Fungal endocarditis in transplant recipients: A systematic review

Surgical Procedure Time and Mortality in Patients with Infective Endocarditis Caused by Staphylococcus aureus or Streptococcus Species

Staphylococcus aureus (SA) and Streptococcus species (SS) show different clinical manifestations in infective endocarditis (IE), but the impact on the complexity of surgical treatment remains unclear. All patients with surgically treated IE due to SA or SS between July 2013 and December 2016 were extracted from a prospectively collected, single-center registry. Data on patient characteristics, surgical procedures, and postprocedural outcomes were collected. SA-IE was more common with prosthetic valves (26.3% vs. 7.3%, p = 0.04), cardiac devices (14.3% vs. 0%, p = 0.03), previous cardiac surgery (28.6% vs. 9.8%, p = 0.03), intravenous drug abuse (14.3% vs. 0%, p = 0.03), and embolic events (57.1% vs. 26.8%, p = 0.007). Preoperative CRP was significantly higher in SA-IE (median 96.1 mg/L vs. 42.4 mg/L, p = 0.002). Otherwise, SS-IE affected more cusps/leaflets (mean 2.4 vs. 1.8, p = 0.03) and led to more valve dysfunction (83.8% vs. 54.3%, p = 0.007). Surgery times did not differ between the groups, though patients with SA spent more time in the intensive care unit (median 7 vs. 4.5 days, p = 0.04). Hospital mortality did not differ, but patients with SA-IE had unfavorable long-term survival (p = 0.001). Future studies need to be larger and focus on the mechanism behind the reduced long-term survival to mitigate the deleterious effect of SA in surgically treated patients with IE.

Mural Endocarditis: The GAMES Registry Series and Review of the Literature

INTRODUCTION

Mural infective endocarditis (MIE) is a rare type of endovascular infection. We present a comprehensive series of patients with mural endocarditis.

METHODS

Patients with infectious endocarditis (IE) from 35 Spanish hospitals were prospectively included in the GAMES registry between 2008 and 2017. MIEs were compared to non-MIEs. We also performed a literature search for cases of MIE published between 1979 and 2019 and compared them to the GAMEs series.

RESULTS

Twenty-seven MIEs out of 3676 IEs were included. When compared to valvular IE (VIE) or device-associated IE (DIE), patients with MIE were younger (median age 59 years, p < 0.01). Transplantation (18.5% versus 1.6% VIE and 2% DIE, p < 0.01), hemodialysis (18.5% versus 4.3% VIE and 4.4% DIE, p = 0.006), catheter source (59.3% versus 9.7% VIE and 8.8% DIE, p < 0.01) and Candida etiology (22.2% versus 2% DIE and 1.2% VIE, p < 0.01) were more common in MIE, whereas the Charlson Index was lower (4 versus 5 in non-MIE, p = 0.006). Mortality was similar. MIE from the literature shared many characteristics with MIE from GAMES, although patients were younger (45 years vs. 56 years, p < 0.001), the Charlson Index was lower (1.3 vs. 4.3, p = 0.0001), catheter source was less common (13.9% vs. 59.3%) and there were more IVDUs (25% vs. 3.7%). S. aureus was the most frequent microorganism (50%, p = 0.035). Systemic complications were more common but mortality was similar.

CONCLUSION

MIE is a rare entity. It is often a complication of catheter use, particularly in immunocompromised and hemodialysis patients. Fungal etiology is common. Mortality is similar to other IEs.

