Incidence and outcome of Staphylococcus aureus endocarditis--a 10-year single-centre northern European experience

Infective endocarditis in a Finnish tertiary care hospital: from etiology to embolic events

BACKGROUND

In this study in a tertiary care hospital, we examined the characteristics of the different microbial etiologies of infective endocarditis (IE) and the factors associated with embolic events.

MATERIALS AND METHODS

We included patients (aged ≥18 years) hospitalized for IE in Turku University Hospital in Finland between 2004-2017. Patient data were derived retrospectively from the mandatory database and patient record system.

RESULTS

Among 342 IE cases in 321 patients, Staphylococcus aureus was isolated in 33.9%, viridans group streptococci in 18.3% and enterococci in 8.8% of the cases. Patients with enterococcal IE had more often a prosthetic valve (p < 0.001), recent major healthcare procedure or hospital admission (p < 0.001) and heart failure during admission (p = 0.006) than the patients with other etiologies. Viridans group streptococci and enterococci vs. S. aureus were associated with a lower rate (OR 0.34, p = 0.007 and OR 0.20, p = 0.006, respectively) and IE of the multiple valves vs. aortic valve with a higher rate (OR 2.30, p = 0.043) of all embolic events but not cerebral embolisms when analyzed separately. Both all embolic events and cerebral embolisms were strongly associated with the occurrence of an echocardiography-disclosed vegetation (OR 3.31, p = 0.004 and OR 2.73, p = 0.019, respectively).

CONCLUSIONS

Our study suggests that enterococcal IE is often associated with a previous healthcare procedure or hospital admission and heart failure. Staphylococcus aureus etiology and IE of the multiple valves are associated with a higher rate of all embolic events but not cerebral embolisms. Echocardiography-disclosed vegetation is associated with a higher occurrence of embolisms.

Staphylococcus aureus Infections and Human Intestinal Microbiota

Staphylococcus aureus (S. aureus) is a common pathogen that can cause many human diseases, such as skin infection, food poisoning, endocarditis, and sepsis. These diseases can be minor infections or life-threatening, requiring complex medical management resulting in substantial healthcare costs. Meanwhile, as the critically ignored "organ," the intestinal microbiome greatly impacts physiological health, not only in gastrointestinal diseases but also in disorders beyond the gut. However, the correlation between S. aureus infection and intestinal microbial homeostasis is largely unknown. Here, we summarized the recent progress in understanding S. aureus infections and their interactions with the microbiome in the intestine. These summarizations will help us understand the mechanisms behind these infections and crosstalk and the challenges we are facing now, which could contribute to preventing S. aureus infections, effective treatment investigation, and vaccine development.

Predictors of mortality of Staphylococcus aureus bacteremia among patients hospitalized in a Swiss University Hospital and the role of early source control; a retrospective cohort study

S. aureus bacteremia is associated with high mortality. The aim was to identify predictors of mortality among patients with S. aureus bacteremia and evaluate the role of early source control. This retrospective study was conducted at the Lausanne University Hospital, Switzerland. All episodes of S. aureus bacteremia among adult patients from 2015 to 2021 were included. During the study period, 839 episodes of S. aureus bacteremia were included, of which 7.9% were due to methicillin-resistant isolates. Bacteremias were related to bone or joint infections (268; 31.9%), followed by bacteremia of unknown origin (158; 18.8%), proven endocarditis (118; 14.1%) and lower-respiratory tract infections (79; 9.4%). Overall 28-day mortality was 14.5%. Cox multivariate regression model showed that Charlson comorbidity index > 5 (P < 0.001), nosocomial bacteremia (P 0.019), time to blood culture positivity ≤ 13 h (P 0.004), persistent bacteremia for ≥ 48 h (P 0.004), sepsis (P < 0.001), bacteremia of unknown origin (P 0.036) and lower respiratory tract infection (P < 0.001) were associated with 28-day mortality, while infectious diseases consultation within 48 h from infection onset (P < 0.001) was associated with better survival. Source control was warranted in 575 episodes and performed in 345 episodes (60.0%) within 48 h from infection onset. Results from a second multivariate analysis confirmed that early source control (P < 0.001) was associated with better survival. Mortality among patients with S. aureus bacteremia was high and early source control was a key determinant of outcome. Infectious diseases consultation within 48 h played an important role in reducing mortality.

