Nosocomial vs. community-acquired infective endocarditis in Greece: changing epidemiological profile and mortality risk

Robinsoniella peoriensis Infections in Humans-A Narrative Review

Robinsoniella peoriensis is a Gram-positive, strictly anaerobic, spore-forming, rod-shaped bacterium belonging to the phylum Firmicutes and the family Lachnospiraceae. Until now, R. peoriensis is the only species of its genus. It was first isolated in 2003 during a study into the flora of lagoons and manure pits. Given the rarity of this microorganism and the sparse information in the literature about its way of transmission, the way to diagnose its infections and identify it in the microbiology laboratory, and its public health relevance, the present study aimed to identify all the published cases of Robinsoniella, describe the epidemiological, clinical, and microbiological characteristics, and provide information about its antimicrobial resistance, treatment, and outcomes. A narrative review was performed based on a Pubmed/Medline and Scopus databases search. In total, 14 studies provided data on 17 patients with infections by Robinsoniella. The median age of patients was 63 years and 47% were male. The most common types of infection were bone and joint infections, bacteremia, infective endocarditis, and peritonitis. The only isolated species was R. peoriensis, and antimicrobial resistance to clindamycin was 50%, but was 0% to the combination of piperacillin with tazobactam, aminopenicillin with a beta-lactamase inhibitor, and metronidazole which were the most commonly used antimicrobials for the treatment of these infections. The overall mortality depends on the type of infection and is notable only for bacteremia, while all other infections had an optimal outcome. Future studies should better assess these infections' clinical and epidemiological characteristics and the mechanisms of the antimicrobial resistance of this microorganism from a mechanistic and genetic perspective.

Epidemiological differences, clinical aspects, and short-term prognosis of patients with healthcare-associated and community-acquired infective endocarditis

Background

The prevalence of healthcare-associated infective endocarditis in Brazil is poorly known.

Aim

To analyze the epidemiological, clinical and microbiological characteristics, and the prognosis of healthcare-associated infective endocarditis (HAIE) compared with community-acquired infective endocarditis (CIE) and identify the associated factors with hospital mortality.

Method

A historical cohort study was carried out, with a data collection period from January 2009 to December 2019 at the Federal University of São Paulo. Data were collected from medical records of patients with infective endocarditis (IE) hospitalized during the study period. Patients were classified into three groups: CIE, non-nosocomial HAIE (NN-HAIE) and nosocomial HAIE (NHAIE).

Results

A total of 204 patients with IE were included; of these, 127 (62.3%) were cases of HAIE, of which 83 (40.7%) were NN-HAIE and 44 (21.6%) were NHAIE. Staphylococcus spp. Were the main causative agents, especially in HAIE groups (P<0.001). Streptococcus spp. were more prevalent in the CIE group (P<0.001). In-hospital mortality was 44.6%, with no differences between groups. Independent risk factors for in-hospital mortality were age ≥ 60 years (odds ratio (OR): 6.742), septic shock (OR 5.264), stroke (OR 3.576), heart failure (OR 7.296), and Intensive Care Unit admission (OR 7.768).

Conclusion

HAIE accounted for most cases in this cohort, with a higher prevalence of non-nosocomial infections. Staphylococcus spp. were the main causative agents. Hospital mortality was high, 44.6%, with no difference between groups.

Infective Endocarditis by Lactobacillus Species-A Narrative Review

Bacteria of the genus Lactobacillus are microaerophilic or aerotolerant anaerobic Gram-positive non-spore-forming rods. They are considered essential members of the human gut microbiome; however, recent studies have revealed that these microorganisms are less predominant in the gut microbiome than initially thought. Lactobacillus spp. is mainly known for its use as a probiotic in foods and supplements to prevent and treat specific issues such as infectious diseases, irritable bowel syndrome, and diabetes mellitus. However, Lactobacillus spp. may occasionally cause infections such as bacteremia or infective endocarditis (IE). The present study aimed to review all cases of IE by Lactobacillus spp. and describe the epidemiology, microbiology, clinical characteristics, treatment, and outcomes of this infection by collecting relevant data from studies existing in Pubmed and Scopus until 28 September 2023. A total of 77 studies containing data for 82 patients were included. The median age was 56 years, and 69.6% were male. A prosthetic valve was present in 16% of patients, and 17.3% had previously been on probiotics. The aortic valve was the most commonly involved intracardiac site, followed by the mitral valve. Fever, embolic phenomena, sepsis, and heart failure were the most common clinical presentations. Aminoglycosides and penicillin were the most commonly used antimicrobials for definitive treatment. Surgery was performed in 53.7% of patients. Overall mortality was 17.1%. IE in prosthetic valves and presentation with shock were independently associated with overall mortality.

Infective Endocarditis by Clostridioides and Clostridium Species-A Narrative Review

Bacteria of the genus Clostridium are anaerobic Gram-positive spore-forming bacilli that include more than 200 species. Some of them are known to cause invasive infections and diseases caused by the production of toxins. Some of the diseases that are mediated by toxins are colitis in patients with specific risk factors, such as previous administration of antimicrobials or foodborne botulism. Invasive diseases include bacteremia, infective endocarditis (IE), clostridial myonecrosis (gas gangrene), and other diseases that involve the destruction of soft tissue due to the local production of toxins. The present study aimed to review all cases of IE by Clostridioides and Clostridium species and describe the epidemiology, clinical characteristics, treatment, and outcomes of these infections. A narrative review was performed based on a search in PubMed and Scopus for studies published until 11 September 2023, providing such data of IE caused by Clostridioides and Clostridium species in humans. A total of 20 studies containing data for 21 patients were included. A prosthetic valve was present in 5 patients (23.8%). The aortic valve was the most commonly involved, followed by the mitral valve. Fever, sepsis, and embolic phenomena were the most common clinical presentations. Beta-lactams and metronidazole were the most commonly used antimicrobials. Surgery was performed in nine patients (45%). Mortality reached 33.3%. IE in multiple valves was associated with increased mortality. Despite the heterogeneous genetic and molecular characteristics that necessitate the taxonomic change of some of this genus's previous members, the clinical syndrome of IE caused by these bacteria seems to have similar characteristics.

Epidemiological Changes and Improvement in Outcomes of Infective Endocarditis in Europe in the Twenty-First Century: An International Collaboration on Endocarditis (ICE) Prospective Cohort Study (2000-2012)

INTRODUCTION

Infective endocarditis (IE) has undergone important changes in its epidemiology worldwide.

METHODS

The study aimed to compare IE epidemiological features and outcomes according to predefined European regions and between two different time periods in the twenty-first century.

RESULTS

IE cases from 13 European countries were included. Two periods were considered: 2000-2006 and 2008-2012. Two European regions were considered, according to the United Nations geoscheme for Europe: Southern (SE) and Northern-Central Europe (NCE). Comparisons were performed between regions and periods. A total of 4195 episodes of IE were included, 2113 from SE and 2082 from NCE; 2787 cases were included between 2000 and 2006 and 1408 between 2008 and 2012. Median (IQR) age was 63.7 (49-74) years and 69.4% were males. Native valve IE (NVE), prosthetic valve IE (PVE), and device-related IE were diagnosed in 68.3%, 23.9%, and 7.8% of cases, respectively; 52% underwent surgery and 19.3% died during hospitalization. NVE was more prevalent in NCE, whereas device-related IE was more frequent in SE. Higher age, acute presentation, hemodialysis, cancer, and diabetes mellitus all were more prevalent in the second period. NVE decreased and PVE and device-related IE both increased in the second period. Surgical treatment also increased from 48.7% to 58.4% (p < 0.01). In-hospital and 6-month mortality rates were comparable between regions and significantly decreased in the second period.

CONCLUSIONS

Despite an increased complexity of IE cases, prognosis improved in recent years with a significant decrease in 6-month mortality. Outcome did not differ according to the European region (SE versus NCE).

