Suppressive antibiotic therapy for infectious endocarditis.

OBJECTIVES: Suppressive antibiotic therapy (SAT) is a long-term antibiotic strategy at times applied when an indicated surgical management of infective endocarditis (IE) is not possible. Our aim was to describe the characteristics and outcomes of patients having received SAT for IE. METHODS: We conducted a retrospective, observational study at Strasbourg University Hospital, France between January 2020 and May 2023. We reviewed all medical files taken into consideration at weekly meetings of the local Multidisciplinary Endocarditis Team (MET) during the study period. We included patients having received SAT following the MET evaluation. The primary endpoint was all-cause mortality at most recent follow-up. Secondary endpoints included all-cause mortality at 3 and 6 months, infection relapse, and tolerance issues attributed to SAT. RESULTS: The MET considered 251 patients during the study time, among whom 22 (9 %) had received SAT. Mean age was 77.2 ± 12.3 years. Patients were highly comorbid with a mean Charlson index score of 6.6 ± 2.5. Main indication for SAT was surgery indicated but not performed or an infected device not removed (20/22). Fourteen patients had prosthetic valve IE, including 9 TAVIs. Six patients had IE affecting cardiac implantable electronic devices. Staphylococcus aureus and enterococci were the main bacteria involved (6/22 each). Median follow-up time was 249 days (IQR 95-457 days). Mortality at most recent follow-up was 23 % (5/22). Three patients (14 %) presented tolerance issues attributed to SAT, and two patients suffered late infectious relapse. CONCLUSION: Mortality at most recent follow-up was low and tolerance issues were rare for patients under SAT, which might be a palliative approach to consider when optimal surgery or device removal is not possible.

Multimodality Imaging of Infective Endocarditis.

Infective endocarditis (IE) is a complex multisystemic disease resulting from infection of the endocardium, the prosthetic valves, or an implantable cardiac electronic device. The clinical presentation of patients with IE varies, ranging from acute and rapidly progressive symptoms to a more chronic disease onset. Because of its severe morbidity and mortality rates, it is necessary for radiologists to maintain a high degree of suspicion in evaluation of patients for IE. Modified Duke criteria are used to classify cases as "definite IE," "possible IE," or "rejected IE." However, these criteria are limited in characterizing definite IE in clinical practice. The use of advanced imaging techniques such as cardiac CT and nuclear imaging has increased the accuracy of these criteria and has allowed possible IE to be reclassified as definite IE in up to 90% of cases. Cardiac CT may be the best choice when there is high clinical suspicion for IE that has not been confirmed with other imaging techniques, in cases of IE and perivalvular involvement, and for preoperative treatment planning or excluding concomitant coronary artery disease. Nuclear imaging may have a complementary role in prosthetic IE. The main imaging findings in IE are classified according to the site of involvement as valvular (eg, abnormal growths [ie, "vegetations"], leaflet perforations, or pseudoaneurysms), perivalvular (eg, pseudoaneurysms, abscesses, fistulas, or prosthetic dehiscence), or extracardiac embolic phenomena. The differential diagnosis of IE includes evaluation for thrombus, pannus, nonbacterial thrombotic endocarditis, Lambl excrescences, papillary fibroelastoma, and caseous necrosis of the mitral valve. The location of the lesion relative to the surface of the valve, the presence of a stalk, and calcification or enhancement at contrast-enhanced imaging may offer useful clues for their differentiation. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Surgical repair and replacement for native mitral valve infective endocarditis.

