Guidelines for the antibiotic treatment of endocarditis in adults: report of the Working Party of the British Society for Antimicrobial Chemotherapy

Severe Tricuspid Regurgitation in a Patient With Previous Tricuspid Valve Surgery for Infective Endocarditis Secondary to Intravenous Drug Use: A Case Report

Tricuspid regurgitation (TR) is an important but underappreciated disease in medical practice, and the severity can vary from moderate to severe. Right-sided infective endocarditis (RSIE) is more common in intravenous drug users (IVDUs), and the vast majority of these involve the tricuspid valve (TV). It is worth mentioning that right-sided valves are challenging to scan compared to left-sided valves. The incidence of severe tricuspid regurgitation (TR) immediately post-repair is not tangible, but it is considered to be rare. We present a case of a 47-year-old patient who had previous TV septal leaflet reconstruction using a bovine pericardial patch using 6/0 prolene, and an annuloplasty was performed by placing an annuloplasty ring in 2017 for infective endocarditis. The patient developed moderate to severe tricuspid regurgitation within a few weeks following the surgery. She was readmitted to the hospital four years later with a reduced consciousness level, and a subsequent repeat echocardiogram showed possible tricuspid valve vegetation. In addition, transoesophageal echocardiogram (TOE) demonstrated biventricular dysfunction and severe tricuspid regurgitation, along with moderate to severe mitral regurgitation (MR) that was variable depending on the rate of atrial fibrillation. The patient was not suitable for surgical intervention and was medically managed accordingly.

Safe shortening of antibiotic treatment duration for complicated Staphylococcus aureus bacteraemia (SAFE trial): protocol for a randomised, controlled, open-label, non-inferiority trial comparing 4 and 6 weeks of antibiotic treatment

INTRODUCTION

A major knowledge gap in the treatment of complicated Staphylococcus aureus bacteraemia (SAB) is the optimal duration of antibiotic therapy. Safe shortening of antibiotic therapy has the potential to reduce adverse drug events, length of hospital stay and costs. The objective of the SAFE trial is to evaluate whether 4 weeks of antibiotic therapy is non-inferior to 6 weeks in patients with complicated SAB.

METHODS AND ANALYSIS

The SAFE-trial is a multicentre, non-inferiority, open-label, parallel group, randomised controlled trial evaluating 4 versus 6 weeks of antibiotic therapy for complicated SAB. The study is performed in 15 university hospitals and general hospitals in the Netherlands. Eligible patients are adults with methicillin-susceptible SAB with evidence of deep-seated or metastatic infection and/or predictors of complicated SAB. Only patients with a satisfactory clinical response to initial antibiotic treatment are included. Patients with infected prosthetic material or an undrained abscess of 5 cm or more at day 14 of adequate antibiotic treatment are excluded. Primary outcome is success of therapy after 180 days, a combined endpoint of survival without evidence of microbiologically confirmed disease relapse. Assuming a primary endpoint occurrence of 90% in the 6 weeks group, a non-inferiority margin of 7.5% is used. Enrolment of 396 patients in total is required to demonstrate non-inferiority of shorter antibiotic therapy with a power of 80%. Currently, 152 patients are enrolled in the study.

ETHICS AND DISSEMINATION

This is the first randomised controlled trial evaluating duration of antibiotic therapy for complicated SAB. Non-inferiority of 4 weeks of treatment would allow shortening of treatment duration in selected patients with complicated SAB. This study is approved by the Medical Ethics Committee VUmc (Amsterdam, the Netherlands) and registered under NL8347 (the Netherlands Trial Register). Results of the study will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NL8347 (the Netherlands Trial Register).

Pathogenesis, Diagnosis, Antimicrobial Therapy, and Management of Infective Endocarditis, and Its Complications

Infective endocarditis in the adult is life-threatening. Bacterial endocarditis is an inner infection lining the heart muscle (endocardium). The scientific study of the causes of diseases is known as etiology. The agents that cause disease fall into five groups: bacteria, viruses, protozoa, fungi, and helminths (worms). Risk factors are past heart defects, damaged or abnormal heart valves, new valves after surgery, chronic hemodialysis, and immunosuppressed state (chemotherapy, HIV, etc.). Infective endocarditis is categorized into two clinical forms: bacterial acute and subacute endocarditis. Acute bacterial endocarditis is usually caused by staphylococci (staph) and streptococci (strep). And occasionally by listeria and brucella bacterial strains. Invasive medical technology has increased the responsibility of healthcare-associated infective endocarditis (HAIE). Microscopy of the disease is the chronic aggressive cells in the deeper zone of nonspecific, composed of fibrin and platelets covering colonies of bacteria. Tuberculous valvular endocarditis due to mycobacterium tuberculosis is a rare clinical entity. Syphilitic endocarditis is pathologically the cutaneous lesions of secondary syphilis. It is caused by infection with the microorganismTreponema pallidum. Fungal endocarditis is a rare and fatal condition. They are infected with fungi such as Candida albicans, Histoplasma capsulatum, and Aspergillus species. Fatal endocarditis associated with Q fever (query fever). Q fever is a chronic or prolonged disease caused by the rickettsial-like bacillus Coxiella burnetii, a rare form of rickettsia in the endocarditis. Varicella-zoster virus (VZV) infection causes chronic and repeated febrile illness. They are followed by pharyngitis, malaise, and a vesicular rash. Chronic Q fever usually manifests as endocarditis or hepatitis. The therapy given to simplify the complications is antimicrobial therapy. The medicines prescribed are ampicillin, cefazolin, ceftazidime, gentamicin, vancomycin, metronidazole, and tobramycin. High medicinal antibiotics are used to control the spread of infective endocarditis.

