Fungal prosthetic valve endocarditis: Mayo Clinic experience with a clinicopathological analysis

Case Commentary: Extending our therapeutic range against multidrug-resistant Candida

Deep-seated Candida spp. infections may necessitate extended durations of antifungal therapy. Increasing resistance to first-line antifungals threatens the most common options for long-term treatment. In this issue, Ponta et al. (Antimicrob Agents Chemother 68:e00750-24, 2024, https://doi.org/10.1128/aac.00750-24) present cases in which they used rezafungin, a novel long-acting echinocandin antifungal, for extended durations. While excellent clinical evidence supports the short-term safety of rezafungin, these cases demonstrate that rezafungin may additionally have a role in long-term suppressive therapy for antifungal-resistant Candida spp. infections.

ISCCM Position Statement on the Management of Invasive Fungal Infections in the Intensive Care Unit

Rationale

Invasive fungal infections (IFI) in the intensive care unit (ICU) are an emerging problem owing to the use of broad-spectrum antibiotics, immunosuppressive agents, and frequency of indwelling catheters. Timely diagnosis which is imperative to improve outcomes can be challenging. This position statement is aimed at understanding risk factors, providing a rational diagnostic approach, and guiding clinicians to optimize antifungal therapy.

Objectives

To update evidence on epidemiology, risk factors, diagnostic approach, antifungal initiation strategy, therapeutic interventions including site-specific infections and role of therapeutic drug monitoring in IFI in ICU and focus on some practice points relevant to these domains.

Methodology

A committee comprising critical care specialists across the country was formed and specific aspects of fungal infections and antifungal treatment were assigned to each member. They extensively reviewed the literature including the electronic databases and the international guidelines and cross-references. The information was shared and discussed over several meetings and position statements were framed to ensure their reliability and relevance in critical practice. The draft document was prepared after obtaining inputs and consensus from all the members and was reviewed by an expert in this field.

Results

The existing evidence on the management of IFI was updated and practice points were prepared under each subheading to enable critical care practitioners to streamline diagnosis and treatment strategies for patients in the ICU with additional detail on site-specific infections therapeutic drug monitoring.

Conclusion

This position statement attempts to address the management of IFI in immunocompetent and non-neutropenic ICU patients. The practice points should guide in optimization of the management of critically ill patients with suspected or proven fungal infections.

How to cite this article

Bhattacharya PK, Chakrabarti A, Sinha S, Pande R, Gupta S, Kumar AAK, et al. ISCCM Position Statement on the Management of Invasive Fungal Infections in the Intensive Care Unit. Indian J Crit Care Med 2024;28(S2):S20-S41.

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.

Trichosporon asahii Infective Endocarditis of Prosthetic Valve: A Case Report and Literature Review

Trichosporon spp. endocarditis is a severe and hard-to-treat infection. Immunosuppressed subjects and carriers of prosthetic valves or intracardiac devices are at risk. This article presents the case of an immunocompetent 74-year-old man affected by endocarditis of the prosthetic aortic valve. After Bentall surgery, cultures of the removed valve demonstrated Trichosporon ashaii as the etiological agent. The patient was treated with amphotericin B at first and subsequently with fluconazole. Given the fragility of the patient and the aggressiveness of the pathogen, life-long prophylactic therapy with fluconazole was prescribed. After 5 years follow-up, no drug-related toxicities were reported and the patient never showed any signs of recurrence. The review of the literature illustrates that Trichosporon spp. endocarditis may present even many years after heart surgery, and it is often associated with massive valve vegetations, severe embolic complications, and unfavorable outcome. Due to the absence of international guidelines, there is no unanimous therapeutic approach, but amphotericin B and azoles are usually prescribed. Additionally, a prompt surgical intervention seems to be of paramount importance. When dealing with a life-threatening disease, such as mycotic endocarditis of prosthetic valves, it is essential to consider and treat even rare etiological agents such as Trichosporon spp.

