Port implantation-related bloodstream infection caused by Wickerhamomyces myanmarensis: A case report

Background and Purpose

Wickerhamomyces myanmarensis is a new opportunistic yeast previously named Pichai myanmarensis, which belongs to the order Saccharomycetales. Since its discovery, one environmental isolate of W. myanmarensis has been reported from Myanmar, and one clinical sample from Iran.

Case Report

We report a case of bloodstream infection related to an implantable venous access port. W. myanmarensis was isolated from patient's blood after chemotherapy, which was meant to control and heal T-cell lymphoblastic lymphoma. Broth dilution minimum inhibitory concentrations were performed according to the CLSI M27-A3 document. The patient recovered with intravenous voriconazole and was discharged with the recommended prescription of oral voriconazole as a maintenance drug.

Conclusion

So far, only one case of W. myanmarensis fungemia has been reported in the world in 2019. This is the second case of bloodstream infection with this yeast from a patient undergoing chemotherapy in Iran.

Genotypic diversity of Iranian Cryptococcus neoformans using multilocus sequence typing (MLST) and susceptibility to antifungals

Cryptococcus species is an opportunistic yeast pathogen and classified into different molecular types according to typing techniques including multilocus sequence typing (MLST). The study aimed to investigate the genotypes of environmental Cryptococcus isolates using MLST and the relationship between the in vitro antifungal susceptibility and sequence types of isolates. Genotyping Cryptococcus isolates was performed by the MLST method at seven nuclear loci. Antifungal susceptibility was determined by using CLSI broth micro-dilution method for amphotericin B, fluconazole, itraconazole, voriconazole, flucytosine, and luliconazole. Seven sequence types (ST) were detected using MLST analysis, with the most frequent (50%) ST77, followed by ST4 (16.7%) among 30 C. neoformans isolates. All antifungals demonstrated excellent activity against isolates, except for itraconazole and amphotericin B that were non-wild type against 53.3% and 10% of isolates, respectively. Although seven sequence types belonging to C. neoformans isolates were detected, ST77 was the main sequence type in Ahvaz. Also, non-wild type isolates were only found against itraconazole and amphotericin B.

The high efficacy of luliconazole against environmental and otomycosis Aspergillus flavus strains

BACKGROUND AND OBJECTIVES

Luliconazole is currently confirmed for the topical therapy of dermatophytosis. Moreover, it is found that luliconazole has in vitro activity against some molds and yeast species. The aim of the present study was to evaluate the efficacy of luliconazole in comparison to routine used antifungals on clinical and environmental isolates of Aspergillus flavus.

MATERIALS AND METHODS

Thirty eight isolates of A. flavus (18 environmental and 20 clinical isolates) were detected based on morphological and microscopic features and also PCR-sequencing of β-tubulin ribosomal DNA gene. All the isolates were tested against luliconazole, voriconazole, amphotericin B and caspofungin. Minimum inhibitory concentration (MIC), MIC₅₀, MIC₉₀ and MIC Geometric (GM) were calculated using CLSI M38-A2 protocol for both environmental and clinical isolates.

RESULTS

Luliconazole with extremely low MIC range, 0.00049-0.00781 μg/mL and MIC_GM 0.00288 μg/mL showed very strong activity against both clinical and environmental A. flavus isolates. Moreover, voriconazole inhibited 100% of isolates at defined epidemiological cutoff values (ECV ≤ 2 μg/ml). 50% and 27.8% of clinical and environmental isolates of A. flavus, were resistant to caspofungin, respectively. Whereas, all the isolates were found to be resistant to amphotericin B.

CONCLUSION

The analysis of our data clearly indicated that luliconazole (with MIC_GM 0.00244 μg/ml for clinical and 0.00336 μg/ml for environmental isolates) had the highest in vitro activity against A. flavus strains.