Infective Endocarditis by Pasteurella Species: A Systematic Review

Pasteurella spp. are non-motile, facultative anaerobic, Gram-negative coccobacilli that are commonly found in the oral cavity and the gastrointestinal tract of some animals and are known to be the cause of infections. Usually, infections by Pasteurella spp. in humans is more common in the context of an animal bite leading to a skin and soft tissue infection (SSTI). Infective endocarditis (IE) is rarely caused by Pasteurella spp.; however, it can pose diagnostic and therapeutic dilemmas due to its rarity. The aim of the present study was to systematically review all cases of IE by Pasteurella spp. in the literature. A systematic review was performed of PubMed, Scopus and the Cochrane Library (through 20 December 2021) for studies providing data on epidemiology and clinical and microbiological characteristics as well as data on treatment and outcomes of IE by Pasteurella spp. A total of 28 studies containing data for 28 patients were included. Prosthetic valve was present in 21.4% of patients. The aorta was the most commonly involved intracardiac site. Fever, sepsis, septic shock and heart failure were the most common clinical presentations. Cephalosporins, aminopenicillins and penicillin were the antimicrobials used most commonly. Overall mortality was 17.9%.

Healthcare-Associated Infective Endocarditis—Surgical Perspectives

Health-care-associated infective endocarditis (HCA-IE), a disease with a poor prognosis, has become increasingly important. As surgical treatment is frequently required, this review aims to outline surgical perspectives on HCA-IE. We searched PubMed to identify publications from January 1980 to March 2022. Reports were evaluated by the authors against a priori inclusion/exclusion criteria. Studies reporting on surgical treatment of HCA-IE including outcome were selected. Currently, HCA-IE accounts for up to 47% of IE cases. Advanced age, cardiac implants, and comorbidity are important predispositions, and intravascular catheters or frequent vascular access are significant sources of infection. Staphylococci and enterococci are the leading causative microorganisms. Surgery, although frequently indicated, is rejected in 24–69% because of prohibitive risk. In-hospital mortality is significant after surgery (29–50%) but highest in patients rejected for operation (52–83%). Furthermore, the length of hospital stay is prolonged. With aging populations, age-dependent morbidity, increasing use of cardiac implants, and growing healthcare utilization, HCA-IE is anticipated to gain further importance. A better understanding of pathogenesis, clinical profile, and outcomes is paramount. Further research on surgical treatment is needed to provide more comprehensive information for defining the most suitable treatment option, finding the optimal time for surgery, and reducing morbidity and mortality.

Infective endocarditis by Nocardia species: a systematic review

Nocardiosis, is a potentially life-threatening disease, especially in immunocompromised individuals where it manifests as a disseminated disease. Infective Endocarditis (IE) is a rare disease with significant morbidity and mortality. Importantly, even though there are scarce data of IE by Nocardia spp. in the literature, a review adequately summarizing systematically all available evidence on the topic is lacking. The aim of this study was to systematically review all cases of IE by Nocardia spp. and describe the epidemiology, microbiology, clinical characteristics, treatment and outcomes of this infection. A systematic review of PubMed, Scopus and Cochrane library (through 7 December 2021) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of patients with IE by Nocardia spp. was performed. A total of 25 studies providing data for 26 patients were included. A prosthetic valve was present in 30.8%, while the most common microorganism was N. asteroides. Aortic valve was the most commonly infected intracardiac site, followed by the mitral valve. Diagnosis was most commonly performed with transthoracic echocardiography, while the diagnosis was made at autopsy in 11.5%. Co-trimoxazole, aminoglycosides and carbapenems were the most commonly used antimicrobials. Clinical cure was noted in 73.1%, while mortality was 26.9%. This systematic review thoroughly describes IE by Nocardia and provides information on epidemiology, clinical presentation, treatment and outcomes.

Infective endocarditis by Actinomyces species: a systematic review

Actinomycosis, is a slowly progressive infection that may mimic malignancy due to the invasiveness of tissues and the ability to form sinus tracts. Infective Endocarditis (IE) is a rare disease with significant morbidity and mortality. Interestingly, even though there are scarce data of IE by Actinomyces spp. in the literature, a review adequately summarizing all available evidence on the topic in a systematic way is lacking. The aim of this study was to systematically review all cases of IE by Actinomyces spp. in the literature and describe the epidemiology, microbiology, clinical characteristics, treatment and outcomes of this infection. A systematic review of PubMed, Scopus and Cochrane library (through 19 August 2021) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE by Actinomyces spp. was performed. A total of 31 studies providing data for 31 patients were included. A prosthetic valve was present in 12.9%, while the most common microorganism was A. meyeri. Aortic valve was the most commonly infected intracardiac site, followed by the mitral valve. Diagnosis was most commonly performed with transesophageal echocardiography, while the diagnosis was made at autopsy in 16.1%. Penicillin, cephalosporins and aminopenicillins were the most commonly used antimicrobials. Clinical cure was noted in 80.6%, while mortality was 19.4%. Development of heart failure was associated with mortality by IE. This systematic review thoroughly describes IE by Actinomyces and provides information on epidemiology, clinical presentation, treatment and outcomes.

Infective Endocarditis by Moraxella Species: A Systematic Review

Moraxella catarrhalis is the most clinically relevant species among Moraxella spp. For decades, it was considered to be part of the normal human flora in the upper respiratory tract. However, since the late 1970s, considerable evidence has proposed that M. catarrhalis is an important pathogen in the human respiratory tract. Even though Infective Endocarditis (IE) is rarely caused by Moraxella spp., these infections can be problematic due to the lack of experience in their management. The aim of this study was to systematically review all published cases of IE by Moraxella spp. A systematic review of PubMed, Scopus and Cochrane library (through 8 December 2021) for studies providing epidemiological, clinical, microbiological data as well as treatment data and outcomes of IE by Moraxella spp. was performed. A total of 27 studies, containing data for 31 patients, were included. A prosthetic valve was present in 25.8%. Mitral valve was the most commonly infected site. Fever, sepsis and embolic phenomena were the most common clinical presentations. Cephalosporins, aminoglycosides, aminopenicillins and penicillin were the most commonly used antimicrobials. Overall mortality was 12.9%.

Epidemiology of infective endocarditis: novel aspects in the twenty-first century

INTRODUCTION

The epidemiology of infective endocarditis (IE) in this millennium has changed with emergence of new risk factors and reemergence of others. This, coupled with modifications in national guidelines in the setting of a pandemic, prompted an address of the topic.

AREAS COVERED

Our goal is to provide a contemporary review of IE epidemiology considering changing incidence of rheumatic heart disease (RHD), cardiac device implantation, and injection drug use (IDU), with SARS-CoV-2 pandemic as the backdrop.

METHODS

PubMed and Google Scholar were used to identify studies of interest.

EXPERT OPINION

Our experience over the past two decades verifies the notion that there is not one 'textbook' profile of IE. Multiple factors have dramatically impacted IE epidemiology, and these factors differ, based, in part on geography. RHD has declined in many areas of the world, whereas implanted cardiovascular devices-related IE has grown exponentially. Perhaps the most influential, at least in areas of the United States, is injection drug use complicating the opioid epidemic. Healthy younger individuals contracting a potentially life-threatening infection has been tragic. In the past year, epidemiological changes due to the COVID-19 pandemic have also occurred. No doubt, changes will characterize IE in the future and serial review of the topic is warranted.

Nosocomial Native Valve Endocarditis due to Methicillin-Susceptible Staphylococcus aureus in a Patient with Psoriatic Arthritis

Nosocomial infective endocarditis is a relatively rare, but critical disease. A Japanese man in his 80s with psoriatic arthritis that was being treated with prednisolone was admitted for dyspnea. The first diagnosis was healthcare-associated pneumonia, and piperacillin/tazobactam was started. The patient's blood culture was negative at the time of admission. During the treatment, acute kidney injury occurred due to the use of antibiotics. Hemodialysis was performed via a central venous catheter in the internal jugular vein. After treatment of pneumonia, the patient experienced a sudden onset of fever accompanied by a loss of consciousness. Blood cultures from the peripheral vein and the central venous catheter were positive for methicillin-susceptible Staphylococcus aureus. A transthoracic echocardiography revealed stringy strands of vegetation attached to the native mitral valve. Magnetic resonance imagings also showed a shower of emboli to the brain. Ceftriaxone and vancomycin were administered; however, the patient died following a massive cerebral infarction. Instances of in-hospital mortality from nosocomial endocarditis are higher than the rates of community-acquired endocarditis. Clinicians should pay close attention to risk factors for nosocomial infective endocarditis. These risk factors include long-term indwelling vascular devices, psoriatic arthritis and corticosteroid therapy.

Endocarditis in Liver Transplant Recipients: A Systematic Review

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

Evolution of epidemiological characteristics of infective endocarditis in Greece

OBJECTIVE

The clinical profile, management and outcome of infective endocarditis (IE) may be influenced by socioeconomic issues.

