Kodamaea ohmeri as an Emerging Human Pathogen: A Review and Update

Diagnosis and management of Cryptococcus neoformans var. grubii detected in an oral mass in a pink-tongued skink (Cyclodomorphus gerarrdii)

Cryptococcus is an encapsulated yeast that is found in both yeast and hyphal forms. Cryptococcus neoformans and C. gattii are the most medically important species, causing disease in both immunocompromised and immunocompetent individuals. A large, friable, sublingual mass was surgically resected from the oral cavity of a pink-tongued skink (Cyclodomorphus gerarrdii). Histopathology, fungal culture and PCR testing with Sanger sequencing confirmed granulomatous inflammation containing large numbers of yeasts identified as Cryptococcus neoformans var. grubii. Surgical excision and treatment with oral amphotericin B and terbinafine was unsuccessful in managing the infection. On Day 67 after surgery, Cryptococcus DNA was detected by PCR in the blood but not oral, cloacal or skin swabs. The skink was euthanised 72 days after surgery due to anorexia, weight loss and progressive neurological signs of disease. Necropsy results showed disseminated cryptococcosis, including meningoencephalitis and ventriculitis. Two in-contact pink-tongued skinks remained asymptomatic and PCR-negative during 198 days of observation. This case suggests Cryptococcus infections should be considered for oral masses presenting with or without neurological signs in skinks. Further investigation is required to determine the best treatment options for disseminated cryptococcosis in reptiles. This report describes the third reported case of Cryptococcus in a reptile and the first case of cryptococcosis in a pink-tongued skink. It is also the first report of Cryptococcus in a reptile identified to the variety level using PCR, including in whole blood samples.

Kodamaea ohmeri Leg Skin Ulcer Infection in an Immunocompetent Patient: A Case Report

INTRODUCTION

Kodamaea ohmeri is an emerging fungus recognised as an important pathogen in immunocompromised hosts, responsible for life-threatening infections.

CASE PRESENTATION

We describe a case of a 69-year-old immunocompetent man with a long history of leg skin ulcers infected by K. ohmeri. This is the first case of leg wounds infected by K. ohmeri in an immunocompetent patient. The infection was successfully treated with voriconazole 200 mg daily.

CONCLUSION

Though rare, K. ohmeri should be considered in patients with skin ulcers that are poorly responsive to medical treatment, even if not immunocompromised.

Microsatellite markers for genotyping of Kodamaea ohmeri: Demonstrating outbreaks based on a multicenter surveillance study in China

Kodamaea ohmeri, an emerging human pathogen, caused both sporadic and nosocomial infections among immunocompromised people with high mortality. However, there is limited research on the molecular epidemiology of K. ohmeri. A total of fifty microsatellite loci were designed based on K. ohmeri type strain NRRL Y-1932 and three loci were finally selected for microsatellite analysis. Non-duplicated K. ohmeri isolates and strains of other species were collected across China as a part of CHIF-NET program for sensitivity and specificity verification. Antifungal susceptibility was determined using Sensititre YeastOne TM YO10. The three loci (P10, P11 and P26), with a cumulative discriminatory power of 0.98, exhibited a prospective specificity and reproducibility in the PCR of 92 K. ohmeri strains from different hospitals. A total of 54 microsatellite types (MT) were identified and most of them distributed sporadically. However, six strains of MT12 clustered in HZ hospital and were isolated in the same department within two months, indicating a potential outbreak. Of seven isolates exhibited MIC values of >8 mg/L for fluconazole, three isolates from LR hospital shared the same genotype of MT44. Herein, we established a set of microsatellite loci for K. ohmeri, as a rapid and specific tool for genotyping K. ohmeri, and identified several potential clusters. This study will help us better understand the molecular epidemiology of the emerging pathogen K. ohmeri.

