Causative Agent Of Infective Endocarditis Research Articles

Epidemiological profile and mortality of infective endocarditis over the past decade: a systematic review and meta-analysis of 133 studies comprising 132,355 cases

Abstract Background Understanding the epidemiology of infective endocarditis (IE) is crucial in the context of an aging population, increased comorbidities, and the heightened occurrence of healthcare-associated cases. Comprehensive data on causative agents, affected valves, and associated mortality are essential for current clinical practice. Methods This systematic review was conducted according to the PRISMA guidelines. A random effects model meta-analysis was conducted. Eligible studies reporting outcomes on IE were identified through a search of the PubMed/Medline database from 2010 to 2021. Results One hundred-thirty-three studies with 132,584 patients from six continents were included in the analysis. The most common causative agents of IE were Staphylococci species in 36% of cases, followed by Streptococci species in 26% of cases and Enterococci species in 10% of cases. Of the studies providing further speciation, the predominant species was Staphylococcus aureus with an incidence of 29%, followed by Viridans Streptococcus with an incidence of 12%. We found an in-hospital/30-day mortality of 17% (CI: 16%-19%) from 109 studies worldwide. In the subgroup analysis, the highest mortality rates were observed in Latin America 33% (CI: 28%-38%) and Africa 25% (CI: 21%-30%), while the lowest mortality rates were reported in Oceania 13% (CI: 8%-19%), followed by North America 14% (CI: 11%-18%), Asia 15% (CI: 12%-18%), and Europe 17% (CI: 16%-19%). The aortic valve was affected in 46% of cases, followed by the mitral valve in 43%. Tricuspid valve IE and multivalvular IE were identified in 7% and 14% of the cases, respectively. Conclusion Our study highlights the shift in epidemiological profile of IE over the last decade with S. aureus identified as the most common causative microorganism of IE in almost one third of cases. IE remains a highly morbid and fatal condition with high mortality rates even in tertiary and high-expertise centers worldwide. While left-sided IE is by far more common, right-sided IE and multivalvular IE are not rare entities and should be considered early in the differential of patients presenting with suspected IE to decrease the risk of future complications.Global burden of infective endocarditis.

An Emerging Threat: A Systematic Review of Endocarditis Caused by Gemella Species.

Infective endocarditis caused by Gemella species is increasingly recognized as an emerging clinical entity. Gemella species are fastidious gram-positive cocci that are typically commensal organisms but can become opportunistic pathogens. This systematic review aimed to provide a comprehensive overview of endocarditis due toGemellaspecies by synthesizing existing evidence. A total of 52 case reports were identified through a rigorous search and selection process. The most prevalent causative species were G. morbillorum (46.3%) and G. haemolysans (25.9%), with a striking male predominance (79.6%). The clinical presentation was largely nonspecific, mirroring typical infective endocarditis. However, the indolent nature of the illness and fastidious growth requirements of Gemella species often led to diagnostic delays. Echocardiography, particularly transesophageal echocardiography, played a crucial role in the diagnosis, enabling the detection of valvular vegetation and the assessment of complications. Management posed significant challenges, including the need for broad-spectrum empirical antibiotic therapy and increasing antimicrobial resistance among Gemella isolates. Surgical intervention was frequently required for severe valvular dysfunction, persistent infection, or embolic complications. Despite advances in diagnosis and treatment, endocarditis due toGemellaspeciesremains associated with significant morbidity and mortality, underscoring the importance of early recognition and multidisciplinary management. This review highlights the emerging clinical significance of Gemella species as causative agents of infective endocarditis and identifies areas for further research.

Impact of Hemoglobin Level, White Blood Cell Count, Renal Dysfunction, and Staphylococcus as the Causative Organism on Prediction of In-Hospital Mortality from Infective Endocarditis.