AIMS: The clinical benefits of mitral valve repair over replacement in the setting of mitral infective endocarditis are not clearly established. METHODS: Data of patients who underwent cardiac surgery for infective endocarditis over a 20-year period (2001-2021) at two cardiac centres were reviewed. Among them, 282 patients underwent native mitral valve surgery and were included in the study. Nearest-neighbour propensity-score matching was performed to account for differences in patients' profile between the repair and replacement subgroups. RESULTS: Mitral valve replacement was performed in 186 patients, while in 96 cases patients underwent mitral valve repair. Propensity match analysis provided 89 well matched pairs. Mean age was 60 ±â€Š15 years; 75% of the patients were male. Mitral valve replacement was more commonly performed in patients with involvement of both mitral leaflets, commissure(s) and mitral annulus. Patients with lesion(s) limited to P2 segment formed the majority of the cases undergoing mitral valve repair. There was no difference in terms of microbiological findings. In-hospital mortality was 7% with no difference between the repair and the replacement cohorts. Survival probabilities at 1, 5 and 10 years were 88%, 72% and 68%, respectively after mitral repair, and 88%, 78% and 63%, respectively after mitral replacement (log-rank P  = 0.94). CONCLUSIONS: Mitral valve repair was more commonly performed in patients with isolated single leaflet involvement and provided good early and 10-year outcomes. Patients with annular disruption, lesion(s) on both leaflets and commissure(s) were successfully served on early and mid-term course by mitral valve replacement.

Burkholderia cepacia: A Rare Source of Endocarditis.

A 37-year-old male with a past medical history of previous mitral valve replacement due to bacterial endocarditis and intravenous (IV) drug use was found to have Burkholderia cepacia bacteremia. Transesophageal echocardiogram revealed large mitral and tricuspid valve vegetations. Medical management was initially attempted but his bacteremia persisted, and he required urgent prosthetic mitral valve replacement and native tricuspid valve replacement. Prosthetic valve endocarditis has been associated with surgery in 48.9% of patients and a mortality of 22.8%. In patients with prosthetic valve endocarditis due to B. cepacia, valve replacement occurred in approximately 61.5% of patients and mortality is estimated to be 33.3%. To our knowledge, this is one of only a few prosthetic valve endocarditis cases caused solely by B. cepacia and our case is the first to affect multiple valves including prosthetic and native valves.

Prognosis of prosthetic valve infective endocarditis due to Streptococcus spp., a retrospective multi-site study to assess the impact of antibiotic treatment duration.

PURPOSE: The duration of antibiotic treatment for prosthetic valve endocarditis caused by Streptococcus spp. is largely based on clinical observations and expert opinion rather than empirical studies. Here we assess the impact of a shorter antibiotic duration. OBJECTIVES: To assess the impact of antibiotic treatment duration for streptococcal prosthetic valve endocarditis on 12-month mortality as well as subsequent morbidity resulting in additional cardiac surgical interventions, and rates of relapse and reinfection. METHODS: This retrospective multisite (N= 3) study examines two decades of data on patients with streptococcal prosthetic valve endocarditis receiving either 4 or 6 weeks of antibiotics. Overall mortality, relapse, and reinfection rates were also assessed for the entire available follow-up period. RESULTS: The sample includes 121 patients (median age 72 years, IQR [53; 81]). The majority (74%, 89/121) received a ß-lactam antibiotic combined with aminoglycoside in 74% (89/121, median bi-therapy 5 days [1; 14]). Twenty-eight patients underwent surgery guided by ESC-guidelines (23%). The 12-month mortality rate was not significantly affected by antibiotic duration (4/40, 10% in the 4-week group vs 3/81, 3.7% in the 6-week group, p=0.34) or aminoglycoside usage (p=0.1). Similarly, there were no significant differences between the 2 treatment groups for secondary surgical procedures (7/40 vs 21/81, p=0.42), relapse or reinfection (1/40 vs 2/81 and 2/40 vs 5/81 respectively). CONCLUSIONS: Our study found no increased adverse outcomes associated with a 4-week antibiotic duration compared to the recommended 6-week regimen. Further randomized trials are needed to ascertain the optimal duration of treatment for streptococcal endocarditis.

Bacteraemia with gram-positive bacteria-when and how do I need to look for endocarditis?