Hospital‑acquired pneumonia caused by Kodamaea ohmeri during extracorporeal membrane oxygenation treatment: A case report and literature review

Kodamaea ohmeri (K. ohmeri) is an ascosporogenic species of yeast that belongs to the genus Ascosporogenous and the family of Saccharomycetaceae. It has recently been found to cause various types of infections, particularly in critically ill immunocompromised patients. The present study describes a case of hospital-acquired pneumonia caused by K. ohmeri during veno-arterial extracorporeal membrane oxygenation. The fungal culture turned negative after the administration of caspofungin and amphotericin B. Extracorporeal membrane oxygenation (ECMO) is an adjunctive medical technique that provides temporary cardiopulmonary support for patients. Previous observations have suggested that the immune function of patients will typically decline during the use of ECMO, rendering infection to be one of the main complications of ECMO. K. ohmeri is a rare pathogenic fungus, particularly in immunocompromised individuals with vascular catheters, while amphotericin B is the most common antifungal therapy administered to treat K. ohmeri infections. It is important to raise awareness of rare fungal infections and actively treat them.

A Repertoire of the Less Common Clinical Yeasts

Invasive fungal diseases are a public health problem. They affect a constantly increasing number of at-risk patients, and their incidence has risen in recent years. These opportunistic infections are mainly due to Candida sp. but less common or rare yeast infections should not be underestimated. These so-called "less common" yeasts include Ascomycota of the genera Candida (excluding the five major Candida species), Magnusiomyces/Saprochaete, Malassezia, and Saccharomyces, and Basidiomycota of the genera Cryptococcus (excluding the Cryptococcus neoformans/gattii complex members), Rhodotorula, and Trichosporon. The aim of this review is to (i) inventory the less common yeasts isolated in humans, (ii) provide details regarding the specific anatomical locations where they have been detected and the clinical characteristics of the resulting infections, and (iii) provide an update on yeast taxonomy. Of the total of 239,890 fungal taxa and their associated synonyms sourced from the MycoBank and NCBI Taxonomy databases, we successfully identified 192 yeasts, including 127 Ascomycota and 65 Basidiomycota. This repertoire allows us to highlight rare yeasts and their tropism for certain anatomical sites and will provide an additional tool for diagnostic management.

Chronic Granulomatous Disease: a Cohort of 173 Patients-10-Years Single Center Experience from Egypt

PURPOSE

Chronic granulomatous disease (CGD) is an inherited primary immunodeficiency disorder of phagocytes, characterized by recurrent fungal and bacterial infections. Our aim is to describe the different clinical presentations, non-infectious auto-inflammatory features, types and sites of infections, and to estimate the mortality among our large cohort.

METHODS

This is a retrospective study conducted at the Pediatric Department of Cairo University Children's Hospital in Egypt, including cases with a confirmed CGD diagnosis.

RESULTS

One hundred seventy-three confirmed CGD patients were included. AR-CGD was diagnosed in 132 patients (76.3%) including 83 patients (48%) with p47phox defect, 44 patients (25.4%) with p22phox defect, and 5 patients (2.9%) with p67phox defect. XL-CGD was diagnosed in 25 patients (14.4%). The most common recorded clinical manifestations were deep-seated abscesses and pneumonia. Gram-negative bacteria and Aspergillus were the most frequently isolated species. Regarding the outcome, 36 patients (20.8%) were lost from follow-up. Among patients with known outcome, 94/137 patients (68.6%) are living, while 43/137 patients (31.4%) died.

CONCLUSION

AR-CGD is predominant in Egypt; CGD must always be ruled out in any patient presenting with typical or atypical mycobacterial or BCG-disease.