Antibiotics and Carbohydrate-Containing Drugs Targeting Bacterial Cell Envelopes: An Overview

Certain bacteria constitute a threat to humans due to their ability to escape host defenses as they easily develop drug resistance. Bacteria are classified into gram-positive and gram-negative according to the composition of the cell membrane structure. Gram-negative bacteria have an additional outer membrane (OM) that is not present in their gram-positive counterpart; the latter instead hold a thicker peptidoglycan (PG) layer. This review covers the main structural and functional properties of cell wall polysaccharides (CWPs) and PG. Drugs targeting CWPs are discussed, both noncarbohydrate-related (β-lactams, fosfomycin, and lipopeptides) and carbohydrate-related (glycopeptides and lipoglycopeptides). Bacterial resistance to these drugs continues to evolve, which calls for novel antibacterial approaches to be developed. The use of carbohydrate-based vaccines as a valid strategy to prevent bacterial infections is also addressed.

Brain abscess due to Aggregatibacter aphrophilus in association with atrial septal defect：Case report and literature review

BACKGROUND

Aggregatibacter aphrophilus（A. aphrophilus）is one of the organisms of the HACEK group. Previously reported cases of brain abscesses caused by A. aphrophilus infection have occurred in children with a basis for congenital heart disease, or in adults with a basis for dental disease. Rare cases of brain abscess caused by A. aphrophilus have been reported in adults with congenital heart disease or in patients without dental disease history. Herein we present a rare case of brain abscess caused by A. aphrophilus, who was in association with atrial septal defect for more than 20 years, and had no dental disease and did not develop infective endocarditis.

CASE PRESENTATION

A 51-year-old female was admitted due to progressively worsening headache and left limb weakness for more than 10 days. She denied the history of chronic diseases such as hypertension and diabetes, and no periodontal disease. While she had a history of atrial septal defect, a form of congenital heart disease with severe pulmonary hypertension for more than 20 years. After admission, echocardiographic illustrated congenital heart disease with severe pulmonary hypertension. CT and MRI showed brain abscess. Cerebrospinal fluid (CSF) results also confirmed the presence of intracranial infection. Empirical therapy with vancomycin 1.0 g i.v q12h and meropenem 2.0 g i.v q8h was initiated from the day of admission. On the fourth day after admission, brain abscess resection and decompressive craniectomy were performed, and the pus drained on operation were cultured and Gram-negative bacilli grew, which was identified as A.aphrophilus. Vancomycin was discontinued and meropenem was continued（2.0 g i.v q8h）for 5 weeks, followed by oral levofloxacin 0.5 qd for 4 weeks of out-patient antibiotics. The patient recovered fully within 9 weeks of treatment.

CONCLUSIONS

This is the first case of A. aphrophilus to cause brain abscess in adult with a history of congenital heart disease for more than 20 years, who had no dental disease and did not develop infective endocarditis. We also highlight the value of bacterial 16 S rDNA PCR amplification and sequencing in identifying bacteria in abscesses which are culture-negative, and prompt surgical treatment，choosing effective antibiotics and appropriate course of treatment will get better clinical effect.

What Is in a Cat Scratch? Growth of Bartonella henselae in a Biofilm

Bartonella henselae (B. henselae) is a gram-negative bacterium that causes cat scratch disease, bacteremia, and endocarditis, as well as other clinical presentations. B. henselae has been shown to form a biofilm in vitro that likely plays a role in the establishment and persistence of the bacterium in the host. Biofilms are also known to form in the cat flea vector; hence, the ability of this bacterium to form a biofilm has broad biological significance. The release of B. henselae from a biofilm niche appears to be important in disease persistence and relapse in the vertebrate host but also in transmission by the cat flea vector. It has been shown that the BadA adhesin of B. henselae is critical for adherence and biofilm formation. Thus, the upregulation of badA is important in initiating biofilm formation, and down-regulation is important in the release of the bacterium from the biofilm. We summarize the current knowledge of biofilm formation in Bartonella species and the role of BadA in biofilm formation. We discuss the evidence that defines possible mechanisms for the regulation of the genes required for biofilm formation. We further describe the regulation of those genes in the conditions that mimic both the arthropod vector and the mammalian host for B. henselae. The treatment for persistent B. henselae infection remains a challenge; hence, a better understanding of the mechanisms by which this bacterium persists in its host is critical to inform future efforts to develop drugs to treat such infections.

Effectiveness of daptomycin against infective endocarditis caused by highly penicillin-resistant viridans group streptococci

Penicillin-resistant viridans group streptococci (VGS) infections are an emerging issue in infectious diseases. Here, we present a case of mitral valve infective endocarditis caused by highly penicillin-resistant VGS (minimum inhibitory concentration >4 μg/mL), which was successfully treated with daptomycin. Although the clinical efficacy of daptomycin has not been established, it can be an alternative for the treatment of highly resistant VGS endocarditis.

The novel use of oral antibiotic monotherapy in prosthetic valve endocarditis caused by Finegoldia magna: a case study

Background

Finegoldia magna, a Gram-positive anaerobic coccus, is part of the human normal microbiota as a commensal of mucocutaneous surfaces. However, it remains an uncommon pathogen in infective endocarditis, with only eight clinical cases previously reported in the literature.

Currently, infective endocarditis is routinely treated with prolonged intravenous antibiotic therapy. However, recent research has found that switching patients to oral antibiotics is non-inferior to prolonged parenteral antibiotic treatment, challenging the current guidelines for the treatment of infective endocarditis.