Nakaseomyces glabrata endocarditis: A therapeutic dilemma

Candida infective endocarditis is a rare but serious entity that often requires aggressive treatment. However, treatment can be challenging in patients infected with drug-resistant fungi and/or with substantial comorbidity. Moreover, recommendations in treatment guidelines for these patients are based on limited clinical data due to their rarity. Here we report a case of Nakaseomyces glabrata (Candida glabrata) prosthetic valve endocarditis in a patient with congenital heart disease. This case illustrates a therapeutic dilemma for Nakaseomyces glabrata prosthetic valve endocarditis and the need for novel antifungal drugs and further clinical studies.

Invasive candidiasis: current clinical challenges and unmet needs in adult populations

Invasive candidiasis (IC) is a serious infection caused by several Candida species, and the most common fungal disease in hospitals in high-income countries. Despite overall improvements in health systems and ICU care in the last few decades, as well as the development of different antifungals and microbiological techniques, mortality rates in IC have not substantially improved. The aim of this review is to summarize the main issues underlying the management of adults affected by IC, focusing on specific forms of the infection: IC developed by ICU patients, IC observed in haematological patients, breakthrough candidaemia, sanctuary site candidiasis, intra-abdominal infections and other challenging infections. Several key challenges need to be tackled to improve the clinical management and outcomes of IC patients. These include the lack of global epidemiological data for IC, the limitations of the diagnostic tests and risk scoring tools currently available, the absence of standardized effectiveness outcomes and long-term data for IC, the timing for the initiation of antifungal therapy and the limited recommendations on the optimal step-down therapy from echinocandins to azoles or the total duration of therapy. The availability of new compounds may overcome some of the challenges identified and increase the existing options for management of chronic Candida infections and ambulant patient treatments. However, early identification of patients that require antifungal therapy and treatment of sanctuary site infections remain a challenge and will require further innovations.

Sars-Cov-2 infection as a possible risk factor for prosthesis endocarditis: A challenging redo-Bentall for subvalvular abscess

BACKGROUND

Candida Parapsilosis is an unusual agent of prosthetic endocarditis in immunocompetent individuals but Coronavirus disease 2019 is reported to be associated with a transient immunodeficency that exposes patientes to opportunistic infections.

CASE REPORT

We describe a dreadful case of Candida Parapsilosis endocarditis in a transient immunosuppressed patient recently infected with severe acute respiratory syndrome-Coronavirus 2019.

CONCLUSION

Considering that the symptoms of Candida Parapsilosis infection and the symptoms of Coronavirus disease-2019 may overlap, it is important never to understimate the non-specific symptoms to improve patient outcome, especially in patient with previous Coronavirurs disease-2019 infection and with prosthetic material grafting.

Clinical features, diagnosis and treatment outcome of fungal endocarditis: A systematic review of reported cases

The landscape of fungal endocarditis (FE) has constantly been evolving in the last few decades. Despite the advancement in diagnostic methods and the introduction of newer antifungals, mortality remains high in FE. This systematic review aimed to evaluate the epidemiology, clinical features, diagnostic and therapeutic interventions in patients with FE. We also aim to examine the aforementioned factors as a determinant of mortality in FE. A literature search was performed in PubMed, Google Scholar and Scopus, and all patients ≥18 years with proven fungal endocarditis were included. A total of 220 articles (250 patients) were included in the final analysis. Candida was the commonest aetiology (49.6%), followed by Aspergillus (30%) and Scedosporium species (3.2%). The proportion of prosthetic valve endocarditis (PVE) and intravenous drug users was 35.2% and 16%, respectively. The overall mortality rate was 40%. On multivariate analysis, Aspergillus endocarditis (HR 3.7, 95% CI 1.4-9.7; p = .009) and immunocompromised state (HR 2.8, 95% CI 1.24-6.3; p = .013) were independently associated with mortality. Patients treated with surgery along antifungals had better survival (HR 0.20, 95% CI 0.09-0.42; p < .001) compared to those treated with antifungals alone. Recurrence of FE was reported in 10.4% of patients. In conclusion, FE carries significant mortality, particularly in immunodeficient and Aspergillus endocarditis. We advocate the use of surgery combined with antifungals to improve clinical outcomes.

