Early Prosthetic Valve Endocarditis with Mycobacterium Tuberculosis after Mitral Valve Replacement: A Case Report

Background: Tuberculous endocarditis is a rare but serious complication of heart valve replacement surgery. We report the case of a 24-year-old patient, who presented with tuberculous endocarditis after mechanical mitral valve replacement, with a favorable clinical course following anti-tuberculosis treatment. Case Presentation: We report a 24-year-old male patient, admitted to the cardiac surgery department of the Fann Hospital (Dakar, Senegal), for the management of severe mixed (rheumatic and endocarditic) mitral insufficiency with associated tricuspid insufficiency. He had a history of recurrent angina and polyarthralgia in childhood, was hospitalized several times for refractory global cardiac decompensation, and for a suspected infective endocarditis a month before his admission. On admission, the clinical examination revealed signs suggestive of mitral and tricuspid insufficiency. Transthoracic echocardiography revealed severe post-endocarditic mitral insufficiency with A3 amputation, highly mobile 15 mm vegetations on the free edge of the large valve, moderate tricuspid insufficiency, and severe pulmonary artery hypertension. Mechanical mitral valve replacement and tricuspid valve annuloplasty using autologous pericardial strip were performed via median sternotomy. After ten days, the patient presented with global cardiac decompensation associated with a clinico-biological infectious syndrome, and tans-oesophageal echography revealed an abscess at the sinotubular junction, communicating with the aorta. A thoraco-abdomino-pelvic CT scan was done, which revealed a bilateral alveolar-interstitial syndrome with mediastinal lymphadenopathy. Anti-tuberculosis treatment with RHZE was initiated for 06 months. The clinical course was favorable. Conclusion: Tuberculous endocarditis in prostheses is a serious complication of heart valve replacement surgery, which may evolve favorably under medical treatment.

Profile of Prosthetic Care Consumers at the Institute of Odontology and Stomatology Clinic of Dakar

The high frequency of dental extractions creates a high demand for prosthetic rehabilitation. Therefore, this study aimed to describe the profile of consumers of prosthetic care at the Institute of Odontology and Stomatology in Dakar. It was a descriptive and retrospective study of patients who had been consulted at the prosthetic clinic of the Institute of Odontology and Stomatology of Dakar. Data were collected from medical records from 09 November 2019 to 09 June 2020. The tools used to collect and process the information were the Sphinx software and the Excel spreadsheet. Out of the 101 patient records, 51% were male and 48% belonged to the age group of 18 to 39 years. Nearly 38.61% of the patients lived less than 5 km from the health care facility and 70.3% of the respondents had a monthly income of fewer than 100,000 FCFA. Clinically, 96% of patients came for functional reasons, 78.2% for aesthetic reasons, and partial edentulism was the most frequent diagnosis (96%). Chi-square tests were performed to find a dependency or non-dependency relationship between diagnosis and age, but also between income and treatment cost. In sum, age and diagnosis were independent of each other, just as patient income was not related to treatment cost. Proximity to health facilities, income, and cost of treatment are factors that influence accessibility to oral health care. It is important to integrate the profile of the consumer of care into global management.

Risk of methicillin-resistant Staphylococcus aureus prosthetic joint infection in elective total hip and knee arthroplasty following eradication therapy

Re-screening following methicillin-resistant Staphylococcus aureus(MRSA) decolonization will be helpful to minimize the development of prosthetic joint infection among MRSA colonizers.

Dynamic Analysis and Performance Verification of a Novel Hip Prosthetic Mechanism

To assist an amputee in regaining his or her daily quality of life,based on analysis of the motion characteristics of the human hip,a 2-UPR/URR parallel mechanism with a passive limb was designed.The inverse kinematics of this mechanism was analyzed based on a closed-loop vector method.The constrained Jacobian matrix and kinematic Jacobian matrix of each limb were then analyzed,and a 6×6 fully Jacobian matrix was constructed.Based on this,kinematic performances were analyzed and summarized.Finally,the dynamic model of the mechanism was constructed based on the virtual work principle,and its theoretical solution was compared with the numerical results,which were obtained in a simulation environment.Results showed that the prosthetic mechanism had a larger rotating workspace and better mechanical performance,which accorded a range of motion and bearing capacity similar to that of the human hip in multiple gait modes.Moreover,the validity of the dynamic model and inverse kinematics were verified by comparing the theoretical and simulation results.Furthermore,with flexion and extension,the torque change in the hip prosthetic mechanism was similar to that of the human hip,which demonstrated the feasibility of the hip prosthetic mechanism and its good dynamic performance.

