Kodamaea ohmeri tricuspid valve endocarditis with right ventricular inflow obstruction in a neonate with structurally normal heart

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.

Fungal Endocarditis: Pathophysiology, Epidemiology, Clinical Presentation, Diagnosis, and Management

Fungal endocarditis accounts for 1% to 3% of all infective endocarditis cases, is associated with high morbidity and mortality (>70%), and presents numerous challenges during clinical care. Candida spp. are the most common causes of fungal endocarditis, implicated in over 50% of cases, followed by Aspergillus and Histoplasma spp. Important risk factors for fungal endocarditis include prosthetic valves, prior heart surgery, and injection drug use. The signs and symptoms of fungal endocarditis are nonspecific, and a high degree of clinical suspicion coupled with the judicious use of diagnostic tests is required for diagnosis. In addition to microbiological diagnostics (e.g., blood culture for Candida spp. or galactomannan testing and PCR for Aspergillus spp.), echocardiography remains critical for evaluation of potential infective endocarditis, although radionuclide imaging modalities such as 18F-fluorodeoxyglucose positron emission tomography/computed tomography are increasingly being used. A multimodal treatment approach is necessary: surgery is usually required and should be accompanied by long-term systemic antifungal therapy, such as echinocandin therapy for Candida endocarditis or voriconazole therapy for Aspergillus endocarditis.

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.

Novel fluconazole-resistant zoonotic yeast isolated from mastitis

A hospital-based cross-sectional study was conducted during 2018-2019 to decipher the prevalence of yeast mastitis. The results indicated a 19.68% prevalence of clinical mastitis in bovines. Among them, 5.51% of samples revealed yeasts constituting 1.09% overall prevalence. Candida albicans was recorded as a significant fungal agent involved in clinical bovine mastitis. We record the association of Kodamaea ohmeri in clinical bovine mastitis. On proteomic and molecular confirmation, K. ohmeri isolates were re-identified from phenotypically identified Candida isolates associated with bovine mastitis. After conventional identification, the yeast isolates were re-identified by MALDI-TOF MS-based proteomic approaches. The D1/D2 domains of 26S-rRNA gene and 5.8S-internal transcribed spacer (ITS) rDNA regions based molecular phylogenetic analysis identified the isolates as K. ohmeri. The isolates were resistant to fluconazole. This study reports the first systemic study of K. ohmeri isolates recovered from bovine clinical mastitis, utilizing conventional, automated, proteomic, and genomic approaches followed by antifungal susceptibility. The findings suggest K. ohmeri as a potent opportunistic emerging pathogen of veterinary and public health concern, need for accurate identification of fungal agents from mycotic mastitis, and use of validated antifungal susceptibility assay because of developing resistance to antimycotic agents. Our findings suggest judicious use of fluconazole and alternative antifungal agents may be considered in case of an outbreak.

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

Background: Kodamaea ohmeri, previously known as Pichia ohmeri or Yamadazyma ohmeri, has been regarded as an emerging human pathogen in recent decades, and has caused various types of infections with high mortality. This study systematically reviewed all the published cases of K. ohmeri infection, aiming to have a better understanding of the clinical and epidemiological characteristics of the organism. Methods: All the published literature (as of March 31, 2021) on K. ohmeri, in four databases: PubMed, Embase, Web of Science, and CNKI, were systematically reviewed to select appropriate studies for summarizing the demographic information, clinical and microbiological characteristics of relevant infections. Results: A total of 51 studies involving 67 patients were included for final analysis, including 49 sporadic cases and two clusters of outbreaks. Neonates and the elderly constituted the majority of patients, and fungemia was the dominant infection type. Comorbidities (like malignancy, diabetes, and rheumatism), invasive operations, previous antibiotic use and prematurity, were commonly described in patients. Gene sequencing and broth microdilution method, were the most reliable way for the identification and antifungal susceptibility testing of K. ohmeri, respectively. Amphotericin B and fluconazole were the commonest antifungal therapies administered. The calculated mortality rates for K. ohmeri infection was higher than that of common candidemia. Conclusion: In this study, we systematically reviewed the epidemiology, clinical characteristics, microbiological features, treatment, and outcomes, of all the published cases on K. ohmeri. Early recognition and increased awareness of K. ohmeri as an emerging human pathogen by clinicians and microbiologists is important for effective management of this organism.

