Infective endocarditis: diagnosis, antimicrobial therapy, and management of complications: a statement for healthcare professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, and the Councils on Clinical Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia, American Heart Association: endorsed by the Infectious Diseases Society of America

Streptococcus bovis endocarditis: Update from a multicenter registry

BACKGROUND

Infective endocarditis (IE) due to Streptococcus bovis has been classically associated with elderly patients, frequently involving >1 valve, with large vegetations and high embolic risk, which make it a high-risk group. Our aim is to analyze the current clinical profile and prognosis of S bovis IE episodes, in comparison to those episodes caused by viridans group streptococci and enterococci.

METHODS

We analyzed 1242 consecutive episodes of IE prospectively recruited on an ongoing multipurpose database, of which 294 were streptococcal left-sided IE and comprised our study group. They were classified into 3 groups: group I (n = 47), episodes of IE due to S bovis; group II (n = 134), episodes due to viridans group streptococci; and group III (n = 113), those episodes due to enterococci.

RESULTS

The incidence of enterococci IE has significantly increased in the last 2 decades (6.4% [1996-2004] vs 11.1% [2005-2013]; P = .005), whereas the incidence of IE due to S bovis and viridans streptococci have remained stable (4% and 10%, respectively). Gender distribution was similar in the 3 groups. Patients with S bovis and enterococci IE were older than those from group II. Nosocomial acquisition was more frequent in group III. Concerning comorbidity, diabetes mellitus (36.7% vs 9.2% vs 26.8%; P < .001) was more common in groups I and III. Chronic renal failure was more prevalent in patients from group III (4.2% vs 1.5% vs 19%; P < .001). Prosthetic valve IE was more frequent in enterococcal IE. Infection upon normal native valves was more frequent in S bovis IE. Colorectal tumors were found in 69% of patients from this group. Vegetation detection was similar in the 3 groups. However, vegetation size was smaller in S bovis IE. During hospitalization, in-hospital complications and in-hospital mortality were higher in enterococci episodes.

CONCLUSIONS

S bovis IE accounts for 3.8% of all IE episodes in our cohort; it is associated with a high prevalence of colonic tumors, with predominance of benign lesions, and affects patients without preexisting valve disease. It is related to small vegetations and a low rate of in-hospital complications, including systemic embolisms. In-hospital mortality is similar to that of viridans group streptococci.

Preclinical Rodent Toxicity Studies for Long Term Use of Ceftriaxone

A 6-month rodent toxicology and pharmacokinetic (PK) study was performed to provide supportive safety data for long-term use of intravenous ceftriaxone in a clinical trial in patients with amyotrophic lateral sclerosis (ALS). Ceftriaxone was administered by subcutaneous injection at up to 2 g/kg/day to Sprague-Dawley Crl:CD (SD) rats. Ceftriaxone was found to be safe and well tolerated. Specifically, no significant differences in body weight and food consumption were observed between the treatment and control groups. With the exception of in red cell parameters decrease, there were no ceftriaxone-related changes in hematology, coagulation, clinical chemistry and urinalysis parameters. Injection site trauma and associated reversible anemia, likely due to chronic blood loss at the injection site, were all attributable to subcutaneous route of administration. Cecum dilatation and some skin changes were reversible after recovery period, while bile duct dilatation, observed only in a few animals, persisted. Changes in the non-glandular stomach do not have a human correlate. The no-observed-adverse-effect dose level (NOAEL) was 0.5 g/kg/day ceftriaxone in both sexes. Ceftriaxone showed rapid absorption with half-life values ranging between 1 and 1.5 hours. Additionally, there was no evidence of accumulation and a virtually complete elimination by 16 hours after the last dose. Overall there were no toxicologically meaningful drug-related animal findings associated with the long-term administration (6 months) of ceftriaxone. These results support safety of long-term use of ceftriaxone in human clinical trials.