Native vs Prosthetic Valve Histoplasma capsulatum Infective Endocarditis: A Case Report and Systemic Literature Review Comparing Patient Presentation, Treatment Modalities, Clinical Outcomes, and Diagnostic Laboratory Testing

Histoplasma capsulatum is a rare cause of fungal endocarditis that affects both native and prosthetic valves. It is associated with a high mortality rate if not diagnosed early and treated with a combination of antifungal therapy and surgical intervention. We present a case of a 47-year-old man with histoplasmosis infective endocarditis. He was successfully treated with antifungal therapy and surgical replacement of the infected bioprosthetic aortic valve. Our systemic literature review includes 52 articles encompassing 60 individual cases of H. capsulatum infective endocarditis from 1940 to 2020. Patient presentations, diagnostic laboratory testing accuracy, treatment modalities, and patient outcomes comparing and contrasting native and prosthetic valve infection are described.

Cardiac Imaging and Management of Prosthetic Valve Candida Parapsilosis Endocarditis

Fungal infective endocarditis is a rare and serious form of endocarditis associated with severe morbidity and mortality. The greatest propensity for infection can be found in patients with implanted prosthetic valves, implanted cardiac devices, and intravenous drug use. We present a case of a 45-year-old male with a prior bioprosthetic mitral valve who was diagnosed with Candida parapsilosis endocarditis. Computed tomography imaging of the abdomen was significant for splenic infarcts, and transesophageal echocardiography demonstrated a 1.23 cm x 0.55 cm lesion and 1.02 cm x 0.545 cm lesion on the bioprosthetic valve. The patient was subsequently treated with Amphotericin B and life-long Fluconazole. This case highlights the imaging findings and treatment of a rare disease process.

Incidence, Predictors, and Outcomes of Endocarditis After Transcatheter Aortic Valve Replacement in the United States

OBJECTIVES

This study sought to evaluate the incidence and outcomes of endocarditis after transcatheter aortic valve replacement (TAVR).

BACKGROUND

Data about endocarditis after TAVR are limited.

METHODS

The study investigated Medicare patients who underwent TAVR from 2012 to 2017 and identified patients admitted with endocarditis during follow-up using a validated algorithm. The main study outcome was all-cause mortality.

RESULTS

Of 134,717 patients who underwent TAVR, 1868 patients developed endocarditis during follow-up (incidence 0.87%/year), with majority of infections (65.0%) occurring within 1 year. Incidence of endocarditis declined in recent years. The most common organisms were Staphylococcus (22.0%), Streptococcus (20.0%), and Enterococcus (15.5%). Important predictors for endocarditis were younger age at TAVR, male sex, prior endocarditis, end-stage renal disease, repeat TAVR procedures, liver and lung disease, and post-TAVR acute kidney injury. Thirty-day and 1-year mortality were 18.5% and 45.6%, respectively. After adjusting for comorbidities and procedural complications, endocarditis after TAVR was associated with 3-fold higher risk of mortality (44.9 vs. 16.2 deaths per 100 person-years; adjusted hazard ratio [aHR]: 2.94; 95% confidence interval [CI]: 2.77 to 3.12; p < 0.0001). End-stage renal disease (aHR: 2.12; 95% CI: 1.72 to 2.60), endocarditis complicated by cardiogenic shock (aHR: 2.50, 95% CI: 1.56 to 4.02), ischemic stroke (aHR: 1.56; 95% CI: 1.07 to 2.28), intracerebral hemorrhage (aHR: 1.67; 95% CI: 1.01 to 2.76), acute kidney injury (aHR: 1.44; 95% CI: 1.27 to 1.63), blood transfusion (aHR: 1.28; 95% CI: 1.09 to 1.50), staphylococcal (aHR: 1.71; 95% CI: 1.49 to 1.97), and fungal endocarditis (aHR: 1.72; 95% CI: 1.23 to 2.39) (p < 0.05 for all) portended higher mortality following endocarditis.

CONCLUSIONS

The incidence of endocarditis after TAVR is low and declining. However, it is associated with poor prognosis with one-half the patients dying within 1 year.