Infective endocarditis (IE) is a highly fatal disease in cases of delayed diagnosis and treatment, although its incidence is low. However, there have been few single-center studies in which the risk of in-hospital death from IE was stratified according to laboratory findings on admission and the organism responsible for IE. In this study, a total of 162 patients who were admitted to our hospital during the period from 2009 to 2021, who were suspected of having IE according to the modified Duke classification, and for whom IE was confirmed by transesophageal echocardiography were retrospectively analyzed. Patients were observed for a mean-period of 43.7 days with the primary endpoint being in-hospital death. The in-hospital death group had a lower level of hemoglobin (Hb), higher white blood cell (WBC) count, lower level of estimated glomerular filtration rate (eGFR), and higher frequency of Staphylococcus being the causative agent than those in the non-in-hospital death group. In overall multivariate analysis, Hb, WBC count, eGFR, and Staphylococcus as the causative agent were identified to be significant prognostic determinants. IE patients with Hb < 10.6 g/dL, WBC count > 1.4 × 104/μL, eGFR < 28.1 mL/minute/1.7 m2, and Staphylococcus as the causative agent had significantly and synergistically increased in-hospital death rates compared to those in other IE patients. Low level of Hb, high WBC count, low eGFR, and Staphylococcus as the causative agent of IE were independent predictors of in-hospital mortality, suggesting that these 4 parameters may be combined to additively stratify the risk of in-hospital mortality.

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

Infective endocarditis (IE) poses a significant health risk, especially in patients with prosthetic heart valves. Despite advances in treatment, mortality rates remain high. This study aims to investigate the antibacterial properties of a copper titanium dioxide (4× Cu-TiO2) coating on cardiovascular implants against Staphylococcus aureus, a common causative agent of IE. Titanium oxide carriers functionalized with copper ions were employed as an antibacterial coating for heart and vascular prostheses. The coating's antibacterial efficacy was assessed using S. aureus ATCC 29213. Microscopic evaluations were conducted on both biological and artificial materials. Antibacterial activity was qualitatively assessed via a modified disc diffusion method and quantitatively measured through colony counts in NaCl suspensions. The coating process was successfully applied to all tested cardiovascular prosthetic materials. Qualitative assessments of antibacterial effectiveness revealed an absence of bacterial growth in the area directly beneath the coated valve. Quantitative evaluations showed a significant reduction in bacterial colonization on coated mechanical valves, with 2.95 × 104 CFU per valve, compared to 1.91 × 105 CFU in control valves. The 4× Cu-TiO2 coating demonstrated promising antibacterial properties against S. aureus, suggesting its potential as an effective strategy for reducing the risk of bacterial colonization of cardiovascular implants. Further studies are needed to assess the longevity of the coating and its efficacy against other pathogens.

Effect of Antibiotic Therapy on the Sensitivity of Etiological Diagnostic Methods in Patients with Infective Endocarditis after Surgery

Aim. Assessment of impact of the duration of preoperative antimicrobial therapy (AMT) on the sensitivity of microbiological examination and polymerase chain reaction (PCR) of blood/tissues of resected valves in operated patients with infective endocarditis (IE).Materials and methods. 52 operated patients with active IE were included prospectively (Duke criteria, 2015). All patients underwent microbiological examination of blood before admission to the cardiac surgery hospital, as well as parallel simultaneous microbiological examination and PCR of blood/tissues of excised valves, followed by Sanger sequencing. The duration of preoperative treatment was calculated from the first day of AMT according to IE diagnosis to the day of surgery.Results. The causative agent of IE was established in 84.6% (n=44) patients by means of complex etiological diagnosis. A significant decrease in the sensitivity of microbiological examination of venous blood was revealed when performed in the period before and after hospitalization to a surgical hospital (up 44.2% to 17.3%, p&lt;0.05). When comparing microbiological examination of blood/tissues of resected valves and PCR of blood/tissues of resected valves, molecular biological methods demonstrated the greatest sensitivity, with a great advantage when examining the tissues of resected valves (17.3% and 19.2% vs. 38.5% and 75.0%, respectively; p&lt;0.001). The microbiological examination of venous blood performed at an early date before admission to the cardiac surgery hospital was comparable in sensitivity to the PCR blood test performed at a later date after prolonged AMT, and significantly less sensitive in relation to the PCR of resected valve tissues [44.2% and 38.5% (p&gt;0.05) vs. 75.0% (p&lt;0.05)]. In course of AMT 1-28 days, there were comparable results of microbiological examination with PCR blood examination and significantly better results of PCR of resected valve tissues [31.0% and 34.5% and 41.4% (p&gt;0.05) vs 72.4% (p&lt;0.001), respectively], and with AMT ≥ 29 days, microbiological examination of any biological material was negative in all patients, and PCR of blood/tissues of resected valves retained high sensitivity (0% and 0% vs. 34.8% and 78.3%, respectively; p&lt;0.01).Conclusion. Long-term preoperative AMT significantly reduced the sensitivity of microbiological examination of resected valve blood/tissue in operated patients with IE, whereas PCR of resected valve blood/tissue was highly sensitive even with preoperative AMT for more than 29 days.