Risk Factors for Mortality in Cardiac Implantable Electronic Device (CIED) Infections: A Systematic Review and Meta-Analysis

Background: Infections following cardiac implantable electronic device (CIED) implantation can require surgical device removal and often results in significant cost, morbidity, and potentially mortality. We aimed to systemically review the literature and identify risk factors associated with mortality following CIED infection. Methods: Electronic searches (up to June 2021) were performed on PubMed and Scopus. Twelve studies (10 retrospective, 2 prospective cohort studies) were included for analysis. Meta-analysis was conducted with the restricted maximum likelihood method, with mortality as the outcome. The overall mortality was 13.7% (438/1398) following CIED infection. Results: On meta-analysis, the male sex (OR 0.77, 95%CI 0.57–1.01, I² = 2.2%) appeared to have lower odds for mortality, while diabetes mellitus appeared to be associated with higher mortality (OR 1.47, 95%CI 0.67–3.26, I² = 81.4%), although these trends did not reach statistical significance. Staphylococcus aureus as the causative organism (OR 2.71, 95%CI 1.76–4.19, I² = 0.0%), presence of heart failure (OR 1.92, 95%CI 1.42–4.19, I² = 0.0%) and embolic phenomena (OR 4.00, 95%CI 1.67–9.56, I² = 69.8%) were associated with higher mortality. Surgical removal of CIED was associated with lower mortality compared with conservative management with antibiotics alone (OR 0.22, 95%CI 0.09–0.50, I² = 62.8%). Conclusion: We identified important risk factors associated with mortality in CIED infections, including Staphyloccocus aureus as the causative organism, and the presence of complications, such as heart failure and embolic phenomena. Surgery, where possible, was associated with better outcomes.

Invasive Procedures Associated With the Development of Infective Endocarditis

BACKGROUND

Various invasive medical procedures might induce bacteremia and, hence, act as triggers for infective endocarditis. However, empirical data in humans on the potential dangers of invasive medical procedures in this regard are very sparse. Due to lack of sufficient data, it is currently debated whether the risk for endocarditis with medical procedures is substantial or rather negligible.

OBJECTIVES

The purpose of this nationwide case-crossover study was to quantify the excess risk for infective endocarditis in association with invasive medical and surgical procedures.

METHODS

The authors identified all adult patients treated for endocarditis in hospitals in Sweden between January 1, 1998, and December 31, 2011. The authors applied a case-crossover design and compared the occurrence of invasive medical procedures 12 weeks before endocarditis with a corresponding 12-week time period exactly 1 year earlier. The authors considered all invasive nondental medical procedures except for those that are likely to be undertaken due to endocarditis or sepsis or due to infections that could possibly lead to endocarditis.

RESULTS

The authors identified 7,013 cases of infective endocarditis during the study period. Among others, several cardiovascular procedures, especially coronary artery bypass grafting; procedures of the skin and management of wounds; transfusion; dialysis; bone marrow puncture; and some endoscopies, particularly bronchoscopy, were strongly associated with an increased risk for infective endocarditis.

CONCLUSIONS

This study suggests that several invasive nondental medical procedures are associated with a markedly increased risk for infective endocarditis.

Carbon monoxide ameliorates Staphylococcus aureus-elicited COX-2/IL-6/MMP-9-dependent human aortic endothelial cell migration and inflammatory responses