Obstructive shock secondary to fungal prosthetic aortic valve endocarditis

Dear editor,Fungal endocarditis is a rare disease with a poor prognosis,suboptimal diagnostic tools responsible for long diagnostic delays in most cases,and poorly defined activity of most antifungal agents in endocarditis.^([1])The burden of diagnosis still lies with clinicians:they need a

Molecularly specific detection of bacterial lipoteichoic acid for diagnosis of prosthetic joint infection of the bone

Discriminating sterile inflammation from infection, especially in cases of aseptic loosening versus an actual prosthetic joint infection, is challenging and has significant treatment implications. Our goal was to evaluate a novel human monoclonal antibody（mAb） probe directed against the Gram-positive bacterial surface molecule lipoteichoic acid（LTA）. Specificity and affinity were assessed in vitro. We then radiolabeled the anti-LTA mAb and evaluated its effectiveness as a diagnostic imaging tool for detecting infection via immuno PET imaging in an in vivo mouse model of prosthetic joint infection（PJI）. In vitro and ex vivo binding of the anti-LTA mAb to pathogenic bacteria was measured with Octet, ELISA, and flow cytometry. The in vivo PJI mouse model was assessed using traditional imaging modalities, including positron emission tomography（PET） with [^（18）F]FDG and [^（18）F]Na F as well as X-ray computed tomography（CT）, before being evaluated with the zirconium-89-labeled antibody specific for LTA（[^（89）Zr]SAC55）.The anti-LTA mAb exhibited specific binding in vitro to LTA-expressing bacteria. Results from imaging showed that our model could reliably simulate infection at the surgical site by bioluminescent imaging, conventional PET tracer imaging, and bone morphological changes by CT. One day following injection of both the radiolabeled anti-LTA and isotype control antibodies, the anti-LTA antibody demonstrated significantly greater（P 〈 0.05） uptake at S. aureus-infected prosthesis sites over either the same antibody at sterile prosthesis sites or of control non-specific antibody at infected prosthesis sites. Taken together, the radiolabeled anti-LTA mAb, [^（89）Zr]SAC55, may serve as a valuable diagnostic molecular imaging probe to help distinguish between sterile inflammation and infection in the setting of PJI. Future studies are needed to determine whether these findings will translate to human PJI.

Left atrial thrombosis in an anticoagulated patient after bioprosthetic valve replacement:Report of a case

We present the case of a 74 year old woman suffering from severe mitral valve incompetence and rapid atrial fibrillation. After an appropriate vitamin K antagonist(VKA) therapy, the patient underwent mitral valve replacement by bioprosthesis. Then, the patient was rehospitalized for jaundice. Suspecting hepatotoxicity, VKA was discontinued and fondaparinux was started. During this treatment, the patient developed a symptomatic atrial thrombus. After exclusion of a hepatic disease, VKA was re-established with hemodynamic and liver enzymes normalization and atrial thrombus resolution. Caution has to be used when considering fondaparinux as an alternative strategy to VKA in patients with multiple thrombotic risk factors.

Non-albicans Candida prosthetic joint infections: A systematic review of treatment

BACKGROUND Non-albicans Candida prosthetic joint infections (PJIs) are rare. Optimal treatment involves a two-stage revision surgery in combination with an antifungal agent. However, no clear guidelines have been developed regarding the agent or treatment duration. Hence, a broad range of antifungal and surgical treatments have been reported so far. AIM To clarify treatment of non-albicans Candida PJIs. METHODS A literature review of all existing non-albicans Candida PJIs cases through April 2018 was conducted. Information was extracted about demographics, comorbidities, responsible species, duration and type of antifungal treatment, type of surgical treatment, time between initial arthroplasty and symptom onset, time between symptom onset and definite diagnosis, outcome of the infection and follow-up. RESULTS A total of 83 cases, with a mean age of 66.3 years, were located. The causative yeast isolated in most cases was C. parapsilosis (45 cases;54.2%), followed by C. glabrata (18 cases;21.7%). The mean Charlson comorbidity index was 4.4 ± 1.5. The mean time from arthropalsty to symptom onset was 27.2 ± 43 mo, while the mean time from symptom onset to culture-confirmed diagnosis was 7.5 ± 12.5 mo. A two stage revision arthroplasty (TSRA), when compared to one stage revision arthroplasty, had a higher success rate (96% vs 73%, P = 0.023). Fluconazole was the preferred antifungal agent (59;71%), followed by amphotericin B (41;49.4%). CONCLUSION The combination of TSRA and administration of prolonged antifungal therapy after initial resection arthroplasty is suggested on the basis of limited data.