Optimal timing for early surgery in infective endocarditis: a meta-analysis

To systematically review early surgery and the optimal timing of surgery in patients with infective endocarditis (IE), a search for foreign and domestic articles on cohort studies about the association between early surgery and infective endocarditis published from inception to January 2015 was conducted in the PubMed, EMBASE, Chinese Biomedical Literature (CBM), Wanfang and Chinese National Knowledge Infrastructure (CNKI) databases. The studies were screened according to the inclusion and exclusion criteria, the data were extracted and the quality of the method of the included studies was assessed. Then, the meta-analysis was performed using the Stata 12.0 software. Sixteen cohort studies, including 8141 participants were finally included. The results of the meta-analysis revealed that, compared with non-early surgery, early surgery in IE lowers the incidence of in-hospital mortality [odds ratio (OR) = 0.57, 95% confidence interval (CI) (0.42, 0.77); P = 0.000, I(2) = 73.1%] and long-term mortality [OR = 0.57, 95% CI (0.43, 0.77); P = 0.001, I(2) = 67.4%]. Further, performing operation within 2 weeks had a more favourable effect on long-term mortality [OR = 0.63, 95% CI (0.41, 0.97); P = 0.192, I(2) = 39.4%] than non-early surgery. In different kinds of IE, we found that early surgery for native valve endocarditis (NVE) had a lower in-hospital [OR = 0.46, 95% CI (0.31, 0.69); P = 0.001, I(2) = 73.0%] and long-term [OR = 0.57, 95% CI (0.40, 0.81); P = 0.001, I(2) = 68.9%] mortality than the non-early surgery group. However, for prosthetic valve endocarditis (PVE), in-hospital mortality did not differ significantly [OR = 0.83, 95% CI (0.65, 1.06); P = 0.413, I(2) = 0.0%] between early and non-early surgery. We concluded that early surgery was associated with lower in-hospital and long-term mortality compared with non-early surgical treatment for IE, especially in NVE. However, the optimal timing of surgery remains unclear. Additional larger prospective clinical trials will be required to clarify the optimal timing for surgical intervention and determine its efficacy in PVE.

Diagnosis of blood culture-negative endocarditis and clinical comparison between blood culture-negative and blood culture-positive cases

PURPOSE

To analyze the clinical characteristics of blood culture-negative endocarditis (BCNE) and how it compares to those of blood culture-positive endocarditis (BCPE) cases and show how molecular tools helped establish the etiology in BCNE.

METHODS

Adult patients with definite infective endocarditis (IE) and having valve surgery were included. Valves were studied by polymerase chain reaction (PCR). Statistical analysis compared BCNE and BCPE.

RESULTS

One hundred and thirty-one patients were included; 53 (40 %) had BCNE. The mean age was 45 ± 16 years; 33 (62 %) were male. BCNE was community-acquired in 41 (79 %). Most patients were referred from other hospitals (38, 73 %). Presentation was subacute in 34 (65 %), with fever in 47/53 (90 %) and a new regurgitant murmur in 34/42 (81 %). Native valves were affected in 74 %, mostly left-sided. All echocardiograms showed major criteria for IE. Antibiotics were used prior to BC collection in 31/42 (74 %). Definite histological diagnosis was established for 35/50 (70 %) valves. PCR showed oralis group streptococci in 21 (54 %), S. aureus in 3 (7.7 %), gallolyticus group streptococci in 2 (5.1 %), Coxiella burnetii in 1 (2.5 %) and Rhizobium sp. in 1 (2.5 %). In-hospital mortality was 9/53 (17 %). Fever (p = 0.06, OR 4.7, CI 0.91-24.38) and embolic complications (p = 0.003, OR 3.3, CI 1.55-6.82) were more frequent in BCPE cases, while new acute regurgitation (p = 0.05, OR 0.3, CI 0.098-0.996) and heart failure (p = 0.02, OR 0.3, CI 0.13-0.79) were less so.