METHODS

A nationwide prospective study evaluated IE during the era of deep economic crisis in Greece. Epidemiological data and factors associated with 60-day mortality were analyzed through descriptive statistics, logistic and Cox-regression models.

RESULTS

Among 224 patients (male 72.3%, mean age 62.4 years), Staphylococcus aureus (n = 62; methicillin-resistant S. aureus (MRSA) 33.8%) predominated in the young without impact on mortality (p = 0.593), whilst Enterococci (n = 36) predominated in the elderly. Complications of IE were associated with mortality: heart failure [OR 2.415 (95% CI: 1.159-5.029), p = 0.019], stroke [OR 3.206 (95% CI: 1.190-8.632), p = 0.018] and acute kidney injury [OR 2.283 (95% CI: 1.085-4.805), p = 0.029]. A 60-day survival benefit was solely related to cardiac surgery for IE during hospitalization [HR 0.386 (95% CI: 0.165-0.903), p = 0.028] and compliance with antimicrobial treatment guidelines [HR 0.487 (95% CI: 0.259-0.916), p = 0.026]. Compared with a previous country cohort study, history of rheumatic fever and native valve predisposition had declined, whilst underlying renal disease and right-sided IE had increased (p < 0.0001); HIV infection had emerged (p = 0.002). No difference in rates of surgery and outcome was assessed.

CONCLUSIONS

A country-wide survey of IE highlighted emergence of HIV, right-sided IE and predominance of MRSA in the youth during a severe socioeconomic crisis. Compliance with treatment guidelines promoted survival.

Infective endocarditis in patients with liver cirrhosis: a systematic review

Liver cirrhosis is an increasing cause of mortality and morbidity in developed countries. Infective Endocarditis (IE) is an uncommon disease with notable morbidity and mortality. Even though cirrhosis is associated with immune dysfunction and increased occurrence of bacterial infection, IE is infrequently diagnosed in these patients. Thus, the purpose of this study was to systematically review all published cases of IE in patients with cirrhosis in the literature. A systematic review of PubMed, Scopus and Cochrane (through 23^th April 2020) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE in patients with cirrhosis was performed. A total of 78 studies, containing data of 602 patients, were included. A prosthetic valve was present in 17.8%, while the most common causative pathogen was S. aureus in 26% followed by Streptococcus spp in 16.8%. Aortic valve was the most commonly infected site, followed by mitral valve. Diagnosis was set with a transthoracic ultrasound in 55.2%, while the diagnosis was set at autopsy in 16.7%. Fever and heart failure were the most common clinical presentations. Aminoglycosides, vancomycin, and cephalosporins were the antimicrobials most frequently used for treatment. Clinical cure was noted in 68.2%, while overall mortality was 41.4%. This systematic review thoroughly describes IE in patients with liver cirrhosis and provides information on epidemiology, clinical presentation, treatment and outcomes.

Endocarditis in kidney transplant recipients: a systematic review

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

A Systematic Review of Human Infections by Pseudomonas mendocina

Pseudomonas mendocina is a Gram-negative, rod-shaped, aerobic bacterium that belongs in the family Pseudomonadaceae and has been isolated from water and soil. Even though it is thought to cause infections quite rarely in humans, it can cause severe infections even in immunocompetent individuals. The aim of this study was to systemically review all cases of human infection by P. mendocina in the literature and describe their epidemiology, microbiology, antimicrobial susceptibility, treatment and outcomes. Thus, a systematic review of PubMed for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of Pseudomonas mendocina infections was conducted. In total, 12 studies, containing data of 16 patients, were included. The commonest P. mendocina infections were infective endocarditis, central nervous system infections and skin and soft tissue infections (SSTIs). Fever was the main presenting symptom, while sepsis was evident in almost half the patients. Pseudomonas mendocina was susceptible to most antibiotics tested. Mortality was low in all different infection types. Third or fourth generation cephalosporins and quinolones are the commonest agents used for treatment, irrespectively of the infection site.

Comparison Between Healthcare-Associated and Community-Acquired Infective Endocarditis at Tertiary Care Hospitals in Japan

BACKGROUND

Healthcare-associated infective endocarditis (HAIE) has become increasingly recognized worldwide because the underlying patient conditions are completely different from those of community-acquired infective endocarditis (CIE). However, data on HAIE in the Japanese population is lacking. We sought to clarify the patient characteristics and prognosis of HAIE in a Japanese population.Methods and Results:A retrospective study was conducted in 158 patients who were diagnosed with infective endocarditis, 53 of whom (33.5%) were classified as HAIE. Compared with patients with CIE, those with HAIE were older (median age 72 vs. 61 years; P=0.0002) and received surgical treatment less frequently (41.5% vs. 62.9%; P=0.01). Regarding causative microorganisms, staphylococci,including methicillin-resistant pathogens, were more common in patients with HAIE (32.1% vs. 14.3%; P=0.01). Patients with HAIE had higher in-hospital mortality (32.1% vs. 4.8%; P<0.0001) and Kaplan-Meier analysis showed worse prognosis for patients with HAIE than CIE (P<0.0001, log-rank test). On multivariate Cox analysis, HAIE (hazard ratio 3.26; 95% confidence interval 1.49-7.14), age ≥60 years, surgical treatment, stroke, and heart failure were independently associated with mortality.

CONCLUSIONS

HAIE has different clinical characteristics and causative microorganisms, as well as worse prognosis, than CIE. Preventive strategies, and the prompt and appropriate identification of HAIE may improve the outcome of infective endocarditis.

Nosocomial Vs. Community-Acquired Infective Endocarditis in Spain: Location, Trends, Clinical Presentation, Etiology, and Survival in the 21st Century

Major changes have occurred in the epidemiology and etiology of infective endocarditis (IE). Nevertheless, the differences between nosocomial infective endocarditis (NIE) and community-acquired infective endocarditis (CIE) have not been addressed in a population-based study. We conducted a retrospective, nationwide, temporal trend study from 1997 to 2014 analyzing the epidemiology, clinical, geographical, meteorological characteristics of patients diagnosed with IE in Spain, to distinguish NIE from CIE. Among 25,952 patients with IE (62.2 ± 18·6 years; 65.9% men), 45.9% had NIE. The incidence of IE increased from 2.83 to 3.73 due to the NIE incidence increment with a decline in CIE. Patients with NIE were older (63.8 years vs. 60.8 years, p < 0·001), presented a higher Charlson index (1.22 vs. 1.03, p < 0.001), a greater history of implanted cardiac devices (8.7% vs. 4.6%, p < 0.001), and higher mortality (31.5% vs. 21.7%, p < 0.001). The most frequent microorganism for both NIE and CIE was Staphylococcus (p < 0.001), and the North reported a higher incidence (p < 0.001). Risk factors of mortality for NIE were age, Charlson index, hemodialysis, shock, heart failure, and stroke. Risk factors for CIE included female sex, renal disease, and cardiac-device carriers. The etiology of IE shifted from community origins to mostly nosocomial-associated infections. Higher morbidity, mortality, and poorer outcomes are associated with NIE.

Pathogenicity of Enterococci

Enterococci are unusually well adapted for survival and persistence in a variety of adverse environments, including on inanimate surfaces in the hospital environment and at sites of infection. This intrinsic ruggedness undoubtedly played a role in providing opportunities for enterococci to interact with other overtly drug-resistant microbes and acquire additional resistances on mobile elements. The rapid rise of antimicrobial resistance among hospital-adapted enterococci has rendered hospital-acquired infections a leading therapeutic challenge. With about a quarter of a genome of additional DNA conveyed by mobile elements, there are undoubtedly many more properties that have been acquired that help enterococci persist and spread in the hospital setting and cause diseases that have yet to be defined. Much remains to be learned about these ancient and rugged microbes, particularly in the area of pathogenic mechanisms involved with human diseases.