Case presentation

This case report focuses on a 52-year-old gentleman, who presented with initially culture-negative infective endocarditis following bioprosthetic aortic valve replacement. Blood cultures later grew Finegoldia magna. Following initial intravenous antibiotic therapy and re-do surgical replacement of the prosthetic aortic valve, the patient was successfully switched to oral antibiotic monotherapy, an unusual strategy in the treatment of infective endocarditis inspired by the recent publication of the POET trial. He made excellent progress on an eight-week course of oral antibiotics and was successfully discharged from surgical follow-up.

Conclusions

This case is the 9th reported case of Finegoldia magna infective endocarditis in the literature. Our case also raises the possibility of a more patient-friendly and cost-effective means of providing long-term antibiotic therapy in suitable patients with prosthetic valve endocarditis and suggests that the principles highlighted in the POET trial can also be applicable to post-operative patients after cardiac surgery.

Adjunctive rifampicin to reduce early mortality from Staphylococcus aureus bacteraemia: the ARREST RCT

BACKGROUND

Staphylococcus aureus bacteraemia is a common and frequently fatal infection. Adjunctive rifampicin may enhance early S. aureus killing, sterilise infected foci and blood faster, and thereby reduce the risk of dissemination, metastatic infection and death.

OBJECTIVES

To determine whether or not adjunctive rifampicin reduces bacteriological (microbiologically confirmed) failure/recurrence or death through 12 weeks from randomisation. Secondary objectives included evaluating the impact of rifampicin on all-cause mortality, clinically defined failure/recurrence or death, toxicity, resistance emergence, and duration of bacteraemia; and assessing the cost-effectiveness of rifampicin.

DESIGN

Parallel-group, randomised (1 : 1), blinded, placebo-controlled multicentre trial.

SETTING

UK NHS trust hospitals.

PARTICIPANTS

Adult inpatients (≥ 18 years) with meticillin-resistant or susceptible S. aureus grown from one or more blood cultures, who had received < 96 hours of antibiotic therapy for the current infection, and without contraindications to rifampicin.

INTERVENTIONS

Adjunctive rifampicin (600-900 mg/day, oral or intravenous) or placebo for 14 days in addition to standard antibiotic therapy. Investigators and patients were blinded to trial treatment. Follow-up was for 12 weeks (assessments at 3, 7, 10 and 14 days, weekly until discharge and final assessment at 12 weeks post randomisation).

MAIN OUTCOME MEASURES

The primary outcome was all-cause bacteriological (microbiologically confirmed) failure/recurrence or death through 12 weeks from randomisation.

RESULTS

Between December 2012 and October 2016, 758 eligible participants from 29 UK hospitals were randomised: 370 to rifampicin and 388 to placebo. The median age was 65 years [interquartile range (IQR) 50-76 years]. A total of 485 (64.0%) infections were community acquired and 132 (17.4%) were nosocomial; 47 (6.2%) were caused by meticillin-resistant S. aureus. A total of 301 (39.7%) participants had an initial deep infection focus. Standard antibiotics were given for a median of 29 days (IQR 18-45 days) and 619 (81.7%) participants received flucloxacillin. By 12 weeks, 62 out of 370 (16.8%) patients taking rifampicin versus 71 out of 388 (18.3%) participants taking the placebo experienced bacteriological (microbiologically confirmed) failure/recurrence or died [absolute risk difference -1.4%, 95% confidence interval (CI) -7.0% to 4.3%; hazard ratio 0.96, 95% CI 0.68 to 1.35; p = 0.81]. There were 4 (1.1%) and 5 (1.3%) bacteriological failures (p = 0.82) in the rifampicin and placebo groups, respectively. There were 3 (0.8%) versus 16 (4.1%) bacteriological recurrences (p = 0.01), and 55 (14.9%) versus 50 (12.9%) deaths without bacteriological failure/recurrence (p = 0.30) in the rifampicin and placebo groups, respectively. Over 12 weeks, there was no evidence of differences in clinically defined failure/recurrence/death (p = 0.84), all-cause mortality (p = 0.60), serious (p = 0.17) or grade 3/4 (p = 0.36) adverse events (AEs). However, 63 (17.0%) participants in the rifampicin group versus 39 (10.1%) participants in the placebo group experienced antibiotic or trial drug-modifying AEs (p = 0.004), and 24 (6.5%) participants in the rifampicin group versus 6 (1.5%) participants in the placebo group experienced drug-interactions (p = 0.0005). Evaluation of the costs and health-related quality-of-life impacts revealed that an episode of S. aureus bacteraemia costs an average of £12,197 over 12 weeks. Rifampicin was estimated to save 10% of episode costs (p = 0.14). After adjustment, the effect of rifampicin on total quality-adjusted life-years (QALYs) was positive (0.004 QALYs), but not statistically significant (standard error 0.004 QALYs).

CONCLUSIONS

Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S. aureus bacteraemia.

FUTURE WORK

Given the substantial mortality, other antibiotic combinations or improved source management should be investigated.

TRIAL REGISTRATIONS

Current Controlled Trials ISRCTN37666216, EudraCT 2012-000344-10 and Clinical Trials Authorisation 00316/0243/001.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 59. See the NIHR Journals Library website for further project information.