CONCLUSIONS

BCNE resulted mostly from prior antibiotics and was associated with severe hemodynamic compromise. Valve histopathology and PCR were useful in confirming the diagnosis and pointing to the etiology of BCNE.

Management and outcomes in patients with Staphylococcus aureus bacteremia after implementation of mandatory infectious diseases consult: a before/after study

Background

Infectious disease (ID) consultations have been shown to increase adherence to guidelines and decrease mortality for patients with Staphylococcus aureus bacteremia (SAB). Here, we assessed the impact of a mandatory ID consultation policy for SAB.

Methods

We retrospectively reviewed all consecutive adult patients with SAB at two tertiary care teaching hospitals in Hamilton, ON, Canada. Mandatory ID consults for SAB were implemented on January 1^st 2012. We compared SAB cases in 2011 (control group) with those in 2012 (intervention group). Outcomes included adherence to the Infectious Diseases Society of America guidelines and patient outcomes.

Results

We reviewed 128 SAB cases in 2011 and 124 in 2012. The majority of S. aureus were methicillin-susceptible (97/128, 75.8 % in 2011 and 100/124, 80.6 % in 2012). ID involvement increased significantly from 93/128 (72.7 %) in 2011, to 103/124 (83.1 %) in 2012 (odds ratio [OR] 1.9, 95 % confidence interval [CI] 1.1–3.3, p = 0.047). There was also a significant decrease in the median time to ID involvement from 2 days to 1 (p = 0.001). In patients who survived the minimum treatment course (greater than 13 days), there was a significant improvement in adherence to IDSA guidelines in 2012 (65/102, 63.7 % vs. 77/96, 80.2 %; OR 2.3, 95 % CI 1.2–4.4, p = 0.01). Mortality and SAB relapse rates were similar in both groups.

Conclusions

Creating an automated ID consultation for SAB led to an increase in involvement of ID, a significant decrease in time to ID involvement, and better adherence to IDSA guidelines. The study was not sufficiently powered to detect significant changes in mortality and SAB relapse rates.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1296-y) contains supplementary material, which is available to authorized users.

Antimicrobial Susceptibilities of Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella elegans

Nutritionally variant streptococci (NVS) are fastidious Gram-positive cocci comprised of the species Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella elegans. NVS are an important cause of bacteremia and infective endocarditis (IE) associated with significant morbidity and mortality. Antimicrobial susceptibility testing (AST) was performed for 14 antimicrobials using the broth microdilution MIC method described in the Clinical and Laboratory Standards Institute (CLSI) M45 guideline. A total of 132 clinical NVS blood isolates collected from 2008 to 2014 were tested. Species level identification of NVS isolates was achieved by 16S rRNA gene sequencing and/or matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Ninety isolates were identified as G. adiacens, 37 as A. defectiva, and 5 as G. elegans. All isolates were susceptible to vancomycin (MIC90 = 1 μg/ml), and none displayed high-level resistance to aminoglycosides. G. adiacens was considerably more susceptible to penicillin than A. defectiva (38.9% versus 10.8% of isolates susceptible) but was less susceptible to cephalosporins than was A. defectiva (43.3% versus 100% of isolates susceptible to ceftriaxone). Several isolates were resistant to levofloxacin (6%), erythromycin (51%), and clindamycin (10%). The MIC90 for daptomycin was ≥ 4 μg/ml for G. adiacens and A. defectiva. G. elegans isolates were 100% susceptible to all antimicrobials tested, with the exception of erythromycin, to which only 20% were susceptible. This study provides antimicrobial susceptibility data for a recent collection of NVS and demonstrates important NVS species-related differences with respect to susceptibility to penicillin, cephalosporins, carbapenems, and daptomycin. Species-level identification of NVS organisms when susceptibility testing is not readily available may aid in treatment decisions.

