The diversity and antifungal susceptibility of the yeasts isolated from coconut water and reconstituted fruit juices in Brazil
Departamento de Microbiologia, ICB, C. P. 486, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil. International journal of food microbiology
(Impact Factor: 3.08).
01/2013; 160(3):201-5. DOI: 10.1016/j.ijfoodmicro.2012.10.012
The aims of this study were to characterise the yeasts present in the reconstituted fruit juices and coconut water extracted with "coconut machines", both collected from commercial outlets in a Brazilian city, and to investigate the antifungal resistance of isolates from these beverages that were able to grow at 37°C. The yeast population counts in the coconut water samples ranged from 1.7 to >6.5logcfu/ml, and in the reconstituted fruit juices, the counts ranged from 1.5 to >5.5logcfu/ml. Aureobasidium pullulans, Candida boidinii, Candidaintermedia, Candidaoleophila, Candidaparapsilosis, Candidasantamariae, Candidatropicalis, Clavispora lusitaniae, Kloeckera apis, Lachancea fermentati, Pichia fermentans and Rhodotorula mucilaginosa were the most frequent species isolated from these beverages. At least 18 yeast species isolated from these beverages have been reported as opportunistic pathogens. Eight yeast isolates were resistant to fluconazole, seven were resistant to itraconazole, and 26 to amphotericin B. Some yeast species were resistant to more than one of the antifungal drugs tested. Two isolates of C. tropicalis from the reconstituted fruit juices exhibited resistance to all three drugs. The presence of yeast strains that are resistant to commonly used antifungal drugs suggests a potential risk, at least to immunocompromised individuals who consume these beverages.
Available from: Jaime Green
- "While L. fermentati has been recognized as a component of fermented drinks, it may be more pervasive than previously thought. L. fermentati was found in more than 50% of olive oil mills tested
, and an investigation of commercially available drinks in Brazil also found L. fermentati in coconut juice and reconstituted fruit juices
. A species with a close evolutionary relationship to L. fermentati, L. thermotolerans, is present on the leaves of deciduous trees in the autumn when fruit would be harvested
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Lachancea fermentati is an environmental yeast that is also used in the fermentation of alcoholic drinks. It has not previously been described as a human pathogen although the closely related yeast, Saccharomyces boulardii, can cause fungemia. Here we report a case of L. fermentati acting as a pathogen in a septic patient with cultures positive from blood, peritoneal fluid, bile, and sputum.
A 36 year-old Caucasian man was hospitalized with acute alcoholic hepatitis complicated by Escherichia coli spontaneous bacterial peritonitis. Three days after admission, he developed new fevers with sepsis requiring mechanical ventilation and vasopressor support. He was found to have a bowel perforation. Cultures from blood, peritoneal fluid, and sputum grew a difficult-to-identify yeast. Micafungin was started empirically. On hospital day 43 the yeast was identified as L. fermentati with low minimum inhibitory concentrations (by Epsilometer test) to all antifungals tested. Micafungin was changed to fluconazole to complete a 3-month course of therapy. Serial peritoneal fluid cultures remained positive for 31 days. One year after his initial hospitalization the patient had ongoing cirrhosis but had recovered from fungemia.
This case demonstrates the need for clinicians to consider host factors when interpreting culture results with normally non-pathogenic organisms. In this immunocompromised host L. fermentati caused disseminated disease. We believe his hobby of brewing alcohol led to colonization with L. fermentati, which then resulted in invasive disease when the opportunity arose.
Available from: Janja Zajc
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Aureobasidium pullulans is a black-yeast-like fungus used for production of the polysaccharide pullulan and the antimycotic aureobasidin A, and as a biocontrol agent in agriculture. It can cause opportunistic human infections, and it inhabits various extreme environments. To promote the understanding of these traits, we performed de-novo genome sequencing of the four varieties of A. pullulans.
The 25.43-29.62 Mb genomes of these four varieties of A. pullulans encode between 10266 and 11866 predicted proteins. Their genomes encode most of the enzyme families involved in degradation of plant material and many sugar transporters, and they have genes possibly associated with degradation of plastic and aromatic compounds. Proteins believed to be involved in the synthesis of pullulan and siderophores, but not of aureobasidin A, are predicted. Putative stress-tolerance genes include several aquaporins and aquaglyceroporins, large numbers of alkali-metal cation transporters, genes for the synthesis of compatible solutes and melanin, all of the components of the high-osmolarity glycerol pathway, and bacteriorhodopsin-like proteins. All of these genomes contain a homothallic mating-type locus.
The differences between these four varieties of A. pullulans are large enough to justify their redefinition as separate species: A. pullulans, A. melanogenum, A. subglaciale and A. namibiae. The redundancy observed in several gene families can be linked to the nutritional versatility of these species and their particular stress tolerance. The availability of the genome sequences of the four Aureobasidium species should improve their biotechnological exploitation and promote our understanding of their stress-tolerance mechanisms, diverse lifestyles, and pathogenic potential.
Available from: Macit Ilkit
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ABSTRACT: Urban life has led to the creation of human-made environments that, from a microbiological perspective, provide extreme life conditions. Certain non-ubiquitous microorganisms such as thermophilic members of the black yeast genus Exophiala are enriched within these habitats for which no counterpart is known in nature. Dishwashers consistently accumulate a number of specific black, white and red yeasts on the rubber seals of doors and in stagnant water at the interior. Several of these yeasts are primarily known as agents of human opportunistic infections. In this review, the literature data are supported by a screening study involving 937 households in 15 cities in Turkey. Fungi were detected in 230 samples (24.5 %). Using rDNA sequencing, the prevalent species were identified as Exophiala dermatitidis (n=116), Candida parapsilosis (n = 44), E. phaeomuriformis (n = 35), Magnusiomyces capitatus (n=22), Rhodotorula mucilaginosa (n=15), and C. lusitaniae (n=14). The possible role of dishwashers in transmitting disease is discussed.
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