Bartonella Species, an Emerging Cause of Blood-Culture-Negative Endocarditis

Since the reclassification of the genus Bartonella in 1993, the number of species has grown from 1 to 45 currently designated members. Likewise, the association of different Bartonella species with human disease continues to grow, as does the range of clinical presentations associated with these bacteria. Among these, blood-culture-negative endocarditis stands out as a common, often undiagnosed, clinical presentation of infection with several different Bartonella species. The limitations of laboratory tests resulting in this underdiagnosis of Bartonella endocarditis are discussed. The varied clinical picture of Bartonella infection and a review of clinical aspects of endocarditis caused by Bartonella are presented. We also summarize the current knowledge of the molecular basis of Bartonella pathogenesis, focusing on surface adhesins in the two Bartonella species that most commonly cause endocarditis, B. henselae and B. quintana. We discuss evidence that surface adhesins are important factors for autoaggregation and biofilm formation by Bartonella species. Finally, we propose that biofilm formation is a critical step in the formation of vegetative masses during Bartonella-mediated endocarditis and represents a potential reservoir for persistence by these bacteria.

Surgical management of tricuspid valve endocarditis in the current era: A review

The incidence of isolated tricuspid valve infective endocarditis is increasing. Medical management is the mainstay of treatment but surgical intervention is required in a subset of patients. Surgical treatment options include valve excision and replacement or valve reconstruction. We searched PubMed and the Cochrane library to identify articles to be included in this review of surgical outcomes. References of selected articles were crosschecked for other relevant studies. Surgical management of tricuspid valve endocarditis can be achieved with satisfactory outcomes. However, the optimal indication and timing of surgery remain unclear, and the frequent association with intravenous drug use complicates management. Repair techniques are preferable though there is no clear evidence supporting one method over another.

Enterococcal endocarditis revisited

The Enterococcus species is the third main cause of infective endocarditis (IE) worldwide, and it is gaining relevance, especially among healthcare-associated cases. Patients with enterococcal IE are older and have more comorbidities than other types of IE. Classical treatment options are limited due to the emergence of high-level aminoglycosides resistance (HLAR), vancomycin resistance and multidrug resistance in some cases. Besides, few new antimicrobial alternatives have shown real efficacy, despite some of them being recommended by major guidelines (including linezolid and daptomycin). Ampicillin plus ceftriaxone 2 g iv./12 h is a good option for Enterococcus faecalis IE caused by HLAR strains, but randomized clinical trials are essential to demonstrate its efficacy for non-HLAR EFIE and to compare it with ampicillin plus short-course gentamicin. The main mechanisms of resistance and treatment options are also reviewed for other enterococcal species.

Puerperal group A streptococcal infection: beyond Semmelweis

Ignaz Semmelweiss made one of the most important contributions to modern medicine when he instituted handwashing in an obstetric clinic in Austria in 1847, decreasing mortality there from more than 10% to 2%. Unfortunately, puerperal sepsis remains a leading cause of maternal mortality throughout the world. Group A streptococcus (GAS), Streptococcus pyogenes, is an organism associated with high rates of morbidity and mortality from puerperal infections. When associated with sepsis, known as streptococcal toxic shock syndrome, mortality rates approach 30-50%. Group A streptococcus can cause invasive infections in the form of endometritis, necrotizing fasciitis, or streptococcal toxic shock syndrome. The clinical presentation of women with puerperal GAS infections is often atypical with extremes of temperature, unusual and vague pain, and pain in extremities. Toxin production by the organism may allow GAS to spread across tissue planes and cause necrosis while evading containment by the maternal immune system in the form of a discrete abscess. Endometrial aspiration in addition to blood cultures may be a useful rapid diagnostic tool. Imaging may appear normal and should not dissuade the clinician from aggressive management. When suspected, invasive GAS infections should be treated emergently with fluid resuscitation, antibiotic administration, and source control. The optimal antibiotic regimen contains penicillin and clindamycin. Source control may require extensive wound or vulvar debridement, hysterectomy, or a combination of these, which may be life-saving. The benefit of immunoglobulins in management of puerperal GAS infections is unclear.

Anti-Candida, anti-enzyme activity and cytotoxicity of 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamides

Because of the need for more effective and less harmful antifungal therapies, and interest in the synthesis of new carboximidamides, the goal of this study was to determine the antifungal and anti-enzyme activities of some new pyrazole carboximidamides and their cytotoxicity. For this purpose, tests were performed to evaluate: minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC); production of proteinases and phospholipase, and cytotoxicity of the extracts. Data were analyzed by ANOVA and Tukey Tests (α = 5%). The results were: MIC and MFC ≥ 62.5 μg/mL (C. albicans, C. parapsilosis, C. famata, C. glabrata, and Rhodotorula mucillaginosa) and MIC and MFC ≥ 15.6 μg/mL (C. lipolytica). The values of proteinase and phospholipase (Pz) of C. albicans before and after exposure to the compounds were: 0.6 (±0.024) and 0.2 (±0.022) and 0.9 (±0.074) and 0.3 (±0.04), respectively. These proteinase results were not significant (p = 0.69), but those of phospholipase were (p = 0.01), and 15.6 μg/mL was the most effective concentration. The cytotoxicity means were similar among the tests (p = 0.32). These compounds could be useful as templates for further development through modification or derivatization to design more potent antifungal agents. Data from this study provide evidence that these new pyrazole formulations could be an alternative source for the treatment of fungal infections caused by Candida. However, a specific study on the safety and efficacy of these in vivo and clinical trials is still needed, in order to evaluate the practical relevance of the in vitro results.