Impact of an Antibiotic-specific Sepsis Bundle on Appropriate and Timely Antibiotic Administration for Severe Sepsis in the Emergency Department

BACKGROUND

Guidelines recommend initiation of appropriate antimicrobial therapy within 1 h of severe sepsis diagnosis. Few sepsis bundles exist in the literature emphasizing initiation of specific antibiotic therapy.

OBJECTIVE

To determine the impact of an antibiotic-specific sepsis bundle on the timely initiation of appropriate antibiotics.

METHODS

For this before-and-after interventional study, the sepsis bundle at this 803-bed academic tertiary-care facility was redesigned to include specific antibiotic selection and dosing, based on suspected source of infection and susceptibility patterns. Protocol education and advertising was completed and bundle-specific antibiotics were put in the automated medication cabinet.

RESULTS

Stepwise analysis of timely initiation of appropriate antibiotics included: 1) Was the initial antibiotic appropriate? 2) If so, was it initiated within 1 h of diagnosis? 3) If so, were all necessary appropriate antibiotics started? and 4) If so, were they started within 3 h of diagnosis? In comparing the 3-month-before group and 3-month-after group (n = 124), the appropriate initial antibiotic was started in 33.9% vs. 54.8% of patients (odds ratio [OR] 0.42, 95% confidence interval [CI] 0.19-0.93, p = 0.03) and within 1 h in 22.6% vs. 14.5% of patients (OR 1.71, 95% CI 0.62-4.92, p = 0.36), respectively. All necessary appropriate antibiotics were initiated in 16.1% vs. 12.9% of patients (OR 1.30, 95% CI 0.42-4.10, p = 0.80), and within 3 h in 14.5% vs. 9.7% of patients, respectively (OR 1.58, 95% CI 0.46-5.78, p = 0.58).

CONCLUSIONS

An updated antibiotic-specific sepsis bundle, with antibiotics put in an automated medication cabinet, can result in improvements in the initiation of appropriate initial antibiotic therapy for severe sepsis in the emergency department.

Management of Ruptured and Rapidly Progressive Mycotic Cerebral Aneurysms in the Setting of Unilateral Carotid Occlusion and Endocarditis with Valve Failure

Mycotic cerebral aneurysms can present unique neurosurgical challenges. We report a patient with left carotid occlusions, a ruptured left middle cerebral artery mycotic aneurysm, and a rapidly appearing unruptured left anterior cerebral artery/anterior communicating artery (ACA/ACom) mycotic aneurysm in the setting of mitral valve endocarditis with a perivalvular leak and evolving congestive heart failure. Following medical stabilization and antibiotic administration, a combined endovascular (with contralateral access via the ACom) and open surgical approach was used to selectively secure both aneurysms with preservation of distal flow, allowing lifesaving cardiac valve replacement. This case illustrates the therapeutic complexity of mycotic cerebral aneurysms, which we discuss in the context of an increasing reliance on endovascular approaches.

Proteus endocarditis in an intravenous drug user

Infective endocarditis (IE) is a life-threatening condition with adverse consequences and increased mortality, despite improvements in treatment options. Diagnosed patients usually require a prolonged course of antibiotics, with up to 40-50% requiring surgery during initial hospital admission. We report a case of a 42-year-old intravenous drug user who presented feeling generally unwell, with lethargy, rigours, confusion and a painful swollen right leg. He was subsequently diagnosed with Proteus mirabilis endocarditis (fulfilling modified Duke criteria for possible IE) and deep vein thrombosis (DVT). He was successfully treated with single antibiotic therapy without needing surgical intervention or requiring anticoagulation for his DVT. Proteus endocarditis is extremely uncommon, with a limited number of case reports available in the literature. This case illustrates how blood cultures are invaluable in the diagnosis of IE, especially that due to unusual microorganisms. Our case also highlights how single antibiotic therapy can be effective in treating Proteus endocarditis.

