Extracellular BSA-degrading SAPs in the rare pathogen Meyerozyma guilliermondii strain SO as potential virulence factors in candidiasis.

Meyerozyma guilliermondii (Candida guilliermondii) is one of the Candida species associated with invasive candidiasis. With the potential for expressing industrially important enzymes, M. guilliermondii strain SO possessed 99 % proteome similarity with the clinical ATCC 6260 isolate and showed pathogenicity towards zebrafish embryos. Recently, three secreted aspartyl proteinases (SAPs) were computationally identified as potential virulence factors in this strain without in vitro verification of SAP activity. The quantification of Candida SAPs activity in liquid broth were also scarcely reported. Thus, this study aimed to characterize M. guilliermondii strain SO's ability to produce SAPs (MgSAPs) in different conditions (morphology and medium) besides analyzing its growth profile. MgSAPs' capability to cleave bovine serum albumin (BSA) was also determined to propose that MgSAPs as the potential virulence factors compared to the avirulent Saccharomyces cerevisiae. M. guilliermondii strain SO produced more SAPs (higher activity) in yeast nitrogen base-BSA-dextrose broth compared to yeast extract-BSA-dextrose broth despite insignificantly different SAP activity in both planktonic and biofilm cells. FeCl3 supplementation significantly increased the specific protein activity (∼40 %). The BSA cleavage by MgSAPs at an acidic pH was proven through semi-quantitative SDS-PAGE, sharing similar profile with HIV-1 retropepsin. The presented work highlighted the MgSAPs on fungal cell wall and extracellular milieu during host infection could be corroborated to the quantitative production in different growth modes presented herein besides shedding lights on the potential usage of retropepsin's inhibitors in treating candidiasis. Molecular and expression analyses of MgSAPs and their deletion should be further explored to attribute their respective virulence effects.

Case report of a rare fungal infection Kodamaea ohmeri in COVID-19 patient in North Malaysian hospital.

ABSTRACT: Kodamaea ohmeri is a rare opportunistic pathogen belonging to Saccharomycetes family. This yeast was also formerly known as Yamadazyma ohmeri or Pichia ohmeri . This opportunistic pathogen causes illness that typically affects people with impaired immune system. In this report, we discuss a fatal case involving a woman in her late 30s who was admitted to the hospital on the sixth day of her sickness after being given a COVID-19 Category 5A diagnosis. For COVID-19, she received subcutaneous heparin, cefuroxime, and intravenous corticosteroids. She was diagnosed with secondary bacterial and fungal infections in the ICU. Multiple antibiotics and antifungal were given to treat bacterial and fungal infections. An unusual fungus, Kodamaea ohmeri , was isolated from the clinical sample. On day 36, she succumbed to her infection in the ICU. The cause of death was multidrug-resistant sepsis with multiple organ failures due to COVID-19 infection, worsened by an embolism and trachea damage during a tracheostomy. To effectively manage K. ohmeri , clinicians and microbiologists must identify and be aware of this emerging human opportunistic pathogen, which can co-infect debilitated patients such as COVID-19 patients, for effective management.

Suspected Macrorhabdosis during a Concurrent Salmonellosis Outbreak in a Wild Yellow-Rumped Warbler (Setophaga coronata).

We describe necropsy lesions of three adult Yellow-rumped Warblers (Setophaga coronata) diagnosed with salmonellosis during a Salmonella enterica serovar Typhimurium outbreak. One warbler had filamentous organisms consistent with Macrorhabdus ornithogaster at the proventricular-ventricular isthmus. There is limited information on Macrorhabdus ornithogaster infections in wild North American birds.

A Short-Type Peptidoglycan Recognition Protein 1 (PGRP1) Is Involved in the Immune Response in Asian Corn Borer, Ostrinia furnacalis (Guenée).

The insect immune response is initiated by the recognition of invading microorganisms. Peptidoglycan recognition proteins (PGRPs) function primarily as pattern recognition receptors by specifically binding to peptidoglycans expressed on microbial surfaces. We cloned a full-length cDNA for a PGRP from the Asian corn borer Ostrinia furnacalis (Guenée) and designated it as PGRP1. PGRP1 mRNA was mainly detected in the fat bodies and hemocytes. Its transcript levels increased significantly upon bacterial and fungal challenges. Purified recombinant PGRP1 exhibited binding activity to the gram-positive Micrococcus luteus, gram-negative Escherichia coli, entomopathogenic fungi Beauveria bassiana, and yeast Pichia pastoris. The binding further induced their agglutination. Additionally, PGRP1 preferred to bind to Lys-type peptidoglycans rather than DAP-type peptidoglycans. The addition of recombinant PGRP1 to O. furnacalis plasma resulted in a significant increase in phenoloxidase activity. The injection of recombinant PGRP1 into larvae led to a significantly increased expression of several antimicrobial peptide genes. Taken together, our results suggest that O. furnacalis PGRP1 potentially recognizes the invading microbes and is involved in the immune response in O. furnacalis.

