normal Mice: Virulence Factors and Molecular Profile Before and After Animal Passage

The genus Cryptococcus includes free-developing species, a few of which are of medical importance. Some, such as C. neoformans and C. gattii, cause infections in man frequently and C. albidus and C. laurentii cause less so. The aims of this study were to evaluate organ colonization after inoculation of C. albidus and C. laurentii isolates in normal BALB/c mice, the virulence factors (growth at 37°C, capsule, melanin, proteinase, and phospholipase production) and the molecular profile (PCR-fingerprinting) of the yeasts before and after infection. The importance of different profiles (virulence and molecular) was considered in relation to the distribution in different organs and to the time intervals of isolation from organs. C. albidus was isolated from animal organs 2 to 10 days after inoculation and C. laurentii from 2 to 120 days. Most isolates of the two species kept the virulence factors showed before inoculation. The high homogeneity of the molecular profile of C. albidus and the high heterogeneity of C. laurentii were kept through the passages in animals. It is concluded that most isolates of both species were recovered from the animal organs after 5 or more days, and phenotypes were not altered by inoculation. No molecular alteration was detected and the virulence factors were not related to the time intervals before isolation from organs.     

Improvement in the biocontrol of postharvest diseases of apples with the use of yeast mixtures

Mixtures of yeasts were tested for theirability to control Penicillium expansum andBotrytis cinerea on Red Delicious apple fruits. The occurrence of synergistic or antagonisticinteractions between yeast strains in differentmixtures was also evaluated. Two strains ofRhodotorula (R. glutinis SL 1 and R. glutinisSL 30) and two strains of Cryptococcus (C. albidus SL 43 and C. laurentii SL 62) were selected fordeveloping yeasts mixtures.The R. glutinis SL 1–R. glutinis SL 30 mixtureexhibited a lower effectiveness than eachstrain alone, against both moulds. Othermixtures (R. glutinis SL 1–C. albidus SL 43 and R. glutinis SL 30–C. albidus SL 43) showedsynergism against P. expansum but not against B. cinerea. The R. glutinis SL 1–C. laurentii SL62 mixture was the only mixture which showedsynergism against gray mould. There was not anymixture, which showed high effectivenessagainst both moulds at the same time. Differentresults could be explained by the dynamics ofthe population of the yeasts.By using yeast mixtures, it was possible toimprove biocontrol without increasing theamount of antagonists applied. The synergismobserved could be useful in enhancingbiological control.     

Yeast diversity in a mesotrophic lake on the karstic plateau of Lagoa Santa,MG-Brazil

The yeast diversity in a paleo-karstic lake of the Lagoa Santa plateau was studied during March 1986–March 1987. Water samples were collected monthly at five stations and the yeasts were isolated at 25 °C on Sabourad dextrose agar supplemented with 0.5% of yeast extract and 10 mg% of chloramphenicol. August and February showed the highest numbers of isolates, coinciding, respectively with the beginning and the ending of stratification. Of 56 isolated species, Aureobasidium pullulans, Candida famata, Cryptococcus albidus, Cryptococcus laurentii, Rhodotorula glutinis, Rhodotorula rubra and Trichosporon cutaneum occurred at the highest frequencies. A. pullulans showed greatest prevalence during the dry period (winter), whereas C. famata, Cr. albidus, Cr. laurentii and Rh. rubra were prevalent during the rainy season (summer). Tr. cutaneum was distributed between July and November. Most isolates yeasts are associated with plants and soils, and are important in decomposition of aquatic macrophytes. Furthermore, a possible role of these species as indicators of pollution is discussed.     

Studies of Antarctic yeast for β-glucosidase production

Moss and lichen samples from the region of the Bulgarian base on Livingston Island, Antarctica were examined for the presence of yeasts. Six pure cultures were obtained. They were screened for -glucosidase production and two of them were selected. These were identified as Cryptococcus albidus AL₂ and C. albidus AL₃, according to their morphology, reproductive behaviour, and growth at different temperatures, salt concentrations, nutritional characteristics and various biochemical tests. These strains were examined for biosynthesis of -glucosidase on different carbon sources under aerobic conditions. High exocellular and endocellular activities were obtained when they were grown on cellobiose, methyl--D-glucopyranoside and salicin. The time course of growth and -glucosidase production of the yeast was examined by cultivation in a medium with cellobiose under aerobic conditions at temperatures 18 and 24 °C for 96 h. Cryptococcus albidus AL₂ and C. albidus AL₃ synthesized exocellular enzyme, respectively 58.33 and 55.83 U/ml and endocellular enzyme 137.75 and 205.34 U/ml at 24 °C for 72 h of the cultivation.     