Treatment of Gram-positive left-sided infective endocarditis with daptomycin

The aim of this study was to evaluate the effectiveness of daptomycin in left-sided infective endocarditis (IE) patients. Fourteen patients with left heart endocarditis, monitored with a diagnosis of IE based on modified Duke criteria between July 2010 and May 2011, and receiving daptomycin as monotherapy, were enrolled. The success of daptomycin in these patients was revealed with improvements in microbiological, biochemical, and radiologic findings, as well as physical examination findings. Patient average age was 63.5 ± 14.2 years (36-80 years); 8 (57 %) were men and 6 (43 %) women. The pathogens methicillin-resistant Staphylococcus aureus (71.5 %), Streptococcus mutans (21.5 %), and methicillin-sensitive Staphylococcus aureus (7 %) were isolated from our patients. Daptomycin was used in initial treatment in 5 (36 %) patients; treatment was subsequently modified to daptomycin in 9 (64 %) patients as a consequence of drug serum level insufficiency, agent sensitivity to the drug administered, or drug side effects. Thirteen patients were discharged in a healthy condition, with successful surgical treatment in 5 (36 %). Only 1, an 80-year-old IE patient, was lost from advanced cardiac failure. No significant side effects were seen in any patient receiving daptomycin. The most frequent side effects were minimal rises in serum CPK levels during treatment; these values returned to normal after treatment. Daptomycin can be used successfully in left heart endocarditis with no significant side effects. Studies involving a wider patient series are now needed to support the use of daptomycin in left heart endocarditis.

Adjunctive rifampicin to reduce early mortality from Staphylococcus aureus bacteraemia (ARREST): study protocol for a randomised controlled trial

Background

Staphylococcus aureus bacteraemia is a common and serious infection, with an associated mortality of ~25%. Once in the blood, S. aureus can disseminate to infect almost any organ, but bones, joints and heart valves are most frequently affected. Despite the infection’s severity, the evidence guiding optimal antibiotic therapy is weak: fewer than 1,500 patients have been included in 16 randomised controlled trials investigating S. aureus bacteraemia treatment. It is uncertain which antibiotics are most effective, their route of administration and duration, and whether antibiotic combinations are better than single agents. We hypothesise that adjunctive rifampicin, given in combination with a standard first-line antibiotic, will enhance killing of S. aureus early in the treatment course, sterilise infected foci and blood faster, and thereby reduce the risk of dissemination, metastatic infection and death. Our aim is to determine whether adjunctive rifampicin reduces all-cause mortality within 14 days and bacteriological failure or death within 12 weeks from randomisation.

Methods

We will perform a parallel group, randomised (1:1), blinded, placebo-controlled trial in NHS hospitals across the UK. Adults (≥18 years) with S. aureus (meticillin-susceptible or resistant) grown from at least one blood culture who have received ≤96 h of active antibiotic therapy for the current infection and do not have contraindications to the use of rifampicin will be eligible for inclusion. Participants will be randomised to adjunctive rifampicin (600-900mg/day; orally or intravenously) or placebo for the first 14 days of therapy in combination with standard single-agent antibiotic therapy. The co-primary outcome measures will be all-cause mortality up to 14 days from randomisation and bacteriological failure/death (all-cause) up to 12 weeks from randomisation. 940 patients will be recruited, providing >80% power to detect 45% and 30% reductions in the two co-primary endpoints of death by 14 days and bacteriological failure/death by 12 weeks respectively.

Discussion

This pragmatic trial addresses the long-standing hypothesis that adjunctive rifampicin improves outcome from S. aureus bacteraemia through enhanced early bacterial killing. If proven correct, it will provide a paradigm through which further improvements in outcome from S. aureus bacteraemia can be explored.

Trial registration

Current Controlled Trial ISRCTN 37666216

Infective endocarditis in intravenous drug abusers: an update

Infective endocarditis despite advances in diagnosis remains a common cause of hospitalization, with high morbidity and mortality rates. Through literature review it is possible to conclude that polymicrobial endocarditis occurs mainly in intravenous drug abusers with predominance in the right side of the heart, often with tricuspid valve involvement. This fact can be associated with the type of drug used by the patients; therefore, knowledge of the patient's history is critical for adjustment of the therapy. It is also important to emphasize that the most common combinations of organisms in polymicrobial infective endocarditis are: Staphylococcus aureus, Streptococcus pneumonia and Pseudomonas aeruginosa, as well as mixed cultures of Candida spp. and bacteria. A better understanding of the epidemiology and associated risk factors are required in order to develop an efficient therapy, although PE studies are difficult to perform due to the rarity of cases and lack of prospective cohorts.

Granulicatella infection: diagnosis and management

Granulicatella species, along with the genus Abiotrophia, were originally known as 'nutritionally variant streptococci'. They are a normal component of the oral flora, but have been associated with a variety of invasive infections in man and are most noted as a cause of bacterial endocarditis. It is often advised that Granulicatella endocarditis should be treated in the same way as enterococcal endocarditis. We review here the published data concerning diagnosis and treatment of Granulicatella infection, and include some observations from local cases, including four cases of endocarditis.

[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.

Guidelines for the diagnosis and antibiotic treatment of endocarditis in adults: a report of the Working Party of the British Society for Antimicrobial Chemotherapy

The BSAC guidelines on treatment of infectious endocarditis (IE) were last published in 2004. The guidelines presented here have been updated and extended to reflect developments in diagnostics, new trial data and the availability of new antibiotics. The aim of these guidelines, which cover both native valve and prosthetic valve endocarditis, is to standardize the initial investigation and treatment of IE. An extensive review of the literature using a number of different search criteria has been carried out and cited publications used to support any changes we have made to the existing guidelines. Publications referring to in vitro or animal models have only been cited if appropriate clinical data are not available. Randomized, controlled trials suitable for the development of evidenced-based guidelines in this area are still lacking and therefore a consensus approach has again been adopted for most recommendations; however, we have attempted to grade the evidence, where possible. The guidelines have also been extended by the inclusion of sections on clinical diagnosis, echocardiography and surgery.

