Yeasts with Fermentative Potential Associated with Fruits of Camu-Camu (Myrciaria dubia, Kunth) from North of Brazilian Amazon

Considering the high biotechnological potential of yeasts associated to edible fruits, a screening for these microorganisms, capable of alcoholic fermentation, was performed in ripe fruits of camu-camu (Myrciaria dubia, Kunth). The fruits were collected from north of Brazilian Amazon, in the floodplain of the Cauamé River. Yeasts were isolated, and fermentation capability was evaluated using Durham tubes. Quantitative assays were performed to calculate ethanol yield (g g−1), specific growth rate (h−1), and ethanol productivity (g L−1·h−1). Taxonomic identification was performed by ribosomal gene nucleotide sequence analysis by alignment using BLASTN. A total of fifteen yeast colonies were isolated, and three of them presented promising ability to ferment glucose to ethanol. These isolates were identified as Candida orthopsilosis, Pichia kudriavzevii, and Meyerozyma caribbica. When cultured in broth containing 180 g·L−1 of glucose, M. caribbica CC003 reached 91.7 percent of the maximum theoretical ethanol concentration (84.4 g·L−1), presenting an ethanol yield and productivity of 0.4688 g·g−1 and 0.781 g·L−1·h−1, respectively. These results indicate a promising potential of this isolate for bioprocess applications. This paper is a rare report of C. orthopsilosis with endophytic habit because most of the references indicate it as a human pathogen. Besides this, M. caribbica is a promising fermenter for alcoholic beverages due to its osmotolerance and high ethanol yield. This is the first paper reporting endophytic yeasts associated with fruits of Myrciaria dubia.

Prevalence and Antifungal Susceptibility of Candida parapsilosis Species Complex in Eastern China: A 15-Year Retrospective Study by ECIFIG

Candida parapsilosis complex is one of the most common non-albicans Candida species that cause candidemia, especially invasive candidiasis. The purpose of this study was to evaluate the antifungal susceptibilities of both colonized and invasive clinical C. parapsilosis complex isolates to 10 drugs: amphotericin (AMB), anidulafungin (AFG), caspofungin (CAS), micafungin (MFG), fluconazole (FLZ), voriconazole (VRZ), itraconazole (ITZ), posaconazole (POZ), 5-flucytosine (FCY), and isaconazole (ISA). In total, 884 C. parapsilosis species complex isolates were gathered between January 2005 and December 2020. C. parapsilosis, Candida metapsilosis, and Candida orthopsilosis accounted for 86.3, 8.1, and 5.5% of the cryptic species, respectively. The resistance/non-wild-type rate of bloodstream C. parapsilosis to the drugs was 3.5%, of C. metapsilosis to AFG and CAS was 7.7%, and of C. orthopsilosis to FLZ and VRZ was 15% and to CAS, MFG, and POZ was 5%. The geometric mean (GM) minimum inhibitory concentrations (MICs) of non-bloodstream C. parapsilosis for CAS (0.555 mg/L), MFG (0.853 mg/L), FLZ (0.816 mg/L), VRZ (0.017 mg/L), ITZ (0.076 mg/L), and POZ (0.042 mg/L) were significantly higher than those of bloodstream C. parapsilosis, for which the GM MICs were 0.464, 0.745, 0.704, 0.015, 0.061, and 0.033 mg/L, respectively (P < 0.05). The MIC distribution of the bloodstream C. parapsilosis strains collected from 2019 to 2020 for VRZ, POZ, and ITZ were 0.018, 0.040, and 0.073 mg/L, significantly higher than those from 2005 to 2018, which were 0.013, 0.028, and 0.052 mg/L (P < 0.05). Additionally, MIC distributions of C. parapsilosis with FLZ and the distributions of C. orthopsilosis with ITZ and POZ might be higher than those in Clinical and Laboratory Standards Institute studies. Furthermore, a total of 143 C. parapsilosis complex isolates showed great susceptibility to ISA. Overall, antifungal treatment of the non-bloodstream C. parapsilosis complex isolates should be managed and improved. The clinicians are suggested to pay more attention on azoles usage for the C. parapsilosis complex isolates. In addition, establishing the epidemiological cutoff values (ECVs) for azoles used in Eastern China may offer better guidance for clinical treatments. Although ISA acts on the same target as other azoles, it may be used as an alternative therapy for cases caused by FLZ- or VRZ-resistant C. parapsilosis complex strains.

Yeasts with Fermentative Potential Associated with Fruits of Camu-Camu (Myrciaria Dubia, Kunth) from North of Brazilian Amazon

PurposeConsidering the high biotechnological potential of yeasts associated to edible fruits, a screening for these microbes able to alcoholic fermentation was performed in ripe fruits of camu-camu.MethodsFruits of camu-camu (Myrciaria dubia, Kunth) were collected in north of brazilian Amazon, in floodplain of Cauamé river. Yeasts were isolated, and fermentation capability was evaluated using Durham tubes. Quantitative assays were performed to calculate ethanol yield (g.g–1), specific growth rate (h–1) and ethanol productivity (g.L–1.h–1). Taxonomic identification was performed by ribosomal genes nucleotides sequences analysis by alignment using BLASTn.ResultsA total of fifteen yeasts colonies were isolated, and eight of them presented the ability to ferment glucose to ethanol. Six of them were identified as three different species: Candida orthopsilosis, Pichia kudriavzevii and Meyerozyma caribbica. When cultured in broth containing 180 g.L–1 of glucose, M. caribbica reaches 91.7 percent of the maximum theoretical ethanol concentration (84.4 g.L–1), presenting ethanol yield and productivity of 0.4688 g.g–1 and 0.781 g.L–1.h–1, respectively.ConclusionsThe endophytic microbiota of camu-camu includes C. orthopsilosis, P. kudriavzevii and M. caribbica. This paper is a rare report of C. orthopsilosis with endophytic habit, because most of the references indicate it as human pathogenic. Besides this, M. caribbica is a promising fermenter for alcoholic beverages, due to its osmotolerance and high ethanol yield. This is the first paper reporting endophytic yeasts associated with fruits of Myrciaria dubia.