Pleiotropic Effects of the P5-Type ATPase SpfA on Stress Response Networks Contribute to Virulence in the Pathogenic Mold Aspergillus fumigatus

Aspergillus fumigatus is a human-pathogenic mold that extracts nutrients from the environment or from host tissues by secreting hydrolytic enzymes. The ability of A. fumigatus to adjust secretion levels in proportion to demand relies on the assistance of the unfolded protein response (UPR), an adaptive stress response pathway that regulates the unique protein-folding environment of the endoplasmic reticulum (ER). The P5-type ATPase Spf1 has recently been implicated in a novel mechanism of ER homeostasis that involves correcting errors in ER-membrane protein targeting. However, the contribution of this protein to the biology of A. fumigatus is unknown. Here, we employed a gene knockout and RNA sequencing strategy to determine the functional role of the A. fumigatus gene coding for the orthologous P5 ATPase SpfA. The data reveal that the spfA gene is induced by ER stress in a UPR-dependent manner. In the absence of spfA, the A. fumigatus transcriptome shifts toward a profile of altered redox and lipid balance, in addition to a signature of ER stress that includes srcA, encoding a second P-type ATPase in the ER. A ΔspfA deletion mutant showed increased sensitivity to ER stress, oxidative stress, and antifungal drugs that target the cell wall or plasma membrane. The combined loss of spfA and srcA exacerbated these phenotypes and attenuated virulence in two animal infection models. These findings demonstrate that the ER-resident ATPases SpfA and SrcA act jointly to support diverse adaptive functions of the ER that are necessary for fitness in the host environment. IMPORTANCE The fungal UPR is an adaptive signaling pathway in the ER that buffers fluctuations in ER stress but also serves as a virulence regulatory hub in species of pathogenic fungi that rely on secretory pathway homeostasis for pathogenicity. This study demonstrates that the gene encoding the ER-localized P5-type ATPase SpfA is a downstream target of the UPR in the pathogenic mold A. fumigatus and that it works together with a second ER-localized P-type ATPase, SrcA, to support ER homeostasis, oxidative stress resistance, susceptibility to antifungal drugs, and virulence of A. fumigatus.

Infective endocarditis and solid organ transplantation: Only worse outcomes during initial transplantation hospitalization

BACKGROUND

The epidemiology, and outcome of infective endocarditis (IE) among solid organ transplant (SOT) recipients is unknown.

METHODS

We used data from the 2013-2018 Nationwide Readmissions Database (NRD). IE- and SOT-associated hospitalizations were identified using diagnosis and procedure codes. Outcomes included inpatient mortality, length of stay, and inpatient costs. Adjusted analyses were performed using weighted regression models.

RESULTS

A total of 99,052 IE-associated hospitalizations, corresponding to a weighted national estimate of 193,164, were included for analysis. Of these, 794 (weighted n = 1,574) were associated with transplant history (SOT-IE). Mortality was not significantly different between SOT-IE and non-SOT-IE (17.2% vs. 15.8%, adjusted relative risk [aRR]: 0.86, 95% confidence interval [CI] [0.71, 1.03]), and fewer SOT-IE patients underwent valve repair or replacement than non-SOT-IE (12.5% vs. 16.2%, aRR 0.82, 95% CI [0.71, 0.95]). We then compared outcomes of patients diagnosed with IE during their index transplant hospitalization (index-SOT-IE) to patients without IE during their transplant hospitalization (index-SOT). Index-SOT-IE occurred most frequently among heart transplant recipients (45.1%), and was associated with greater mortality (27.1% vs. 2.3%, aRR 6.07, 95% CI [3.32, 11.11]).

CONCLUSION

Dual diagnosis of SOT and IE was associated with worse outcomes among SOT recipients during index hospitalization, but not overall among patients with IE.

A Case Report of Cystic Fibrosis Plus Tuberous Sclerosis: A Cautionary Tale Regarding Lung Transplantation

BACKGROUND

Cystic fibrosis (CF) and tuberous sclerosis complex (TSC) are 2 rare genetic diseases that often affect the lungs. Pulmonary compromise in TSC or CF can be severe enough to require lung transplantation. In rare instances patients with CF undergo pneumonectomy to control recurrent lung infections and lung necrosis affecting one lung more than the other. Lung transplantation in these patients is exceedingly rare because preexistent pneumonectomy increases the risk of lung transplant-associated morbidity and mortality.