Endocarditis in the Mediterranean Basin

Infective endocarditis is a severe disease with high mortality. Despite a global trend towards an increase in staphylococcal aetiologies, in older patients and a decrease in viridans streptococci, we have observed in recent studies great epidemiologic disparities between countries. In order to evaluate these differences among Mediterranean countries, we performed a PubMed search of infective endocarditis case series for each country. Data were available for 13 of the 18 Mediterranean countries. Despite great differences in diagnostic strategies, we could classify countries into three groups. In northern countries, patients are older (>50 years old), have a high rate of prosthetic valves or cardiac electronic implantable devices and the main causative agent is Staphylococcus aureus. In southern countries, patients are younger (<40 years old), rheumatic heart disease remains a major risk factor (45–93%), viridans streptococci are the main pathogens, zoonotic and arthropod-borne agents are frequent and blood culture–negative endocarditis remains highly prevalent. Eastern Mediterranean countries exhibit an intermediate situation: patients are 45 to 60 years old, the incidence of rheumatic heart disease ranges from 8% to 66%, viridans streptococci play a predominant role and zoonotic and arthropod-borne diseases, in particular brucellosis, are identified in up to 12% of cases.

Epidemiology, Microbiological and Clinical Features, Treatment, and Outcomes of Infective Endocarditis in Crete, Greece

Background

This study aimed to evaluate the epidemiology, clinical and microbiological features, treatment, and outcomes of infective endocarditis (IE) on the island of Crete, a region with high levels of antimicrobial resistance.

Materials and Methods

Medical records of all hospitalized patients diagnosed with IE at the University Hospital of Heraklion, Crete, Greece, from 1995 to 2015, were retrospectively reviewed. Patients who met the modified Duke's criteria for definite or possible IE were included.

Results

A total of 82 IE patients (median age 67 [range 21–86] years) were included. Most patients suffered from left-sided IE (94%), while most cases of infection occurred in native valves (53.6%). Systemic inflammatory response syndrome criteria were lacking in almost half of the patient population. The leading causative microorganism was Staphylococcus aureus, isolated in 24 cases (29%), followed by Streptococcus spp. in 15 (18%) and Enterococcus spp. in 12 (14.5%). A number of rare and difficult to treat microorganisms had been identified, such as Gemella morbillorum in four cases (4.5%), Streptococcus lugdunensis in two (2.5%) and Streptococcus pneumoniae in one (1%). One patient was serologically positive for Coxiella burnetii (1%). All patients received empirical antimicrobial treatment, proven appropriate in 39 blood culture-positive patients (56.5%). Thirteen (16%) patients were classified as culture negative. Seven patients (8.5%) were surgically treated. In-hospital death occurred in 9 patients (11%).

Conclusion

Changes in IE profile requires continuous epidemiological updates. Staphylococcus and Streptococcus spp. remain the most common etiologic agents. However, the presence of uncommon and/or difficult to treat pathogens raise concerns on the appropriate prophylaxis as well as empirical treatment.

Risk factors for poor prognosis in nosocomial infective endocarditis

BACKGROUND/AIMS

The aim of our study was to compare the characteristics of nosocomial infective endocarditis (NIE) with community-acquired infective endocarditis (CIE) and to determine independent risk factors for in-hospital death.

METHODS

We retrospectively reviewed the medical records of 560 patients diagnosed with infective endocarditis. NIE was defined by a diagnosis made > 72 hours after hospital admission or within 2 months of hospital discharge.

RESULTS

Among the 560 cases reviewed, 121 were classified as NIE. Compared with patients with CIE, patients with NIE were older (mean ± SD, 51.30±18.01 vs. 59.76±14.87, p < 0.001). The in-hospital death rate of the NIE group was much higher than that of the CIE group (27.3% vs. 5.9%, p < 0.001). More patients with NIE had central intravenous catheters, and were undergoing hemodialysis (p < 0.001). Methicillin-resistant Staphylococcus aureus (MRSA) was the most common causal microorganism of NIE, and MRSA (p < 0.001) and fungus (p = 0.002) were more common in NIE compared with CIE. On multiple analysis, age, liver cirrhosis, cancer chemotherapy, central intravenous catheter, hemodialysis, and genitourinary tract manipulation were independent clinical risk factors for NIE. Among the patients with NIE, 33 died during their hospital admission. The independent risk factors for in-hospital death were older age (adjusted odds ratio [OR], 1.04; 95% confidence interval [CI], 1.01 to 1.07; p = 0.037) and chemotherapy for malignancy (adjusted OR, 3.89; 95% CI, 1.18 to 12.87; p = 0.026).

CONCLUSIONS

Because of the considerable incidence of NIE and its poor prognosis, we should pay attention to early diagnosis and active management of NIE, especially for older patients and patients receiving chemotherapy.

Model systems for the study of Enterococcal colonization and infection

Enterococcus faecalis and Enterococcus faecium are common inhabitants of the human gastrointestinal tract, as well as frequent opportunistic pathogens. Enterococci cause a range of infections including, most frequently, infections of the urinary tract, catheterized urinary tract, bloodstream, wounds and surgical sites, and heart valves in endocarditis. Enterococcal infections are often biofilm-associated, polymicrobial in nature, and resistant to antibiotics of last resort. Understanding Enterococcal mechanisms of colonization and pathogenesis are important for identifying new ways to manage and intervene with these infections. We review vertebrate and invertebrate model systems applied to study the most common E. faecalis and E. faecium infections, with emphasis on recent findings examining Enterococcal-host interactions using these models. We discuss strengths and shortcomings of each model, propose future animal models not yet applied to study mono- and polymicrobial infections involving E. faecalis and E. faecium, and comment on the significance of anti-virulence strategies derived from a fundamental understanding of host-pathogen interactions in model systems.

The Changing Epidemiology of Infective Endocarditis in the Twenty-First Century

PURPOSE OF THE REVIEW

Infective endocarditis (IE) is a relatively infrequent infectious disease. It does, however, causes serious morbidity, and its mortality rate has remained unchanged at approximately 25%. Changes in IE risk factors have deeply impacted its epidemiology during recent decades but literature from low-income countries is very scarce. Moreover, prophylaxis guidelines have recently changed and the impact on IE incidence is still unknown.

RECENT FINDINGS

In high-income countries, the proportion of IE related to prior rheumatic disease has decreased significantly and has been replaced proportionally by cases related to degenerative valvulopathies, prosthetic valves, and cardiovascular implantable electronic devices. Nosocomial and non-nosocomial-acquired cases have risen, as has the proportion caused by staphylococci, and the median age of patients. In low-income countries, in contrast, rheumatic disease remains the main risk factor, and streptococci the most frequent causative agents. Studies performed to evaluate impact of guidelines changes' have shown contradictory results. The increased complexity of cases in high-income countries has led to the creation of IE teams, involving several specialties. New imaging and microbiological techniques may increase sensitivity for diagnosis and detection of IE cases. In low-income countries, IE remained related to classic risk factors. The consequences of prophylaxis guidelines changes are still undetermined.

The causative agents in infective endocarditis: a systematic review comprising 33,214 cases

Infective endocarditis (IE) incidence remains high with considerable fatality rates; guidelines for prophylaxis against IE are currently under review in some settings which highlights the importance of maintaining up-to-date epidemiological estimates about the most common microbial causes. The objective of this systematic review, following PRISMA guidelines, was to identify the most common microbial causes of IE in recent years. Medline was searched from January 1, 2003 to March 31, 2013 for all articles containing the term "infective endocarditis". All relevant studies reporting diagnostic results were included. Special patient subpopulations were assessed separately. A total of 105 studies were included, from 36 countries, with available data on a total of 33,214 cases. Staphylococcus aureus was found to be the most common microorganism, being the most frequent in 54.3 % of studies (N = 57) (and in 55.4 % of studies using Duke's criteria for diagnosis [N = 51]). Viridans group streptococci (VGS), coagulase-negative staphylococci (CoNS), Enterococcus spp and Streptococcus bovis were among the most common causes. S. aureus was the most common pathogen in almost all population subgroups; however, this was not the case in patients with implantable devices, prosthetic valves, or immunocompromised non-HIV, as well as in the sub-group from Asia, emphasizing that a global one-size-fits-all approach to the management of suspected IE is not appropriate. This review provides an evidence-based map of the most common causative agents of IE, highlighting S. aureus as the leading cause in the 21st century. The changing epidemiology of IE in some patient sub-groups in the last decade and the very high number of microbiologically undiagnosed cases (26.6 %) suggest the need to revisit IE prophylaxis and diagnostic strategies.

