Polymerase chain reaction assay for specific identification of Candida guilliermondii (Pichia guilliermondii)

Meyerozyma guilliermondii species complex: review of current epidemiology, antifungal resistance, and mechanisms

Meyerozyma guilliermondii has been accepted as a complex composed of Meyerozyma guilliermondii, Meyerozyma carpophila, and Meyerozyma caribbica. M. guilliermondii is a saprophyte detected on human mucosa and skin. It can lead to serious infections in patients with risk factors like chemotherapy, immunodeficiency, gastrointestinal or cardiovascular surgery, and oncology disorders. Most deaths related to M. guilliermondii infections occur in individuals with malignancy. In recent decades, incidence of M. guilliermondii infections is increased. Sensitivity of this microorganism to conventional antifungals (e.g., amphotericin B, fluconazole, micafungin and anidulafungin) was reduced. Prophylactic and empirical uses of these drugs are linked to elevated minimal inhibitory concentrations (MICs) of M. guilliermondii. Drug resistance has concerned many researchers across the world. They are attempting to discover appropriate solution to combat this challenge. This study reviews the most important mechanisms of resistance to antifungals developed by in M. guilliermondii species complex.

Biotechnological applications of the non-conventional yeast Meyerozyma guilliermondii

Unconventional yeasts have attracted increased attentions owning to their unique biochemical properties and potential application in the biotechnological process. With the rapid development of microbial isolation tools and synthetic biology, more promising industrial yeasts have been isolated and characterized. Meyerozyma guilliermondii (anamorph Candida guilliermondii) is an ascomycetous yeast with several unique characteristics and physiology, such as the wide substrates spectrum and capability of various chemicals synthesis. The potential physiological and metabolic capabilities of M. guilliermondii, which can utilize various carbon sources including typical hydrophilic and hydrophobic materials were first reviewed in this review. Moreover, the wide applications of M. guilliermondii, such as for industrial enzymes production, metabolites synthesis and biocontrol were also reviewed. With the development of system and synthetic biology, M. guilliermondii will provide new opportunities for potential applications in biotechnology sectors in the future.

Development of Candida-Specific Real-Time PCR Assays for the Detection and Identification of Eight Medically Important Candida Species

Culture-based identification methods have been the gold standard for the diagnosis of fungal infection. Currently, molecular technologies such as real-time PCR assays with short turnaround time can provide desirable alternatives for the rapid detection of Candida microbes. However, most of the published PCR primer sets are not Candida specific and likely to amplify DNA from common environmental contaminants, such as Aspergillus microbes. In this study, we designed pan-Candida primer sets based on the ribosomal DNA-coding regions conserved within Candida but distinct from those of Aspergillus and Penicillium. We demonstrate that the final two selected pan-Candida primer sets would not amplify Aspergillus DNA and could be used to differentiate eight medically important Candida pathogens in real-time PCR assays based on their melting profiles, with a sensitivity of detection as low as 10 fg of Candida genomic DNA. Moreover, we further evaluated and selected species-specific primer sets covering Candida albicans, Candida glabrata, Candida tropicalis, and Candida dubliniensis and show that they had high sensitivity and specificity. These real-time PCR primer sets could potentially be assembled into a single PCR array for the rapid detection of Candida species in various clinical settings, such as corneal transplantation.

Assessment of the Factors Contributing to the Growth or Spoilage of Meyerozyma guilliermondii in Organic Yogurt: Comparison of Methods for Strain Differentiation

In this work we analyze the spoiling potential of Meyerozyma guilliermondii in yogurt. The analysis was based on contaminated samples sent to us by an industrial laboratory over two years. All the plain and fruit yogurt packages were heavily contaminated by yeasts, but only the last ones, containing fermentable sugars besides lactose, were spoiled by gas swelling. These strains were unable to grow and ferment lactose (as the type strain); they did grow on lactate plus galactose, fermented glucose and sucrose, and galactose (weakly), but did not compete with lactic acid bacteria for lactose. This enables them to grow in any yogurt, although only those with added jam were spoiled due to the fermentation of the fruit sugars. Fermentation, but not growth, was strongly inhibited at 8 °C. In consequence, in plain yogurt as well as in any yogurt maintained at low temperature, yeast contamination would not be detected by the consumer. The risk could be enhanced because the species has been proposed for biological control of fungal infections in organic agriculture. The combination of the IGS PCR-RFLP (amplification of the intergenic spacer region of rDNA followed by restriction fragment length polymorphism analysis) method and mitochondrial DNA-RFLP makes a good tool to trace and control the contamination by M. guilliermondii.