CASE PRESENTATION

We present the case of a young woman with co-occurrence of TSC and CF, who underwent left-sided pneumonectomy and, approximately 2 years later, right-sided single lung transplant. The posttransplant clinical course was complicated by phrenic nerve injury, ventilator dependency, Aspergillus endocarditis with embolic shower, and death. Pretransplant pneumonectomy, Aspergillus colonization, and posttransplant phrenic nerve injury contributed to the complex postoperative course, ventilatory dependence, and poor outcome.

CONCLUSION

This cautionary case should alert physicians on the challenges associated with single lung transplant in patients with preexistent pneumonectomy.

Pathogens in Vasculitis: Is It Really Idiopathic?

Vasculitis is an autoimmune disease characterized by the infiltration of leukocytes in blood vessels. An increasing number of studies on human and animal models have implicated various microorganisms in the pathogenesis of vasculitis. Previous studies have shown the presence of infectious agents, including viruses, bacteria, and fungi, in diseased vessels. However, despite continued research, the link between infection and vasculitis is not fully understood, possibly owing to the lack of appropriate animal models that mirror human disease and the technical limitations of pathogen detection in blood vessels. Among the pathogen-induced animal models, Candida albicans water-soluble fraction (CAWS)-induced coronary arteritis is currently considered one of the representative models of Kawasaki (KD) disease. Advances in metagenomic next-generation sequencing have enabled the detection of all nucleic acids in tissue, which can help identify candidate pathogens, including previously unidentified viruses. In this review, we discuss the findings from reports on pathogen-associated vasculitis in animal models and humans, with a specific focus on the investigation of the pathogenesis of vasculitis. Further studies on animal models and microbes in diseased vessels may provide important insights into the pathogenesis of vasculitis, which is often considered an idiopathic disease.

Endocarditis in Liver Transplant Recipients: A Systematic Review

Infective Endocarditis (IE) is associated with significant mortality. Interestingly, IE in patients with liver transplantation has not been adequately described. The aim of this review was to systematically review all published cases of IE in liver transplant recipients and describe their epidemiology, microbiology, clinical characteristics, treatment and outcomes. A systematic review of PubMed, Scopus and Cochrane Library (through 2 January 2021) for studies providing epidemiological, clinical, microbiological, treatment data and outcomes of IE in liver transplant recipients was conducted. A total of 39 studies, containing data for 62 patients, were included in the analysis. The most common causative pathogens were gram-positive microorganisms in 69.4%, fungi in 25.8%, and gram-negative microorganisms in 9.7% of cases, while in 9.3% IE was culture-negative. The aortic valve was the most commonly infected valve followed by mitral, tricuspid and the pulmonary valve. Aminoglycosides, vancomycin and aminopenicillins were the most commonly used antimicrobials, and surgical management was performed in half of the cases. Clinical cure was noted in 57.4%, while overall mortality was 43.5%. To conclude, this systematic review thoroughly describes IE in liver transplant recipients and provides information on epidemiology, clinical presentation, treatment and outcomes.

Case Report: Infective Endocarditis Caused by Aspergillus flavus in a Hemodialysis Patient

Fungal endocarditis (FE) is a rare but fatal disease. The incidence of infective endocarditis (IE) in hemodialysis patients with catheters is thought to be obviously higher than that in the general population. We reported a case of IE caused by Aspergillus flavus (A. flavus) in a 36-year-old woman on hemodialysis. Because the blood cultures were persistently negative, so we used mNGS (Metagenomic next generation sequencing) for early clinical diagnosis. After treatment with voriconazole, the patient's condition improved rapidly. She continued oral voriconazole treatment 1 year after discharge and is in good condition. The diagnosis and treatment strategies of FE in hemodialysis patients were discussed.

Infective endocarditis complicated by embolic events: Pathogenesis and predictors

BACKGROUND

Infective endocarditis (IE) continues to be associated with great challenges. Embolic events (EE) are frequent and life-threatening complications in IE patients. It remains challenging to predict and assess the embolic risk in individual patients with IE accurately.