The fibronectin-binding protein EfbA contributes to pathogenesis and protects against infective endocarditis caused by Enterococcus faecalis

EfbA is a PavA-like fibronectin adhesin of Enterococcus faecalis previously shown to be important in experimental urinary tract infection. Here, we expressed and purified the E. faecalis OG1RF EfbA and confirmed that this protein binds with high affinity to immobilized fibronectin, collagen I, and collagen V. We constructed an efbA deletion mutant and demonstrated that its virulence was significantly attenuated (P < 0.0006) versus the wild type in a mixed inoculum rat endocarditis model. Furthermore, efbA deletion resulted in diminished ability to bind fibronectin (P < 0.0001) and reduced biofilm (P < 0.001). Reintroduction of efbA into the original chromosomal location restored virulence, adherence to fibronectin, and biofilm formation to wild-type levels. Finally, vaccination of rats with purified recombinant EfbA protein protected against OG1RF endocarditis (P = 0.008 versus control). Taken together, our results demonstrate that EfbA is an important factor involved in E. faecalis endocarditis and that rEfbA immunization is effective in preventing such infection, likely by interfering with bacterial adherence.

Global and regional burden of infective endocarditis, 1990-2010: a systematic review of the literature

Infective endocarditis (IE) is a life-threatening disease associated with serious complications. The GBD 2010 (Global Burden of Disease, Injuries, and Risk Factors) study IE expert group conducted a systematic review of IE epidemiology literature to inform estimates of the burden on IE in 21 world regions in 1990 and 2010. The disease model of IE for the GBD 2010 study included IE death and 2 sequelae: stroke and valve surgery. Several medical and science databases were searched for IE epidemiology studies in GBD high-, low-, and middle-income regions published between 1980 and 2008. The epidemiologic parameters of interest were IE incidence, proportions of IE patients who developed stroke or underwent valve surgery, and case fatality. Literature searches yielded 1,975 unique papers, of which 115 published in 10 languages were included in the systematic review. Eligible studies were population-based (17%), multicenter hospital-based (11%), and single-center hospital-based studies (71%). Population-based studies were reported from only 6 world regions. Data were missing or sparse in many low- and middle-income regions. The crude incidence of IE ranged between 1.5 and 11.6 cases per 100,000 people and was reported from 10 countries. The overall mean proportion of IE patients that developed stroke was 0.158 ± 0.091, and the mean proportion of patients that underwent valve surgery was 0.324 ± 0.188. The mean case fatality risk was 0.211 ± 0.104. A systematic review for the GBD 2010 study provided IE epidemiology estimates for many world regions, but highlighted the lack of information about IE in low- and middle-income regions. More complete knowledge of the global burden of IE will require improved IE surveillance in all world regions.

Epidemiology and the prognosis of healthcare-associated infective endocarditis in China: the significance of non-nosocomial acquisition

Limited research has been conducted on healthcare-associated infective endocarditis (HAIE), although it is of increasing importance. The aim of this study is to compare the epidemiology, clinical characteristics, and prognosis of community-acquired IE (CA-IE) with HAIE and non-nosocomial healthcare-associated IE (NNHCA-IE). A retrospective, consecutive case-series analysis was organized and performed during the 20-year study period in Huashan Hospital, Shanghai, China. A total of 154 patients were enrolled, including 126 (81.8%) who had CA-IE and 28 (18.2%) who had HAIE, among whom 20 (71.4%) had non-nosocomial IE. Patients with HAIE compared to patients with CA-IE had poorer clinical conditions (Charlson comorbidity index ≥2: 35.7% vs. 15.1%, P = 0.012; immunosuppressive therapy: 21.4% vs. 4.0%, P = 0.005), underwent more prosthetic valve replacement (35.7% vs. 7.1%, P <0.001), had less streptococcus infection (16.7% vs. 51.1%, P = 0.007) but more atypical bacterial infection (50.0% vs. 21.1%, P = 0.017) and poorer outcomes (17.9% vs. 4.0%, P = 0.019). It is noteworthy that the results were quite similar between the comparison of patients with NNHCA-IE and those with CA-IE. Overall, in-hospital mortality was 6.5%. The IE acquisition site and low serum albumin levels (odds ratio (OR): 0.8; P = 0.04) were significantly associated with an increased risk of mortality. Nosocomial IE patients had an 8.3-fold and NNHCA-IE patients had 6.5-fold increase in the risk of mortality compared to CA-IE patients. In conclusion, HAIE and NNHCA-IE have important epidemiological and prognostic implications. Because NNHCA-IE usually occurs in patients residing in the community, it is suggested that these patients should be identified and treated by the community primary care clinical staff as early as possible.

Healthcare-associated infective endocarditis: a case series in a referral hospital from 2006 to 2011

Background

Healthcare-associated infective endocarditis (HCA-IE), a severe complication of medical care, shows a growing incidence in literature.

Objective

To evaluate epidemiology, etiology, risk factors for acquisition, complications, surgical treatment, and outcome of HCA-IE.

Methods

Observational prospective case series study (2006-2011) in a public hospital in Rio de Janeiro.

Results

Fifty-three patients with HCA-IE from a total of 151 cases of infective endocarditis (IE) were included. There were 26 (49%) males (mean age of 47 ± 18.7 years), 27 (51%) females (mean age of 42 ± 20.1 years). IE was acute in 37 (70%) cases and subacute in 16 (30%) cases. The mitral valve was affected in 19 (36%) patients and the aortic valve in 12 (36%); prosthetic valves were affected in 23 (43%) patients and native valves in 30 (57%). Deep intravenous access was used in 43 (81%) cases. Negative blood cultures were observed in 11 (21%) patients, Enterococcus faecalis in 10 (19%), Staphylococcus aureus in 9 (17%), and Candida sp. in 7 (13%). Fever was present in 49 (92%) patients, splenomegaly in 12 (23%), new regurgitation murmur in 31 (58%), and elevated C-reactive protein in 44/53 (83%). Echocardiograms showed major criteria in 46 (87%) patients, and 34 (64%) patients were submitted to cardiac surgery. Overall mortality was 17/53 (32%).

Conclusion

In Brazil HCA-IE affected young subjects. Patients with prosthetic and native valves were affected in a similar proportion, and non-cardiac surgery was an infrequent predisposing factor, whereas intravenous access was a common one. S. aureus was significantly frequent in native valve HCA-IE, and overall mortality was high.

What's New in the Treatment of Enterococcal Endocarditis?

Enterococcus spp. are among the common pathogens causing infective endocarditis (IE). Despite major medical advances and new potent antimicrobial agents, the mortality has not significantly improved for several decades. The usual lack of bactericidal activity of penicillin or ampicillin, the toxicity from the combination of penicillin plus aminoglycosides, and the increased reports of high-level resistance to aminoglycosides have led to the exploration of other regimens for treatment of Enterococcus faecalis IE. As an example, ampicillin plus ceftriaxone is now a well-recognized regimen for this organism. However, the emerging of new drug resistances in Enterococcus faecium dramatically reduces the therapeutic alternatives for this organism in IE which continues to be an immense challenge for clinicians even with the availability of newer antimicrobial agents. This article summarizes the current treatment options for enterococcal endocarditis and reviews of recent publications on the topic.

Pathologic findings in native infective endocarditis

BACKGROUND

There are few studies on the histologic findings in native infective endocarditis, especially regarding mimics of autoimmune valvulitis.

METHODS

We prospectively studied 106 surgical specimens from 95 patients with a clinical diagnosis of infective endocarditis on native valves, and compared gross and histologic findings with culture results, underlying valve disease, risk factors and time interval from symptom onset to surgical intervention.

RESULTS

There were 41 (39%) aortic, 33 (31%) mitral, 9 (9%) tricuspid, 1(.9%) pulmonic and 11 (10%) multiple valve replacements. Underlying valve disease was present in 26 (27%) patients (non-calcified bicuspid aortic valve, 10 (38%) cases; mitral valve prolapse, 5 (19%) cases; calcified trileaflet aortic valve, 5 (19%) cases; calcified bicuspid aortic valve, 2 (8%) cases; post-rheumatic mitral valve disease, 2 (8%) cases; hypertrophic cardiomyopathy-related mitral valve disease, 1 (4%) case, trileaflet aortic insufficiency 1 (4%) case) and associated with streptococcal infection (p = .001). Absence of underlying valve disease was associated with intravenous drug abuse (p = .01) and dialysis dependent renal disease (p = .006). Intravenous drug abuse was associated with staphylococcal infection (p = .03). Vegetations were present in 80 (75%) of cases, and on the nonflow surface of the valve in 65 (81%) of these. Gram-stain positivity and neutrophilic microabscesses were associated with staphylococcal infection (p = .03). Epithelioid macrophages with palisading features mimicking necrobiotic granulomas were seen in 42 (40%) valves and more frequently associated with streptococcal infection (p=.03). As expected, the presence of valve necrosis and acute inflammation decreased with an increase in time with respect to symptomatic onset.