Candida Parapsilosis Endocarditis Following Transcatheter Pulmonary Valve Implantation

Fungal prosthetic valve endocarditis (PVE) is rare and carries a high mortality rate. While uncommon, fungal endocarditis in transcatheter aortic valves has been reported. We present a unique case of Candida parapsilosis fungal PVE in a patient with a transcatheter pulmonary valve replacement.

A case report of Histoplasma capsulatum prosthetic valve endocarditis: an extremely rare presentation with characteristic findings

Background 

Histoplasma capsulatum is an extremely rare cause of prosthetic valve endocarditis (PVE) and can present with non-specific symptoms leading to a delay in diagnosis with unfavourable outcomes.

Case summary 

A 65-year-old male patient with a history of a bioprosthetic aortic valve replacement and non-obstructive coronary artery disease was admitted for altered mentation, failure to thrive, and a 20-pound unintentional weight loss over the past 4 months. Upon examination, he was lethargic but afebrile and haemodynamically stable. A late peaking ejection murmur was heard on exam. Skin exam was significant for embolic phenomenon involving the extremities. Inflammatory markers and serum calcium were elevated. A bedside echocardiogram showed severe obstruction across the aortic valve prosthesis. Two years prior, he had an echocardiogram with a normal functioning prosthesis. Routine blood cultures were negative and serologic screening was unrevealing. Urine Histoplasma antigen screen was positive on hospital day 3 and on hospital day 10, fungal blood cultures were positive for H. capsulatum. Unfortunately, the patient died shortly afterwards as a result of multiorgan failure from embolic manifestations of the infection.

Discussion 

Based on our patient's findings and those of previously reported cases in the literature, H. capsulatum PVE should be strongly considered in patients from endemic areas with non-specific symptoms and negative routine blood cultures.

Combination antifungal therapy for treatment of Candida parapsilosis prosthetic valve endocarditis and utility of T2Candida Panel®: A case series

Although Candida species are common pathogens for nosocomial infections, Candida endocarditis is still considered a rare entity. Here, we report two cases of Candida parapsilosis endovascular infections in patients with prosthetic valves, both of which responded to combination antifungal therapy without surgical intervention. Additionally, T2 magnetic resonance (T2MR) was used to assess for resolution of invasive candidiasis. The first case is of an elderly man with Candida parapsilosis endovascular infection who responded to combination antifungal therapy with micafungin and fluconazole followed by suppressive therapy, without surgical intervention. The second case is of a middle-aged man with Candida parapsilosis prosthetic valve endocarditis who also responded to combination antifungal therapy with micafungin, flucytosine and fluconazole, without surgical intervention.

Cryptococcus neoformans infective endocarditis of native valves in an immunocompetent host

With the emergence of Human immunodeficiency virus (HIV) and the resulting immunocompromised state, Cryptococcus neoformans infections have gained more importance in clinical practice. Cryptococcal infections in immunocompetent hosts continue to be uncommon. We present a rare case of Cryptococcus neoformans infective endocarditis (IE) in a young immunocompetent male. As per our literature review, this is the first reported case of native valve Cryptococcus neoformans endocarditis in an immunocompetent host. All cases till date have been reported in patients with underlying immunocompromised state or prosthetic valve.

Prosthetic Valve Candida spp. Endocarditis: New Insights Into Long-term Prognosis-The ESCAPE Study

BACKGROUND

Prosthetic valve endocarditis caused by Candida spp. (PVE-C) is rare and devastating, with international guidelines based on expert recommendations supporting the combination of surgery and subsequent azole treatment.

METHODS

We retrospectively analyzed PVE-C cases collected in Spain and France between 2001 and 2015, with a focus on management and outcome.

RESULTS

Forty-six cases were followed up for a median of 9 months. Twenty-two patients (48%) had a history of endocarditis, 30 cases (65%) were nosocomial or healthcare related, and 9 (20%) patients were intravenous drug users. "Induction" therapy consisted mainly of liposomal amphotericin B (L-amB)-based (n = 21) or echinocandin-based therapy (n = 13). Overall, 19 patients (41%) were operated on. Patients <66 years old and without cardiac failure were more likely to undergo cardiac surgery (adjusted odds ratios [aORs], 6.80 [95% confidence interval [CI], 1.59-29.13] and 10.92 [1.15-104.06], respectively). Surgery was not associated with better survival rates at 6 months. Patients who received L-amB alone had a better 6-month survival rate than those who received an echinocandin alone (aOR, 13.52; 95% CI, 1.03-838.10). "Maintenance" fluconazole therapy, prescribed in 21 patients for a median duration of 13 months (range, 2-84 months), led to minor adverse effects.