Fosfomycin plus β-Lactams as Synergistic Bactericidal Combinations for Experimental Endocarditis Due to Methicillin-Resistant and Glycopeptide-Intermediate Staphylococcus aureus

The urgent need of effective therapies for methicillin-resistant Staphylococcus aureus (MRSA) infective endocarditis (IE) is a cause of concern. We aimed to ascertain the in vitro and in vivo activity of the older antibiotic fosfomycin combined with different beta-lactams against MRSA and glycopeptide-intermediate-resistant S. aureus (GISA) strains. Time-kill tests with 10 isolates showed that fosfomycin plus imipenem (FOF+IPM) was the most active evaluated combination. In an aortic valve IE model with two strains (MRSA-277H and GISA-ATCC 700788), the following intravenous regimens were compared: fosfomycin (2 g every 8 h [q8h]) plus imipenem (1 g q6h) or ceftriaxone (2 g q12h) (FOF+CRO) and vancomycin at a standard dose (VAN-SD) (1 g q12h) and a high dose (VAN-HD) (1 g q6h). Whereas a significant reduction of MRSA-227H load in the vegetations (veg) was observed with FOF+IPM compared with VAN-SD (0 [interquartile range [IQR], 0 to 1] versus 2 [IQR, 0 to 5.1] log CFU/g veg; P = 0.01), no statistical differences were found with VAN-HD. In addition, FOF+IPM sterilized more vegetations than VAN-SD (11/15 [73%] versus 5/16 [31%]; P = 0.02). The GISA-ATCC 700788 load in the vegetations was significantly lower after FOF+IPM or FOF+CRO treatment than with VAN-SD (2 [IQR, 0 to 2] and 0 [IQR, 0 to 2] versus 6.5 [IQR, 2 to 6.9] log CFU/g veg; P < 0.01). The number of sterilized vegetations after treatment with FOF+CRO was higher than after treatment with VAN-SD or VAN-HD (8/15 [53%] versus 4/20 [20%] or 4/20 [20%]; P = 0.03). To assess the effect of FOF+IPM on penicillin binding protein (PBP) synthesis, molecular studies were performed, with results showing that FOF+IPM treatment significantly decreased PBP1, PBP2 (but not PBP2a), and PBP3 synthesis. These results allow clinicians to consider the use of FOF+IPM or FOF+CRO to treat MRSA or GISA IE.

Trends in incidence of infective endocarditis at the Medical Center of Alkmaar

INTRODUCTION

Infective endocarditis (IE) is a life-threatening illness with a high morbidity and mortality, and with a rise in incidence in patients with prosthetic valves and cardiac devices. Recently the Dutch guidelines of IE prophylaxis have been revised, limiting IE prophylaxis to the highest-risk population. The aim of the present study was to investigate the incidence of IE and its trend between 2008-2013 in a regional hospital in the Netherlands.

METHODS

This is an observational descriptive study of all patients who were admitted with IE to the Medical Center of Alkmaar (MCA) from 1 January 2008 to 31 December 2013.

RESULTS

A total of 89 patients with IE, including 7 patients (7.9 %) with a cardiac device IE (CDIE), were identified. In 2008 there were 8 patients with IE, this increased to 26 patients in 2013. Patients with a prosthetic valve IE increased from 25 % in 2008 to 34.6 % in 2013. This increase was not seen in patients with CDIE.

CONCLUSION

In the MCA we have observed an increase in patients with IE since 2010. This increase was in part attributable to prosthetic valve IE. A larger observational study is needed to investigate the increase of IE in the Netherlands.

Midterm results of mitral valve repair with lifting annuloplasty strip for acute phase infective endocarditis

Background

Mitral valve repair is favored over replacement due to superior outcomes. However, extensive infective endocarditis (IE) often has been considered unreconstructable. We retrospectively analyzed the mid-term outcomes of an individualized repair approach using a lifting annuloplasty strip.