BACKGROUND: Patients with bacteraemia caused by gram-positive bacteria are at risk for infective endocarditis (IE). Because IE needs long antibiotic treatment and sometimes heart valve surgery, it is very important to identify patients with IE. OBJECTIVES: In this narrative review we present and discuss how to determine which investigations to detect IE that are needed in individual patients with gram-positive bacteraemia. SOURCES: Published original studies and previous reviews in English, within the relevant field are used. CONTENT: First, the different qualities of the bacteraemia in relation to IE risk are discussed. The risk for IE in bacteraemia is related to the species of the bacterium but also to monomicrobial bacteraemia and the number of positive cultures. Second, patient-related factors for IE risk in bacteraemia are presented. Next, the risk stratification systems to determine the risk for IE in gram-positive bacteraemia caused by Staphylococcus aureus, viridans streptococci, and Enterococcus faecalis are presented and their use is discussed. In the last part of the review, an account for the different modalities of IE-investigations is given. The main focus is on echocardiography, which is the cornerstone of IE-investigations. Furthermore, 18F-fluorodesoxyglucose positron emission tomography/computed tomography and cardiac computed tomography are presented and their use is also discussed. A brief account for investigations used to identify embolic phenomena in IE is also given. Finally, we present a flowchart suggesting which investigations to perform in relation to IE in patients with gram-positive bacteraemia. IMPLICATIONS: For the individual patient as well as the healthcare system, it is important both to diagnose IE and to decide when to stop looking for IE. This review might be helpful in finding that balance.

Sex differences in infective endocarditis: a Danish nationwide study.

PURPOSE: Sex differences in infective endocarditis (IE) are reported, but patient characteristics are sparse and conflicting findings on the association between sex and short-term outcomes demand further research. We aimed to characterize sex differences in IE in terms of patient characteristics, frailty, microbiology, socioeconomic status, management and outcome on a nationwide scale. METHODS: Between 2010 and 2020, we used Danish national registries to characterize patients with IE according to sex using ICD codes and microbiological lab reports. Frailty was assessed with the Hospital Frailty Risk Score. Mortality was reported with Kaplan-Meier estimates. Logistic regression and Cox regression were used for adjusted analyses. RESULTS: We included 6259 patients with IE with 2047 (32.7%) female patients and 4212 (67.3%) male patients. Female patients were older (median age 75.0 years (64.3-82.2) vs. 71.7 (61.7-78.9)) and more frail (Intermediate frailty: 36.5% vs. 33.1%, High frailty: 11.4% vs. 9.2%). Staphylococcus aureus-IE were most common in both sexes (34.6% vs. 28.8%), but fewer female patients had Enterococcus-IE (10.5% vs. 18.1%). Female patients were less surgically treated (14.0% vs. 21.2%). Female sex was associated with increased in-hospital mortality (adj. OR 1.33, 95% CI 1.16-1.52), but no statistically significant difference in associated 1- and 5-year mortality from hospital discharge were identified (adj. HR 1.09, 95% CI 0.95-1.24 and 1.02, 95% CI 0.92-1.12, respectively). CONCLUSION: Female sex is associated with increased in-hospital mortality, but not in long-term mortality as compared with male patients. Female patients have a lower prevalence of Enterococcus-IE and rates of surgery. Further research is needed to understand these differences.

Risk factors for and consequences of positive valve cultures in patients who undergo cardiac surgery while receiving antimicrobial treatment for infective endocarditis.

INTRODUCTION: Cardiac surgery is required in up to half of the patients with infective endocarditis (IE). Positive valve cultures have been associated with higher in-hospital mortality. The aims were to identify risk factors for positive valve cultures and its relation to outcome. METHODS: Patients subjected to heart valve cultures due to surgery for IE in Skåne University Hospital, Lund, between 2012 and 2021 were identified through microbiology records. Risk factors for positive valve cultures and information on mortality and relapse were retrieved through medical records. Univariable and multivariable logistic regressions were performed. RESULTS: A total of 345 episodes with IE in 337 patients subjected to cardiac surgery were included and valve cultures were positive in 78 (23%) episodes. In multivariable logistic regression, preoperative fever (adjusted odds ratio (AOR) 2.6, 95% confidence interval (CI) 1.2-5.6, p = 0.02), prosthetic heart valve (AOR 3.3, CI 1.4-7.9, p = 0.01), a single affected valve (AOR 4.8, CI 1.2-20, p = 0.03), blood culture findings of S. aureus, enterococci, or coagulase negative staphylococci compared to viridans streptococci (AOR 20-48, p < 0.001), and a shorter duration of antibiotic treatment (p < 0.001), were associated to positive valve culture. One-year mortality was 13% and a relapse was identified in 2.5% of episodes. No association between positive valve cultures and one-year mortality or relapse was identified. CONCLUSIONS: Positive valve cultures were associated to short preoperative antibiotic treatment, IE caused by staphylococci, preoperative fever and prosthetic valve but not to relapse or mortality.

