Prosthetic valve endocarditis

Parvimonas micra-induced prosthetic valve endocarditis: a challenging case report and literature review

Parvimonas micra, a gram-positive anaerobic bacterium, has garnered increased attention due to its role in infective endocarditis. We present a challenging prosthetic valve endocarditis caused by Parvimonas micra in a patient with a complex cardiac history involving multiple surgeries. The case highlights the difficulties in diagnosis and treatment, emphasizing the importance of advanced diagnostic techniques, including metagenomics next-generation sequencing (mNGS). Additionally, it underscores the need for heightened vigilance regarding oral symptoms and the potential risk of bacteremia in post-valvular surgery patients. This report contributes to a better understanding of Parvimonas micra-associated endocarditis and its unique characteristics.

Antibacterial copper-filled TiO2 coating of cardiovascular implants to prevent infective endocarditis-A pilot study

BACKGROUND

Infective endocarditis (IE) poses a significant health risk, especially in patients with prosthetic heart valves. Despite advances in treatment, mortality rates remain high. This study aims to investigate the antibacterial properties of a copper titanium dioxide (4× Cu-TiO2) coating on cardiovascular implants against Staphylococcus aureus, a common causative agent of IE.

METHODS

Titanium oxide carriers functionalized with copper ions were employed as an antibacterial coating for heart and vascular prostheses. The coating's antibacterial efficacy was assessed using S. aureus ATCC 29213. Microscopic evaluations were conducted on both biological and artificial materials. Antibacterial activity was qualitatively assessed via a modified disc diffusion method and quantitatively measured through colony counts in NaCl suspensions.

RESULTS

The coating process was successfully applied to all tested cardiovascular prosthetic materials. Qualitative assessments of antibacterial effectiveness revealed an absence of bacterial growth in the area directly beneath the coated valve. Quantitative evaluations showed a significant reduction in bacterial colonization on coated mechanical valves, with 2.95 × 104 CFU per valve, compared to 1.91 × 105 CFU in control valves.

CONCLUSIONS

The 4× Cu-TiO2 coating demonstrated promising antibacterial properties against S. aureus, suggesting its potential as an effective strategy for reducing the risk of bacterial colonization of cardiovascular implants. Further studies are needed to assess the longevity of the coating and its efficacy against other pathogens.

Mortality patterns in older adults with infective endocarditis in the US: A retrospective analysis

BACKGROUND

Infective Endocarditis (IE) has become a significant cause of morbidity and mortality over the last two decades. Despite management advancements, mortality trends in the USA's geriatric population are unexplored. The aim of this study was to assess the trends and regional differences in IE related mortality among geriatric patients in the USA.

METHODS

We analyzed death certificates sourced from the CDC WONDER database spanning 1999 to 2020. The research targeted individuals aged 65 and older. Age-adjusted mortality rates (AAMRs) per 100,000 and annual percent change (APC), along with 95% CI, were calculated through joinpoint regression analysis.

RESULTS

From 1999 to 2020, infective endocarditis caused 222,573 deaths, showing a declining trend (APC: -0.8361). Males had higher AAMR (26.8) than females (22.2). NH White had the highest AAMR (25.8), followed by NH American Indians or Alaska Natives (19.6). Geographically, the Midwest had the highest AAMR (27.4), followed by the Northeast (25.8). Rural areas consistently had higher AAMRs (26.6) than urban areas (23.6), while 80.16% of deaths occurring in urban settings. North Dakota, Nebraska, and Montana had the highest state AAMRs, approximately double than the states with the lowest mortality rates: Mississippi, Hawaii, California, and Massachusetts. Those aged 85 and above accounted for 42.9% of deaths.

CONCLUSION

IE mortality exhibited a clear pattern: rising till 2004, declining from 2004 to 2018, and increasing again till 2020. Key risk factors were male gender, Midwest residence, NH White ethnicity, and age ≥85.Targeted interventions are essential to reduce IE mortality, especially among vulnerable older populations.

Valvulitis: a new echocardiographic criterion for the diagnosis of bioprosthetic aortic valve infective endocarditis

INTRODUCTION AND OBJECTIVES

Diffuse homogeneous hypoechoic leaflet thickening, with a wavy leaflet motion documented by transesophageal echocardiography (TEE), has been described in some cases of prosthetic valve endocarditis (PVE) involving aortic bioprosthesis (AoBio-PVE). This echocardiographic finding has been termed valvulitis. We aimed to estimate the prevalence of valvulitis, precisely describe its echocardiographic characteristics, and determine their clinical significance in patients with AoBio-PVE.

METHODS

From 2011 to 2022, 388 consecutive patients with infective endocarditis (IE) admitted to a tertiary care hospital were prospectively included in a multipurpose database. For this study, all patients with AoBio-PVE (n=86) were selected, and their TEE images were thoroughly evaluated by 3 independent cardiologists to identify all cases of valvulitis.

RESULTS

The prevalence of isolated valvulitis was 12.8%, and 20.9% of patients had valvulitis accompanied by other classic echocardiographic findings of IE. A total of 9 out of 11 patients with isolated valvulitis had significant valve stenosis, whereas significant aortic valve regurgitation was documented in only 1 patient. Compared with the other patients with AoBio-PVE, cardiac surgery was less frequently performed in patients with isolated valvulitis (27.3% vs 62.7%, P=.017). In 4 out of 5 patients with valve stenosis who did not undergo surgery but underwent follow-up TEE, valve gradients significantly improved with appropriate antibiotic therapy.