Clinical and diagnostic value of including PCR blood test in the traditional algorithm for identifying causative agents of infective endocarditis: a cohort study of 124 patients

If infective endocarditis (IE) is suspected, the determination of the etiology is of fundamental importance for the verification of the disease and the appointment of effective therapy. Microbiological diagnostic features are important, but they often need to be supplemented by culture-independent studies of pathological agents. To investigate of the diagnostic advantage and value of quantitative analysis of molecular biological methods (polymerase chain reaction - PCR, sequencing) in addition to microbiological examination of whole venous blood in IE. We examined 124 patients with suspected or significant IE (DUKE 2015) hospitalized in the Vinogradov City Clinical Hospital (2015-2021). All patients underwent parallel microbiological (cultural) and molecular biological (PCR or PCR followed by sequencing) examination of venous whole blood samples. The introduction of an early parallel PCR study into the algorithm for the etiological diagnosis of IE made it possible to obtain an additional advantage in 43/124 (34.7%) patients, which made it possible to exclude unreliable results in the determination of CoNS skin commensals and pathogens atypical for IE or contamination and identify the true pathogens, and also for the first time to isolate the etiopathogenetic pathogen with a negative microbiological study. It was shown that in IE associated with CoNS, the association with the disease was confirmed by PCR in 21.4% (3/14) and refuted in 71.4% (10/14). The coincidence of the results of microbiological and PCR studies of blood samples was obtained only in 35/95 (36.8%). Positive results of PCR analysis of blood of biological material with negative results of culture were obtained in 22/51 (43.1%), of which 2/22 (9.0%) were able to confirm the presence of Bartonella spp DNA. The presented complex algorithm made it possible to significantly increase the possibility of intravital identification of the pathogen in the blood from 58.9 to 76.6%. IE with unknown etiology was present in 29/124 (23.4%) patients. A parallel PCR study allowed timely correction of antibiotic therapy in 43/124 (34.7%) patients. Expansion of indications for the use of PCR studies, primarily whole venous blood samples, is justified, not only in IE with negative results of microbiological examination, but also as a control method for the reliability of the results of traditional (cultural) diagnostic methods.

Infective endocarditis caused by Gemella haemolysans in a patient with bicuspid aortic valve: A case report

Gemella haemolysans is a gram-positive coccus, and commensal of the upper respiratory tract and oral mucosa. In rare cases, it has been identified as an opportunistic pathogen in the development of endocarditis. Here, we describe a case of Gemella haemolysans endocarditis in a patient with bicuspid aortic valve. A 14-year-old male presented to our hospital with a 1-month history of intermittent fever. Gemella haemolysans was isolated from the patient’s blood cultures. Transesophageal echocardiography revealed severe aortic stenosis and a pseudoaneurysm of the mitral–aortic intervalvular fibrosa. The patient underwent aortic valve replacement with pseudoaneurysm of the mitral–aortic intervalvular fibrosa repair and remained symptom-free during follow-up. This case highlights the importance of considering atypical pathogens as causative agents of infective endocarditis.