Occurrence of Yeasts in Cloacae of Migratory Birds

Several species of yeast have been reported as pathogens in humans based on increases in immunodeficiency syndromes and as a result of immunosuppressant chemotherapy in cancer treatment. Domestic and wild birds are known to act as carriers of human pathogenic fungi. To gain additional information on the yeasts present in the cloacae of some species of migratory birds, 421 wild birds (24.39% out of 1726 birds caught in Romania, Hungary and Bulgaria) were sampled with the permission of the local judicial authority. The state of conservation of the birds (i.e. post-mortem alterations, colour of the mucosae etc.), along with their age and sex were determined. Samples were collected directly from the cloacae and cultured, and colonies were identified in each positive sample. Yeasts were isolated from 15.7% of the animals sampled, with the highest percentage found in coots (Fulica atra −58.8%) and the lowest in quails (Coturnix coturnix −1.7%). A total of 131 isolates belonging to 15 species of yeast were identified. Rhodotorula rubra was the yeast with the highest number of isolates (28.2%), followed by Cryptococcus albidus (18.4%), Candida albicans (9.2%), Trichosporon cutaneum (8.4%), Candida guilliermondii (6.1%), Candida tropicalis (6.1%) and other species. The present study represents the first survey on the occurrence of yeasts in the cloacae of migratory birds. The prevalence and species of yeasts isolated is discussed on the basis of the ecology, diet, and habitat of the birds.     

Prevalence of yeast-like fungi and evaluation of several virulence factors from feral pigeons in Seoul, Korea

Aims: Studies of pigeon‐borne yeasts have tended to focus on species, such as Cryptococcus neoformans and Candida albicans, with scant attention to feral pigeons in Korea. We studied the prevalence of yeasts from faecal samples of feral pigeons obtained in various public places in Seoul, Korea, and assessed their potential capacity as human pathogens. Methods and Results: Three hundred and six pigeon faeces samples were collected at city squares and parks in 21 localities in Seoul and Seoul Grand Park and analysed for yeast with conventional methods. Of the 306 samples, 126 (41·2%) were positive for yeast. Seventeen species of yeast were identified. The most frequent species were Candida glabrata (34·1%), Candida famata (12·7%), Cryptococcus albidus (14·3%) and Cryptococcus laurentii (7·9%). The yeast isolates were tested for virulence. Of the 116 isolates (ten isolates missing), 70·7% (n = 82) grew at 37°C. All the Cryptococcus spp. isolates possessed a capsule, 16·4% (n = 19) produced melanin, and 33·6% (n = 39) produced proteinase. Two Ca. glabrata, a Ca. famata and Ca. albicans as well as three C. neoformans, a C. laurentii and Ca. albicans isolates had three virulence factors. Accordingly, 29·3% (n = 34) isolates possessed more than two virulence factors except capsule formation. Conclusions: These results of this study indicate that feral pigeons harbour a variety of yeasts and are a reservoir of human pathogenic fungi. Significance and Impact of the Study: This study is the first time about the microflora (fungi) presents in faecal samples collected from a variety of public areas throughout Seoul, Korea.     

Role of opportunistic fungi in ocular infections in Nigeria

The importance of opportunistic fungal pathogens in causing ocular infections is emphasized. A study was conducted over a period of 4 years (1974–1977) to investigate the role of opportunistic fungi in causing mycotic keratitis and to elucidate certain aspects of epidemiology of this disease in Nigeria. Fifty-nine cases of corneal ulcers of suspected mycotic etiology were investigated. Fungal etiology was confirmed in 42 of these cases. The predominant etiological agent was Fusarium solani in 14 cases (33.33%) followed by Penicillium citrinum in 8 cases (19.04%) and Aspergillus fumigatus in 5 cases (11.90%). The yeasts were responsible for only 3 cases (7.14%) i.e. one each caused by Candida albicans, C. parapsilosis and C. guilliermondii. Among the remaining 12 cases, one was caused by F. moniliforme, 3 by A. flavus, 2 each by A. niger, Penicillium expansum and Penicillium sp., and one each by Cladosporium cladosporioides and Cladosporium sp. The clinical features of the cases are briefly described.The incidence of mycotic keratitis in relation to sex, age, occupation, trauma and other factors has been analysed. Corneal trauma appeared to be an important predisposing factor as 27 (67.28%) of the patients gave a history of injuries to the eye. Notably, a large number of patients were farmers and trauma was most often from palm tree leaf, thorn, kernel or other plant objects. Topical application of corticosteroids or broad spectrum antibiotics did not seem to play an important role in the etiology of keratomycosis. Cases were recorded throughout the year although the number of cases was higher in the months of March –May, and November–December than that during the rest of the year.The isolates of the causative agents were studied in detail for their morphological and cultural characters. The isolates of F. solani grew well at 37°C and survived at 40°C for more than 3 weeks. In vitro drug sensitivity tests indicated good antifungal activity of pimaricin and econazole for F. solani, clotrimazole and econazole for Aspergillus fumigatus, A. flavus and Penicillium citrinum, and 5-fluorocytosine for Candida spp.Investigations on the incidence of fungi in normal healthy eyes of 450 persons comprising 204 adults and 246 children yielded 204 isolates belonging to 21 genera of fungi. Cladosporium was most frequent (12.88%) followed by Penicillium (10.22%) and Aspergillus (6.66%). Another important fungus was Fusarium represented by 10 isolates, viz. 4 of F. solani, 2 of F. moniliforme, 1 of F. exysporum, and 3 of Fusarium sp. The yeasts were represented by two isolates each of Candida tropicalis, C. pseudotropicalis, C. krusei, Trichosporon sp and Cryptococcus albidus, and one of Candida guilliermondii. Successive culturing of fungi from normal eyes in a small group indicated that fungi occur in the outer eye generally as transients.The epidemiology of mycotic keratitis has been discussed in relation to the present findings and in comparison with observations of other investigators.     