An in vitro model of lissencephaly: expanding the role of DCX during neurogenesis

Lissencephaly comprises a spectrum of brain malformations due to impaired neuronal migration in the developing cerebral cortex. Classical lissencephaly is characterized by smooth cerebral surface and cortical thickening that result in seizures, severe neurological impairment and developmental delay. Mutations in the X-chromosomal gene DCX, encoding doublecortin, is the main cause of classical lissencephaly. Much of our knowledge about DCX-associated lissencephaly comes from post-mortem analyses of patient's brains, mainly since animal models with DCX mutations do not mimic the disease. In the absence of relevant animal models and patient brain specimens, we took advantage of induced pluripotent stem cell (iPSC) technology to model the disease. We established human iPSCs from two males with mutated DCX and classical lissencephaly including smooth brain and abnormal cortical morphology. The disease was recapitulated by differentiation of iPSC into neural cells followed by expression profiling and dissection of DCX-associated functions. Here we show that neural stem cells, with absent or reduced DCX protein expression, exhibit impaired migration, delayed differentiation and deficient neurite formation. Hence, the patient-derived iPSCs and neural stem cells provide a system to further unravel the functions of DCX in normal development and disease.

Mannose-Binding Lectin Serum Levels in Patients With Candiduria

Background:

Candida species are normal mycoflora of human body which are capable to cause urinary tract infection (UTI). Mannose-binding lectin (MBL) is a kind of innate immune system and decreasing plasma levels of MBL may disrupt the natural immune response and increase susceptibility to infections.

Objectives:

The aim of the present study was to assess MBL in the serum of patients with candiduria and compare them with control.

Patients and Methods:

The blood and urine samples were collected from 335 patients (hospitalized in Golestan hospital, Ahvaz) using standard methods and the growing colonies on CHROMagar were identified using routine diagnostic tests. MBL activity in the serum of 45 patients with candiduria and 45 controls was measured using Eastbiopharm enzyme-linked immunosorbent assay (ELISA) kit.

Results:

In this study, 45 (13.4 %) urine samples were positive for Candida species (17 males and 28 females). The most common isolated yeast was Candida albicans (34%), followed by C. glabrata (32.1%), C. tropicalis (9.4%), other Candida species (22.6%), and Rhodotorula species (1.9%). The mean serum levels of MBL were 0.85 ± 0.01 ng/mL and 1.02 ± 0.03 ng/mL among candiduric patients and controls, respectively, and there was no significant difference between the two groups (P = 0.6).

Conclusions:

Our results showed that there was no significant relationship between MBL serum levels and candiduria.

Use of the Saccharomyces cerevisiae endopolygalacturonase promoter to direct expression in Escherichia coli

In Saccharomyces cerevisiae, an endopolygalacturonase encoded by the PGL1 gene catalyzes the random hydrolysis of the α-1,4 glycosidic linkages in polygalacturonic acid. To study the regulation of the PGL1 gene, we constructed a reporter vector containing the lacZ gene under the control of PGL1 promoter. Surprisingly, when Escherichia coli DH5α was transformed by this vector, cells harboring the constructed plasmid produced blue colonies. Sequence analysis of this promoter revealed that E. coli consensus sequences required to express an in-frame lacZ alpha product were present. We next decided to investigate how the PGL1 promoter is regulated in E. coli compared to yeast. In this study, we examined the modulation of the PGL1 promoter in E. coli, and the results indicated that its activity is greatly induced by saturated digalacturonic acid and is indirectly regulated by the transcriptional regulators the 2-keto-3-deoxygluconate repressor. Moreover, PGL1 expression is enhanced under aerobic conditions. We found that β-galactosidase activity in E. coli could reach 180 units, which is 40-fold greater than the activity produced in S. cerevisiae, and greater than recombinant protein expression previously reported by other researchers. We thus demonstrate that this vector can be considered as a dual expression plasmid for both E. coli and S. cerevisiae hosts. So far, no modulation of endoPG promoters expressed in E. coli has been reported.