Infected tricuspid valve myxoma with Kodamaea ohmeri: Case report.

A 46-year-old male was having un-resolving fever for six weeks. Trans-esophageal echocardiography showed tricuspid valve myxoma (TVM). Kodamaea ohmeri was identified in 2 blood cultures and confirmed by 28S rDNA sequencing. Over three weeks of liposomal Amphotericin-B, fever has subsided thus indicated a clinical response. Subsequent echocardiography revealed no regression of suspected vegetation, and it was removed, and TV replacement was done. Histopathology revealed an infected myxoma and K. omeri was detected following 28S rDNA sequencing. For cardiac myxoma, excision is offered while for IE prolonged use of antifungals with or without vegetectomy is offered. So proper identification is important.

A Sge1 homolog in Cytospora chrysosperma governs conidiation, virulence and the expression of putative effectors.

SIX Gene Expression 1 (Sge1) is an important and well-recognized fungal-specific transcription regulator from the Gti1/Pac2 family that exhibits a conserved function in the vegetative growth, regulating the expression of effector genes and pathogenicity in plant pathogenic fungi. However, its functions in Cytospora chrysosperma, a notorious phytopathogenic fungus in forestry, remain poorly understood. Here, we characterized a Sge1 orthologue, CcSge1, in C. chrysosperma and deleted its Gti1/Pac2 domain for functional analysis. The CcSge1 deletion mutants showed obvious defects in hyphal growth, conidial production and response to hydrogen peroxide. Correspondingly, significantly lower expression of conidiation related genes were found in deletion mutants compared to that of the wild type. Importantly, the CcSge1 deletion mutants totally lost their pathogenicity to the host. Further analysis demonstrated that CcSge1 was responsible for the expression of putative effector genes and the transcription of CcSge1 was under tight control by pathogenicity-related MAP Kinase 1 (CcPmk1). What's more, one of the putative effector gene CCG_07874 was positively regulated by both CcSge1 and CcPmk1. Taken together, these data indicate that CcSge1is indispensable for hyphal radial growth, conidiation, the expression of effector genes and fungal virulence.

Pulmonary infection secondary to Blastobotrys raffinosifermentans in a cystic fibrosis patient: Review of the literature.

BACKGROUND: The genus Blastobotrys consists of at least 20 species. Disease in humans has been reported with B adeninivorans, B raffinosifermentans, B proliferans and B serpentis, mostly in immunocompromised patients and those with cystic fibrosis. OBJECTIVE: We report a lung infection secondary to B raffinosifermentans in a cystic fibrosis patient successfully treated with isavuconazole and review the literature of invasive infections caused this genus. We also evaluated clinical isolates in our laboratory for species identification and antifungal susceptibility. METHODS: Phylogenetic analysis was performed on a collection of 22 Blastobotrys isolates in our reference laboratory, and antifungal susceptibility patterns were determined for nine clinically available antifungals against 19 of these isolates. RESULTS: By phylogenetic analysis, 21 of the 22 isolates in our collection were identified as B raffinosifermentans and only 1 as B adeninivorans. Most were cultured from the respiratory tract, although others were recovered from other sources, including CSF and blood. Isavuconazole, caspofungin and micafungin demonstrated the most potent in vitro activity, followed by amphotericin B. In contrast, fluconazole demonstrated poor activity. The patient in this case responded to isavuconazole treatment for breakthrough infection due to B raffinosifermentans that was cultured from pleural fluid while on posaconazole prophylaxis post-bilateral lung transplantation for cystic fibrosis. CONCLUSIONS: Blastobotrys species are rare causes of infections in humans and primarily occur in immunocompromised hosts. In our collection, the majority of isolates were identified as B raffinosifermentans. To our knowledge, this is the first report of successful treatment of such an infection with isavuconazole.

Kazachstania slooffiae: An unexpected journey to a human pleural sample.