A cardiac intimal sarcoma mimicking infective endocarditis.

Primary malignant cardiac tumors are rare and usually misdiagnosed because they can mimic more common intracardiac lesions, therefore, in clinical practice it is important to always consider even uncommon diseases in order to avoid delayed diagnosis and to plan the most appropriate therapeutic strategy in a timely fashion. We report a case of a 73-year-old man with clinical signs and imaging findings (echocardiography) suggesting infective bacterial endocarditis of the mitral valve. However, intraoperative evaluation raised suspicion that the mitral lesions had a different nature. Surgical removal of the mass was performed, and the final correct diagnosis was made through pathologic examination, revealing a mitral valve sarcoma thus allowing for the beginning of specific oncological treatment.

Isolated mitral valve endocarditis: Patient, disease, and surgical factors that influence outcomes.

OBJECTIVE: The objectives of this study were to investigate patient characteristics, valve pathology, bacteriology, and surgical techniques related to outcome of patients who underwent surgery for isolated native (NVE) or prosthetic (PVE) mitral valve endocarditis. METHODS: From January 2002 to January 2020, 447 isolated mitral endocarditis operations were performed, 326 for NVE and 121 for PVE. Multivariable analysis of time-related outcomes used random forest machine learning. RESULTS: Staphylococcus aureus was the most common causative organism. Of 326 patients with NVE, 88 (27%) underwent standard mitral valve repair, 43 (13%) extended repair, and 195 (60%) valve replacement. Compared with NVE with standard repair, patients who underwent all other operations were older, had more comorbidities, worse cardiac function, and more invasive disease. Hospital mortality was 3.8% (n = 17); 0 (0%) after standard valve repair, 3 (7.0%) after extended repair, 8 (4.1%) after NVE replacement, and 6 (5.0%) after PVE re-replacement. Survival at 1, 5, and 10 years was 91%, 75%, and 62% after any repair and 86%, 62%, and 44% after replacement, respectively. The most important risk factor for mortality was renal failure. Risk-adjusted outcomes, including survival, were similar in all groups. Unadjusted extended repair outcomes, particularly early, were similar or worse than replacement in terms of reinfection, reintervention, regurgitation, gradient, and survival. CONCLUSIONS: A patient- and pathology-tailored approach to surgery for isolated mitral valve endocarditis has low mortality and excellent results. Apparent superiority of standard valve repair is related to patient characteristics and pathology. Renal failure is the most powerful risk factor. In case of extensive destruction, extended repair shows no benefit over replacement.

The Silent Threat: Bartonella quintana Endocarditis Unveiling Heart Failure and Severe Pulmonary Hypertension.

BACKGROUND Bartonella quintana is a slow-growing gram-negative bacterium that can cause severe culture-negative endocarditis. In many cases, its insidious onset can be difficult to diagnose given the variable symptoms in the early phases of the disease. This delay in detection and thus treatment can cause advanced consequences of the disease, including heart failure and severe pulmonary hypertension. CASE REPORT A 51-year-old man presented to the Emergency Department with signs and symptoms indicating an acute stroke. Further investigation showed that the source was cardioembolic, and despite negative blood cultures, endocarditis was suspected due to echocardiogram findings. Bartonella endocarditis was diagnosed based on serology results. Further testing indicated severe pulmonary hypertension, a sequelae of chronic heart failure in the setting of endocarditis. This caused a significant delay in valvular repair surgery. This case illustrates the progression from acute to chronic infection, the sequelae of this disease process, and the considerations involved in management. CONCLUSIONS Bartonella is an under-appreciated cause of endocarditis and can evolve into chronic disease with clinical consequences requiring nuanced management. We described a case of chronic culture-negative endocarditis that presented with acute embolic stroke and the sequelae of severe multi-valvular disease in a patient with recent incarceration and unstable housing. This case provides clinicians with valuable insight into the recognition of Bartonella endocarditis, the variable clinical presentations of this pathology, the nuanced and multifactorial approaches to medical management, and the indications for surgery.