Infective Endocarditis Caused by Multi-Drug Resistant Corynebacterium Species: A Case Report

Corynebacteria species are anaerobic, facultative, non-sporing, gram-positive bacilli that can cause infective endocarditis. In recent years, non-diphtherial Corynebacterium (diphtheroids) has increasingly been recognised as a cause of both localised and systemic infections. Determining the exact species of Corynebacteria is challenging due to their similar characteristics. Infective Endocarditis (IE) caused by Corynebacteria species is uncommon because positive blood cultures might be considered contaminants, leading to missed diagnoses. However, they can indeed cause IE, which is a severe condition. Antibiotic resistance among Corynebacteria species is common and has been increasing, making treatment challenging. In-vitro resistance to vancomycin cannot be detected reliably. Literature on IE caused by Corynebacteria species is limited, and more comprehensive information is needed. In cases of IE caused by Corynebacteria species, prosthetic valves are mainly affected, especially in elderly patients, and surgery is often required. Within the Corynebacterium genus, Corynebacterium striatum is a major causative agent of IE. Although Corynebacteria species in blood cultures are often considered contaminants from skin flora, they can also cause invasive infections such as sepsis and IE. The present case report describes the isolation of Corynebacteria species from the blood specimen of a 50-year-old male who presented with fever, headache, decreased appetite, and fatigue.

A rare association of invasive infective endocarditis due to Abiotrophia defectiva with ventricular septal defect and recurrent Henoch-Schonlein purpura in a child

BackgroundHenoch-Schonlein purpura is the most common vasculitis in childhood, usually triggered by an upper respiratory tract infection and rarely observed in infective endocarditis patients. Abiotrophia defectiva is a rare causative agent of infective endocarditis associated with pre-existing heart disease, immunocompromised and prosthetic valves. Dental procedures are also a common predisposing factor.Case presentationWe present the first pediatric congenital heart disease case of infective endocarditis caused by Abiotrophia defectiva combined with recurrent Henoch-Schonlein purpura. A 10-year-old girl with uncorrected congenital heart defects and Henoch-Schonlein purpura developed a purple petechial rash again. Transthoracic echocardiography evaluation revealed multiple irregular vegetations on the right ventricular side of the ventricular septal defect and on the tricuspid valve leaflets. Blood cultures grew Abiotrophia defectiva. The girl received cardiac surgery for vegetation resection as well as congenital heart defect correction and tricuspid valve replacement. Five months after the surgery, the patient was in satisfactory condition without any signs of endocarditis or valve insufficiency and her purpuric rash disappeared.ConclusionsThe coexistence of recurrent Henoch-Schonlein purpura and infective endocarditis is possible. Abiotrophia defectiva belongs to the streptococcus with a high virulence. In addition, cardiovascular surgery is often required for pediatric infective endocarditis associated with Abiotrophia defectiva, and bioprosthetic valve replacement is considered feasible for irreparable tricuspid valve in children.

Abiotrophia spp. and Granulicatella spp. Infective Endocarditis: A Contemporary Perspective.