Horseshoe thrombus in a patient with mechanical prosthetic mitral valve: A case report and review of literature

Patients with prosthetic cardiac valves are at high risk for thromboembolic complications and need life long anticoagulation with warfarin, which can be associated with variable dose requirements and fluctuating level of systemic anticoagulation and may predispose to thromboembolic and or hemorrhagic complications. Prosthetic cardiac valve thrombosis is associated with high morbidity and mortality. A high index of suspicion is essential for prompt diagnosis. Transthoracic echocardiography, and if required transesophageal echocardiography are the main diagnostic imaging modalities. Medically stable patients can be managed with thrombolytic therapy and anticoagulation, while some patients may require surgical thrombectomy or valve replacement. We present a case report of a patient with prosthetic mitral valve and an unusually large left atrial thrombus with both thromboembolic and hemorrhagic complications.

Risk of methicillin-resistant staphylococcus aureus prosthetic joint infection in elective total hip and knee arthroplasty following eradication therapy

BACKGROUND Prosthetic joint infection(PJI)is a devastating complication requiring prolonged treatment and multiple operations,leading to significant morbidity for the patient.Patients are routinely tested for methicillin-resistant staphylococcus aureus(MRSA)colonisation.MRSA positive patients are given eradication therapy.We hypothesise that patients who are MRSA positive pre-operatively,have increased risk of developing PJI.AIM To identify deep wound infection(PJI)rates in patients who are colonised MRSA positive compared with those who are not colonised;and long term clinical and radiological outcomes.METHODS All patients who underwent total hip and knee replacements(THR/TKR)between December 2009 and December 2019 were identified.Patients who were also identified as being MRSA positive at pre-operative assessment were then selected.Confirmation of prescribing eradication treatment was recorded.Patient records,including consultation letters,operation notes and microbiology results were reviewed retrospectively.Comparison of outcomes for each MRSA positive patient was made with 2 MRSA negative patients undergoing the same operation of a similar age by the same consultant.RESULTS Screening identified 42 knee and 32 hip arthroplasty patients as MRSA positive,84 MRSA negative knee and 64 hip patients were reviewed.Patients were matched with medical co-morbidities in each group.Mean follow up was 5 years.PJI was identified in 4/32(12.5%)of THR MRSA positive and 3/42(7%)of TKR patients.All patients had PJI within one year of surgery.CONCLUSION MRSA positive patients are given eradication therapy routinely.However,no confirmation of eradication is sought.Patients who have MRSA colonisation preoperatively,in our study had a significantly increased risk of PJI,when compared to negative patients.We would recommend establishing true eradication after treatment prior to arthroplasty.

Technetium-99m-labeled annexin V imaging for detecting prosthetic joint infection in a rabbit model

Accurate and timely diagnosis of prosthetic joint infection is essential to initiate early treatment and achieve a favorable outcome. In this study, we used a rabbit model to assess the feasibility of technetium-99m-labeled annexin V for detecting prosthetic joint infection. Right knee arthroplasty was performed on 24 New Zealand rabbits. After surgery, methicillin-susceptible Staphylococcus aureus was intra-articularly injected to create a model of prosthetic joint infection （the infected group, n = 12）. Rabbits in the control group were injected with sterile saline （n= 12）. Seven and 21 days after surgery, technetium-99m-labeled annexin V imaging was per- formed in 6 rabbits of each group. Images were acquired 1 and 4 hours after injection of technetium-99m- labeled annexin V （150 MBq）. The operated-to-normal-knee activity ratios were calculated for quantitative ana- lysis. Seven days after surgery, increased technetium-99m-labeled annexin V uptake was observed in all cases. However, at 21 days a notable decrease was found in the control group, but not in the infected group. The operated-to-normal-knee activity ratios of the infected group were 1.84 ±0.29 in the early phase and 2.19 ±0.34 in the delay phase, both of which were significantly higher than those of the control group （P=0.03 and P=0.02）. The receiver operator characteristic curve analysis showed that the operated-to-normal-knee activity ratios of the delay phase at 21 days was the best indicator, with an accuracy of 80%. In conclusion, technetium- 99m-labeled annexin V imaging could effectively distinguish an infected prosthetic joint from an uninfected prosthetic joint in a rabbit model.

Univariate Risk Factors for Prolonged Mechanical Ventilation in Patients Undergoing Prosthetic Heart Valves Replacement Surgery

Data from 736 patients undergoing prosthetic heart valve replacement surgery and concomitant surgery （combined surgery） from January 1998 to January 2004 at Union Hospital were retrospectively reviewed. Univariate logistic regression analyses were conducted to identity risk factors for prolonged mechanical ventilation. The results showed that prolonged cardiopulmonary bypass duration, prolonged aortic cross clamp time and low ejection fraction less than 50 percent （50 %） were found to be independent predictors for prolonged mechanical ventilation. Meanwhile age, weight, and preoperative hospital stay （days） were not found to be associated with prolonged mechanical ventilation. It was concluded that. for age and weight, this might be due to the lower number of old age patients （70 years and above） included in our study and genetic body structure of majority Chinese population that favor them to be in normal weight, respectively.