Postpartum culture negative endocarditis: a case report and review of the current guidelines

Culture-negative endocarditis (CNE) presents physicians with diagnostic and treatment challenges. Postpartum endocarditis is rare and usually culture negative. Empirical antimicrobial regimes lead to the risk of aggressive treatment with potentially toxic drugs. This paper presents a case of postpartum CNE, discussing the issues of diagnosis and treatment. European and American guidelines for CNE are then reviewed and compared.

Audit of antibiotic therapy used in 66 cases of endocarditis

OBJECTIVES

We wanted to assess the quality of antibiotic therapy prescribed for infective endocarditis in our ward.

DESIGN

We conducted a retrospective audit of all adult patients with endocarditis hospitalized over a 3-year period in the Infectious Diseases Unit of the Nice University Hospital, France. The quality of antibiotic therapy was assessed using the 2004 European Society of Cardiology guidelines as a reference. Antibiotic therapy was considered as appropriate only if the five following items complied with guidelines: antibiotic, dose, route, interval of administration, and duration of antibiotic treatment.

RESULTS

Sixty-six patients were included, 63years of age on average. Antibiotic therapy complied with guidelines in 14% of the cases. The most frequent causes of inappropriate therapy were: gentamicin prescribed as a single daily dose in 55% (27/49) of the cases, unnecessary prescriptions of rifampin in 72% (18/25) of the cases, and too long duration of gentamicin course for staphylococcal endocarditis in 32% (9/28) of the cases. Antibiotic therapy was switched from intravenous to oral route in 29% of the patients (n=19), 18±9 days after starting therapy on average. These endocarditis were mainly left-sided (n=12) and/or complicated (n=15). There was no significant association between mortality and inappropriate antibiotic therapy (14% if inappropriate vs. 22%, P=0.62) or between mortality and oral switch (0% if oral switch vs. 21%, P=0.052).

CONCLUSIONS

Infective endocarditis antibiotic treatment rarely complied with the 2004 European guidelines, but this did not have a negative impact on mortality. Switching antibiotic therapy from intravenous to oral route was common, even for complicated left-sided endocarditis, and was associated with a favorable outcome in all cases.

Infective endocarditis in congenital heart disease

Congenital heart disease (CHD) has become the leading risk factor for pediatric infective endocarditis (IE) in developed countries after the decline of rheumatic heart disease. Advances in catheter- and surgery-based cardiac interventions have rendered almost all types of CHD amenable to complete correction or at least palliation. Patient survival has increased, and a new patient population, referred to as adult CHD (ACHD) patients, has emerged. Implanted prosthetic material paves the way for cardiovascular device-related infections, but studies on the management of CHD-associated IE in the era of cardiovascular devices are scarce. The types of heart malformation (unrepaired, repaired, palliated) substantially differ in their lifetime risks for IE. Streptococci and staphylococci are the predominant pathogens. Right-sided IE is more frequently seen in patients with CHD. Relevant comorbidity caused by cardiac and extracardiac episode-related complications is high. Transesophageal echocardiography is recommended for more precise visualization of vegetations, especially in complex type of CHD in ACHD patients. Antimicrobial therapy and surgical management of IE remain challenging, but outcome of CHD-associated IE from the neonate to the adult is better than in other forms of IE.

CONCLUSION

Primary prevention of IE is vital and includes good dental health and skin hygiene; antibiotic prophylaxis is indicated only in high-risk patients undergoing oral mucosal procedures.

Clinical Features and Rate of Infective Endocarditis in Non-Faecalis and Non-faecium Enterococcal Bacteremia

Non-faecalis and non-faecium enterococci are an occasional cause of bacteremia, and some cases of infective endocarditis caused by these pathogens have been reported. However, the rate of infective endocarditis in non-faecalis and non-faecium enterococcal bacteremia is still undetermined. We compared the clinical features and the rate of infective endocarditis of 70 cases of non-faecalis and non-faecium enterococcal bacteremia with those of 65 cases of Enterococcus faecalis bacteremia. Non-faecalis and non-faecium enterococcal bacteremia was more frequently associated with biliary tract infection and polymicrobial bacteremia, and was less frequently associated with infective endocarditis, than was E. faecalis bacteremia (57% vs. 28%, p<0.01; 47% vs. 31%, p=0.05; 1% vs. 14%, p<0.01, respectively).

Streptococcus pneumoniae endocarditis on replacement aortic valve with panopthalmitis and pseudoabscess

A 63-year-old woman with a previous episode of Streptococcus agalactiae endocarditis requiring a bioprosthetic aortic valve replacement presented with a short history of malaise, a right panopthalmitis with a Roth spot on funduscopy of the left eye and Streptococcus pneumoniae grown from vitreous and aqueous taps as well as blood cultures. She developed first degree heart block and her ECG was suggestive of an aortic root abscess. This gradually resolved over 6 weeks, during which she was treated with intravenous antibiotics. After careful consideration, it is likely that what was thought to be an aortic root abscess was instead an area of perivalvular inflammation.

Once versus twice daily gentamicin dosing for infective endocarditis: a randomized clinical trial

OBJECTIVES

The aim of this randomized study was to investigate the effects of once versus twice daily gentamicin dosing on renal function and measures of infectious disease in a population with infective endocarditis (IE).

METHODS

Seventy-one IE patients needing gentamicin treatment according to guidelines were randomized to either once (n = 37) or twice daily (n = 34) doses of gentamicin. Kidney function (glomerular filtration rate, GFR) was measured with an isotope method ((51)Cr-EDTA) at the beginning of treatment and at discharge. Treatment efficacy was assessed by C-reactive protein (CRP) time to half-life, mean CRP and leukocytes.