Abiotrophia spp. and Granulicatella spp. are Gram-positive cocci, formerly known as nutritionally variant or deficient Streptococcus. Their role as causative agents of infective endocarditis (IE) is numerically uncertain, as well as diagnostic and clinical management of this infection. The aim of our study is to describe the clinical, microbiological, therapeutic, and prognosis of patients with IE caused by these microorganisms in a large microbiology department. Retrospective analysis of all the patients with Abiotrophia spp. and Granulicatella spp. IE registered in our centre in the period 2004-2021. Of the 822 IE in the study period, 10 (1.2%) were caused by Abiotrophia spp. (7) or Granulicatella spp. (3). The species involved were A.defectiva (7), G.adiacens (2) and G.elegans (1). Eight patients were male, their mean age was 46 years and four were younger than 21 years. The most frequent comorbidities were congenital heart disease (4; 40%) and the presence of intracardiac prosthetic material (5; 50%). IE occurred on 5 native valves and 5 prosthetic valve or material. Blood cultures were positive in 8/10 patients, within a mean incubation period of 18.07 hours. In the other two patients, a positive 16SPCR from valve or prosthetic material provided the diagnosis. Surgery for IE was performed in seven patients (70%) and in all cases positive 16S rRNA PCR and sequencing from valve or prosthetic material was demonstrated. Valves and/or prosthetic removed material cultures were positive in four patients. Nine patients received ceftriaxone (4 in monotherapy and 5 in combination with other antibiotics). The mean length of treatment was 6 weeks and IE-associated mortality was 20% at one year follow-up. Abiotrophia spp. or Granulicatella spp. IE were infrequent but not exceptional in our environment and particularly affected patients with congenital heart disease or prosthetic material. Blood cultures and molecular methods allowed the diagnosis. Most of them required surgery and the associated mortality, in spite of a mean age of 46 years, was high.

Etiology, Risk Factors and Clinical Outcomes in Infective Endocarditis Patients Requiring Cardiac Surgery.

Background: Infective endocarditis, which may be caused by various microbial agents, severely affects the innermost layer of the heart and often leads to poor clinical outcomes. The purpose of this study was to investigate the etiology, risk factors and short and long-term outcomes of infective endocarditis caused by various bacterial agents in patients requiring cardiac surgery. Methods: One hundred and forty-four patients aged 18 years or above with indications for cardiac surgery due to S. aureus, Streptococcus spp., E. faecalis or coagulase-negative staphylococci caused infective endocarditis were included in this study. Results: S. aureus, Streptococcus spp., E. faecalis and coagulase-negative staphylococci were the causative agents of infective endocarditis in 44 (30.6%), 35 (24.3%), 33 (22.9%) and 32 (22.2%) patients, respectively. The presence of bicuspid aortic valve was the most common predisposing factor confirmed in 19 (23.5%), whereas intravenous drug usage was the most common in 17 (11.8%) patients. No significant differences in intrahospital mortality due to infective endocarditis caused by various bacterial agents were found, however, the worsening of long-term prognosis of endocarditis caused by S. aureus when compared to E. faecalis was confirmed (p = 0.03). The presence of S. aureus was associated with significantly higher rates of embolic complications (p = 0.003). The presence of coagulase-negative staphylococci was associated with prosthetic valve endocarditis (p = 0.015) and perivalvular complications (p = 0.024). Conclusions: In contrast to E. faecalis, the presence of S. aureus determines the worsening of the long-term mortality from infective endocarditis. Perivalvular complications are associated with the presence of coagulase-negative staphylococci.

Infective Endocarditis Due to Corynebacterium Species: Clinical Features and Antibiotic Resistance

Background Corynebacterium species are often dismissed as contaminants in blood cultures, but they can also cause infective endocarditis (IE), which is a severe condition. Antibiotic resistance of corynebacteria is increasing making treatment challenging. Reports on IE caused by Corynebacterium species are scarce and more knowledge is needed.MethodsCases of IE caused by Corynebacterium species were identified through the Swedish Registry of Infective Endocarditis. Isolates were collected for species redetermination by matrix-assisted laser desorption ionization-time of flight and for antibiotic susceptibility testing using Etests.ResultsThirty episodes of IE due to Corynebacterium species were identified between 2008 and 2017. The median age of patients was 71 years (interquartile range, 60–76) and 77% were male. Corynebacterium striatum (n = 11) was the most common IE causing pathogen followed by Corynebacterium jeikeium (n = 5). Surgery was performed in 50% and in-hospital mortality rate was 13%. Patients with IE caused by Corynebacterium species were significantly more likely to have prosthetic valve endocarditis (70%), compared with patients with IE due to Staphylococcus aureus or non-beta-hemolytic streptococci (14% and 26%, respectively) (P < .0001). Vancomycin was active towards all Corynebacterium isolates, whereas resistance towards penicillin G was common.Conclusions Corynebacterium species cause IE, where prosthetic valves are mainly affected and surgery is often performed. Corynebacterium striatum is an important causative agent of IE within the genus. Antibiotic resistance of corynebacteria is relatively common but resistance towards vancomycin could not be detected in vitro.