CONCLUSIONS

Valvulitis can be the only echocardiographic finding in infected AoBio and needs to be identified by imaging specialists for early diagnosis. However, this entity is a diagnostic challenge and additional imaging techniques might be required to confirm the diagnosis. Larger series are needed.

A customized technique for confluent aortic annular and selective sinus of Valsalva endocarditis

We describe a novel technical modification for reoperative aortic valve replacement in destructive recurrent prosthetic aortic valve endocarditis. We encountered complex anatomy in a previously operated aortic root wherein the aortic annulus and the right coronary sinus of Valsalva were destroyed. This precluded secure suture placement. We modified a composite mechanical Valsalva conduit to create a separate sinus of Valsalva left in continuity with the mechanical valve. This approach allowed us to exclude the infected right sinus of Valsalva and the corresponding aortic annulus.

Non-typhoidal Salmonella enteritidis prosthetic valve endocarditis

In this case, we present a rare cause of prosthetic valve endocarditis. A man in his 80s presented to the emergency department with fever and diarrhoea. The patient underwent a transcatheter aortic valve replacement 17 years earlier. A negative PCR result in faeces for Salmonella and positive blood cultures with Salmonella gave rise to the suspicion of an intravascular Salmonella infection, which was confirmed with a positron emission tomography. Due to the low prevalence of Salmonella endocarditis, there is no consensus on the most effective treatment. Guidelines recommend early surgery and long-term antimicrobial treatment in endocarditis with Gram-negative bacteria. In this case, surgery was not deemed feasible given the patient his advanced age and multiple comorbidities. Despite treatment with intravenous antibiotics, the patient succumbed to progression of endocarditis 37 days after admission.

Prosthetic valve endocarditis caused by Campylobacter fetus: a case report and literature review

Campylobacter fetus is a Gram-negative bacillus typically associated with bacteremia in immunocompromised patients. Prosthetic valve endocarditis (PVE) is a serious complication of prosthetic valve surgery, with a high mortality rate if not treated promptly. We present a rare case of PVE caused by C. fetus. A man in his mid-60s presented to the Emergency Department with a fever and showed elevated C-reactive protein concentrations. He had prosthetic mitral and aortic valve replacement surgery 15 years previously. Gram-negative rods were detected in a blood culture. These rods were identified as C. fetus using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and confirmed by 16S rRNA sequencing. The patient was treated with gentamicin and imipenem, and underwent valve replacement surgery. C. fetus was isolated in a left atrial appendage swab obtained during the surgery. Follow-up blood cultures were negative after treatment. However, after a cardiac arrest event, the patient's general condition deteriorated, and he died. To the best of our knowledge, this is the first case of PVE caused by C. fetus in Korea and the second fatality to date. This case highlights the importance of considering C. fetus as a potential cause of PVE, even in patients without known risk factors.

Ultra-multiplex PCR technique to guide treatment of Aspergillus-infected aortic valve prostheses

Prosthetic valve endocarditis is a serious complication after heart valve replacement, accounting for about 20-30% of infective endocarditis (IE). Aspergillosis infection accounts for 25-30% of fungal endocarditis, and the mortality rate is 42-68%. Aspergillus IE often has negative blood cultures and lacks fever, which makes diagnosis difficult and delays antifungal therapy. Our study reported a case of IE in a patient with Aspergillus infection after aortic valve replacement. Ultra-multiplex polymerase chain reaction was used to identify Aspergillus infection and guide treatment. The purpose of this study was to enhance the understanding of the management of patients with endocarditis infected by fungi after valve replacement regarding the early detection, timely intervention, and treatment of the fungal infection to reduce the risk of death and improve the long-term survival of patients.

A high-hydrophilic Cu2O-TiO2/Ti2O3/TiO coating on Ti-5Cu alloy: Perfect antibacterial property and rapid endothelialization potential

In order to make novel antibacterial Ti-Cu alloy more suitable for cardiovascular implant application, a Cu-containing oxide coating was manufactured on Ti-Cu alloy by plasma-enhanced oxidation deposition in plasma enhanced chemical vapor deposition (PECVD) equipment to further improve the antibacterial ability and the surface bioactivity. The results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and water contact angle indicated that a sustainably high-hydrophilic Cu₂O-TiO₂/Ti₂O₃/TiO coating with nano-morphology on Ti-5Cu was successfully constructed. The corrosion performance results showed that the coating enhanced the corrosion resistance while releasing more Cu²⁺, compared with Ti-5Cu. Antibacterial tests confirmed the perfect antibacterial property of the coating (R ≥ 99.9 %), superior to Ti-Cu alloy (R > 90 %). More delightfully, it was observed by phalloidin-FITC and DAPI staining that the coating improved the early adhesion of HUVEC cells mainly due to strong hydrophilicity and nano-morphology. It was demonstrated that the extract of the coated sample significantly promoted proliferation (RGR = 112 %-138 % after cultivation for 1 to 3 days) and migration of HUVEC cells due to the appropriate Cu²⁺ release concentration. Hemolysis assay and platelet adhesion results showed that the coating had excellent blood compatibility. All results suggested that the coating on Ti-Cu alloy might be a promising surface with the perfect antibacterial ability, blood compatibility and evident promoting endothelialization ability for the cardiovascular application.

The prevalence of persistent bacteraemia in patients with a non-staphylococcal infective endocarditis, a retrospective cohort study

BACKGROUND

Current guidelines on the management of infective endocarditis (IE) recommend follow-up blood cultures (FUBCs) to identify persistent bacteraemia, as this has prognostic value and guides treatment decisions. While persistent bacteraemia frequently occurs in Staphylococcus aureus bacteraemia and IE, its prevalence and impact in non-staphylococcal IE is largely unknown. We determined prevalence and prognostic value of persistent bacteraemia in non-staphylococcal IE.