We report a case of a 50-year-old shepherd hospitalized in intensive care unit for hiatal hernia complicated by an occlusive syndrome. In post-surgery, an acute respiratory distress occurs due to mediastinitis with large pleural effusion. At the laboratory, direct examination of the pleural sample revealed the presence of pseudohyphae. Kazachstania slooffiae was identified by Mass Spectrometry and confirmed by DNA sequencing. This uncommon yeast has never been previously described in human infections. Although its pathogenicity is not well known, K. slooffiae should be considered in the case of critically ill patients.

A case-series of bloodstream infections caused by the Meyerozyma guilliermondii species complex at a reference center of oncology in Brazil.

Bloodstream infections (BSI) caused by Candida species are the fourth cause of healthcare associated infections worldwide. Non-albicans Candida species emerged in the last decades as agents of serious diseases. In this study, clinical and microbiological aspects of six patients with BSI due to the Meyerozyma (Candida) guilliermondii species complex from an oncology reference center in Brazil, were evaluated. To describe demographic and clinical characteristics, medical records of the patients were reviewed. Molecular identification of the isolates was performed by ITS1-5.8S-ITS2 region sequencing. Antifungal susceptibility was evaluated by the EUCAST method and the minimal inhibitory concentrations (MIC) assessed according to the epidemiological cutoff values. Virulence associated phenotypes of the isolates were also studied. Ten isolates from the six patients were evaluated. Five of them were identified as Meyerozyma guilliermondii and the others as Meyerozyma caribbica. One patient was infected with two M. caribbica isolates with different genetic backgrounds. High MICs were observed for fluconazole and echinocandins. Non-wild type isolates to voriconazole appeared in one patient previously treated with this azole. Additionally, two patients survived, despite infected with non-wild type strains for fluconazole and treated with this drug. All isolates produced hemolysin, which was not associated with a poor prognosis, and none produced phospholipases. Aspartic proteases, phytase, and esterase were detected in a few isolates. This study shows the reduced antifungal susceptibility and a variable production of virulence-related enzymes by Meyerozyma spp. In addition, it highlights the poor prognosis of neutropenic patients with BSI caused by this emerging species complex. LAY ABSTRACT: Our manuscript describes demographic, clinical and microbiological characteristics of patients with bloodstream infection by the Meyerozyma guilliermondii species complex at a reference center in oncology in Brazil.

Candida auris: Epidemiology, biology, antifungal resistance, and virulence.

First described in 2009 in Japan, the emerging multidrug-resistant fungal pathogen Candida auris is becoming a worldwide public health threat that has been attracting considerable attention due to its rapid and widespread emergence over the past decade. The reasons behind the recent emergence of this fungus remain a mystery to date. Genetic analyses indicate that this fungal pathogen emerged simultaneously in several different continents, where 5 genetically distinct clades of C. auris were isolated from distinct geographical locations. Although C. auris belongs to the CTG clade (its constituent species translate the CTG codon as serine instead of leucine, as in the standard code), C. auris is a haploid fungal species that is more closely related to the haploid and often multidrug-resistant species Candida haemulonii and Candida lusitaniae and is distantly related to the diploid and clinically common fungal pathogens Candida albicans and Candida tropicalis. Infections and outbreaks caused by C. auris in hospitals settings have been rising over the past several years. Difficulty in its identification, multidrug resistance properties, evolution of virulence factors, associated high mortality rates in patients, and long-term survival on surfaces in the environment make C. auris particularly problematic in clinical settings. Here, we review progress made over the past decade on the biological and clinical aspects of C. auris. Future efforts should be directed toward understanding the mechanistic details of its biology, epidemiology, antifungal resistance, and pathogenesis with a goal of developing novel tools and methods for the prevention, diagnosis, and treatment of C. auris infections.

C-Terminal Motifs of the MTW1 Complex Cooperatively Stabilize Outer Kinetochore Assembly in Budding Yeast.

Kinetochores are macromolecular protein assemblies at centromeres that mediate accurate chromosome segregation during cell division. The outer kinetochore KNL1SPC105, MIS12MTW1, and NDC80NDC80 complexes assemble the KMN network, which harbors the sites of microtubule binding and spindle assembly checkpoint signaling. The buildup of the KMN network that transmits microtubule pulling forces to budding yeast point centromeres is poorly understood. Here, we identify 225 inter-protein crosslinks by mass spectrometry on KMN complexes isolated from Saccharomyces cerevisiae that delineate the KMN subunit connectivity for outer kinetochore assembly. C-Terminal motifs of Nsl1 and Mtw1 recruit the SPC105 complex through Kre28, and both motifs aid tethering of the NDC80 complex by the previously reported Dsn1 C terminus. We show that a hub of three C-terminal MTW1 subunit motifs mediates the cooperative stabilization of the KMN network, which is augmented by a direct NDC80-SPC105 association.