A case of infective endocarditis caused by Arthrobacter woluwensis

Corynebacteria are rare causative agents of infective endocarditis. This is a reported case of a destructive aorto-mitral infective endocarditis caused by Arthrobacter woluwensis. Microbial identification was achieved by 16S rRNA polymerase chain reaction on valve tissue samples. Outcome was favorable after surgical valve replacement and 4-week antibiotic treatment.

Clinical and morphological characteristics of infective endocarditis

The aim of the study was to identify the features of the clinical course and morphogenesis of infective endocarditis (IE) in HIVinfected injecting drug users with concomitant hepatitis C virus infection in comparison with the clinical and morphological picture of endocarditis in persons without drug dependence. It was found that the causative agent of IE in HIV-infected patients was staphylococcus aureus (71.8%), and in persons without drug dependence in the etiology of the disease the conditionally pathogenic flora prevailed. In HIV-infected drug-dependent patients, the tricuspid valve was affected (82.7%), and in persons without drug dependence — isolated aortic valve damage (40%) and combined mitral and aorticvalve lesions (36.4%). Purulent sepsis complications in drug-dependent patients with IE are less common than in patients without drug dependence due to immunosuppression, which is present in HIV-infected persons.

Contribution of Severe Dental Caries Induced by Streptococcus mutans to the Pathogenicity of Infective Endocarditis.

Streptococcus mutans, a major pathogen of dental caries, is regarded as a causative agent of infective endocarditis (IE), which mainly occurs in patients with underlying heart disease. However, it remains unknown whether severe dental caries that extend to pulp space represent a possible route of infection. In the present study, we evaluated the virulence of S. mutans for IE development using rats with concurrent severe dental caries and heart valve injury. Dental caries was induced in rats through the combination of a caries-inducing diet and the administration of S. mutans into the oral cavity. Then, the heart valves of a subset of rats were injured using a sterile catheter and wire under general anesthesia. The rats were euthanized at various times with various stages of dental caries. The number of teeth affected by dental caries with pulp exposure was increased in the rats in a time-dependent manner. S. mutans was recovered from injured heart tissue, which was mainly observed in rats with higher number of S. mutans bacteria in mandibular bone and a larger number of teeth in which caries extended to pulp. Dental caries was more severe in rats with heart injury than in rats without heart injury. Sequencing analysis targeting 16S rRNA revealed that specific oral bacteria appeared only in rats with heart injury, which may be related to the development of dental caries. Our findings suggest that dental caries caused by the combination of S. mutans infection and sucrose intake may contribute to S. mutans colonization in injured heart tissue.

Characteristics of Species Composition of Causative Agents in Infective Endocarditis