METHODS

We conducted a retrospective analysis of all patients diagnosed with definite non-staphylococcal endocarditis according to the modified Duke Criteria in two university hospital endocarditis registries We determined the prevalence and prognostic value of persistent bacteraemia.

RESULTS

Of the included 159 patients 70 (44%) had prosthetic valve endocarditis (PVE). A median number of two [IQR 1-3] FUBCs were taken during the first week, with 134/159 (84%) having at least one FUBC in the first four days. Seven patients (4,4%) had persistent bacteraemia 48 h after start of antibiotic treatment: 5/70 patients (7.1%) with PVE and 2/89 (2.2%) with native valve endocarditis. Among 97 patients with streptococcal IE, nine patients with HACEK IE and six patients with Cutibacterium IE, no persistent bacteraemia was observed. Enterococcus faecalis was the causative microorganism in five patients with persistent bacteraemia, the other two had non-HACEK Gram-negative endocarditis.

CONCLUSION

Persistent bacteraemia in non-staphylococcal endocarditis was rare. It was more frequently observed in PVE and was restricted to more resilient microorganisms such as enterococci and non-HACEK Gram-negative bacteria. Routine collection of FUBCs in patients with streptococcal endocarditis has a low yield and may require re-evaluation.

Rapid Progression of Bioprosthetic Aortic Valve Endocarditis: From Paraprosthetic Abscesses into Tricuspid Valve Infiltration

We present a case of prosthetic valve endocarditis (PVE) in a 49-year-old gentleman with a history of bioprosthetic valve replacement following infective endocarditis of the aortic valve. He was pyrexial on arrival and electrocardiogram showed complete heart block. Transthoracic echocardiography and transoesophageal echocardiography revealed evidence of multiple echogenic, hypodensities within the paraprosthetic regions of the aortic bioprosthetic valve, suggestive of paravalvular abscesses, and infiltration into the right ventricle via the septal leaflet of the tricuspid valve. Early PVE is often nosocomial and ultimate management include radical debridement and major reconstruction with an expectedly high risk for mortality and post-operative complications.

Maltohexaose-indocyanine green (MH-ICG) for near infrared imaging of endocarditis

Infectious endocarditis is a life-threatening disease, and diagnostics are urgently needed to accurately diagnose this disease especially in the case of prosthetic valve endocarditis. We show here that maltohexaose conjugated to indocyanine green (MH-ICG) can detect Staphylococcus aureus (S. aureus) infection in a rat model of infective endocarditis. The affinity of MH-ICG to S. aureus was determined and had a Km and Vmax of 5.4 μM and 3.0 X 10⁻⁶ μmol/minutes/10⁸ CFU, respectively. MH-ICG had no detectable toxicity to mammalian cells at concentrations as high as 100 μM. The in vivo efficiency of MH-ICG in rats was evaluated using a right heart endocarditis model, and the accumulation of MH-ICG in the bacterial vegetations was 2.5 ± 0.2 times higher than that in the control left ventricular wall. The biological half-life of MH-ICG in healthy rats was 14.0 ± 1.3 minutes, and approximately 50% of injected MH-ICG was excreted into the feces after 24 hours. These data demonstrate that MH-ICG was internalized by bacteria with high specificity and that MH-ICG specifically accumulated in bacterial vegetations in a rat model of endocarditis. These results demonstrate the potential efficacy of this agent in the detection of infective endocarditis.

A case series of medically managed Candida parapsilosis complex prosthetic valve endocarditis

Background

In recent years, Candida parapsilosis is recognized as a species complex and is composed of Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis. Candida parapsilosis complex prosthetic valve endocarditis (PVE) is rare and the survival rate is still low despite of optimal therapeutic strategies. In our report, it is novel to report cases as Candida parapsilosis complex PVE at species and identify Candida parapsilosis using MALDI-TOF MS.

Case presentation

A series of 4 cases of Candida parapsilosis complex PVE from our institution was reported. Three were infected by Candida parapsilosis sensu stricto and one was infected by Candida metapsilosis. The condition of two cases got better and the other died.

Conclusions

More attention should be paid to Candida parapsilosis complex PVE and early diagnosis and prompt antibiotic therapy may play a role in the treatment for Candida parapsilosis complex PVE. It is recommended to identify Candida parapsilosis complex at species level and MALDI-TOF MS as an easy, fast and efficient identification method is worth promoting in clinical microbiology

Pre-implant screening guided by cardiac silhouette fluoroscopy: a way to increase eligibility for the subcutaneous implantable cardioverter-defibrillator: a case report

BACKGROUND

Suitability for the subcutaneous implantable cardioverter-defibrillator (S-ICD) depends on a pre-implant electrocardiogram (ECG) screening to ensure appropriate sensing of electrical cardiac signals. Screening is performed positioning electrodes guided by chest surface anatomical landmarks.

CASE SUMMARY

We report a case of a patient with an initially negative conventional automatic screening for S-ICD, who underwent a modified screening guided by cardiac silhouette position, as seen under fluoroscopy, resulting in eligibility for the S-ICD.

DISCUSSION

The S-ICD reduces endovascular infection risk, providing therefore a potentially safer alternative in patients with prosthetic valves. It might be reasonable to perform a pre-implant ECG screening guided by fitting the cardiac silhouette in the shock vector, as this modified screening position could increase eligibility in patients who may benefit from S-ICD therapy such as the one presented.