RESULTS

Baseline GFR was similar in the two groups. Both groups displayed a significant fall in GFR from admission to discharge. The mean decrease in GFR was as follows: with once daily gentamicin, 17.0% (95% confidence interval 7.5-26.5), and with twice daily gentamicin, 20.4% (95% confidence interval 12.0-28.8). However, there was no significant difference in the GFR decrease between the once and twice daily regimens (p = 0.573). No difference in infection parameters was demonstrated between the two dosing regimens.

CONCLUSIONS

A twice daily gentamicin dosing regimen is neither less nephrotoxic nor more efficient than a once daily regimen in the treatment of IE patients. When indicated, gentamicin may therefore also be administered as a single-dose regimen in the treatment of IE patients.

Clinical management of Staphylococcus aureus bacteraemia

Staphylococcus aureus bacteraemia is one of the most common serious bacterial infections worldwide. In the UK alone, around 12,500 cases each year are reported, with an associated mortality of about 30%, yet the evidence guiding optimum management is poor. To date, fewer than 1500 patients with S aureus bacteraemia have been recruited to 16 controlled trials of antimicrobial therapy. Consequently, clinical practice is driven by the results of observational studies and anecdote. Here, we propose and review ten unanswered clinical questions commonly posed by those managing S aureus bacteraemia. Our findings define the major areas of uncertainty in the management of S aureus bacteraemia and highlight just two key principles. First, all infective foci must be identified and removed as soon as possible. Second, long-term antimicrobial therapy is required for those with persistent bacteraemia or a deep, irremovable focus. Beyond this, the best drugs, dose, mode of delivery, and duration of therapy are uncertain, a situation compounded by emerging S aureus strains that are resistant to old and new antibiotics. We discuss the consequences on clinical practice, and how these findings define the agenda for future clinical research.

Use of daptomycin in complicated cases of infective endocarditis

Infective endocarditis (IE) is a serious form of infection with a high mortality. Medical management can be a challenge because of organ dysfunction, lack of clinical response or allergy to the recommended antibiotics. Daptomycin is a lipopeptide antibiotic with a potent bactericidal activity against Gram-positive bacteria. There are limited data on the use of daptomycin in complicated cases of IE. We aim to report our experience of daptomycin use in complicated cases of IE through a prospective observational study (from 1 October 2008 to 30 September 2009). Daptomycin was prescribed for cases that were either unresponsive or allergic to the standard therapy. Clinical characteristics and outcomes were reviewed. Success was defined as clinical improvement accompanied with the resolution of laboratory markers of sepsis and continuation of the above findings for at least 8 weeks after the end of therapy. Eight cases were evaluable. Native and prosthetic valves were involved in equal proportions. The range of organisms was wide: Staphylococcus aureus, two cases; S. epidermidis, two cases; streptococci, two cases; and Enterococcus faecalis, two cases. The median duration of therapy was 42 days. All patients were successfully treated. Daptomycin was well tolerated. Daptomycin is useful in the management of complicated cases of IE.

Are bloodstream leukocytes Trojan Horses for the metastasis of Staphylococcus aureus?

Staphylococcus aureus bacteraemia remains very difficult to treat, and a large proportion of cases result in potentially lethal metastatic infection. Unpredictable and persistent bacteraemia in the face of highly active, usually bactericidal antibiotics is the strongest predictor of death or disseminated disease. Although S. aureus has conventionally been considered an extracellular pathogen, much evidence demonstrates that it can survive intracellularly. In this Opinion article, we propose that phagocytes, and specifically neutrophils, represent a privileged site for S. aureus in the bloodstream, offering protection from most antibiotics and providing a mechanism by which the bacterium can travel to and infect distant sites. Furthermore, we suggest how this can be experimentally confirmed and how it may prompt a change in the current paradigm of S. aureus bacteraemia and identify better treatment options for improved clinical outcomes.

The management of Staphylococcus aureus bacteremia in the United Kingdom and Vietnam: a multi-centre evaluation

Background

Staphylococcus aureus bacteremia is a common and serious infection worldwide and although treatment guidelines exist, there is little consensus on optimal management. In this study we assessed the variation in management and adherence to treatment guidelines of S. aureus bacteremia.

Methodology/Principal Findings

We prospectively recorded baseline clinical characteristics, management, and in-hospital outcome of all adults with S. aureus bacteremia treated consecutively over one year in eight centres in the United Kingdom, three in Vietnam and one in Nepal. 630 adults were treated for S. aureus bacteremia: 549 in the UK (21% methicillin-resistant), 80 in Vietnam (19% methicillin-resistant) and 1 in Nepal. In the UK, 41% had a removable infection focus (50% intravenous catheter-related), compared to 12% in Vietnam. Significantly (p<0.001) higher proportions of UK than Vietnamese patients had an echocardiogram (50% versus 28%), received more than 14 days antibiotic therapy (84% versus 44%), and received >50% of treatment with oral antibiotics alone (25% versus 4%). UK centres varied significantly (p<0.01) in the proportions given oral treatment alone for >50% of treatment (range 12–40%), in those treated for longer than 28 days (range 13–54%), and in those given combination therapy (range 14–94%). 24% died during admission: older age, time in hospital before bacteremia, and an unidentified infection focus were independent predictors of in-hospital death (p<0.001).

Conclusions/Significance

The management of S. aureus bacteremia varies widely between the UK and Vietnam and between centres in the UK with little adherence to published guidelines. Controlled trials defining optimal therapy are urgently required.