&#x0D; Introduction. The frequency of infective endocarditis (IE) in children with congenital heart disease (CHD) is 15– 140 times higher than that in the overall population and varies from 2 to 18% according to different authors.&#x0D; The aim. To define the main groups of causative agents of infective endocarditis in children and adults in order to build up an antibiotic treatment algorithm.&#x0D; Materials and methods. The analysis of examination findings and treatment outcomes in 124 patients was conducted from 2014 to 2019. These patients received medical treatment at the Ukrainian Children`s Cardiac Center (UCCC), Kyiv. The patients were divided into two groups by age: group 1 included children aged from 6 days to 18 years (62 [50.0%]), group 2 comprised adults aged from 18 to 79 years (62 [50.0%]).&#x0D; Results and discussion. Forty-nine isolates were recovered from 124 patients during the analysis of microbiological study results. The frequency of bacterial IE causative agents was 26 (41.9%) in group 1, and 17 (27.4%) in group 2. Comparative analysis of the spectrum of IE pathogens revealed differences in the two study groups. Coagulase-negative staphylococcus was the most common causative agent in group 1 (46.7% of all isolated strains; n = 12) and in group 2 (44.4%; n = 8). Staphylococcus aureus in children was detected in 5 (8.1%) cases, whereas in adults only in 2 (11.1%) cases. Pathogens of the Enterococcus spp. family (E. faecalis) were recovered in both study groups: in 6.5% (n = 2) and 16.6% (n = 3) of the patients, respectively. Gram-negative flora was detected in 3 (9.7%) patients of group 1 and, in 2 (11.1%) patients of group 2. Fungal flora was more commonly found in children (7 [22.6%] cases represented by the Candida family), whereas in adults only 1 (5.6%) case represented by the Mucor family was revealed.&#x0D; Conclusions. Etiological structure of the infective endocarditis pathogens in both groups was represented mainly by gram-positive bacteria, with S. epidermidis (24.5%) being the most essential. The changes were revealed in the species composition of the pathogens in group 1 with fungal microflora dominance: Candida parapsilosis in 9.7%, C. albicans and C. famata in 6.5% of the total number of plated cultures in this group. The difference in surgical operations due to possible IE in both groups was established based on the specific features of operations determined by the age factor.

Antimicrobial Treatment of Infective Endocarditis, Caused by &lt;i&gt;Enterococcus Faecalis

The frequency of infective endocarditis (IE) has increased 3 times over the past 30 years. The incidence of IE morbidity is recorded in all countries of the world and in the Russian Federation more than 40 people per 1 million population get sick. One of the most frequent causative agents of infective endocarditis is Enterococcus faecalis (E. faecalis), which takes the third place in the structure of the frequency of IE pathogens. Enterococcal IE remains a disease with high mortality, despite the emergence of new groups of antibacterial drugs. This review includes the results of studies of the efficacy and safety of various antimicrobial regimens of IE caused by E. faecalis. The analysis of data from foreign and native studies of antimicrobial treatment in patients with infective endocarditis, accompanied by enterococcal bacteremia is presented in the review. The search for literature performed by using medical databases: MEDLINE, EMBASE, eLIBRARY. The current review included studies of the efficacy and safety of antimicrobial treatment. The main antibiotic therapy regimens of IE caused by E. faecalis include 2 beta-lactam antibiotics or a combination of ampicillin and gentamicin, according to the results of 5 found studies. Found antimicrobial regimens significantly did not affect mortality. Data from international registries testify to the efficacy and safety of daptomycin monotherapy for enterococcal endocarditis. Linezolid and daptomycin are the main drugs of treating infective endocarditis caused by vancomycin-resistant enterococci. Native studies report of a high level of resistance of enterococcal strains to beta-lactam antibacterial drugs. The duration of fever, the frequency of surgical heart valves interventions, the duration of bacteremia are not fully represented in each of the studies, and it is difficult to evaluate these factors. Ampicillin+ceftriaxone and ampicillin+gentamicin are the main antimicrobial treatment regimens of enterococcal endocarditis. Efficacy of these regimens is not significantly different. Treatment of IE should be carried out taking into the epidemiological situation and the strain resistance.

Pasteurella canis infective endocarditis in a dog

Infective endocarditis, an infrequent clinical syndrome in dogs, is typically associated with nondescript clinical signs such as fever, malaise and loss of appetite. Although an uncommonly reported infection in dogs, Pasteurella canis is an emerging pathogen with increasing relevance in the human microbiology literature. The goal of this study is to detail the clinical presentation and microbiological findings associated with a novel causative agent of infective endocarditis in the dog. Diagnostic evaluation as well as conventional, automated and molecular microbiological methods are highlighted. The recent literature regarding P. canis and infective endocarditis in companion animals and humans is reviewed. Although an unusual etiologic agent of infective endocarditis, awareness of P. canis as a diagnostic possibility is crucial to accurate microbial surveillance.