Trueperella pyogenes endocarditis in a Swiss farmer: a case report and review of the literature.

BACKGROUND: Trueperella pyogenes (T. pyogenes) is a bacterium that colonizes the skin and mucosal surfaces of various domestic and wild animals. It rarely leads to infections in humans, with only a few descriptions available in the literature. CASE PRESENTATION: A 71-year-old Swiss farmer with a history of recurring basal cell carcinoma and metastasized pancreatic neuroendocrine tumor presented with signs of sepsis after a three-day history of general weakness, malaise and fever. Clinical and echocardiographic findings, as well as persistent bacteremia were consistent with mitral valve endocarditis caused by T. pyogenes. The patient's condition gradually improved under antibiotic treatment with piperacillin/tazobactam (empiric therapy of sepsis), and later penicillin G based on resistance testing. He was discharged after 13 days and continued outpatient antibiotic therapy with ceftriaxone, resulting in a total antibiotic treatment duration of six weeks. This is the first literature review of T. pyogenes endocarditis in humans. Among nine cases of T. pyogenes endocarditis, three patients had documented contact with farm animals and five had an underlying condition that compromised the immune system. While antibiotic resistance of T. pyogenes is an emerging concern, susceptibility to beta-lactam antibiotics seems to persist. The mortality of T. pyogenes endocarditis described in the literature was high, with 66% of patients not surviving the disease. CONCLUSIONS: T. pyogenes is a rare causative organism of infectious endocarditis in humans and descriptions are mainly restricted to case reports. In our review of the literature, we found that both an impaired immune system and contact with farm animals might be risk factors. Growth of T. pyogenes in blood cultures is unlikely to be missed during routine analysis, as it shows marked beta-hemolysis on blood agar culture plates, which generally leads to further characterization of the bacteria. Susceptibility to penicillin, ceftriaxone, and macrolides seems to be retained and the reported mortality in the few patients with T. pyogenes endocarditis is high.

Evaluating the heart valve tissue diffusion of amoxicillin in infective endocarditis: a pilot prospective observational non-comparative study.

OBJECTIVES: Treating patients with infective endocarditis (IE) due to streptococci and enterococci currently involves high-dosage antibiotics. Recent literature suggests a 30%-70% diffusion rate could be extrapolated to human heart valve tissue. The objective of this study was to evaluate the diffusion coefficient of amoxicillin in heart valve tissue of patients operated for IE. METHODS: Adult patients were prospectively included that underwent surgery at the European Hospital Georges Pompidou for IE due to streptococci and enterococci and had previous IV amoxicillin treatment. Plasma (taken 48 h preoperatively) and heart valve tissue amoxicillin concentrations were measured with a validated LC-MS/MS method. The MIC values of amoxicillin were measured for all available isolates. RESULTS: Seventeen patients were included. Eleven (64.7%) patients had native valve IE and six (35.3%) had prosthetic valve IE. Fourteen IE cases (82.4%) were due to streptococci, one (5.9%) was due to enterococci and two (11.8%) were Haemophilus spp, Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae group infections. Median (IQR) amoxicillin dose administered was 10.5 (8.0-12.0) g/day corresponding to 138.2 (112.5-160.0) mg/kg/day. The median amoxicillin plasma concentrations pre-surgery and intra-tissular weighted concentrations were 31.9 (25.9-51.9) mg/L and 19.0 (7.9-31.4) µg/g, respectively. Median tissue/plasma concentration ratio was 0.47 (0.24-0.67), with a median amoxicillin plasma/MIC ratio of 487 (179-745), and median amoxicillin tissue/MIC ratio of 42 (14-116). CONCLUSIONS: With a significant diffusion coefficient, amoxicillin dosage in heart valve tissues showed a concentration/MIC ratio well above current recommendations for bactericidal activity. Our study suggests that lower doses can be considered for susceptible bacteria.