Utilization of cellobiose and production of β-clucosidase by nine yeast species

A comparative study of 9 yeasts namely, Candida blankii,C.humicola,C.ishiwadae,C.rhagii,C.tropicalis,Hensenula subpelliculosa,Saccharomyces cerevisiae,Trichosporon cutaneum and Tr.pullulans was carried out for the production of extracellular and cell bound β-glucosidase using cellobiose as the substrate. Trichosporon cutaneum was found to be the best extracellular as well as cell bound β-clucosidase producer and the former activity was more than the latter. In the rest of the yeasts most of them showed more cell bound β-glucosidase as compared to the extracellular.     

Survey of bovine mycotic mastitis in dairy herds in the State of São Paulo,Brazil

The purpose of this study was to isolate fungi from the quarter milk of cow udders from several dairy herds and to identify the different genera and species involved in mastitis. A total of 2078 milk samples from normal, clinical and subclinical mastitis quarters from 22 dairy herds of 16 districts in the State of São Paulo, Brazil was utilized in this survey. Two hundred and fifty one (12.07%) fungi were isolated from the samples. Two hundred and eight of these (82.86%) were yeasts and 30 (11.95%) were moulds. The fungi were isolated in pure culture (24.77%) or in cultures mixed with bacteria (72.22%). The yeasts isolated were:Cryptococcus spp. (71 strains),Rhodotorula spp. (40),Candida spp. (68),Trichosporon cutaneum (21),Aureobasidium pullulans (7), andPichia ohmeri (1). Moulds classified in following genera were also isolated:Aspergillus (3),Penicillium (3),Alternaria (3),Phoma (3),Epicoccum (2), andGeotrichum (16).     

Assessing the absolute configuration of (7S,8R)-(−)-epoxyjasmone

The absolute configuration of cis-epoxyjasmone (−)-2, isolated from Trichosporum cutaneum CCT 1903 whole cells, has been unambiguously established as (7S,8R), [α]_D²⁰ −29.0° (c 1.3, CHCl₃), by a new two step method, using a regioselective epoxide opening as the key step followed by Mosher acid derivatization.     

Temperature and seedling age affect susceptibility of perennial ryegrass seedlings to pathogenic fungi

Summary Effects of temperature and seedling age on survival of perennial ryegrass (Lolium perenne L.) seedlings grown on sand-wheat wholemeal cultures of different isolates ofFusarium spp. (9 isolates),Pythium spp. (9 isolates), andChaetomium spp. (1 isolate) are reported. Some isolates were virulent over the whole range of temperatures tested (7.5–27.5°C). The virulence of others depended on temperature. Most isolates were less virulent at intermediate temperatures (12.5–22.5°C) than at higher or lower temperatures. At 25°C ryegrass seedlings were susceptible to fungal attack for only a limited period after germination commenced. This period differed for different fungi, but for most isolates tested, seedlings were resistant after 2–3 days.     