A case series of medically managed Candida parapsilosis complex prosthetic valve endocarditis

Background In recent years, Candida parapsilosis is recognized as a species complex and is composed of Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis. Candida parapsilosis complex prosthetic valve endocarditis (PVE) is rare and the survival rate is still low despite of optimal therapeutic strategies. In our report, it is novel to report cases as Candida parapsilosis complex PVE at species and identify Candida parapsilosis using MALDI-TOF MS. Case presentation A series of 4 cases of Candida parapsilosis complex PVE from our institution was reported. Three were infected by Candida parapsilosis sensu stricto and one was infected by Candida metapsilosis. The condition of two cases got better and the other died. Conclusions More attention should be paid to Candida parapsilosis complex PVE and early diagnosis and prompt antibiotic therapy may play a role in the treatment for Candida parapsilosis complex PVE. It is recommended to identify Candida parapsilosis complex at species level and MALDI-TOF MS as an easy, fast and efficient identification method is worth promoting in clinical microbiology

Identification of Candida parapsilosis Species Complex and Lodderomyces elongisporus Isolates with MALDI-TOF MS

Objective: Candida parapsilosis species complex and Lodderomyces elongisporus may have differences in terms of their virulence, prevalence, and antifungal susceptibility profiles. These species are difficult to identify with biochemical methods. Therefore, there is a need for more efficient identification methods in terms of time, cost, and applicability. This study aims to evaluate the diagnostic performance of the MALDI-TOF MS method in discriminating between isolates belonging to the C. parapsilosis species complex and L. elongisporus. Method: In the current study, a total of 32 reference strains, including the C. parapsilosis (n=8), Candida orthopsilosis (n=7), Candida metapsilosis (n=6), and L. elongisporus (n=11) species were identified using the MALDI-TOF MS method. Results: The species names of 31 (93.7%) isolates belonging to the C. parapsilosis species complex and L.elongisporus were correctly identified. Twenty four isolates including eight (100%) C. parapsilosis, five (83%) C. metapsilosis, five (71%) C. orthopsilosis, and six (54%) L. elongisporus isolates were identified with score values ranging from 1.7 to 2.14. According to the secure identification reference score of ≥ 1.7, the sensitivity and specificity of the MALDI-TOF MS method were determined as 54.5–100% and 96.3–100%, respectively. Conclusion: Although the MALDI-TOF MS method has been shown to be effective in the rapid molecular phenotypic diagnosis of species that were difficult to discriminate using biochemical methods such as C. parapsilosis species complex and L. elongisporus, there is a clear need to optimize the method and develop a larger MS library for species-level identification within secure score ranges.

Identification of The Mating Type (MTL) Genotypes of Clinical Candida parapsilosis Complex Species isolated from Blood Cultures

Objective: Candida parapsilosis is one of the most common species after Candida albicans among the causative factors of systemic candidosis. In Candida species, determination of the cell identity and the sexual reproduction process take place under the control of the mating type (MTLα) locus. This region has completely different sequences in two different mating types (a and α) and is called an idiomorph. While the MTLa idiomorph encodes the transcription factors a1 and a2, MTLα encodes α1 and α2 proteins. Apart from these genes, both idiomorphs have a or α versions of PAB, OBP, and PIK genes, whose functions in sexual reproduction are unknown. On the other hand, up to now neither Candida parapsilosis nor the closely related species Candida orthopsilosis or Candida metapsilosis has been reported to have sexual cycles. While C. orthopsilosis was found to have a mixed population structure harboring MTLa and MTLα homozygous and MTLa/MTLα heterozygous genotypes in realized studies, the majority of C. metapsilosis isolates were MTLa/MTLα heterozygotes. Nevertheless, all C. parapsilosis isolates analyzed were found to be of a single mating type (MTLa). Method: This study was aimed to determine the MTL genotypes of C. parapsilosis isolates of Turkey origin, and 167 blood isolates were used for this purpose. The isolates identified as C. parapsilosis by PCR-amplifying and sequencing the ITS region were screened for MTLa1, MTLa2, MTLα1 and MTLα2 genes. Results: Only MTLa1 and MTLa2 genes were detected in PCR; therefore, all isolates were determined to have the MTLa genotype. Conclusion: When the results are assessed with previous findings, it could be inferred that the MTLα mating type of C. parapsilosis has been lost or extremely rare in yet unanalyzed geographical regions.

A case series of medically managed Candida Parapsilosis complex prosthetic valve endocarditis and literature review

Background: In recent years, Candida parapsilosis is recognized as a species complex and is composed of Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis and Candida Parapsilosis complex prosthetic valve endocarditis (PVE) is rare and the survival rate is still low despite of optimal therapeutic strategies. Our paper is the first to report cases as Candida Parapsilosis complex PVE. Case presentation: A series of 4 cases of Candida Parapsilosis complex PVE from our institution was reported. Three were infected by Candida parapsilosis sensu stricto and one was infected by Candida metapsilosis. The condition of two cases got better and the other died. Conclusions: More attention should be paid to Candida Parapsilosis complex PVE and early diagnosis and prompt antibiotic therapy may play a role in the treatment for Candida Parapsilosis complex PVE