Evaluation of the Current Knowledge About Bacterial Endocarditis Prevention Among General Dentists in the City of Santo Domingo, Dominican Republic

Infective endocarditis (IE) is a life-threatening disease caused by bacterial adherence to the lining of the heart and heart valve, and it can be caused by bacterial contamination of the bloodstream during invasive dental procedures. The American Heart Association (AHA) recommended guidelines for antibiotic prophylaxis in 2008 before invasive dental procedures; however, in the Dominican Republic, no official guidelines or regulations on this topic have been yet established. This study aimed to evaluate the current knowledge about bacterial endocarditis prevention among dentists in Santo Domingo. The study participants were dentists who attended a conference organized by Universidad Federico Henríquez y Carvajal (n = 95), of which 74 responded to the questionnaire survey. Seventy-eight percentage of the participants responded that an indication of antibiotics is recommended in cases of prophylaxis for IE. The prescription of antibiotics was applied to patients with prosthetic valves (78.4%), presented a history of previous IE (77%) among others. Among all the interventions in which the respondents would prescribe antibiotics, tooth extraction (70.7%) was the most frequent. Amoxicillin was the preferred drug choice (63.5%) and clindamycin was the antibiotic of choice in allergic patients (55.4%). Even though the choice of antibiotics were according to AHA guidelines (2008), majority of the dentists (58.82 and 55.4%) were not aware of the correct dosage and timing of administration of azithromycin and clindamycin in drugs in patients allergic to penicillin.

The role of endocarditis in sudden cardiac death: highlighting the value of the autopsy, pathological features and cardiac complications

OBJECTIVE

Endocarditis is increasing in incidence due to growing numbers of cardiac interventions, valve replacements and immunosuppressants. It can be difficult to diagnose clinically, has high mortality and can present as sudden cardiac death (SCD) with few/subtle preceding symptoms. True incidence of SCD related to endocarditis is unknown.

METHODS

Retrospective analysis of UK national database of 6000 cases of SCD, 1994-2020, for "endocarditis" as cause of death.

RESULTS

Of 30 cases (0.50%), 19(63%) were male and mean age was 36.2 ± 20.1 years. Postmortem examination showed the aortic valve was solely affected in 13 (43%), mitral in 9 (30%), tricuspid in 2(6.7%) and pulmonary in 1 (3.3%). Three cases (10%) had more than one valve affected and 2 (6.7%) were nonvalvular affecting the ascending aorta. Vegetations ranged from small easily missed irregularities to large fungating masses. Ten (33%) patients developed aortic abscesses, 2 of which had aneurysms, 13 (43%) had coronary artery septic emboli with micro-abscesses and myocardial microinfarction, and 2 (6.7%) were healed endocarditis with perforation and regurgitation with ventricular remodeling. Thirteen (43%) had an identifiable underlying valve abnormality or replacement, most common being a bicuspid aortic valve (7; 54%).

CONCLUSIONS

This study highlights that although rare, endocarditis is an important cause of SCD in those with normal valves, valvular disease and valve replacement surgery. Absence of a premortem diagnosis in 70% of our cohort highlights the need for detailed analysis of the heart and cardiac valves at autopsy. Gross appearance of vegetations varies widely and can be missed. Awareness of associated cardiac complications is required for elucidation of the cause of death and will provide valuable lessons for clinicians.

Three-valve endocarditis in a patient with bioprosthetic aortic valve replacement and intravenous drug use: a case report

Background

Here, we outline the case of a US Veteran’s Health Administration (VA) patient with a history of recent bioprosthetic aortic valve replacement (AVR) and recent intravenous drug use (IVDU) who was found to have three-valve infective endocarditis (IE) resulting in septic shock. We highlight this case because it represents an uncommon case of three-valve IE in the setting of recent bioprosthetic valve replacement and IVDU, and it raises the need for continued awareness of mental health and drug rehabilitation in the US military veteran population.

Case summary

A 62-year-old gentleman with recent bioprosthetic AVR presented with dyspnoea and lower extremity oedema and was found to have a heart failure exacerbation. He developed sepsis and was found to have three-valve endocarditis, as well as aortic root abscess and pacemaker lead infection. He was treated with broad-spectrum antibiotics and evaluated for surgical intervention. After discussion with the surgical team, the patient decided not to pursue surgery due to prohibitively high perioperative mortality risk. The patient was transferred to hospice and expired within 2 weeks.

Discussion

Three-valve IE is sparingly documented in published literature and can be difficult to treat. Providers must be cognizant of prosthetic valve endocarditis as an uncommon but known complication of valve replacement surgery. Intravenous drug use is a common risk factor for endocarditis and is prevalent in the US military veteran population. Prosthetic valve endocarditis should be treated with broad-spectrum antibiotics, and in general, if it leads to new significant valvular abnormalities, the valve should be replaced.

Enterococcal prosthetic valve endocarditis secondary to transurethral prostatic resection

Prosthetic valve endocarditis (PVE) is a catastrophic complication of cardiac valve replacement, associated with high mortality rates. Staphylococci (both Staphylococcus aureus and coagulase-negative Staphylococcui) are the most common cause of PVE. Diagnosis may often be difficult because of its complications and extracardiac manifestations. Positive blood and valve cultures are one of the most important diagnostic criteria for IE. Transesophageal echography should be performed without delay in all patients suspected to have PVE. As for treatment, according to the guidelines sensitive antimicrobials should be administered for 6 weeks. Surgery is recommended in case of PVE complicated by heart failure, severe prosthetic dysfunction, abscess or persistent fever. We present a case of PVE after transurethral resection of the prostate in a 63-year-old male patient with a history of mitral valve replacement. The patient was treated by appropriate antimicrobials for 6 weeks and recovered completely.