Staphylococcus aureus (S. aureus) can often lead to many life-threatening diseases. It has the ability to invade normal endovascular tissue. Acute inflammation and its resolution are important to ensure bacterial clearance and limit tissue injury. Carbon monoxide (CO) has been shown to exert anti-inflammatory effects in various tissues and organ systems. In our study, we investigated the effects and the mechanisms of carbon monoxide releasing molecule-2 (CORM-2) on S. aureus-induced inflammatory responses in human aortic endothelial cells (HAECs). We proved that S. aureus induced cyclooxygenase-2 (COX-2)/prostaglandin E₂ (PGE₂)/interleukin-6 (IL-6)/matrix metallopeptidase-9 (MMP-9) expression and cell migration, which were decreased by CORM-2. Moreover, CORM-2 had no effects on TLR2 mRNA levels in response to S. aureus. Interestingly, we proved that S. aureus decreased intracellular ROS generation, suggesting that the inhibition of ROS further promoted inflammatory responses. However, CORM-2 significantly inhibited S. aureus-induced inflammation by increasing intracellular ROS generation. S. aureus-induced NF-κB activation was also inhibited by CORM-2. Finally, we proved that S. aureus induced levels of the biomarkers of inflammation in cardiovascular diseases, which were inhibited by CORM-2. Taken together, these results suggest that CORM-2 inhibits S. aureus-induced COX-2/PGE₂/IL-6/MMP-9 expression and aorta inflammatory responses by increasing the ROS generation and reducing the inflammatory molecules levels.

Infective endocarditis in Western Norway: a 20-year retrospective survey

BACKGROUND

To investigate epidemiological trends of infective endocarditis (IE) in western Norway a retrospective study was performed.

METHODS

Characteristics of 706 IE admissions from 1996 to 2005 and 2006 to 2015 were analysed and compared using the Chi-square test for categorical variables and the t-test for age. Survival was analysed by multiple Cox regression and reported by the hazard ratio (HR).

RESULTS

Mean annual incidence rates increased from 4.6 to 7.4 per 100,000 inhabitants (rate ratio: 1.97, 95% confidence interval: 1.52-2.56, p < .001). Non-viridans streptococci, enterococci and Staphylococcus aureus (S. aureus), were all independently associated with increased mortality. The frequency of IE caused by enterococci increased from 3.7 to 13.0% (p < .001). The proportion of intravenous drug users (IVDU) increased from 16.5 to 23.5% (p = .015) and had increasing aortic valve involvement (p = .023). Prosthetic valve endocarditis (PVE) constituted 30% of IE cases in both decades with biological PVE increasing from 9.4 to 22.1% (p < .001) and mechanical PVE decreasing from 18.7 to 8.9% (p < .001). In the last decade, valve replacement surgery was performed in 37.6% of the patients, of which 85.5% received a bioprosthesis.

CONCLUSIONS

The incidence of IE increased significantly. Non-viridans streptococci, enterococci and S. aureus were all significantly associated with increased mortality. The increased number of enterococcal IE and the increased number of IVDUs with left-sided IE constituted new challenges. Biological implants were preferred in a majority of patients requiring surgery.

Staphylococcus aureus bacteraemia and endocarditis - epidemiology and outcome: a review

PURPOSE

To review the epidemiology of Staphylococcus aureus bacteraemia (SAB) and endocarditis (SAE), and discuss the short- and long-term outcome.  Materials and methods: A literature review of the epidemiology of SAB and SAE.

RESULTS

The reported incidence of SAB in Western countries is 16-41/100,000 person-years. Increasing incidence has been observed in many regions, in Iceland by 27% during 1995-2008. The increase is believed to depend on changes in population risk factors and possibly better and more frequent utilization of diagnostic procedures. S. aureus is now the leading causes of infective endocarditis (IE) in many regions of the world. It accounts for 15-40% of all IE cases, and the majority of cases in people who inject drugs (PWID). Recently, the incidence of SAE in PWID in Stockholm, Sweden, was found to be 2.5/1000 person-years, with an in-hospital mortality of 2.5% in PWID as compared to 15% in non-drug users. The 30-day mortality associated with SAB amounts to 15-25% among adults in Western countries, but is lower in children (0-9%). Mortality associated with SAE is high (generally 20-30% in-hospital mortality), and symptomatic cerebral embolizations are common (12-35%). The 1-year mortality reported after SAB and SAE is 19-62% and reflects deaths from underlying diseases and complications caused by the infection. In a subset of SAE cases, valvular heart surgery is needed (15-45%), but active intravenous drug use seems to be a reason to refrain from surgery. Despite its importance, there are insufficient data on the optimal management of SAB and SAE, especially on the required duration of antibiotic therapy.  Conclusions: The epidemiology of SAB and SAE has been changing in the past decades. They still carry a substantial morbidity and mortality. Intensified studies on treatment are warranted for improving patient outcome.