Pulmonary valve infective endocarditis caused by Mycobacterium abscessus.

Infective endocarditis caused by Mycobacterium abscessus is an uncommon event that, when it does occur, usually requires surgical valve replacement. The pulmonary valve is the least common heart valve involved in infective endocarditis. We present a rare case of isolated pulmonary valve endocarditis with Mycobacterium abscessus in a patient with recurrent sternal infections following repeated coronary artery bypass.

16S rRNA Gene PCR/Sequencing of Heart Valves for Diagnosis of Infective Endocarditis in Routine Clinical Practice.

Sequencing is increasingly used for infective endocarditis (IE) diagnosis. Here, the performance of 16S rRNA gene PCR/sequencing of heart valves utilized in routine clinical practice was compared with conventional IE diagnostics. Subjects whose heart valves were sent to the clinical microbiology laboratory for 16S rRNA gene PCR/sequencing from August 2020 through February 2022 were studied. A PCR assay targeting V1 to V3 regions of the 16S rRNA gene was performed, followed by Sanger and/or next-generation sequencing (NGS) (using an Illumina MiSeq), or reported as negative, depending on an algorithm that included the PCR cycle threshold value. Fifty-four subjects, including 40 with IE, three with cured IE, and 11 with noninfective valvular disease, were studied. Thirty-one positive results, 11 from NGS and 20 from Sanger sequencing, were generated from analysis of 16S rRNA gene sequence(s). Positivity rates of blood cultures and 16S rRNA gene PCR/sequencing of valves were 55% and 75%, respectively (P = 0.06). In those with prior antibiotic exposure, positivity rates of blood cultures and 16S rRNA gene PCR/sequencing of valves were 11% and 76%, respectively (P < 0.001). Overall, 61% of blood culture-negative IE subjects had positive valve 16S rRNA gene PCR/sequencing results. 16S rRNA gene-based PCR/sequencing of heart valves is a useful diagnostic tool for pathogen identification in patients with blood culture-negative IE undergoing valve surgery in routine clinical practice.

The three-noes right-sided infective endocarditis: An unrecognized type of right-sided endocarditis.

The "3 noes right-sided infective endocarditis" (3no-RSIE: no left-sided, no drug users, no cardiac devices) was first described more than a decade ago. We describe the largest series to date to characterize its clinical, microbiological, echocardiographic and prognostic profile. Eight tertiary centers with surgical facilities participated in the study. Patients with right-sided endocarditis without left sided involvement, absence of drug use history and no intracardiac electronic devices were retrospectively included in a multipurpose database. A total of 53 variables were analyzed in every patient. We performed a univariate analysis of in-hospital mortality to determine variables associated with worse prognosis. the study was comprised of 100 patients (mean age 54.1 ± 20 years, 65% male) with definite 3no-RSIE were included (selected from a total of 598 patients with RSIE of all the series, which entails a 16.7% of 3no-RSIE). Most of the episodes were community-acquired (72%), congenital cardiopathies were frequent (32% of the group of patients with previous known predisposing heart disease) and fever was the main manifestation at admission (85%). The microbiological profile was led by Staphylococci spp (52%). Vegetations were detected in 94% of the patients. Global in-hospital mortality was 19% (5.7% in patients operated and 26% in patients who received only medical treatment, P < .001). Non-community acquired infection, diabetes mellitus, right heart failure, septic shock and acute renal failure were more common in patients who died. the clinical profile of 3no-RSIE is closer to other types of RSIE than to LSIE, but mortality is higher than that reported on for other types of RSIE. Surgery may play an important role in improving outcome.

Bacterial endocarditis following COVID-19 infection: two case reports.