A case of bovine valve endocarditis caused by Engyodontium album

We report the first case of Engyodontium album bioprosthetic valve endocarditis in a 44-year-old male with a history of juvenile rheumatoid arthritis. There is only one other report of Engyodontium album as a human pathogen. The present case supports the increased incidence of fungal endocarditis especially in patients receiving immunotherapy.

A rifampicin-containing antibiotic treatment improves outcome of staphylococcal deep sternal wound infections

BACKGROUND

Deep sternal wound infection (DSWI) is a severe complication after cardiac surgery, mostly caused by staphylococci. Little is known about the optimal antibiotic management.

METHODS

A 10 year retrospective analysis of 100 patients with staphylococcal DSWI after cardiac surgery in a tertiary hospital. Treatment failure was defined as sternal wound dehiscence or fistula at the end of the prescribed antibiotic therapy, 12 months later, or DSWI-related death.

RESULTS

Most patients were male (83%) and the median age was 72 years [interquartile range (IQR) 63-76]. Coronary artery bypass was the most frequent preceding procedure (93%). The median time to diagnosis of DSWI was 13 days (IQR 10-18) after surgery. Clinical presentation consisted of wound discharge in 77% of patients. Coagulase-negative staphylococci were isolated in 54 and Staphylococcus aureus in 46 patients. All patients received antibiotics and 95% underwent surgical debridement. The median duration of antibiotic treatment was 47 days (IQR 41-78). During follow-up, 21 out of 100 patients experienced treatment failure. Of these, 8/21 patients (38%) died from DSWI after a median of 12 days (IQR 8-30). In the multivariate analysis, a rifampicin-containing antibiotic regimen was the only factor associated with lower risk of treatment failure (hazard ratio 0.26, 95% confidence interval 0.10-0.64, P = 0.004). Prolonged treatment (12 weeks instead of 6 weeks) did not alter outcome (P = 0.716) in patients without prosthetic valve endocarditis.

CONCLUSIONS

Treatment of rifampicin-susceptible staphylococcal DSWI with a rifampicin-containing antibiotic regimen may improve the outcome. After surgical debridement an antibiotic treatment of 6 weeks may be adequate for staphylococcal DSWI.

Medical treatment of endocarditis

Infective endocarditis (IE) remains a serious and deadly disease. The incidence, which varies by gender and on the presence of predisposing factors, has not decreased, due in part to the aging population with more healthcare exposures and predisposing risk factors such as prosthetic heart valves and intracardiac devices. The most important aspects of treatment in IE hinge upon early diagnosis, microorganism identification with susceptibility testing, and early initiation of appropriate antibiotic therapy. In addition, echocardiographic imaging is critical for both diagnostic and prognostic purposes. Early evaluation for surgery should be considered. Once a therapeutic strategy is begun, careful attention to the clinical course is necessary to ensure appropriate response to therapy and to identify complications early.

Treatment strategies for infective endocarditis

IMPORTANCE OF THE FIELD

Despite significant advances in medical, surgical, and critical care interventions, infective endocarditis (IE) remains a disease associated with considerable morbidity and mortality. Estimates from the American Heart Association place the incidence of IE in the US at 10,000 - 15,000 new cases each year. This may be due to the changing epidemiology of IE, including increasing antimicrobial resistance, increasing heart surgeries, prosthetic valve implantation, and widespread use of intravenous drugs. Furthermore, a new form of the disease, healthcare-associated IE, which is associated with new therapeutic modalities such as intravenous catheters, hyperalimentation lines, pacemakers, and dialysis shunts, has emerged.

AREAS COVERED IN THIS REVIEW

We present the latest therapeutic and preventive strategies for IE caused by a variety of bacterial and fungal pathogens. The general methods employed included an extensive literature search, confined to the last 10 years, using key words such as 'infective endocarditis', 'culture-negative endocarditis', 'treatment guidelines for IE', and 'prophylaxis for IE'.

WHAT THE READER WILL GAIN

Comprehensive information regarding the changing epidemiology of IE is provided. The latest guidelines with respect to therapy and prophylaxis of IE are reviewed.

TAKE HOME MESSAGE

Successful management of IE depends on maintaining a high index of suspicion for the disease and, when IE is diagnosed, close cooperation of medical and surgical disciplines is required. Further research is needed to better understand and provide optimal therapy for complex situations such as multidrug-resistant and polymicrobial IE.

Clinical features, risk factors and outcomes of bacteremia due to enterococci with high-level gentamicin resistance: comparison with bacteremia due to enterococci without high-level gentamicin resistance

High-level gentamicin resistance (HLGR) in enterococci has increased since the 1980s, but the clinical significance of the resistance and its impact on outcome have not been established. One hundred and thirty-six patients with bacteremia caused by enterococci with HLGR (HLGR group) were compared with 79 patients with bacteremia caused by enterococci without HLGR (non-HLGR group). Hematologic malignancy, neutropenia, Enterococcus faecium infection, nosocomial infection and monomicrobial bacteremia were more common in the HLGR group than the non-HLGR group, and APACHE II scores were also higher (P<0.05, in each case). Neutropenia, monomicrobial infection, stay in intensive care at culture, and use of 3rd generation cephalosporin, were independent risk factors for acquisition of HLGR enterococcal bacteremia. Fourteen-day and 30-day mortalities were higher in the HLGR group than the non-HLGR group in univariate analysis (37% vs. 15%, P=0.001; 50% vs. 22%, P<0.001). However, HLGR was not an independent risk factor for mortality due to enterococcal bacteremia in multivariate analysis. Therefore, HLGR enterococcal bacteremia is associated with more severe comorbid conditions and higher mortality than non-HLGR enterococcal bacteremia but the HLGR itself does not contribute significantly to mortality.