Induction of sporulation in food-spoilage yeasts

Four yeasts, Hansenula anomala, Kluyveromyces fragilis, Lodderomyces elongisporus and Saccharomyces cerevisiae, were cultured in two presporulation media at 30 ° C. Media consisted of yeast extract — peptone — acetate and yeast extract — peptone — dextrose broths. Except for K. fragilis, the test yeasts reached a high degree of sporulation when transferred to acetate- and ethanol-supplemented sporulation media. The percentage of S. cerevisiae cells forming asci was as high as 79% after 24 h incubation. H. anomala and L. elongisporus sporulated more rapidly in ethanol- compared to acetate-containing medium. Within test parameters, the concentration of acetate or ethanol, _pH, and incubation temperature (25 ° C and 30 ° C) did not substantially influence the extent of sporulation.     

Ecological and enzymatic studies on fungi associated with biscuits in Egypt

Some 43 species and four varieties belonging to nineteen genera were collected from 30 samples of six types of biscuit on 30% sucrose and 1% starch Czapek-Dox agars at 28°C. The most contaminated samples were chocolate wafers with 327 and 195 colonies g⁻¹, 12 and 8 genara and 18 and 13 species on the media, respectively. Samples of wafers without jam and jam wafers were less contaminated with fungi. The most frequently isolated fungi on the two media were Alternaria alternata, Aspergillus alutaceus, A. fumigatus, A. niger, A. sydowii, Cladosporium cladosporioides, C. herbarum, Penicillium chrysogenum, P. janczewskii and yeasts (Saccharomyces spp.). The osmophiles, Eurotium amstelodami and E. repens, were infrequently isolated from chocolates and jam-wafer biscuits.All 69 isolates tested produced invertase and could produce 90%, respectively, amylase, caseinase, and catalase.     

Prevalence of superficial mycoses in the Aosta Valley Region of Italy from 1984 to 1989

Two hundred and thirty soil samples from different localities were examined for the presence of geophilic keratinophilic fungi. Six species namely Microsporum gypseum — 34 isolates, Chrysosporium keratinophilum –29, C. tropicum –20, Keratinophyton terreum –4, Trichophyton terrestre –8 and Chrysosporium species – 3 — were isolated. Most of these fungi were recovered from garden, field and river bank soil. The importance of these findings is briefly discussed.     

Presence of <Emphasis Type="Italic">C. albidus</Emphasis>, <Emphasis Type="Italic">C. laurentii</Emphasis> and <Emphasis Type="Italic">C. uniguttulatus</Emphasis> in Crop and Droppings of Pigeon Lofts (<Emphasis Type="Italic">Columba livia</Emphasis>)

Columba livia is an important reservoir and carrier of Cryptococcus neoformans, Cryptococcus uniguttulatus, Cryptococcus laurentii and Cryptococcus albidus. Upper digestive tract of this species is also known as a habitat for Cryptococcus neoformans. Given the increasing clinical interest of this microorganism, 331 swabs from crop and 174 dropping samples from pigeon lofts in Grand Canary Island have been studied. The obtained results show an extensive presence samples 81 positive (24.47%) of Cryptococcus spp. in analysed crops: 32 (9.66%) for C. neoformans, 24 (7.2%) for C. uniguttulatus, 23 (6.9%) for C. albidus and 2 (0.6%) for C. laurentii. In the same way, Cryptococcus spp was also isolated in 82 (47.13%), dropping samples: C. neoformans in 59 (33.9%), C. uniguttulatus, in 9 (5.17%), C. laurentii in 8 (4.59%) and C. albidus in 6 (3.44%) of the investigated samples, respectively. The cryptococcosis produced by species of cryptococci other than C. neoformans has become more important during the last decade, supporting the study on the role of pigeon in the epidemiology of this disease.     

In Vitro Investigation of Antifungal Activity of Allicin Alone and in Combination with Azoles Against <Emphasis Type="Italic">Candida</Emphasis> Species

Candidiasis is a term describing infections by yeasts from the genus Candida, and the type of infection encompassed by candidiasis ranges from superficial to systemic. Treatment of such infections often requires antifungals such as the azoles, but increased use of these drugs has led to selection of yeasts with increased resistance to these drugs. In this study, we used allicin, an allyl sulfur derivative of garlic, to demonstrate both its intrinsic antifungal activity and its synergy with the azoles, in the treatment of these yeasts in vitro. In this study, the MIC₅₀ and MIC₉₀ of allicin alone against six Candida spp. ranged from 0.05 to 25 μg/ml. However, when allicin was used in combination with fluconazole or ketoconazole, the MICs were decreased in some isolates. Our results demonstrated the existing synergistic effect between allicin and azoles in some of the Candida spp. such as C. albicans, C. glabrata and C. tropicalis, but synergy was not demonstrated in the majority of Candida spp. tested. Nonetheless, In vivo testing needs to be performed to support these findings.     