Diverse signatures of convergent evolution in cacti-associated yeasts

Many distantly related organisms have convergently evolved traits and lifestyles that enable them to live in similar ecological environments. However, the extent of phenotypic convergence evolving through the same or distinct genetic trajectories remains an open question. Here, we leverage a comprehensive dataset of genomic and phenotypic data from 1,049 yeast species in the subphylum Saccharomycotina (Kingdom Fungi, Phylum Ascomycota) to explore signatures of convergent evolution in cactophilic yeasts, ecological specialists associated with cacti. We inferred that the ecological association of yeasts with cacti arose independently ~17 times. Using machine-learning, we further found that cactophily can be predicted with 76% accuracy from functional genomic and phenotypic data. The most informative feature for predicting cactophily was thermotolerance, which is likely associated with duplication and altered evolutionary rates of genes impacting the cell envelope in several cactophilic lineages. We also identified horizontal gene transfer and duplication events of plant cell wall-degrading enzymes in distantly related cactophilic clades, suggesting that putatively adaptive traits evolved through disparate molecular mechanisms. Remarkably, multiple cactophilic lineages and their close relatives are emerging human opportunistic pathogens, suggesting that the cactophilic lifestyle-and perhaps more generally lifestyles favoring thermotolerance-may preadapt yeasts to cause human disease. This work underscores the potential of a multifaceted approach involving high throughput genomic and phenotypic data to shed light onto ecological adaptation and highlights how convergent evolution to wild environments could facilitate the transition to human pathogenicity.

Clonal Diversity of Candida auris, Candida blankii, and Kodamaea ohmeri Isolated from Septicemia and Otomycosis in Bangladesh as Determined by Multilocus Sequence Typing

Candida auris, Candida blankii, and Kodamaea ohmeri have been regarded as emerging fungal pathogens that can cause infections with high mortality. For genotyping of C. auris, a multilocus sequence typing (MLST) scheme based on four locus sequences has been reported, while there is no typing scheme for C. blankii and K. ohmeri. In the present study, the existing MLST scheme of C. auris was modified by adding more locus types deduced from sequence data available in the GenBank database. Furthermore, MLST schemes of C. blankii and K. ohmeri were developed using the four cognate loci (ITS, RPB1, RPB2, D1/D2) and similar sequence regions to those of C. auris. These MLST schemes were applied to identify the ST (sequence type) of clinical isolates of C. auris (n = 7), C. blankii (n = 9), and K. ohmeri (n = 6), derived from septicemia or otomycosis in Bangladesh in 2021. All the C. auris isolates were classified into a single ST (ST5) and clade I, having a Y132F substitution in ERG11p, which is associated with azole resistance. Similarly, all the C. blankii isolates belonged to a single type (ST1). In contrast, six K. ohmeri isolates were assigned to five types (ST1-ST5), suggesting its higher genetic diversity. These findings revealed the availability of MLST schemes for these three fungal species for understanding their clonal diversity among clinical isolates.

Gut-derived fungemia due to Kodamaea ohmeri combined with invasive pulmonary aspergillosis: a case report

BACKGROUND

Kodamaea ohmeri is a rare pathogen with high mortality and is found among blood samples in a considerable proportion; however, gastrointestinal infection of K. ohmeri is extremely rare. Invasive pulmonary aspergillosis is also an uncommon fungal; these two fungal infections reported concomitantly are unprecedented.

CASE PRESENTATION

We described a case of a 37-year-old male who got infected with K. ohmeri and invasive pulmonary aspergillosis. We used the mass spectrometry and histopathology to identify these two fungal infections separately. For the treatment of K. ohmeri, we chose caspofungin. As for invasive pulmonary aspergillosis, we used voriconazole, amphotericin B, and then surgery. The patient was treated successfully through the collaboration of multiple disciplines.

CONCLUSIONS

We speculate that the destruction of the intestinal mucosa barrier can make the intestine one of the ways for certain fungi to infect the human body.