Multimodality imaging in the diagnosis and management of prosthetic valve endocarditis:A contemporary narrative review

Infective endocarditis is one of the leading life-threatening infections around the world.With the exponential growth in the field of transcatheter interventions and advances in specialized surgical techniques,the number of prosthetic valves and cardiac implantable devices has significantly increased.This has led to a steep rise in the number of cases of prosthetic valve endocarditis(PVE)comprising up to 30%of all cases.Clinical guidelines rely on the use of the modified Duke criteria;however,the diagnostic sensitivity of the modified Duke criteria is reduced in the context of PVE.This is in part attributed to prosthesis related artifact which greatly affects the ability of echocardiography to detect early infective changes related to PVE in certain cases.There has been increasing recognition of the roles of complementary imaging modalities and updates in international society recommendations.Prompt diagnosis and treatment can prevent the devastating consequences of this condition.Imaging modalities such as cardiac computed tomography and 18-fluorodeoxyglucose positron emission tomography/computed tomography are diagnostic tools that provide a complementary role to echocardiography in aiding diagnosis,pre-operative planning,and treatment decisionmaking process in these challenging cases.Understanding the strengths and limitations of these adjuvant imaging modalities is crucial for the implementation of appropriate imaging modalities in clinical practice.

Prosthetic joint infections-a clinico-microbiological perspective: Review article

Prosthetic joint infections(PJIs),although not very common,currently pose a very significant threat since they are associated with severe complications,high morbidity rates and substantial costs.PJIs are most commonly caused by Staphylococcus aureus and coagulase-negative staphylococci.The diagnosis of implant-associated infections is very challenging since no single routinely used laboratory or clinical test has been shown to demonstrate adequate results with respect to sensitivity,specificity and accuracy.In most cases,a sum of clinical signs and symptoms,histopathology,blood tests,radiography,bone scans and microbiological testing is considered to arrive at an accurate diagnosis.Treatment of PJIs is also very difficult since most of the infections are caused by biofilm-producing microorganisms which are significantly more resistant to the hosts natural defense mechanisms and antibiotic treatment.For successful management,a combination of both antibiotic and surgical treatment is most often required,and early diagnosis is of the utmost importance.Thus,a multidisciplinary approach is potentially the best option in dealing with PJI,and should include the involvement of microbiologists,orthopedic specialists,clinicians,pathologists and radiologists in order to improve decision-making processes and ensure overall success.The following review aims at briefly outlining the microbiology,diagnostic and treatment options,and preventive measures associated with such infections.

Status of Oral Prosthetic Rehabilitation of Edentulism at the University Clinics of Kinshasa (CUK), DR Congo

Objective: The present work aimed to identify the most common edentulousness and prosthesis type (prosthetic treatment), to improve the management in oral prosthetic rehabilitation in DR Congo. Material and Methods: It was a documentary, longitudinal, and retrospective study of the medical records of edentulous patients admitted to the prosthetic service of the Dental Department/Kinshasa University from January 1983 to December 2020. Age, sex, cause of teeth loss, and prosthetic treatment (partial removable prosthesis, complete removable prosthesis) were evaluated. The Chare square test was performed to compare significant differences between the variables and the P-value < 0.05 was set as significant. Results: One thousand six hundred and ninety patients in that 901 were men (47 ± 16 years) and 789 women (42 ± 15 years) had undergone prosthetic treatment. One thousand eight hundred and forty-four edentulous teeth were viewed according to the Kennedy classification. Kennedy class 1 was the most predominant (61.4%) followed by Kennedy class 3 (24.8%). Two thousand one hundred and ninety-one prostheses were performed. The removable partial prosthesis with plate (acrylic resin) was the most performed (78.8%;n = 1727) and followed by the joint (17.4%;n = 384). Dental caries (52.6%) and periodontitis (36.4%) were the main causes of these edentulous teeth. Conclusion: The present study showed that edentulism is becoming a concern for the implementation of a real oral health policy.