Successful treatment of acute renal failure secondary to complicated infective endocarditis by peritoneal dialysis: a case report

BACKGROUND

Infective endocarditis is one of the most common infections among intravenous drug addicts. Its complications can affect many systems, and these can include acute renal failure. There is a scarcity of cases in the literature related to acute renal failure secondary to infective endocarditis treated with peritoneal dialysis. In this paper, the case of a 48-year-old Saudi male is reported, who presented with features suggestive of infective endocarditis and who developed acute kidney injury that was treated successfully with high tidal volume automated peritoneal dialysis. To our knowledge, this is the second report of such an association in the literature.

CASE PRESENTATION

A 48-year-old Saudi gentleman diagnosed to have a glucose-6-phosphate dehydrogenase deficiency and hepatitis C infection for the last 9 years, presented to the emergency department with a history of fever of 2 days' duration. On examination: his temperature = 41 °C, there was clubbing of the fingers bilaterally and a pansystolic murmur in the left parasternal area. The results of the blood cultures and echocardiogram were supportive of the diagnosis of infective endocarditis, and the patient subsequently developed acute kidney injury, and his creatinine reached 5.2 mg/dl, a level for which dialysis is essential for the patient to survive.

CONCLUSION

High tidal volume automated peritoneal dialysis is highly effective as a renal replacement therapy in acute renal failure secondary to infective endocarditis if no contraindication is present.

Low mortality but increasing incidence of Staphylococcus aureus endocarditis in people who inject drugs: Experience from a Swedish referral hospital

Staphylococcus aureus is a leading cause of infective endocarditis in people who inject drugs (PWID). The management of S aureus endocarditis (SAE) in PWID can be problematic. The objective of this retrospective observational study was to assess the epidemiology, clinical characteristics, and mortality of S aureus endocarditis (SAE) in PWID in Stockholm, Sweden.The Department of Infectious Diseases at the Karolinska University Hospital serves as a regional referral center for drug users with severe infections. Patients with active intravenous drug use treated for SAE at the department between January 2004 and December 2013 were retrospectively identified. Clinical and microbiological data were obtained from medical records and the diagnosis verified according to the modified Duke criteria.In total, 120 SAE episodes related to intravenous drug use were identified. Its incidence in Stockholm was 0.76/100,000 adult person-years for the entire period, increasing from 0.52/100,000 person-years in 2004 to 2008 to 0.99 in 2009 to 2013 (P = 0.02). The SAE incidence among PWID specifically was 249 (range 153-649) /100,000 person-years. Forty-two (35%) episodes were left-sided, and multiple valves were involved in 26 (22%). Cardiac valve surgery was performed in 10 (8%) episodes, all left-sided. The in-hospital and 1-year mortality rates were 2.5% (3 deaths) and 8.0% (9 deaths), respectively.We noted a high and increasing incidence over time of SAE related to intravenous drug use in Stockholm. The increased incidence partly reflects a rising number of PWID during the study period. The low mortality noted, despite a substantial proportion with left-sided endocarditis, probably in part reflects the quality of care obtained at a large and specialized referral center for drug users with severe infections.

Valvular Cytomegalovirus Endocarditis

Endocarditis is a rare presentation for cytomegalovirus (CMV) infection. We present the case of a 49-year-old man who underwent mitral and tricuspid valve replacement for valvular CMV endocarditis. The patient's past medical history was significant for human immunodeficiency virus, intravenous drug abuse, and chronic hepatitis B. During his clinical course, he was found to have tricuspid and mitral valve vegetations. After progressive valvular destruction despite antibiotic therapy, he underwent successful mitral and tricuspid valve replacement. Pathologic analysis of the culture-negative valve specimens were found to contain inclusion bodies consistent with CMV, and quantitative serum polymerase chain reaction returned a highly elevated CMV DNA count.