Clinical Characteristics and Outcomes of Candidemia Caused by Meyerozyma guilliermondii Complex in Cancer Patients Undergoing Surgery.

Although Meyerozyma guilliermondii complex is an uncommon cause of invasive candidiasis worldwide, reported cases, mainly regarding bloodstream infections, increased over years, and patients with cancer who have undergone recent surgery are most commonly affected. However, the clinical characteristics and outcomes of candidemia caused by M. guilliermondii complex remain poorly understood. A retrospective case-control study was conducted to evaluate the clinical characteristics and mortality of candidemia caused by M. guilliermondii complex in cancer patients undergoing surgery. Demographic and clinical data were collected from the hospital medical records system with a standardized data collection form and were analyzed with SPSS 20.0. Sixty-six cancer patients who have undergone recent surgery and were diagnosed with candidemia caused by M. guilliermondii complex were included in the study. Regarding the clinical manifestations, most patients' body temperatures ranged from 38 to 40 °C, with a median fever duration of 4 (IQR: 3-6) days. Multivariate analysis indicated that the presence of central venous catheter (OR: 6.68; 95% CI 2.80-15.94) and gastric tube (OR: 3.55; 95% CI 1.22-10.34) were independent risk factors for M. guilliermondii complex fungemia. The 30-day crude mortality of candidemia caused by M. guilliermondii complex was 12.1%, twice that of the control group. Moreover, increased WBC count, age ≥ 60 years, septic shock, and ICU admission were identified as predictors of mortality through univariate analysis. These findings will provide a foundation for the clinical management of candidemia caused by M. guilliermondii complex in post-surgical cancer patients.

Kodamaea ohmeri infections in humans: A systematic review.

BACKGROUND: Kodamaea ohmeri, previously known as Pichia ohmeri or Yamadazyma ohmeri, belongs to the Saccharomycetaceae family and the Ascomycetae class, is the telomorphic form of C guilliermondii var. membranaefaciens and is frequently mistaken for Candida, as they belong to the same family. It has been isolated from environmental sources, such as sand, pools, seawater and fruits, while the last decades it is recognised as a rare pathogen that causes life-threatening infections in humans. The purpose of this study was to systemically review all published cases of K ohmeri infections in the literature and describe the epidemiology, microbiology, antimicrobial susceptibility, treatment and outcomes of these infections in humans. METHODS: Systematic review of PubMed (through 27th December 2019) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of K ohmeri infections. RESULTS: A total of 35 studies, containing data of 44 patients, were included in the analysis. The most common K ohmeri infections were those of the bloodstream, infective endocarditis and onychomycosis. Previous antibiotic use, presence of a central venous catheter, parenteral nutrition and cancer were very common among patients. Mortality was high in the case of fungemias but low for other types of infections. Amphotericin B and fluconazole are the most common agents used for treatment, even though alarming MICs for fluconazole were noted. CONCLUSIONS: This systematic review thoroughly describes infections by K ohmeri and provides information on their epidemiology, clinical presentation, microbiology, antibiotic resistance patterns, treatment and outcomes.

Major Latex Protein MdMLP423 Negatively Regulates Defense against Fungal Infections in Apple.

Major latex proteins (MLPs) play critical roles in plants defense and stress responses. However, the roles of MLPs from apple (Malus × domestica) have not been clearly identified. In this study, we focused on the biological role of MdMLP423, which had been previously characterized as a potential pathogenesis-related gene. Phylogenetic analysis and conserved domain analysis indicated that MdMLP423 is a protein with a 'Gly-rich loop' (GXGGXG) domain belonging to the Bet v_1 subfamily. Gene expression profiles showed that MdMLP423 is mainly expressed in flowers. In addition, the expression of MdMLP423 was significantly inhibited by Botryosphaeria berengeriana f. sp. piricola (BB) and Alternaria alternata apple pathotype (AAAP) infections. Apple calli overexpressing MdMLP423 had lower expression of resistance-related genes, and were more sensitive to infection with BB and AAAP compared with non-transgenic calli. RNA-seq analysis of MdMLP423-overexpressing calli and non-transgenic calli indicated that MdMLP423 regulated the expression of a number of differentially expressed genes (DEGs) and transcription factors, including genes involved in phytohormone signaling pathways, cell wall reinforcement, and genes encoding the defense-related proteins, AP2-EREBP, WRKY, MYB, NAC, Zinc finger protein, and ABI3. Taken together, our results demonstrate that MdMLP423 negatively regulates apple resistance to BB and AAAP infections by inhibiting the expression of defense- and stress-related genes and transcription factors.