Incidence and Surgical Outcomes of Patients With Native and Prosthetic Aortic Valve Endocarditis

BACKGROUND

The aim of this study was to retrospectively evaluate the incidence and surgical outcomes of patients with native infective endocarditis (IE) and prosthetic aortic valve endocarditis (PVE) over the past decade at a single institution.

METHODS

Between January 2005 and December 2015, 289 patients (mean age, 63.3 ± 14.2 years) suffering from native IE (n = 186) and PVE (n = 103) of the aortic valve underwent surgical procedures. Perioperative data were acquired retrospectively for statistical analysis.

RESULTS

During the study period the mean incidence of endocarditis increased from 22.0 ± 4.2 (2005-2009) to 29.8 ± 10.1 (2010-2015) cases per year. In-hospital mortality was significantly increased in PVE (22.3%) versus IE (9.1%) patients (P < .001). In elective cases in-hospital mortality between the 2 groups was comparable (2.2% vs 4.6%; P = .288). Multivariate analysis identified urgent surgery (odds ratio [OR], 6.461; 95% CI, 1.941-21.509; P = .002), mitral regurgitation II (OR, 4.230; 95% CI, 1.249-14.331; P = .021), previous homograft operation (OR, 66.096; 95% CI, 2.369-1844.272; P = .0.14), and left ventricular ejection fraction < 40% (OR, 8.267; 95% CI, 1.931-35.388; P = .004) as independent risk factors for in-hospital mortality, whereas pathogen identification by preoperative blood cultures (OR, .228; 95% CI, 0.063-0.817; P = .023) was found to be independently protective.

CONCLUSIONS

Surgery for native IE and PVE of the aortic valve may be performed with satisfactorily results at experienced cardiac surgical centers. In comparison PVE patients suffer from a more than twice as high in-hospital mortality, more postoperative complications, and inferior long-term survival. However preoperative identification of causative pathogens in IE and PVE allows for improved in-hospital survival.

Late prosthetic valve endocarditis with Mycobacterium tuberculosis after the Bentall procedure

Background

Prosthetic valve endocarditis (PVE) is a rare but severe complication of valve replacement surgery, with an incidence rate of 0.3–1.2% per patient-year. At present, staphylococci are the predominant causative microorganism of PVE. Herein, we report a confirmed case of late PVE in a mechanical aortic valve caused by Mycobacterium tuberculosis.

Case presentation

A 32-year-old immunocompetent man with recurrent fever and 5-kg weight loss had a history of having undergone the Bentall procedure due to congenital heart disease. Nine years after the operation, he developed a paravalvular abscess in the mechanical aortic valve, presented with evidence of pulmonary tuberculosis on CT scan and was diagnosed with tuberculous endocarditis. This case report highlights a rare and non-negligible example of tuberculous endocarditis involving a mechanical valve.

Conclusions

Tuberculous PVE should be considered in patients with a history of valve replacement, recurrent fever, unexplained weight loss, pulmonary tuberculosis and meaningful valvular findings on echocardiogram.

Prosthetic valve endocarditis - A trouble or a challenge?

Prosthetic valve endocarditis (PVE) represents a rare and serious complication of valve replacement associated with high morbidity and mortality, which significantly differs from native valve endocarditis (NVE). There are two major problems: establishing diagnosis and treatment of PVE. Diagnosis in PVE is challenging and often requires several imaging methods besides standard microbiological analyzes. Transesophageal echocardiographic examination remains the widely used imaging technique in PVE diagnosis, but additional techniques such as computed tomography (CT) and ¹⁸F-fluodeoxyglucose positron emission tomography/CT are often necessary. Persistent fever, embolic complications, valve dehiscence, intracardial abscess, heart failure, as well as staphylococcal and fungal PVE require surgical treatment to avoid lethal outcome. The introduction of transcatheter valve implantations and devices significantly complicated the approach - diagnostic and therapeutic to PVE patients. Despite constantly increasing knowledge regarding pathogenesis and treatment of PVE, the optimal therapy remains a matter of debate. Additional studies are necessary to define therapeutic strategies for this potentially fatal complication.

Novel PET and Near Infrared Imaging Probes for the Specific Detection of Bacterial Infections Associated With Cardiac Devices

OBJECTIVES

The aim of this study was to develop imaging agents to detect early stage infections in implantable cardiac devices.

BACKGROUND

Bacteria ingest maltodextrins through the specific maltodextrin transporter. We developed probes conjugated with either a fluorescent dye (maltohexaose fluorescent dye probe [MDP]) or a F-18 (F18 fluoromaltohexaose) and determined their usefulness in a model of infections associated with implanted cardiac devices.

METHODS

Stainless steel mock-ups of medical devices were implanted subcutaneously in rats. On post-operative day 4, animals were injected with either Staphylococcus aureus around the mock-ups to induce a relatively mild infection or oil of turpentine to induce noninfectious inflammation. Animals with a sterile implant were used as control subjects. On post-operative day 6, either the MDP or F18 fluoromaltohexaose was injected intravenously, and the animals were scanned with the appropriate imaging device. Additional positron emission tomography imaging studies were performed with F18-fluorodeoxyglucose as a comparison of the specificity of our probes (n = 5 to 9 per group).