BACKGROUND: COVID-19, an emerging disease raised as a pandemic, urgently needed treatment choices. Some options have been confirmed as lifesaving treatments, but long-term complications must be clearly illustrated. Bacterial endocarditis is a less frequent disease among patients infected with SARS_COV_2 compared to other cardiac comorbidities in these patients. This case report discusses bacterial endocarditis as a potential adverse effect after administering tocilizumab, corticosteroids, and COVID-19 infection. CASE PRESENTATION: In the first case, a 51-year-old Iranian female housewife was admitted to the hospital with fever, weakness, and monoarthritis symptoms. The second case is a 63-year-old Iranian woman who is a housewife admitted with weakness, shortness of breath, and extreme sweating. Both cases tested positive for Polymerase chain reaction (PCR) less than one month ago and were treated with tocilizumab and corticosteroid. Both patients were suspected of infective endocarditis. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in the blood cultures of both patients. The diagnosis of endocarditis is confirmed for both cases. Cases are subjected to open-heart surgery, a mechanical valve is placed, and they are treated with medication. In subsequent visits, their condition was reported to be improving. CONCLUSION: Adjacent to cardiovascular inclusion as COVID-19 disease complications, secondary infection taken after the organisation of immunocompromising specialists can result in basic maladies and conditions counting infective endocarditis.

Clinical Significance of a 16S-rDNA Analysis of Heart Valves in Patients with Infective Endocarditis: a Retrospective Study.

A substantial proportion of patients with infective endocarditis (IE) are subjected to heart valve surgery. Microbiological findings on valves are important both for diagnostics and for tailored antibiotic therapy, post-operatively. The aims of this study were to describe microbiological findings on surgically removed valves and to examine the diagnostic benefits of 16S-rDNA PCR and sequencing (16S-analysis). Adult patients who were subjected to heart valve surgery for IE between 2012 and 2021 at Skåne University Hospital, Lund, where a 16S-analysis had been performed on the valve, constituted the study population. Data were gathered from medical records, and the results from blood cultures, valve cultures, and 16S-analyses of valves were compared. A diagnostic benefit was defined as providing an agent in blood culture negative endocarditis, providing a new agent in episodes with positive blood cultures, or confirming one of the findings in episodes with a discrepancy between blood and valve cultures. 279 episodes in 272 patients were included in the final analysis. Blood cultures were positive in 259 episodes (94%), valve cultures in 60 episodes (22%), and 16S-analyses in 227 episodes (81%). Concordance between the blood cultures and the 16S-analysis was found in 214 episodes (77%). The 16S-analyses provided a diagnostic benefit in 25 (9.0%) of the episodes. In blood culture negative endocarditis, the 16S-analyses had a diagnostic benefit in 15 (75%) of the episodes. A 16S-analysis should be routinely performed on surgically removed valves in blood culture negative endocarditis. In patients with positive blood cultures, 16S-analysis may also be considered, as a diagnostic benefit was provided in some patients. IMPORTANCE This work demonstrates that it can be of importance to perform both cultures and analysis using 16S-rDNA PCR and sequencing of valves excised from patients undergoing surgery for infective endocarditis. 16S-analysis may help both to establish a microbiological etiology in cases of blood culture negative endocarditis and to provide help in situations where there are discrepancies between valve and blood cultures. In addition, our results show a high degree of concordance between blood cultures and 16S-analyses, indicating that the latter has a high sensitivity and specificity for the etiological diagnosis of endocarditis in patients who were subjected to heart valve surgery.

Aggregatibacter aphrophilus and Eikenella corrodens: a case of brain abscess.

We report a case of a 26-year-old female who developed a brain abscess that was strongly suspected to be caused by Staphylococcus epidermidis, A. aphrophilus, and E. corrodens species. In general, A. aphrophilus and E. corrodens, members of the HACEK group (Haemophilus spp., Aggregatibacter spp., C. hominis, E. corrodens, and K. kingae), have been associated with the development of endocarditis, meningitis, sinusitis, otitis media, pneumonia, osteomyelitis, peritonitis, and wound infections. Cerebral abscesses are a rare manifestation of these bacteria; only a few cases are described in the literature, generally related to the diffusion of these organisms through the bloodstream after a dental procedure or a heart disease. Our case is unique because the rarity of the infection site appeared apparently in absence of risk factors. The patient underwent surgery to drain the abscess and was subsequently put on intravenous antibiotic treatment with ceftriaxone, vancomycin, and metronidazole. After 6 months, brain imaging revealed that the lesion had disappeared. The patient achieved excellent results with this approach.