CONCLUSION

Histologic findings that mimic autoimmune inflammation are frequent in infective endocarditis and associated with streptococcal infection. Risk factors for infective endocarditis include calcific valve disease.

Epidemiology of infective endocarditis in a large Belgian non-referral hospital

OBJECTIVES

Guidelines for diagnosis of infective endocarditis are largely based upon epidemiological studies in referral hospitals. Referral bias, however, might impair the validity of guidelines in non-referral hospitals. Recent studies in non-referral care centres on infective endocarditis are sparse. We conducted a retrospective epidemiological study on infective endocarditis in a large non-referral hospital in a Belgian city (Kortrijk).

METHODS

The medical record system was searched for all cases tagged with a putative diagnosis of infective endocarditis in the period 2003-2010. The cases that fulfilled the modified Duke criteria for probable or definite infective endocarditis were included.

RESULTS

Compared to referral centres, an older population with infective endocarditis, and fewer predisposing cardiac factors and catheter-related infective endocarditis is seen in our population. Our patients have fewer prosthetic valve endocarditis as well as fewer staphylococcal endocarditis. Our patients undergo less surgery, although mortality rate seems to be highly comparable with referral centres, with nosocomial infective endocarditis as an independent predictor of mortality.

CONCLUSION

The present study suggests that characteristics of infective endocarditis as well as associative factors might differ among non-referral hospitals and referral hospitals.

Infective endocarditis epidemiology over five decades: a systematic review

AIMS

To Assess changes in infective endocarditis (IE) epidemiology over the last 5 decades.

METHODS AND RESULTS

We searched the published literature using PubMed, MEDLINE, and EMBASE from inception until December 2011.

DATA FROM

Einstein Medical Center, Philadelphia, PA were also included. Criteria for inclusion in this systematic review included studies with reported IE microbiology, IE definition, description of population studied, and time frame. Two authors independently extracted data and assessed manuscript quality. One hundred sixty studies (27,083 patients) met inclusion criteria. Among hospital-based studies (n=142; 23,606 patients) staphylococcal IE percentage increased over time, with coagulase-negative staphylococcus (CNS) increasing over each of the last 5 decades (p<0.001) and Staphylococcus aureus (SA) in the last decade (21% to 30%; p<0.05). Streptococcus viridans (SV) and culture negative (CN) IE frequency decreased over time (p<0.001), while enterococcal IE increased in the last decade (p<0.01). Patient age and male predominance increased over time as well. In subgroup analysis, SA frequency increased in North America, but not the rest of the world. This was due, in part, to an increase in intravenous drug abuse IE in North America (p<0.001). Among population-based studies (n=18; 3,477 patients) no significant changes were found.

CONCLUSION

Important changes occurred in IE epidemiology over the last half-century, especially in the last decade. Staphylococcal and enterococcal IE percentage increased while SV and CN IE decreased. Moreover, mean age at diagnosis increased together with male:female ratio. These changes should be considered at the time of decision-making in treatment of and prophylaxis for IE.

Impact of haplotypes of TNF in the natural course of infective endocarditis

Based on previous findings for the role of single nucleotide polymorphisms (SNPs) of TNF for the predisposition for bloodstream infections, this study investigates the role of these SNPs at the promoter positions -376, -308, -238 in infective endocarditis (IE). In a case-control study, 83 patients with IE and 83 controls were enrolled. Blood genotyping for the presence of G or A alleles of the three SNPs was carried out using restriction fragment length polymorphisms. Haplotypes were calculated. Patients were mostly infected by Staphylococcus aureus (32.5%) and by species of enterococci (14.3%) and streptococci (14.3%). Carriage of the minor frequency A alleles at -238 of the promoter region of TNF was greater than in controls (8.4% versus 1.2%, p 0.003). The presence of any of the three GGA/GAA/AGA haplotypes was more frequent in patients with IE (OR 8.22, 95CI% 1.8-37.4, p 0.001). After multivariate logistic regression analysis, it was found that the only factor related to fatal outcome was carriage of the wild-type GGG haplotype (OR, 3.29, 95CI%, 1.05-10.29, p 0.04). GGA, AGA and GAA haplotypes were more frequent in patients with IE than in controls, suggesting a predisposition for IE and a potential protective role against fatal outcome, as the wild-type GGG haplotype was independently related with death.

Infective endocarditis in previously healthy children with structurally normal hearts

Structural heart disease, intravascular catheters, and invasive procedures are predisposing factors for infective endocarditis (IE). Data on IE in children with structurally normal hearts and no predisposing factors are limited. We aim to characterize IE (definite or possible by Duke criteria) in such a subgroup of pediatric patients (age <18 years) who were treated at our medical center. Of 51 events of IE in 50 children, 9 (18 %) had no predisposing factors. These infections were all community-acquired and presented with fever, a newly detected heart murmur, diagnostic echocardiographic findings, and left-sided infection. Clinical course was characterized by acute onset (n = 8 of 9) with a 100 % complication rate (heart failure or embolic phenomena). Emergency cardiac surgery was performed in 7 children (Ross surgery [n = 4], mitral valve replacement [MVR; n = 2], and valve repair [n = 1]). Causative organisms were S. aureus (n = 3), S. pneumoniae (n = 2), H. parainfluenzae (n = 1), and K. kingae (n = 1). In contrast, IE in children with predisposing factors (42 of 51 [82 %]) was frequently health care-associated (30 of 42), right-sided (20 of 42, p = 0.041), and with lower rates of diagnostic echocardiographic findings (28 of 42, p = 0.041), complications (16 of 42, p < 0.001), and surgical intervention (9 of 42, p = 0.002). Causative organisms were mainly viridans streptococci (n = 9), Candida species (n = 8), coagulase-negative staphylococci (n = 6), enteric Gram-negative bacilli (n = 6), S. aureus (n = 5), and K. kingae (n = 3). Mortality was 11 % in both groups. We conclude that pediatric IE in children with and without predisposing factors differs significantly. Due to the acute and complicated course of the latter, high awareness among pediatricians and prompt diagnosis are crucial.

Unmet needs and prospects for oritavancin in the management of vancomycin-resistant enterococcal infections

The treatment of infections caused by vancomycin-resistant enterococci (VRE) has become an important clinical challenge and compromises the care of critically ill patients. A striking increase in the frequency of nosocomial isolation of multidrug-resistant Enterococcus faecium has dramatically reduced the therapeutic alternatives because the majority of E. faecium isolates are resistant to ampicillin and vancomycin. Only 2 agents have US Food and Drug Administration approval for the treatment of VRE (E. faecium) infections, namely, linezolid and quinupristin/dalfopristin (Q/D). However, the use of these compounds in severe VRE infections is hampered by the lack of in vivo bactericidal activity, reports of therapeutic failures with monotherapy, a requirement for central venous access for administration (Q/D), and adverse-effect profile. The lipopeptide antimicrobial daptomycin has in vitro bactericidal activity against VRE; however, clinical use of this compound for VRE has not been well studied, and the reports of resistance emerging during therapy at the approved doses are worrisome. Tigecycline has in vitro bacteriostatic activity against VRE, but its clinical use for serious enterococcal infections is unclear due to low serum levels and static effect. Thus, current reliable therapies for VRE appear to be limited, and clinical data that use the above compounds are certainly scant. Oritavancin is an investigational semisynthetic glycopeptide with potent in vitro activity against VRE (both VanA and VanB phenotypes). Although review of the available preclinical data indicates that this compound used as a single agent is likely to have important limitations for the treatment of a severe VRE infection (ie, endocarditis), combination of oritavancin with other agents such as aminoglycosides may offer promise and deserves further investigation, as does use of oritavancin for less serious infections as monotherapy for vancomycin-susceptible and multidrug-resistant enterococci.