CONCLUSION

L-amB induction treatment improves survival in patients with PVE-C. Medical treatment followed by long-term maintenance fluconazole may be the best treatment option for frail patients.

Surgical Versus Medical Therapy for Prosthetic Valve Endocarditis: A Meta-Analysis of 32 Studies

Prosthetic valve endocarditis (PVE) is associated with significant morbidity, and the optimal treatment strategy has not been clearly defined. A systematic review and meta-analysis of 32 studies comparing valve reoperation and medical therapy was performed; it included 2,636 patients, with a mean follow-up of 22 months. A valve reoperation was associated with a lower risk of 30-day mortality, greater survival at follow-up, and a similar rate of PVE recurrence. Prospective studies are warranted to confirm these findings and to clarify clinical decision-making regarding the timing and necessity of a valve reoperation, as opposed to treatment with medical therapy alone.

[Strategies for antifungal treatment failure in intensive care units]

Recent epidemiologic studies reveal both an increasing incidence and an escalation in resistance of invasive fungal infections in intensive care units. Primary therapy fails in 70 % of cases, depending on the underlying pathogens and diseases. The purpose of this review is to raise awareness for the topic of antifungal therapy failure, describe the clinical conditions in which it occurs, and suggest a possible algorithm for handling the situation of suspected primary therapy failure.

The clinical importance of fungal biofilms

Fungal biofilms have become an increasingly important clinical problem. The widespread use of antibiotics, frequent use of indwelling medical devices, and a trend toward increased patient immunosuppression have resulted in a creation of opportunity for clinically important yeasts and molds to form biofilms. This review will discuss the diversity and importance of fungal biofilms in the context of clinical medicine, provide novel insights into the clinical management of fungal biofilm infection, present evidence why these structures are recalcitrant to antifungal therapy, and discuss how our knowledge and understanding may lead to novel therapeutic intervention.

Clinical Practice Guideline for the Management of Candidiasis: 2016 Update by the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association

BACKGROUND

Infective endocarditis is a potentially lethal disease that has undergone major changes in both host and pathogen. The epidemiology of infective endocarditis has become more complex with today's myriad healthcare-associated factors that predispose to infection. Moreover, changes in pathogen prevalence, in particular a more common staphylococcal origin, have affected outcomes, which have not improved despite medical and surgical advances.

METHODS AND RESULTS

This statement updates the 2005 iteration, both of which were developed by the American Heart Association under the auspices of the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease of the Young. It includes an evidence-based system for diagnostic and treatment recommendations used by the American College of Cardiology and the American Heart Association for treatment recommendations.

CONCLUSIONS

Infective endocarditis is a complex disease, and patients with this disease generally require management by a team of physicians and allied health providers with a variety of areas of expertise. The recommendations provided in this document are intended to assist in the management of this uncommon but potentially deadly infection. The clinical variability and complexity in infective endocarditis, however, dictate that these recommendations be used to support and not supplant decisions in individual patient management.

Recurrent candida prosthetic endocarditis over fifteen years managed with medical therapy and four valvular surgeries: a case report and review of literature

Background

Candida prosthetic endocarditis (CPE) is an uncommon disease involving less than 1 % of infective endocarditis patients and associated with high recurrence rate. Immunosuppresion, intravenous drug abuse, cardiac surgery and indwelling foreign bodies are the major risk factors for CPE. There are very few reported cases of CPE where more than one surgery was performed and there has generally been limited follow up on these cases.