RESULTS

The accumulation of the MDP in the infected rats was significantly increased at 1 h after injection when compared with the control and noninfectious inflammation groups (intensity ratio 1.54 ± 0.07 vs. 1.26 ± 0.04 and 1.20 ± 0.05, respectively; p < 0.05) and persisted for more than 24 h. In positron emission tomography imaging, both F18 fluoromaltohexaose and F18 fluorodeoxyglucose significantly accumulated in the infected area 30 min after the injection (maximum standard uptake value ratio 4.43 ± 0.30 and 4.87 ± 0.28, respectively). In control rats, there was no accumulation of imaging probes near the device. In the noninfectious inflammation rats, no significant accumulation was observed with F18 fluoromaltohexaose, but F18 fluorodeoxyglucose accumulated in the mock-up area (maximum standard uptake value 2.53 ± 0.39 vs. 4.74 ± 0.46, respectively; p < 0.05).

CONCLUSIONS

Our results indicate that maltohexaose-based imaging probes are potentially useful for the specific and sensitive diagnosis of infections associated with implantable cardiac devices.

Comparison of prognoses of Staphylococcus aureus left-sided prosthetic endocarditis and prosthetic endocarditis caused by other pathogens

BACKGROUND

Staphylococcus aureus prosthetic valve endocarditis (SAPIE) is a serious disease.

AIMS

Our objective was to study the clinical, echocardiographic and prognostic characteristics of left-sided SAPIE, and to compare these characteristics with those of left-sided non-S. aureus prosthetic infective endocarditis (NSAPIE) (i.e. left-sided prosthetic infective endocarditis caused by another germ).

METHODS

This was a retrospective analysis of 35 cases of SAPIE among 247 cases of left-sided prosthetic valve endocarditis hospitalized at two university hospitals (Amiens and Marseille, France).

RESULTS

SAPIE accounted for 14.1% of the cases of left-sided prosthetic valve endocarditis. SAPIE complications included heart failure (in 42.8% of cases), acute renal failure (in 51.4%), sepsis (in 51.4%), neurological events (in 31.4%), systemic embolic event (in 34.2%) and abscess (in 60.0%). In-hospital mortality occurred in 48.5% of SAPIE cases compared with 16% of NSAPIE cases. A comparison of the SAPIE and NSAPIE groups showed a significant difference in terms of 4-year survival (31.8±7.3% vs 60.1±4.1%; P=0.001). Severe sepsis was the only prognostic factor associated with in-hospital mortality (odds ratio 5.7; P=0.03) and long-term mortality (odds ratio 3.7; P=0.01) in cases of SAPIE. Sepsis-induced multiple organ dysfunction syndrome was the main cause of in-hospital mortality (70.5%).

CONCLUSIONS

SAPIE is a very serious disease, with elevated in-hospital mortality resulting from sepsis-induced multiple organ dysfunction syndrome. Emergency surgery is recommended in these cases, when possible, before the occurrence of complications, especially severe sepsis.

A comparison of different antibiotic regimens for the treatment of infective endocarditis

BACKGROUND

Infective endocarditis is a microbial infection of the endocardial surface of the heart. Antibiotics are the cornerstone of treatment, but their use is not standardised, due to the differences in presentation, populations affected and the wide variety of micro-organisms that can be responsible.

OBJECTIVES

To assess the existing evidence about the clinical benefits and harms of different antibiotics regimens used to treat people with infective endocarditis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE Classic and EMBASE, LILACS, CINAHL and the Conference Proceedings Citation Index on 30 April 2015. We also searched three trials registers and handsearched the reference lists of included papers. We applied no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of antibiotic regimens for treating possible infective endocarditis diagnosed according to modified Duke's criteria. We considered all-cause mortality, cure rates and adverse events as the primary outcomes. We excluded people with possible infective endocarditis and pregnant women.

DATA COLLECTION AND ANALYSIS

Three review authors independently performed study selection, 'Risk of bias' assessment and data extraction in duplicate. We constructed 'Summary of findings' tables and used GRADE methodology to assess the quality of studies. We described the included studies narratively.

MAIN RESULTS

Four small randomised controlled trials involving 728 allocated/224 analysed participants met our inclusion criteria. These trials had a high risk of bias. Drug companies sponsored two of the trials. We were unable to pool the data due to the heterogeneity in outcome definitions and the different antibiotics used.The included trials compared the following antibiotic schedules. The first trial compared quinolone (levofloxacin) plus standard treatment (anti-staphylococcal penicillin (cloxacillin or dicloxacillin), aminoglycoside (tobramycin or netilmicin) and rifampicin) versus standard treatment alone reporting uncertain effects on all-cause mortality (8/31 (26%) with levofloxacin plus standard treatment versus 9/39 (23%) with standard treatment alone; RR 1.12, 95% CI 0.49 to 2.56, very low quality evidence). The second trial compared daptomycin versus low-dose gentamicin plus an anti-staphylococcal penicillin (nafcillin, oxacillin or flucloxacillin) or vancomycin. This showed uncertain effects in terms of cure rates (9/28 (32.1%) with daptomycin versus 9/25 (36%) with low-dose gentamicin plus anti-staphylococcal penicillin or vancomycin, RR 0.89 95% CI 0.42 to 1.89; very low quality evidence). The third trial compared cloxacillin plus gentamicin with a glycopeptide (vancomycin or teicoplanin) plus gentamicin. In participants receiving gentamycin plus glycopeptide only 13/23 (56%) were cured versus 11/11 (100%) receiving cloxacillin plus gentamicin (RR 0.59, 95% CI 0.40 to 0.85; very low quality evidence). The fourth trial compared ceftriaxone plus gentamicin versus ceftriaxone alone and found no conclusive differences in terms of cure (15/34 (44%) with ceftriaxone plus gentamicin versus 21/33 (64%) with ceftriaxone alone, RR 0.69, 95% CI 0.44 to 1.10; very low quality evidence).The trials reported adverse events, need for cardiac surgical interventions, uncontrolled infection and relapse of endocarditis and found no conclusive differences between comparison groups (very low quality evidence). No trials assessed septic emboli or quality of life.