[Associated factors and descriptive analysis of healthcare-related infective endocarditis in a tertiary reference hospital]

INTRODUCTION AND OBJECTIVES

The primary aim of this study was to evaluate associated factors, clinical features and prognosis of healthcare-related infective endocarditis cases compared with community-acquired and intravenous drug user-related episodes. Changes in the distribution of healthcare-related infective endocarditis were also analysed over time in our setting.

METHODS

A prospective, observational, comparative study was performed. We included all the cases of infective endocarditis from January 2003 to June 2010, which were then classified into 2 groups: group 1: community-acquired and intravenous drug user origin, and group 2: nosocomial and non-nosocomial healthcare-related cases. The episodes were classified into 2 periods: period I: January/2003-June/2006 and period II: July/2006-June 2010. Univariate and multivariate analyses were performed.

RESULTS

A total of 212 cases were included (group 1: 138, group 2: 74). The variables of age (risk ratio 1.026; 95%CI, 1.003 to 1.049), Charlson index (risk radio 1.242; 95%CI, 1.067 to 1.445), and previous heart surgery (risk ratio 2.522; 95%CI, 1.353 to 4.701) were independently associated with healthcare-related infective endocarditis on multivariate analysis. A non-significant increase was observed in healthcare-related cases of infective endocarditis in period II (40/104; 38.4% vs. 34/108; 31.4%).

CONCLUSIONS

The recent increase in healthcare-related infective endocarditis seems to be associated with the use of invasive procedures in elderly patients with prosthetic cardiac valve, and those with a greater number of underlying diseases, especially patients with chronic renal failure on haemodialysis.

[Infective endocarditis in the XXI century: epidemiological, therapeutic, and prognosis changes]

Infective endocarditis (IE) is an uncommon and severe disease. Nowadays, in developed countries, IE patients are older, usually have a degenerative heart valve disease, and up to 30% acquire this infection within the health care system. In consequence, staphylococci species are the most frequently isolated microorganisms. Antimicrobial treatment for IE has significantly changed over the last decades. In IE episodes due to Staphylococcus aureus, cloxacillin-resistance makes antimicrobial election more difficult. Other microorganisms, such as enterococci and some species of streptococci, show high rates of resistance to antimicrobial agents established in guidelines. Despite improvements in the diagnosis, and medical and surgical treatment of IE, this disease continues to be associated with high rates of in-hospital mortality. At present, due to epidemiological changes, antimicrobial prophylaxis can avoid few cases of IE. Prevention of nosocomial bacteremia, an early diagnosis of IE, prompt identification of IE patients at a higher risk of mortality, and a multidisciplinary approach of this disease could be valid strategies in order to improve the outcome of these patients.

Nosocomial methicillin-sensitive Staphylococcal aureus (MSSA) native mitral valve acute bacterial endocarditis (ABE) due to radiofrequency catheter ablation (RCA) procedure

Nosocomial endocarditis (NE) has been recognized with increasing frequency. Most cases of NE attributable to virulent pathogens (eg, Staphylococcus aureus) present as acute bacterial endocarditis (ABE). The increase in NE is related to the widespread use of cardio-invasive procedures involving cardiac catheterization or temporary or semipermanent central venous catheters. We present a 58-year-old man who developed nosocomial methicillin-sensitive S. aureus native mitral valve ABE a week after a radiofrequency catheter ablation (RCA) procedure. Cardiac valvular vegetations attributable to S. aureus ABE may be visualized by cardiac echocardiography as early as a week after the onset of valvular infection, as was the case here. Clinicians should be alert to the possibility of NE in patients who develop fevers and high-grade/continuous (MSSA / MRSA) bacteremias after cardiac catheterization-related interventions, eg, RCA procedures.

Contribution of the enterococcal surface protein Esp to pathogenesis of Enterococcus faecium endocarditis

The enterococcal surface protein Esp, specifically linked to nosocomial Enterococcus faecium, is involved in biofilm formation. To assess the role of Esp in endocarditis, a biofilm-associated infection, an Esp-expressing E. faecium strain (E1162) or its Esp-deficient mutant (E1162Δesp) were inoculated through a catheter into the left ventricle of rats. After 24 h, less E1162Δesp than E1162 were recovered from heart valve vegetations. In addition, anti-Esp antibodies were detected in Esp-positive E. faecium bacteremia and endocarditis patient sera. In conclusion, Esp contributes to colonization of E. faecium at the heart valves. Furthermore, systemic infection elicits an Esp-specific antibody response in humans.

Non-nosocomial healthcare-associated infective endocarditis in Taiwan: an underrecognized disease with poor outcome

BACKGROUND

Non-nosocomial healthcare-associated infective endocarditis (NNHCA-IE) is a new category of IE of increasing importance. This study described the clinical and microbiological characteristics and outcome of NNHCA-IE in Taiwan.

METHODS

A retrospective study was conducted of all patients with IE admitted to the Kaohsiung Veterans General Hospital in Kaohsiung, Taiwan over a five-year period from July 2004 to July 2009. The clinical and microbiological features of NNHCA-IE were compared to those of community-acquired and nosocomial IE. Predictors for in-hospital death were determined.

RESULTS

Two-hundred episodes of confirmed IE occurred during the study period. These included 148 (74%) community-acquired, 30 (15%) non-nosocomial healthcare-associated, and 22 (11%) nosocomial healthcare-associated IE. Staphylococcus aureus was the most frequent pathogen. Patients with NNHCA-IE compared to community-acquired IE, were older (median age, 67 vs. 44, years, p < 0.001), had more MRSA (43.3% vs. 9.5%, p < 0.001), more comorbidity conditions (median Charlson comorbidity index [interquartile range], 4[2-6] vs. 0[0-1], p < 0.001), a higher in-hospital mortality (50.0% vs. 17.6%, p < 0.001) and were less frequently recognized by clinicians on admission (16.7% vs. 47.7%, p = 0.002). The overall in-hospital mortality rate for all patients with IE was 25%. Shock was the strongest risk factor for in-hospital death (odds ratio 7.8, 95% confidence interval 2.4-25.2, p < 0.001).

CONCLUSIONS

NNHCA-IE is underrecognized and carries a high mortality rate. Early recognition is crucial to provide optimal management and improve outcome.

Healthcare-associated versus community-associated infective endocarditis in children

BACKGROUND

Infective endocarditis (IE) in children is continuously changing in regard to underlying conditions, predisposing factors, etiologic agents, clinical manifestations, treatment, and outcome. We describe current characteristics and compare healthcare-associated and community-associated disease.

PATIENTS AND METHODS

All children (<18 years) who were treated at our center between January 1992 through June 2004 and met the Duke criteria for definite or possible IE were included. Demographic, clinical, and laboratory data were collected. Cases were categorized as healthcare- or community-associated.

RESULTS

A total of 50 children with IE were identified (51 events; 0.32/1000 hospitalizations). Twenty children (41%) had an isolated congenital heart disease, 13 (25%) had an underlying chronic disease, 9 (18%) were previously healthy, and 8 (16%) were preterm. Mortality rate was 12% (6/51). Compared with the community-associated cases (21/51, 41%), the healthcare-associated cases (30/51, 59%) showed female preponderance, younger age, 1.7-fold longer hospitalization, 1.6-fold longer time to pathogen eradication, and 3.4-fold higher mortality. The leading causes of healthcare-associated IE were Candida sp (8/30, 27%), coagulase-negative staphylococci (6/30, 20%), and Gram-negative bacilli (5/30, 16%). By contrast, the leading causes of community-associated IE were viridans streptococci (8/21, 38%) and Staphylococcus aureus (4/21, 19%).

CONCLUSIONS

A high proportion of pediatric IE is healthcare-associated that occurs in younger and sicker children. Healthcare-associated IE differs from community-associated IE in the patients' age, causative pathogens, and mortality. These trends and the different etiologies may affect future antibiotic management of this important pediatric infection.