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.

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.

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.

Identification and antifungal susceptibility profiles of Kodamaea ohmeri based on a seven-year multicenter surveillance study

Background

Kodamaea ohmeri has been a rare fungal pathogen in the past decades but is now becoming more common in various invasive fungal diseases, with high mortality. There are limited data on the occurrence and distribution of K. ohmeri.

Methods

Sixty-two K. ohmeri isolates collected from 24 hospitals in China over a 7-year period were studied. Performance of three phenotypic methods in the identification of this organism was assessed against a gold standard, 26S rDNA sequencing. Original identification results submitted by the participating local hospitals were reviewed. The Sensititre YeastOne YO10 (SYY) was evaluated in determining the in vitro antifungal susceptibilities using standard broth microdilution method (BMD) as a reference, and essential agreement (EA) was calculated.

Results

Accurate species identification was achieved in 82.3% and 96.8% of the cases by Vitek 2 Compact and Vitek mass spectrometry (MS), respectively. For Bruker MS, 12.9% and 96.8% of the isolates were correctly identified to species level using the direct transfer and protein extraction methods, respectively. Only 29 (46.8%) isolates were initially correctly identified as K. ohmeri by the local hospitals. The highest misidentification rate (100%, 16/16) was observed in CHROMagar. According to BMD, the highest MIC₉₀ was seen in fluconazole (8 μg/mL), followed by 1 μg/mL for micafungin, caspofungin, 5-fluorocytosine, and amphotericin B, 0.5 μg/mL for itraconazole, 0.25 μg/mL for posaconazole and voriconazole. Significant differences in EAs for different drugs were observed, ranging from 95.2% for amphotericin B to 22.6% for itraconazole between SYY and BMD.

Conclusion

Our study emphasizes the need for accurate identification of clinical K. ohmeri isolates and the importance of validating antifungal susceptibility by standard BMD.

Fungal endocarditis in paediatrics: a review of 192 cases (1971-2016)

BACKGROUND

The aims of this article were to review the published literature on fungal endocarditis in children and to discuss the aetiology and diagnosis, with emphasis on non-invasive methods and various treatment regimes.

METHODS

We systematically reviewed published cases and case series of fungal endocarditis in children. We searched the literature, including PubMed and individual references for publications of original articles, single cases, or case series of paediatric fungal endocarditis, with the following keywords: "fungal endocarditis", "neonates", "infants", "child", and "cardiac vegetation".

RESULTS

There have been 192 documented cases of fungal endocarditis in paediatrics. The highest number of cases was reported in infants (93/192, 48%) including 60 in neonates. Of the neonatal cases, 57 were premature with a median gestational age of 27 weeks and median birth weight of 860 g. Overall, 120 yeast - fungus that grows as a single cell - infections and 43 mould - fungus that grows in multicellular filaments, hyphae - infections were reported. With increasing age, there was an increased infection rate with moulds. All the yeast infections were detected by blood culture. In cases with mould infection, diagnosis was mainly established by culture or histology of emboli or infected valves after invasive surgical procedures. There have been a few recent cases of successful early diagnosis by non-invasive methods such as blood polymerase chain reaction (PCR) for moulds. The overall mortality for paediatric fungal endocarditis was 56.25%. The most important cause of death was cardiac complications due to heart failure. Among the various treatment regimens used, none of them was significantly associated with better outcome.

CONCLUSIONS

Non-invasive methods such as PCR tests can be used to improve the chances of detecting and identifying the aetiological agent in a timely manner. Delays in the diagnosis of these infections may result in high mortality and morbidity. No significant difference was noted between combined surgical and medical therapy over exclusively combined medical therapy.