Identification of Streptococcus gallolyticus subsp. gallolyticus (Biotype I) Competence-Stimulating Peptide Pheromone.

Streptococcus gallolyticus subsp. gallolyticus, a member of the group D streptococci, is normally found in the bovine rumen and human gut. It is an opportunistic pathogen that was recently determined to be a bacterial driver of colorectal cancer, in addition to causing other diseases, such as infective endocarditis, bacteremia, neonatal meningitis, and septicemia. As an emerging pathogen, not much is known about this bacterium, its virulence mechanisms, or its virulence regulatory pathways. Previous studies suggest that S. gallolyticus subsp. gallolyticus uses a ComRS pathway, one of many Streptococcus quorum-sensing circuitries, for competence. However, thus far, the ubiquitous ComABCDE pathway has not been studied, nor has its regulatory role in S. gallolyticus subsp. gallolyticus We therefore sought to study the S. gallolyticus subsp. gallolyticus ComABCDE quorum-sensing pathway and have identified its peptide pheromone, which is termed the competence-stimulating peptide (CSP). We further determined that this peptide regulates the production of bacteriocin-like inhibitory substances (BLISs), a phenotype that has been linked with the ComABCDE pathway in both Streptococcus pneumoniae and Streptococcus mutans Our data show that S. gallolyticus subsp. gallolyticus TX20005 produces a 21-mer CSP signal, which differs from CSP signals of other Streptococcus species in that its active form begins three residues after the double-glycine leader signal of the ComC precursor peptide. Additionally, our data suggest that this peptide might not be related to competence induction, as opposed to CSP signaling peptides in other Streptococcus species. This study provides the first evidence that S. gallolyticus subsp. gallolyticus utilizes quorum sensing to eliminate competitors, presenting a potential pathway to target this emerging human pathogen.IMPORTANCEStreptococcus gallolyticus subsp. gallolyticus is an emerging human pathogen known as a causative agent of infective endocarditis, and recently, of colorectal cancer. In this work, we revealed a functional quorum-sensing circuitry in S. gallolyticus subsp. gallolyticus, including the identification of the central signaling peptide pheromone, competence-stimulating peptide (CSP), and the regulatory role of this circuitry in the production of bacteriocin-like inhibitory substances (BLISs). This work uncovered a mechanism by which this bacterium outcompetes other bacterial species and thus provides a potential tool to study this opportunistic pathogen.

Macrophage Polarization Alters Postphagocytosis Survivability of the Commensal Streptococcus gordonii.

Oral streptococci are generally considered commensal organisms; however, they are becoming recognized as important associate pathogens during the development of periodontal disease as well as being associated with several systemic diseases, including as a causative agent of infective endocarditis. An important virulence determinant of these bacteria is an ability to evade destruction by phagocytic cells, yet how this subversion occurs is mostly unknown. Using Streptococcus gordonii as a model commensal oral streptococcus that is also associated with disease, we find that resistance to reactive oxygen species (ROS) with an active ability to damage phagosomes allows the bacterium to avoid destruction within macrophages. This ability to survive relies not only on the ROS resistance capabilities of the bacterium but also on ROS production by macrophages, with both being required for maximal survival of internalized bacteria. Importantly, we also show that this dependence on ROS production by macrophages for resistance has functional significance: S. gordonii intracellular survival increases when macrophages are polarized toward an activated (M1) profile, which is known to result in prolonged phagosomal ROS production compared to that of alternatively (M2) polarized macrophages. We additionally find evidence of the bacterium being capable of both delaying the maturation of and damaging phagosomes. Taken together, these results provide essential insights regarding the mechanisms through which normally commensal oral bacteria can contribute to both local and systemic inflammatory disease.