HYPOTHESIS

Accurate prediction of embolization is critical in the early identification and treatment of risky and potentially embolic lesions in patients with IE.

METHODS

We searched the PubMed, Web of Science, and Google Scholar databases using a range of related search terms, and reviewed the literatures about the pathogenesis and embolic predictors of IE.

RESULTS

The development of IE and its complications is widely accepted as the result of complex interactions between microorganisms, valve endothelium, and host immune responses. The predictive value of echocardiographic characteristics is the most powerful for EE. In addition, both easily obtained blood biomarkers such as C-reactive protein, mean platelet volume, neutrophil-to-lymphocyte ratio, anti-β2-glycoprotein I antibodies, D-Dimer, troponin I, matrix metalloproteinases, and several microbiological or clinical characteristics might be promising as potential predictors of EE.

CONCLUSION

Our review provides a synthesis of current knowledge regarding the pathogenesis and predictors of embolism in IE along with a review of potentially emerging biomarkers.

Endocarditis in kidney transplant recipients: a systematic review

Infective Endocarditis (IE) carries significant mortality. Bacteremia, which is a predisposing factor for IE, occurs more frequently in immunocompromised individuals. Interestingly, IE in kidney transplant recipients has not been adequately described. The aim of this study was to systematically review all published cases of IE in kidney transplant recipients and describe their epidemiology, microbiology, clinical characteristics, treatment and outcomes. A systematic review of PubMed (through 13^th December 2019) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE in kidney transplant recipients was performed. A total of 60 studies, containing data of 117 patients, were included in the analysis. The most common causative pathogens were gram-positive microorganisms in 57.4%, gram-negative microorganisms in 14.8%, fungi in 20%, while in 18.9% of cases, IE was culture-negative. Aortic valve was the most commonly infected valve followed by mitral, tricuspid and the pulmonary valve. Diagnosis was set with a transthoracic ultrasound in half the cases, followed by transesophageal ultrasound and autopsy. Fever was present in most cases, while embolic phenomena were noted in two out of five cases. Aminoglycosides, cephalosporins and aminopenicillins were the most commonly used antimicrobials, and surgical management was performed in one out of three cases. Clinical cure was noted in 60.9%, while overall mortality was 45.3%. To conclude, this systematic review thoroughly describes IE in kidney transplant recipients and provides information on epidemiology, clinical presentation, treatment and outcomes. Moreover, it identifies the emerging role of Enterococci, gram-negatives and fungi in IE in this population.

Opportunist Coinfections by Nontuberculous Mycobacteria and Fungi in Immunocompromised Patients

Nontuberculous mycobacteria (NTM) and many fungal species (spp.) are commonly associated with opportunistic infections (OPIs) in immunocompromised individuals. Moreover, occurrence of concomitant infection by NTM (mainly spp. of Mycobacterium avium complex and Mycobacterium abscessus complex) and fungal spp. (mainly, Aspergillus fumigatus, Histoplasma capsulatum and Cryptococcus neoformans) is very challenging and is associated with poor patient prognosis. The most frequent clinical symptoms for coinfection and infection by single agents (fungi or NTM) are similar. For this reason, the accurate identification of the aetiological agent(s) is crucial to select the best treatment approach. Despite the significance of this topic it has not been sufficiently addressed in the literature. This review aims at summarizing case reports and studies on NTM and fungi coinfection during the last 20 years. In addition, it briefly characterizes OPIs and coinfection, describes key features of opportunistic pathogens (e.g., NTM and fungi) and human host predisposing conditions to OPIs onset and outcome. The review could interest a wide spectrum of audiences, including medical doctors and scientists, to improve awareness of these infections, leading to early identification in clinical settings and increasing research in the field. Improved diagnosis and availability of therapeutic options might contribute to improve the prognosis of patients' survival.