Case presentation

We report a case of a 35 year old woman who had mitral valve annuloplasty complicated by recurrent episodes of CPE leading to multiple mitral valve replacements (MVR). She underwent MVR surgeries a total of four times over an eighteen year period and had good functionality during most of this time while being on antifungal suppressive treatment. This is a unique case in terms of numbers of surgeries performed, the length of the follow up and the involvement of three different Candida species.

Conclusion

Current guidelines for the treatment of candida endocarditis recommend surgical treatment followed by long term antifungal therapy although the cure rate by all treatments is low. However we feel that based on this one case it is reasonable to consider multiple redo valve replacement surgeries in conjunction with antifungal treatment for selected patients stable enough to tolerate the surgery.

Histoplasma capsulatum endocarditis: multicenter case series with review of current diagnostic techniques and treatment

Infective endocarditis is an uncommon manifestation of infection with Histoplasma capsulatum. The diagnosis is frequently missed, and outcomes historically have been poor. We present 14 cases of Histoplasma endocarditis seen in the last decade at medical centers throughout the United States. All patients were men, and 10 of the 14 had an infected prosthetic aortic valve. One patient had an infected left atrial myxoma. Symptoms were present a median of 7 weeks before the diagnosis was established. Blood cultures yielded H. capsulatum in only 6 (43%) patients. Histoplasma antigen was present in urine and/or serum in all but 3 of the patients and provided the first clue to the diagnosis of histoplasmosis for several patients. Antibody testing was positive for H. capsulatum in 6 of 8 patients in whom the test was performed. Eleven patients underwent surgery for valve replacement or myxoma removal. Large, friable vegetations were noted at surgery in most patients, confirming the preoperative transesophageal echocardiography findings. Histopathologic examination of valve tissue and the myxoma revealed granulomatous inflammation and large numbers of organisms in most specimens. Four of the excised valves and the atrial myxoma showed a mixture of both yeast and hyphal forms on histopathology. A lipid formulation of amphotericin B, administered for a median of 29 days, was the initial therapy in 11 of the 14 patients. This was followed by oral itraconazole therapy, in all but 2 patients. The length of itraconazole suppressive therapy ranged from 11 months to lifelong administration. Three patients (21%) died within 3 months of the date of diagnosis. All 3 deaths were in patients who had received either no or minimal (1 day and 1 week) amphotericin B.

Predicting the occurrence of embolic events: an analysis of 1456 episodes of infective endocarditis from the Italian Study on Endocarditis (SEI)

Background

Embolic events are a major cause of morbidity and mortality in patients with infective endocarditis. We analyzed the database of the prospective cohort study SEI in order to identify factors associated with the occurrence of embolic events and to develop a scoring system for the assessment of the risk of embolism.

Methods

We retrospectively analyzed 1456 episodes of infective endocarditis from the multicenter study SEI. Predictors of embolism were identified. Risk factors identified at multivariate analysis as predictive of embolism in left-sided endocarditis, were used for the development of a risk score: 1 point was assigned to each risk factor (total risk score range: minimum 0 points; maximum 2 points). Three categories were defined by the score: low (0 points), intermediate (1 point), or high risk (2 points); the probability of embolic events per risk category was calculated for each day on treatment (day 0 through day 30).

Results

There were 499 episodes of infective endocarditis (34%) that were complicated by ≥ 1 embolic event. Most embolic events occurred early in the clinical course (first week of therapy: 15.5 episodes per 1000 patient days; second week: 3.7 episodes per 1000 patient days). In the total cohort, the factors associated with the occurrence of embolism at multivariate analysis were prosthetic valve localization (odds ratio, 1.84), right-sided endocarditis (odds ratio, 3.93), Staphylococcus aureus etiology (odds ratio, 2.23) and vegetation size ≥ 13 mm (odds ratio, 1.86). In left-sided endocarditis, Staphylococcus aureus etiology (odds ratio, 2.1) and vegetation size ≥ 13 mm (odds ratio, 2.1) were independently associated with embolic events; the 30-day cumulative incidence of embolism varied with risk score category (low risk, 12%; intermediate risk, 25%; high risk, 38%; p < 0.001).