Geotrichum capitatum Invasive Infection Early After Liver Transplant.

Geotrichum capitatum is a rare fungal pathogen that has infrequently affected immunocompromised patients with onco-hematologic diseases. Geotrichum capitatum invasive infection has been associated with poor prognosis, with a mortality rate ranging from 50% to 90%. Here, we report the first case of Geotrichum capitatum invasive fungal infection in a liver transplant recipient from an unrelated deceased donor, who was effectively treated with amphotericin B and voriconazole. We also reviewed the available literature in the field.

Transcriptomic changes in wheat during tan spot (Pyrenophora tritici-repentis) disease.

OBJECTIVES: Tan spot is a yield-reducing disease that affects wheat and is caused by the fungus Pyrenophora tritici-repentis (Ptr). Eight races of Ptr have been identified based upon production of the effectors Ptr ToxA, Ptr ToxB, and Ptr ToxC. Wheat cultivars have also been characterized by their resistance and susceptibility to races of Ptr and sensitivity to the effectors. The objective of this research was to assess differences in gene expression between Ptr resistant and susceptible wheat cultivars when either inoculated with Ptr race 2 spores or directly infiltrated with Ptr ToxA. DATA DESCRIPTION: A greenhouse experiment was used to assess wheat-Ptr interaction. Wheat seedlings were grown for two weeks prior to the experiment under greenhouse conditions. Four treatments were used: (1) spray-inoculation with a suspension of Ptr spores (3000 spores/mL) (2) spray inoculation with water as a control (3) needleless syringe injection with Ptr ToxA, and (4) needleless syringe injection with water as a control. Plants were transferred to a humidity chamber and leaf sample were taken at 0, 8, and 16 h. After RNA extraction and sequencing, 48 RNA datasets are reported. This data will be useful in understanding how resistant wheat responds to Ptr compared to susceptible wheat.

Evaluation, characterization, expression profiling, and functional analysis of DXS and DXR genes of Populus trichocarpa.

1-Deoxy-D-xylulose-5-phosphate synthasse (DXS) and 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) are key enzymes in terpenoid biosynthesis. DXS catalyzes the formation of 1-deoxy-D-xylulose 5-phosphate (DXP) from pyruvate and D-glyceraldehyde-3-phosphate. DXR catalyzes the formation of 2-C-methyl-D-erythritol 4-phosphate (MEP) from DXP. Previous studies of the DXS and DXR genes have focused on herbs, such as Arabidopsis thaliana, Salvia miltiorrhiza, and Amomum villosum, but few studies have been conducted on woody plants. For that reason, we chose Populus trichocarpa as a model woody plant for investigating the DXS and DXR genes. PtDXS exhibited the highest expression level in leaves and the lowest expression in roots. PtDXR showed maximum expression in young leaves, and the lowest expression in mature leaves. The expression profiles revealed by RT-PCR following different elicitor treatments such as abscisic acid, NaCl, PEG6000, H2O2, and cold stress showed that PtDXS and PtDXR were elicitor-responsive genes. Our results showed that the PtDXS gene exhibited diurnal changes, but PtDXR did not. Moreover, overexpression of PtDXR in transgenic poplars improved tolerance to abiotic and biotic stresses. Those results showed that the PtDXR encoded a functional protein, and widely participates in plant growth and development, stress physiological process.

A case report of fungemia due to Kodamaea ohmeri.

BACKGROUND: Kodamaea ohmeri is a yeast is frequently mistaken for Candida, which belongs to the same family. This micro-organism has been reported to cause life-threatening infections in humans. CASE PRESENTATION: A 81-year-old woman developed a severe fungemic pulmonary infection due to Kodamaea ohmeri that was identified from bronchoalveolar fluid and blood cultures, which is unusual in immunocompetent patients. Because K. ohmeri was first wrongly identified as Candida albicans, the patient inadequately received caspofungin, which was clinically ineffective, especially as the strain was resistant to echinocandins. Clinical cure was obtained after treatment was switched to voriconazole. CONCLUSIONS: An increasing number of serious infections due to K. ohmeri has been reported in the literature, but the correct identification of this micro-organism remains difficult.