Fungemia caused by Candida species in a children's public hospital in the city of São Paulo, Brazil: study in the period 2007-2010

Candidemia remains a major cause of morbidity and mortality in the health care environment. The epidemiology of Candida infection is changing, mainly in relation to the number of episodes caused by species C. non-albicans. The overall objective of this study was to evaluate the frequency of yeasts of the genus Candida, in a four-year period, isolated from blood of pediatric patients hospitalized in a public hospital of the city of São Paulo, Brazil. In this period, yeasts from blood of 104 patients were isolated and, the identified species of Candida by phenotypic and genotypic methods were: C. albicans (39/104), C. tropicalis (25/104), C. parapsilosis (23/104), Pichia anomala (6/104), C. guilliermondii (5/104), C. krusei (3/104), C. glabrata (2/104) and C. pararugosa (1/104). During the period of the study, a higher frequency of isolates of C. non-albicans (63.55%) (p = 0.0286) was verified. In this study we verified the increase of the non-albicans species throughout the years (mainly in 2009 and 2010). Thus, considering the peculiarities presented by Candida species, a correct identification of species is recommended to lead to a faster diagnosis and an efficient treatment.

Candida guilliermondii: biotechnological applications, perspectives for biological control, emerging clinical importance and recent advances in genetics

Candida guilliermondii (teleomorph Meyerozyma guilliermondii) is an ascomycetous species belonging to the Saccharomycotina CTG clade which has been studied over the last 40 years due to its biotechnological interest, biological control potential and clinical importance. Such a wide range of applications in various areas of fundamental and applied scientific research has progressively made C. guilliermondii an attractive model for exploring the potential of yeast metabolic engineering as well as for elucidating new molecular events supporting pathogenicity and antifungal resistance. All these research fields now take advantage of the establishment of a useful molecular toolbox specifically dedicated to C. guilliermondii genetics including the construction of recipient strains, the development of selectable markers and reporter genes and optimization of transformation protocols. This area of study is further supported by the availability of the complete genome sequence of the reference strain ATCC 6260 and the creation of numerous databases dedicated to gene ontology annotation (metabolic pathways, virulence, and morphogenesis). These genetic tools and genomic resources represent essential prerequisites for further successful development of C. guilliermondii research in medical mycology and in biological control by facilitating the identification of the multiple factors that contribute to its pathogenic potential. These genetic and genomic advances should also expedite future practical uses of C. guilliermondii strains of biotechnological interest by opening a window into a better understanding of the biosynthetic pathways of valuable metabolites.

Candida palmioleophila: characterization of a previously overlooked pathogen and its unique susceptibility profile in comparison with five related species

Candida palmioleophila has previously been misidentified as C. famata or C. guilliermondii. We have investigated traditional and modern identification methods for the identification of this and related species. Forty-one clinical isolates previously identified as C. famata or C. guilliermondii and 8 reference strains were included. Color development on CHROMagar, growth temperature ranges, micromorphologies, carbon assimilation (ID32C), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) profiles, and susceptibility profiles (mica- and anidulafungin and itra-, vori-, posa-, and fluconazole MICs were determined by EUCAST method EDef 7.1, and caspofungin MICs were determined by Etest) were determined, and results were compared to those of molecular identification (ITS1 and ITS2 sequencing). The following five different species were identified among the clinical isolates by sequencing, but no C. famata isolates were found: C. guilliermondii (22 isolates), C. palmioleophila (8 isolates), C. fermentati (6 isolates), C. lusitaniae (3 isolates), and C. intermedia (2 isolates). C. palmioleophila developed a distinct scintillating color of turquoise to rose, grew at 40°C, and failed to produce pseudohyphae within 14 days. The ID32C profile for 7/9 C. palmioleophila isolates was 5367352315, and all were unable to hydrolyze esculin (Esc). The six related species were well discriminated by MALDI-TOF MS. The susceptibility pattern for C. palmioleophila was unique, as the echinocandin MICs were low (range, 0.008 to 0.125 μg/ml) and fluconazole MICs were high (range, 8 to >16 μg/ml). Correct identification of C. palmioleophila is important due to its unique susceptibility profile. Identification is possible yet laborious with conventional techniques, whereas MALDI-TOF MS easily separated the related species.