Conclusions

Staphylococcus aureus etiology and vegetation size are associated with an increased risk of embolism. In left-sided endocarditis, a simple scoring system, which combines etiology and vegetation size with time on antimicrobials, might contribute to a better assessment of the risk of embolism, and to a more individualized analysis of indications and contraindications for early surgery.

ESCMID* guideline for the diagnosis and management of Candida diseases 2012: non-neutropenic adult patients

This part of the EFISG guidelines focuses on non-neutropenic adult patients. Only a few of the numerous recommendations can be summarized in the abstract. Prophylactic usage of fluconazole is supported in patients with recent abdominal surgery and recurrent gastrointestinal perforations or anastomotic leakages. Candida isolation from respiratory secretions alone should never prompt treatment. For the targeted initial treatment of candidaemia, echinocandins are strongly recommended while liposomal amphotericin B and voriconazole are supported with moderate, and fluconazole with marginal strength. Treatment duration for candidaemia should be a minimum of 14 days after the end of candidaemia, which can be determined by one blood culture per day until negativity. Switching to oral treatment after 10 days of intravenous therapy has been safe in stable patients with susceptible Candida species. In candidaemia, removal of indwelling catheters is strongly recommended. If catheters cannot be removed, lipid-based amphotericin B or echinocandins should be preferred over azoles. Transoesophageal echocardiography and fundoscopy should be performed to detect organ involvement. Native valve endocarditis requires surgery within a week, while in prosthetic valve endocarditis, earlier surgery may be beneficial. The antifungal regimen of choice is liposomal amphotericin B +/- flucytosine. In ocular candidiasis, liposomal amphotericin B +/- flucytosine is recommended when the susceptibility of the isolate is unknown, and in susceptible isolates, fluconazole and voriconazole are alternatives. Amphotericin B deoxycholate is not recommended for any indication due to severe side effects.

BRG1 and NRG1 form a novel feedback circuit regulating Candida albicans hypha formation and virulence

In the opportunistic fungal pathogen Candida albicans both cellular morphology and the capacity to cause disease are regulated by the transcriptional repressor Nrg1p. One of the genes repressed by Nrg1p is BRG1, which encodes a putative GATA family transcription factor. Deletion of both copies of this gene prevents hypha formation. We discovered that BRG1 overexpression is sufficient to overcome Nrg1p-mediated repression and drive the morphogenetic shift from yeast to hyphae even in the absence of environmental stimuli. We further observed that expression of BRG1 influences the stability of the NRG1 transcript, thus controlling filamentation through a feedback loop. Analysis of this phenomenon revealed that BRG1 expression is required for the induction of an antisense NRG1 transcript. This is the first demonstration of a role for mRNA stability in regulating the key C. albicans virulence trait: the ability to form hyphae.

Histopathologic diagnosis of fungal infections in the 21st century

Fungal infections are becoming more frequent because of expansion of at-risk populations and the use of treatment modalities that permit longer survival of these patients. Because histopathologic examination of tissues detects fungal invasion of tissues and vessels as well as the host reaction to the fungus, it is and will remain an important tool to define the diagnostic significance of positive culture isolates or results from PCR testing. However, there are very few instances where the morphological characteristics of fungi are specific. Therefore, histopathologic diagnosis should be primarily descriptive of the fungus and should include the presence or absence of tissue invasion and the host reaction to the infection. The pathology report should also include a comment stating the most frequent fungi associated with that morphology as well as other possible fungi and parasites that should be considered in the differential diagnosis. Alternate techniques have been used to determine the specific agent present in the histopathologic specimen, including immunohistochemistry, in situ hybridization, and PCR. In addition, techniques such as laser microdissection will be useful to detect the now more frequently recognized dual fungal infections and the local environment in which this phenomenon occurs.

Histoplasma capsulatum prosthetic valve endocarditis with negative fungal blood cultures and negative histoplasma antigen assay in an immunocompetent patient

We report a case of Histoplasma capsulatum endocarditis in which Histoplasma antigen assay and fungal blood cultures were negative. The diagnosis was made by microscopic examination and culture of the excised valve. Histoplasma capsulatum should be considered in the differential diagnosis of culture-negative endocarditis in regions where it is endemic and in travelers.