Catheter-related bloodstream infection caused by Kodamaea ohmeri: A case report and literature review

Kodamaea ohmeri is a rare yeast pathogen that has recently emerged as an important cause of fungemia in immunocompromised patients. However, appropriate therapy for this infection remains unclear. We report a case of catheter-related blood stream infection caused by K. ohmeri in a 58-year-old patient who improved after removal of the central venous catheter and administration of micafungin. Considering the antibiotic susceptibility of this pathogen and reviewing literature, echinocandins may be the first choice for an empiric therapy for this pathogen.

Fungemia due to Kodamaea ohmeri: First isolating in Italy. Case report and review of literature

Kodamaea ohmeri, also known as Pichia ohmeri, is a yeast belonging to the Saccharomycetes family. In 2012, our hospital has recorded the first case of fungemia caused by K. ohmeri in an 80-year-old male, admitted to intensive care following an acute anterior-lateral myocardial infarction. K. ohmeri grew in blood cultures. Biochemical identification was confirmed using Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) mass spectrometry and molecular sequencing. Antifungal susceptibility has been performed by broth dilution technique. This case confirms that K. ohmeri is an emergent pathogen even though rarely isolated in human disease. Permanent catheterization is a risk factor and may cause the persistence of a K. ohmeri infection, as well as support treatments (mechanical ventilation, tracheotomy, dialysis). Our therapeutic strategy has been empirical and based exclusively on tested antifungals MIC because EUCAST recommendations does not indicate breakpoints.

Fungal Endocarditis in Neonates: A Review of Seventy-one Cases (1971-2013)

BACKGROUND

Fungal endocarditis (FE) remains an uncommon but life-threatening complication of invasive fungal infections. As data on neonatal FE are scant, we aimed to review all published experience regarding this serious infection.

METHODS

Neonatal FE cases published in PubMed (1971-2013) as single cases, or case series were identified using the terms "fungal endocarditis, neonates and cardiac vegetation." Data on predefined criteria including demographics, predisposing factors, mycology, sites of cardiac involvement, therapy and outcome were collected and analyzed.

RESULTS

The dataset comprised 71 neonates with FE. Median birth weight was 940 g [interquartile range (IQR): 609], median gestational age 27 weeks (IQR: 6) and median postnatal age at diagnosis 20 days (IQR: 20). Ninety-two percent of the patients were premature. Right atrium was the most common vegetation site (63%). Seventy-one percent of the cases reported were associated with previous central venous catheters. Candida albicans was the most predominant fungal species (59%). Amphotericin B monotherapy was used in 42.2% and fluconazole in 2.8%. Amphotericin B with flucytosine (25.3%) was the most frequent combined regimen. Surgical treatment was conducted in 28%. Overall mortality was 42.2%. Initiation with combined antifungal treatment was associated with lower mortality than monotherapy (24.2% vs. 51.7%, respectively, P = 0.036).

CONCLUSIONS

Neonatal FE most frequently occurs in very premature infants and is associated with central venous catheters. C. albicans is the predominant fungus. Although outcome has been dismal, it may be improved with combined antifungal therapy.

Kodameae ohmeri - An Emerging Yeast: Two Cases and Literature Review

Kodameae ohmeri is an emerging pathogen in various types of infections. Most infections are seen in patients with compromised immunity like cancer patients. Few cases of neonatal infections due to K. ohmeri have been reported earlier in premature neonates with fatal outcomes. We report two cases of fungemia; the first case was a patient with hematological malignancy, who complained of fever spikes and grew K. ohmeri in blood despite prophylactic voriconazole therapy. The second case was in a mature neonate, who developed respiratory distress and features of sepsis two days after birth, multiple blood cultures were positive for K. ohmeri. Both the patients responded well to Amphotericin B. Repeat blood cultures were sterile and patients were discharged. K. ohmeri is an unusual and emerging fungal pathogen of late an increasing number of cases of fungemia, funguria, endocarditis, peritonitis and wound infections due to the same are being reported. Some occur in immunocompromised patients and some inapparently immunocompetent patients, neonates with an inclination for preterm babies. We report two case of fungemia, one with lymphoma and the second in a neonate.