What Is Hiding in the Israeli Mediterranean Seawater and Beach Sand

Objective: In the present study, we aimed to investigate the presence of fungi that may affect human health in sand and water on Israeli Mediterranean Sea coast beaches. Methods: The study included screening of the sand and water of six urban beaches from north to south on the Israeli Mediterranean coast. Sand samples were extracted with water, and the water wash was cultured and quantitated. Water samples were quantitated as well. MALDI-TOF MS analysis and ITS sequencing identified the fungi. Results: The study considered several parameters: 1. Presence of fecal-contamination-related fungi; 2. Presence of dermal-infection-related fungi. 3. Presence of allergy-related fungi; 4. Presence of fungi posing risk for immunocompromised individuals. The screen revealed that about 80% of the isolates were molds and about 20% yeasts. The mold species included opportunistic pathogens and potential allergens: Aspergillus fumigatus and other Aspergillus species, Fusarium, Penicillium, and Mucorales species. Yeast isolates included Candida—including the human commensals Candida albicans and Candida tropicalis—Cryptococcus, and Rhodotorula species. Conclusions: The results suggest that beaches should be monitored for fungi for safer use, better management, and the benefit of public health.

Prevalence and Antifungal Susceptibility of Clinically Relevant Candida Species, Identification of Candida auris and Kodamaea ohmeri in Bangladesh

Candida species are major fungal pathogens in humans. The aim of this study was to determine the prevalence of individual Candida species and their susceptibility to antifungal drugs among clinical isolates in a tertiary care hospital in Bangladesh. During a 10-month period in 2021, high vaginal swabs (HVSs), blood, and aural swabs were collected from 360 patients. From these specimens, Candida spp. was isolated from cultures on Sabouraud dextrose agar media, and phenotypic and genetic analyses were performed. A total of 109 isolates were recovered, and C. albicans accounted for 37%, being derived mostly from HVSs. Among non-albicans Candida (NAC), C. parapsilosis was the most frequent, followed by C. ciferrii, C. tropicalis, and C. glabrata. Three isolates from blood and two isolates from aural discharge were genetically identified as C. auris and Kodamaea ohmeri, respectively. NAC isolates were more resistant to fluconazole (overall rate, 29%) than C. albicans (10%). Candida isolates from blood showed 95% susceptibility to voriconazole and less susceptibility to fluconazole (67%). Two or three amino acid substitutions were detected in the ERG11 of two fluconazole-resistant C. albicans isolates. The present study is the first to reveal the prevalence of Candida species and their antifungal susceptibility in Bangladesh.

Antifungal and antibiofilm activities of bee venom loaded on chitosan nanoparticles: a novel approach for combating fungal human pathogens

The prevalence of opportunistic human fungal pathogens is increasing worldwide, and antimicrobial resistance is one of the greatest medical challenges the world faces. Therefore, this study aimed to develop a novel agent to control fungal pathogens. The honeybee products (honey, royal jelly, propolis, bee bread, and bee venom) were screened against unicellular fungal (UCF) pathogens (Cryptococcus neoformans, Kodamaea ohmeri, and Candida albicans) and the bee venom was only exhibited an inhibitory effect against them. The protein contents of crude bee venom were separated using the gel filtration technique into eight fractions which were visualized on sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) to confirm the presence of five bands with molecular weights of 65, 43, 21, 15, and 3 KDa. Bee venom (BV) of Apis mellifera loaded chitosan nanoparticles were prepared by the ionotropic gelation method. The encapsulation efficiency%, average size, zeta potentials, and surface appearance by Transmission electron microscope (TEM) were evaluated for the prepared nanoparticles. The minimum inhibitory concentration (MIC) of crude BV and BV loaded chitosan nanoparticles (BV-CNPs) was evaluated against the offer mentioned UCF where the MIC values of crude BV were 6.25, 3.12 & 6.25 while MIC values in the case of BV-CNPs were decreased to 3.12, 3.12 & 1.56 mg/ml against C. neoformans, K. ohmeri and C. albicans, respectively. Also, the results showed that BV-CNPs suppressed the biofilm formation as well as yeast to hyphal transition formed by the examined UCF. These results revealed that BV-CNPs are a promising natural compound for fungal pathogens treatment.