AUTHORS' CONCLUSIONS

Limited and very low quality evidence suggested that there were no conclusive differences between antibiotic regimens in terms of cure rates or other relevant clinical outcomes. However, because of the very low quality evidence, this needs confirmation. The conclusion of this Cochrane review was based on randomised controlled trials with high risk of bias. Accordingly, current evidence does not support or reject any regimen of antibiotic therapy for treatment of infective endocarditis.

Resistance to infection of long-term cryopreserved human aortic valve allografts

OBJECTIVE

To analyze the in vitro antimicrobial activity of 3 antibiotic regimens (group A, gentamicin-piperacillin-vancomycin-metronidazole-amphotericin B; group B, gentamicin-piperacillin-flucloxacillin-metronidazole-amphotericin B; and group C, meropenem-vancomycin-tobramycin-colistin-amphotericin B) used in the processing of cryopreserved human ascending aortic tissue and aortic valves against Staphylococcus epidermidis and Staphylococcus aureus. The results were additionally compared with the infection resistance of cryopreserved ascending aortic tissue against Escherichia coli and Pseudomonas aeruginosa.

MATERIALS

Each of 10 cryopreserved human allografts (CHAs) was divided into 25 pieces (separating aortic wall and valve). Eighteen segments were microbiologically tested, and 7 pieces underwent scanning electron microscopy. A bacterial solution (4 mL; optical density, 0.20 ± 0.02) was used for contamination. After incubation, the optical density of the solution was measured. CHAs underwent sonication to release viable adherent bacteria. The number of attached bacteria was quantified by the colony forming units per square centimeter of CHA surface.

RESULTS

Antibiotic regimen groups B and C were more efficient than group A in eradicating gram-positive organisms adherent to the aortic wall (P < .001). Group C showed enhanced resistance against E coli compared with group A or B (P < .001), whereas group B appeared to be more effective against P aeruginosa (P < .001). With reference to each antibiotic regimen, ascending aortic tissue showed significantly less bacterial contamination with staphylococcal bacteria than valve grafts (P ≤ .01).

CONCLUSIONS

CHAs possess antibacterial activity despite long-term storage over 5 years. Antibiotic combinations applied during CHA processing have a significant influence on their infection resistance. Ascending aortic tissue shows a significantly enhanced bacterial resistance against staphylococcal bacteria compared with aortic valves.

Total Artificial Heart as Bridge to Transplantation for Severe Culture-Negative Prosthetic Valve Endocarditis Due to Gemella haemolysans

We report a rare case of a patient with prosthetic valve endocarditis (PVE) requiring implantation of a total artificial heart (TAH) as a bridge to heart transplantation. Gemella haemolysans, an unusual cause of PVE, was identified as the organism responsible only by 16s rRNA polymerase chain reaction analysis of surgical tissue samples. We also describe one of the first uses of combined TAH and veno-venous extracorporeal membrane oxygenation therapy in the setting of severe respiratory and cardiac failure. Implantation of a TAH may be considered in situations where more traditional reconstructive methods are not feasible.

Strategies for combating bacterial biofilm infections

Formation of biofilm is a survival strategy for bacteria and fungi to adapt to their living environment, especially in the hostile environment. Under the protection of biofilm, microbial cells in biofilm become tolerant and resistant to antibiotics and the immune responses, which increases the difficulties for the clinical treatment of biofilm infections. Clinical and laboratory investigations demonstrated a perspicuous correlation between biofilm infection and medical foreign bodies or indwelling devices. Clinical observations and experimental studies indicated clearly that antibiotic treatment alone is in most cases insufficient to eradicate biofilm infections. Therefore, to effectively treat biofilm infections with currently available antibiotics and evaluate the outcomes become important and urgent for clinicians. The review summarizes the latest progress in treatment of clinical biofilm infections and scientific investigations, discusses the diagnosis and treatment of different biofilm infections and introduces the promising laboratory progress, which may contribute to prevention or cure of biofilm infections. We conclude that, an efficient treatment of biofilm infections needs a well-established multidisciplinary collaboration, which includes removal of the infected foreign bodies, selection of biofilm-active, sensitive and well-penetrating antibiotics, systemic or topical antibiotic administration in high dosage and combinations, and administration of anti-quorum sensing or biofilm dispersal agents.

A case of prosthetic valve endocarditis caused by Streptococcus constellatus as a rare agent of endocarditis

We present a case of prosthetic valve endocarditis, which was caused by a rare etiological agent, Streptococcus constellatus. In our case, transesophageal echocardiography showed a large and broad abscess formation throughout the patient's aortic prosthetic valve ring and left atrium. Despite specific intravenous antibiotic therapy, the infection was uncontrollable, and the patient underwent surgical treatment. The pathogen rarely causes endocarditis, but it is known to have a strong potential to form abscess, and therefore its infection may be more serious than other Streptococcus species. Our case seems to be the first report of surgical treatment of PVE caused by S. constellatus. As in our case, transesophageal echocardiography is useful for the detection of vegetation and abscess, and early cardiac surgery may be a more appropriate therapeutic approach for endocarditis caused by S. constellatus.