Right-sided infective endocarditis: recent epidemiologic changes

BACKGROUND

Infective endocarditis (IE) has been increasingly reported, however, little is available regarding recent development of right-sided IE.

METHODS

Right-sided IE was comprehensively analyzed based on recent 5⅓-year literature.

RESULTS

Portal of entry, implanted foreign material, and repaired congenital heart defects were the main predisposing risk factors. Vegetation size on the right-sided valves was much smaller than those beyond the valves. Multiple logistic regression analysis revealed that predisposing risk factors, and vegetation size and locations were independent predictive risks of patients' survival.

CONCLUSIONS

Changes of right-sided IE in the past 5⅓ years included younger patient age, and increased vegetation size, but still prominent Staphylococcus aureus infections. Complication spectrum has changed into more valve insufficiency, more embolic events, reduced abscess formation, and considerably decreased valve perforations. With effective antibiotic regimens, prognoses of the patients seemed to be better than before.

Tricuspid valve mycetoma in an infant successfully treated by excision and complex tricuspid valve repair followed by fluconazole therapy

BACKGROUND

Fungal valve endocarditis in children is an uncommon and lethal disease. The risk increases with use of central venous catheters (CVC), total parenteral nutrition (TPN), and use of broad-spectrum antibiotics during the neonatal period. Due to high mortality, a combination of surgery and antifungal therapy is usually recommended for treatment.

METHODS

Case report and review of the literature.

RESULTS

We present a case of an asymptomatic infant with multiple Candida tricuspid valve mycetomas. Complete cure was achieved by combined tricuspid valve repair and fluconazole therapy. We also review 26 cases of tricuspid valve Candida endocarditis in children published in the literature.

CONCLUSION

From being uniformly fatal five decades ago to a current survival rate of 64% to 100%, the prognosis of Candida endocarditis has changed dramatically with the use of antifungal therapy alone or in combination with surgery. Our case re-emphasizes the role of valve-sparing debridement with repair of the native valve using autologous pericardium in combination with long-term antifungal therapy as a feasible option in managing tricuspid valve Candida endocarditis.

Identification and antifungal susceptibility of a large collection of yeast strains isolated in Tunisian hospitals

In this study, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used as a rapid method to identify yeasts isolated from patients in Tunisian hospitals. When identification could not be exstablished with this procedure, sequencing of the internal transcribed spacer with 5.8S ribosomal DNA (rDNA) (ITS1-5.8S-ITS2) and D1/D2 domain of large-subunit (LSU rDNA) were employed as a molecular approach for species differentiation. Candida albicans was the dominant species (43.37% of all cases), followed by C. glabrata (16.55%), C. parapsilosis (13.23%), C. tropicalis (11.34%), C. dubliniensis (4.96%), and other species more rarely encountered in human diseases such as C. krusei, C. metapsilosis, C. lusitaniae, C. kefyr, C. palmioleophila, C. guilliermondii, C. intermedia, C. orthopsilosis, and C. utilis. In addition, other yeast species were obtained including Saccharomyces cerevisiae, Debaryomyces hansenii (anamorph known as C. famata), Hanseniaspora opuntiae, Kodamaea ohmeri, Pichia caribbica (anamorph known as C. fermentati), Trichosporon spp. and finally a novel yeast species, C. tunisiensis. The in vitro antifungal activities of fluconazole and voriconazole were determined by the agar disk diffusion test and Etest, while the susceptibility to additional antifungal agents was determined with the Sensititre YeastOne system. Our results showed low incidence of azole resistance in C. albicans (0.54%), C. tropicalis (2.08%) and C. glabrata (4.28%). In addition, caspofungin was active against most isolates of the collection with the exception of two K. ohmeri isolates. This is the first report to describe caspofungin resistant isolates of this yeast.