Tensile and Stress Analysis of Hybrid Composite Prosthetic Socket Reinforced with Natural Fibers

Natural fibers and their composites are the evolving movements in material science,and with that,the utmost use of plant-based fibers has become the focus of this research.Sisal and cotton natural fibers were used to construct a prosthetic socket as an attempt to substitute material currently available in the manufacturing of sockets.The vacuum bagging technique was adopted to produce a below-knee socket.The influence of different fiber layering sequences on the volumetric and mechanical characteristics was estimated experimentally and numerically.Mechanical tensile tests were used to assess laminated specimens,such as tensile strength,young modulus,and elongation percentage.The number and type of reinforcing layers had an effect on mechanical properties,and the best composite specimens were three layers of sisal with two layers of carbon fiber,with tensile strength and modulus of elasticity reaching(261–4760)MPa,respectively.The finite element method(ANSYS-16.1)was used to anatomize by seeing the contours distribution of safety factor,equivalent Von Mises stress,equivalent Von Mises strain,and total deformation.This procedure was executed by building ten models for the socket,which served as three-dimensional structural composite materials.The results of the present study advocate that the arrangement of natural and synthetic reinforcements allow the preparation of bio-composites with enhanced performance.This work revealed the assets of sisal and cotton fiber hybrid reinforced PMMA resin composites(hybridized at diverse volume percentages and lamination layup),which have not been tried up to now.

Limitations of multimodality imaging in the diagnosis of pannus formation in prosthetic aortic valve and review of the literature

Pannus formation is a rare complication and occurs almost exclusively in mechanical prosthetic valves.It consists of fibrous tissue that covers the surface of the prosthesis either concentrically or eccentrically,resulting in valve dysfunction.The pathophysiology seems to be associated to a chronic inflammatory process that explains the late and insidious clinical presentation.This diagnosis should be considered in patients with high transvalvular gradients on transthoracic echo,and workup should be completed with fluoroscopy and transesophageal echocardiography.Treatment is always surgical and recurrence is rare.We present a case of pannus formation in a prosthetic aortic valve and a review of the literature regarding this disorder.

One-stage revision in two cases of Salmonella prosthetic hip infection

We describe two cases of prosthetic joint infection(PJI) of the hip due to Salmonella. The first patient presented with an early infection 5 d after being discharged following a total hip replacement and the second patient presented at the emergency ward with a late infection, thirteen years following a total hip replacement. Both cases occurred within one month of each other at our institution and both were successfully treated with a one-stage revision. PJI caused by Salmonella species is very rare: so far only 20 Salmonella PJIs of the hip have been described. Therefore, full consensus on the best treatment approach has not yet been reached. An aggressive two-stage approach is advised because of the virulence of Salmonella, although a limited number of successful one-stage approaches have been describedas well. According to the latest guidelines, one-stage revision has comparable success rates and less morbidity compared to two-stage treatment, when selecting the right patients. In our opinion, PJI caused by Salmonella should be treated just as PJI caused by other bacteria, with consideration of the selection criteria as mentioned in several treatment guidelines. As illustrated by these two cases, one-stage revision can be successful in both early and late Salmonella PJI of the hip.

Role of radionuclide imaging for diagnosis of device and prosthetic valve infections

Cardiovascular implantable electronic device(CIED) infection and prosthetic valve endocarditis(PVE) remain a diagnostic challenge.Cardiac imaging plays an important role in the diagnosis and management of patients with CIED infection or PVE.Over the past few years,cardiac radionuclide imaging has gained a key role in the diagnosis of these patients,and in assessing the need for surgery,mainly in the most difficult cases.Both ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG PET/CT) and radiolabelled white blood cell single-photon emission computed tomography/computed tomography(WBC SPECT/CT) have been studied in these situations.In their 2015 guidelines for the management of infective endocarditis,the European Society of Cardiology incorporated cardiac nuclear imaging as part of their diagnostic algorithm for PVE,but not CIED infection since the data were judged insufficient at the moment.This article reviews the actual knowledge and recent studies on the use of ^(18)F-FDG PET/CT and WBC SPECT/CT in the context of CIED infection and PVE,and describes the technical aspects of cardiac radionuclide imaging.It also discusses their accepted and potential indications for the diagnosis and management of CIED infection and PVE,the limitations of these tests,and potential areas of future research.

A Palladium Based Alloy for Prosthetic Dentistry: Structure and Properties

Using the results of physical and chemical researches and mechanical tests of the Pd-Au-Cu-Sn system alloys, a new palladium-based alloy has been chosen and studied in detail. It has a higher plasticity and a lower hardness than the Palladent alloy, widely used in prosthetic dentistry: its hardness is lower than 300 MPa, and its specific elongation is 10%~14 %. At the same time, such important practical characteristics of the alloys as the strength of adhesion to ceramics and thermal expansion coefficient are almost similar.