Conservation of Ebp-type pilus genes among Enterococci and demonstration of their role in adherence of Enterococcus faecalis to human platelets

Ebp are endocarditis- and biofilm-associated pili of Enterococcus faecalis that are also important in experimental urinary tract infections (UTIs). Our analyses, using available genomes, found that the ebp locus is unique to enterococci. In E. faecalis, the ebp locus is very highly conserved and only 1/473 E. faecalis isolates tested lacked ebpABC, while only 1.2% had the bee pilus locus. No other pilus-encoding operon was identified in 55 available genomes, indicating that the vast majority of E. faecalis strains (unlike Enterococcus faecium and streptococci) have a single pilus locus. Surface expression studies showed that Ebp pili were produced in vitro by 91/91 brain heart infusion (BHI) plus serum-grown E. faecalis isolates and that strain OG1RF expressed pili at even higher levels in rat endocarditis vegetations. However, Ebp expression was restricted to 30 to 72% of E. faecalis cells, consistent with a bistability mode of expression. We also evaluated E. faecalis interactions with human platelets and found that growth of E. faecalis in BHI plus serum significantly enhanced adherence to human platelets and that sortase deletion mutants (the ΔsrtA, Δbps, and ΔbpsΔsrtA mutants) were markedly defective. Further studies identified that Ebp pili, but not the microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) Ace and Fss2, mediate adherence of E. faecalis to platelets. Taken together, our data show that the immunogenic (in human endocarditis patients) and commonly expressed Ebp pili, which are known to be important for experimental endocarditis, are highly conserved and mediate adherence to platelets, suggesting that Ebp pili may be a reasonable immunotherapeutic target for prevention or possibly treatment of endocarditis caused by this species.

Importance of the collagen adhesin ace in pathogenesis and protection against Enterococcus faecalis experimental endocarditis

Ace is an adhesin to collagen from Enterococcus faecalis expressed conditionally after growth in serum or in the presence of collagen. Here, we generated an ace deletion mutant and showed that it was significantly attenuated versus wild-type OG1RF in a mixed infection rat endocarditis model (P<0.0001), while no differences were observed in a peritonitis model. Complemented OG1RFΔace (pAT392::ace) enhanced early (4 h) heart valve colonization versus OG1RFΔace (pAT392) (P = 0.0418), suggesting that Ace expression is important for early attachment. By flow cytometry using specific anti-recombinant Ace (rAce) immunoglobulins (Igs), we showed in vivo expression of Ace by OG1RF cells obtained directly from infected vegetations, consistent with our previous finding of anti-Ace antibodies in E. faecalis endocarditis patient sera. Finally, rats actively immunized against rAce were less susceptible to infection by OG1RF than non-immunized (P = 0.0004) or sham-immunized (P = 0.0475) by CFU counts. Similarly, animals given specific anti-rAce Igs were less likely to develop E. faecalis endocarditis (P = 0.0001) and showed fewer CFU in vegetations (P = 0.0146). In conclusion, we have shown for the first time that Ace is involved in pathogenesis of, and is useful for protection against, E. faecalis experimental endocarditis.

Enterococcus faecalis was recognized as a common cause of infective endocarditis (IE) by the early 1900s. It is still third in community-onset IE, but is the second most common cause of hospital-associated IE. Complications due to E. faecalis IE include congestive heart failure, septic emboli and death and current management involves a combination of antimicrobials, often with surgery. Emergence of antimicrobial resistance has created the need for alternative strategies (such as immunoprophylaxis) that target in vivo expressed virulence-associated surface proteins. One such E. faecalis protein is Ace, which is antigenic during human IE and mediates attachment of E. faecalis cells to host extracellular matrix proteins collagen and laminin. Using a rat model, we now show that ace contributes to E. faecalis IE pathogenesis and demonstrate that Ace is expressed at high levels during IE even though produced at low levels under laboratory conditions; both active and passive immunization based on the collagen-binding domain of Ace conferred significant protection against IE. These observations, along with data that human antibodies against Ace inhibit collagen adherence of E. faecalis, indicate that Ace is an important virulence-associated factor and a promising target for prophylactic and possibly therapeutic strategies against E. faecalis IE.

Enterococcal surface protein Esp is not essential for cell adhesion and intestinal colonization of Enterococcus faecium in mice

Background

Enterococcus faecium has globally emerged as a cause of hospital-acquired infections with high colonization rates in hospitalized patients. The enterococcal surface protein Esp, identified as a potential virulence factor, is specifically linked to nosocomial clonal lineages that are genetically distinct from indigenous E. faecium strains. To investigate whether Esp facilitates bacterial adherence and intestinal colonization of E. faecium, we used human colorectal adenocarcinoma cells (Caco-2 cells) and an experimental colonization model in mice.

Results

No differences in adherence to Caco-2 cells were found between an Esp expressing strain of E. faecium (E1162) and its isogenic Esp-deficient mutant (E1162Δesp). Mice, kept under ceftriaxone treatment, were inoculated orally with either E1162, E1162Δesp or both strains simultaneously. Both E1162 and E1162Δesp were able to colonize the murine intestines with high and comparable numbers. No differences were found in the contents of cecum and colon. Both E1162 and E1162Δesp were able to translocate to the mesenteric lymph nodes.

Conclusion

These results suggest that Esp is not essential for Caco-2 cell adherence and intestinal colonization or translocation of E. faecium in mice.

Contemporary epidemiology and prognosis of health care-associated infective endocarditis

BACKGROUND

The aim of this study was to describe the characteristics of health care-associated infective endocarditis (HAIE) and to establish the risk factors for mortality.

METHODS

We conducted a prospective, observational cohort study. HAIE was defined according to the following conditions: (1) symptom onset >48 h after hospitalization or within 6 months after hospital discharge; or (2) ambulatory manipulations causing endocarditis.

RESULTS

Eighty-three episodes of HAIE (accounting for 28.4% of all cases of endocarditis) were diagnosed. Compared with patients with community-acquired endocarditis, patients with HAIE were older (median age +/- standard deviation, 65.3 +/- 16.4 years vs. 57.8 +/- 17.0 years; P = .001), were in poorer health before disease onset (Charlson index, 2.5 +/- 2.3 vs. 1.7 +/- 2.1; P = .006), had more staphylococcal (55.4% vs. 28.3% of cases) and enterococcal infections (22.9% vs. 7.7% of cases; P < .005), underwent fewer surgeries (22.9% vs. 45.9% of cases; P < .005), and experienced a higher rate of in-hospital (45.8% vs. 22.0%) and 1-year mortality (59.5% vs. 29.6%; P < .005). In the HAIE cohort, independent predictors of in-hospital death were stroke (odds ratio [OR], 8.95; 95% confidence interval [CI], 2.04-39.31; P = .004), congestive heart failure (OR, 5.48; 95% CI, 1.77-17.03; P = .003), surgery indicated but not performed (OR, 3.74; 95% CI, 1.22-11.45; P = .021), and enterococcal infection (OR, 0.18; 95% CI, 0.04-0.78; P = .022). Independent predictors of 1-year mortality were surgery indicated but not performed (OR, 7.81; 95% CI, 2.06-29.67; P = .003), acute renal failure (OR, 7.18; 95% CI, 1.32-39.18; P = .023), and enterococcal infection (OR, 0.18; 95% CI, 0.04-0.81; P = .026). For the series overall (292 episodes), HAIE was an independent predictor of in-hospital (OR, 2.83; 95% CI, 1.34-5.98; P = .007) and 1-year mortality (OR, 2.59; 95% CI, 1.25-5.39; P = .011).

CONCLUSIONS

HAIE is an important health problem associated with considerable mortality. New strategies to prevent HAIE should be assessed.

Contribution of the collagen adhesin Acm to pathogenesis of Enterococcus faecium in experimental endocarditis

Enterococcus faecium is a multidrug-resistant opportunist causing difficult-to-treat nosocomial infections, including endocarditis, but there are no reports experimentally demonstrating E. faecium virulence determinants. Our previous studies showed that some clinical E. faecium isolates produce a cell wall-anchored collagen adhesin, Acm, and that an isogenic acm deletion mutant of the endocarditis-derived strain TX0082 lost collagen adherence. In this study, we show with a rat endocarditis model that TX0082 Deltaacm::cat is highly attenuated versus wild-type TX0082, both in established (72 h) vegetations (P < 0.0001) and for valve colonization 1 and 3 hours after infection (P or=50-fold reduction relative to an Acm producer) were found in three of these five nonadherent isolates, including the sequenced strain TX0016, by quantitative reverse transcription-PCR, indicating that acm transcription is downregulated in vitro in these isolates. However, examination of TX0016 cells obtained directly from infected rat vegetations by flow cytometry showed that Acm was present on 40% of cells grown during infection. Finally, we demonstrated a significant reduction in E. faecium collagen adherence by affinity-purified anti-Acm antibodies from E. faecium endocarditis patient sera, suggesting that Acm may be a potential immunotarget for strategies to control this emerging pathogen.