Clinical significance of congestive heart failure in prosthetic valve endocarditis. A multicenter study with 257 patients

INTRODUCTION AND OBJECTIVES

There have been no studies conducted in the past that focus on the significance of congestive heart failure in patients with prosthetic valve endocarditis. We studied the incidence of congestive heart failure in patients with prosthetic valve endocarditis and analyzed its profile. In this study, we addressed the prognostic significance of heart failure in patients with prosthetic valve endocarditis and analyzed its outcome based on chosen therapeutic strategies.

METHODS

A total of 639 episodes of definite left-sided endocarditis were prospectively enrolled. Of them, 257 were prosthetic. Of the 257 episodes, 145 (56%) were diagnosed with heart failure. We compared the profiles of patients with prosthetic valve endocarditis based on the presence of heart failure, and performed a multivariate logistic regression model to establish the prognostic significance of heart failure in patients with prosthetic valve endocarditis and identified the prognostic factors of in-hospital mortality in these patients.

RESULTS

Persistent infection (odds ratio=3.6; 95% confidence interval, 1.9-6.9) and heart failure (odds ratio=3; 95% confidence interval, 1.5-5.8) are the strongest predictive factors of in-hospital mortality in patients with prosthetic valve endocarditis. The short-term determinants of prognosis in patients with prosthetic valve endocarditis and heart failure are persistent infection (odds ratio=2.8; 95% confidence interval, 1.2-6.5), aortic involvement (odds ratio=2.5; 95% confidence interval, 1.1-5.8), abscess (odds ratio=3.6; 95% confidence interval, 1.4-9.5), diabetes mellitus (odds ratio=2.9; 95% confidence interval, 1.1-7.7), and cardiac surgery (odds ratio=0.2; 95% confidence interval, 0.1-0.5).

CONCLUSIONS

The incidence of heart failure in patients with prosthetic valve endocarditis is very high. Heart failure increases the risk of in-hospital mortality by threefold in patients with prosthetic valve endocarditis. Persistent infection, aortic involvement, abscess, and diabetes mellitus are the independent risk factors associated with mortality in patients with prosthetic valve endocarditis and heart failure; however, cardiac surgery is shown to decrease mortality in these patients.

Left ventricular pseudoaneurysm following aortic valve prosthesis endocarditis

A 63-year-old man underwent aortic valve replacement and an early reoperation for recurrent endocarditis. Sixteen months later he presented with persistent fever and a 64-slice computed tomography (CT) scan revealed a subannular left ventricular pseudoaneurysm. He underwent successful left ventricular outflow tract reconstruction and aortic valve prosthesis, partial root and ascending aorta replacement.

Bacterial invasion of vascular cell types: vascular infectology and atherogenesis

To portray the chronic inflammation in atherosclerosis, leukocytic cell types involved in the immune response to invading pathogens are often the focus. However, atherogenesis is a complex pathological deterioration of the arterial walls, where vascular cell types are participants with regards to deterioration and disease. Since other recent reviews have detailed the role of both the innate and adaptive immune response in atherosclerosis, herein we will summarize the latest developments regarding the association of bacteria with vascular cell types: infections as a risk factor for atherosclerosis; bacterial invasion of vascular cell types; the atherogenic sequelae of bacterial presence such as endothelial activation and blood clotting; and the identification of the species that are able to colonize this niche. The evidence of a polybacterial infectious component of the atheromatous lesions opens the doors for exploration of the new field of vascular infectology and for the study of atherosclerosis microbiome.

Usefulness of fluorine-18 fluorodeoxyglucose PET/computed tomography in diagnosis of aortitis and treatment response evaluation in a patient with aortic prosthesis

We report the case of an 82-year-old man with aortic prosthesis inflammation in whom fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography has been useful in the detection of the cause of fever of unknown origin. We also describe the correlation between decrease of FDG uptake in the vascular prosthesis after treatment and clinical improvement with normalization of the serological levels of inflammatory markers.

The use of whole-cell protein profile analysis by SDS-PAGE as an accurate tool to identify species and subspecies of coagulase-negative staphylococci

We used sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) as a tool to characterize coagulase-negative staphylococci (CoNS). Of 253 clinical isolates and 10 control strains, five species and four subspecies were analyzed. All the isolates were identified using conventional phenotypic tests and SDS-PAGE. Discrepant results between these methods, as well as less common species and subspecies, were confirmed by sodA and 16S rDNA gene sequencing. Intraspecies similarities, calculated by the Dice coefficient, were significantly higher when compared to interspecies similarities. The conventional method failed to identify eight (3.2%) molecularly defined and SDS-PAGE-determined isolates. Therefore, SDS-PAGE was able to discriminate between all unidentified or misidentified isolates using a phenotypic method. In addition, SDS-PAGE identified all atypical isolates using biochemistry and CoNS at the subspecies level.

Streptococcus pneumoniae endocarditis on replacement aortic valve with panopthalmitis and pseudoabscess

A 63-year-old woman with a previous episode of Streptococcus agalactiae endocarditis requiring a bioprosthetic aortic valve replacement presented with a short history of malaise, a right panopthalmitis with a Roth spot on funduscopy of the left eye and Streptococcus pneumoniae grown from vitreous and aqueous taps as well as blood cultures. She developed first degree heart block and her ECG was suggestive of an aortic root abscess. This gradually resolved over 6 weeks, during which she was treated with intravenous antibiotics. After careful consideration, it is likely that what was thought to be an aortic root abscess was instead an area of perivalvular inflammation.