Microbiological studies on amylolytic oriental fermentation starters

Ragi and ragi-like starters were obtained from China, India, Indonesia (Java and Bali), Malaysia, Nepal, Philippines, and Taiwan. These starters have a number of names in each country (murcha, bubod, Chinese yeast). The microorganisms found in 41 samples examined were 3 genera of the Mucorales (Rhizopus, Mucor, Amylomyces), yeasts and bacteria. Except for a few chance contaminants only Mucoraceous fungi were found, and the appearance and growth of colonies of yeasts and bacteria indicate that only 2 or 3 species of each were present. The starters from different countries sold under different names are identical in their flora except that Amylomyces was rarely, if ever, a part of the murcha flora in samples from Nepal. The range in counts were 4x10³ to 2.1×10⁸ bacteria, 4×10³ to 6.1×10⁸ for molds and yeasts, and 3×10³ to 6.1×10⁸ for yeasts alone. The anaerobic count ranged from 3×10² to 1.5×10⁸ and was made up of both yeasts and bacteria. Every sample contained yeast and at least one Mucoraceous mold. Amylomyces was shown to survive long periods of time — as many as 5 years at room temperature resulted in retained amylolytic activity. There was a considerable reduction in isolates of Mucor and Rhizopus with long periods of storage. Chlamydospore germination was seen for the first time in Amylomyces.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Prevalence and Antifungal Susceptibility of Yeasts Obtained from the Oral Cavity of Elderly Individuals

Infections caused by Candida yeasts are common in elderly individuals. Seventy-five isolates of Candida spp. were obtained from saliva samples of 136 institutionalized elderly individuals resident in six retirement homes of Belo Horizonte, Brazil. Forty-seven isolates (62.66%) were identified as Candida albicans, 15 (20%) as C. tropicalis, 7 (9.33%) as C. glabrata, 4 (5.33) as C. parapsilosis, and 2 (2.67%) as C. guilliermondii. Among the 136 elderly individuals studied, 49 (36%) were male and 87 (64%) were female. Ages ranged from 60 to 90 years old. Sixty-three (46.3%) of the institutionalized individuals were denture wearers and, among them, 53 (84.1%) carried Candida yeasts in the oral cavity. Forty-four subjects presented lesions in the oral mucosa and among these, 36 (82%), had positive culture for Candida spp. The samples were tested for the in vitro susceptibility to amphotericin B, itraconazole, fluconazole and 5-flucytosin, and great variations were observed in the minimum inhibitory concentrations (MIC) of these drugs according to the species.     

Association of anurans with pathogenic fungi

In a study of 450 Amazonian anurans, we isolated yeasts and yeast-like fungi from 54 animals (Bufo granulosus, B. marinus, Dendrophrynyscus sp., Hyla geographica, H. lanciformes, Ololygon rubra, Adenomera hylaedactyla, Eleutherodactylus fenestratus, Leptodactylus fuscus, L. ocellatus, L. pentadactylus). The internal organs of these animals did not show any macroscopic anomaly nor histopathology. We recovered 105 fungal isolates from the anuran liver, lung, kidney, spleen, heart and gonad. The isolates were made up of 30 fungal species, 9 of which (48 isolates, 46%) were fungi with known pathogenic potentials, namely: Candida guilliermondii, C. parapsilosis, C. tropicalis, C. glabrata, Geotrichum candidum, Aureobasidium pullulans, Wangiella dermatitidis, Trichosporon cutaneum and Exophiala werneckii. Eleven animals harbored identical fungi in more than one of their internal organs; seven animals had more than one fungal species colonizing a single organ. Our findings indicated probable natural subclinical infections of candidiasis, geotrichosis or phaeohyphomycosis, and also symbiotic presence of non-pathogenic fungi among neotropical anurans.     

Microflora and Invert Sugars in Juice from Healthy Tissue of Stored Sugarbeets

Bacterial populations increased in juice of healthy tissue of sugarbeet roots stored at 5 C. Average counts showed a sixfold increase after 150 days of storage. Invert sugar levels increased over threefold in “American 4 Hybrid A” and remained fairly constant in “Mono-Hy D-2.” The former cultivar also had significantly higher bacterial colony counts than the latter before 90 days of storage. Of 36 isolates identified, 16 were Pseudomonas spp. including P. chlororaphis; 6 Bacillus spp. including B. subtilis; 5 Arthrobacter spp. including A. globiformis; 4 yeasts; 2 Erwinia spp.; 2 Flavobacterium spp. including F. aquatile; and Streptomyces longisporus. Isolates of all genera except S. longisporus were able to hydrolyze sucrose in vitro.