Methods

Between December 2007 and March 2014, 27 consecutive patients with acute single mitral valve IE (age 43 ± 16 years, 11 men) underwent lifting mitral annuloplasty (LMA) with a strip (Mitracon® strip, 28 mm in 4, 32 mm in 10, and 34 mm in 13). Blood culture was positive in 70 % (Streptococcus 10, Staphylococcus 4, HACEK 3, Enterococcus 1, Gram negative bacilli 1). One case (4 %) had a previously repaired mitral valve—the repair was redone. Via right thoracotomy (74 %) or median sternotomy (26 %), repair was performed by removal of vegetation and resection of infected tissue, the defect typically then being repaired using a bovine pericardial patch (81 %). Artificial chordae were formed in 5 patients. Nine (33 %) of them had posterior leaflet augmentation (PLA) to get sufficient coaptation height. Clinical and echocardiographic follow-up were performed.

Results

Compared with preoperative ones, postoperative echocardiograms revealed decreases of left ventricular (LV) end-diastolic dimensions (57.2 ± 6.3 versus, 45.4 ± 6.2, or 44.8 ± 4.1 mm, all p < 0.01). The LV ejection fraction decreased immediately, but recovered (64.4 ± 9.6 % vs. 54.5 ± 9.8 %, or 65.2 ± 6.1 %, p = 0.002, p = 1.000, respectively). The latest follow-up echocardiograms (median 28 months) universally showed no or minimal regurgitation, with a preserved mitral valve opening area (2.27 ± 0.48 cm²). During the clinical follow-up (median, 54 months), one (3.7 %) death was observed (in-hospital, due to biliary sepsis and pneumonia). There was no reoperation or major cardiovascular event. The 5 year survival rate was 96.3 %.

Conclusions

The repair technique of LMA and/or PLA in patients with IE achieved good structural and functional outcomes as well as an excellent 5 year survival rate. An individualized repair approach should be recommended in patients with acute phase IE.

Moraxella catarrhalis bacteraemia and prosthetic valve endocarditis

Moraxella catarrhalis, once considered a non-pathogenic coloniser of the oropharynx, has now been recognised as a true pathogen and is reported in cases of bacteraemia. A 63-year-old man with an aortic bioprosthetic valve was brought to the emergency room with altered mental status. Initial blood cultures revealed Gram-negative diplococci on Gram stain; echocardiogram showed a 5 mm vegetation on the aortic bioprosthetic valve. The blood cultures grew M. catarrhalis and the patient was treated medically for prosthetic valve endocarditis with 6 weeks of ceftriaxone and had a favourable clinical outcome. M. catarrhalis has a high prevalence of β-lactamase production and hence the patient was treated with ceftriaxone. This case highlights the importance of considering M. catarrhalis as a pathogen in cases of invasive disease.

How do physicians cope with controversial topics in existing guidelines for the management of infective endocarditis? Results of an international survey

International guidelines are available to help physicians prescribe appropriate antibiotic regimens to patients with infective endocarditis (IE). However some topics of these guidelines are controversial. We conducted an international survey to assess physicians' adherence to these guidelines, focusing on these controversial items. An invitation to participate to a 15-question online survey was sent in 2012-2013 to European Society of Clinical Microbiology and Infectious Diseases (ESCMID) members, scientific societies and corresponding authors of publications on IE mentioned in PubMed from 1990 to 2012, inclusive. Eight hundred thirty-seven physicians participated in the survey, and 625 (74.7%) completed it over the first question. The results showed great heterogeneity of practices. Claiming to follow guidelines was marginally associated with more guideline-based strategies. Gentamicin use depended on causative pathogens (p <0.001) and physician specialty (p 0.02). Eighty-six per cent of the physicians favoured vancomycin alone or in combination with gentamicin or rifampicin as a first-line treatment for left-sided native valve methicillin-resistant Staphylococcus aureus IE, 31% considered switching to oral therapy as a therapeutic option and 33% used the ampicillin and ceftriaxone combination for enterococcal IE as a first-line therapy. Physician specialty significantly affected the choice of a therapeutic strategy, while practicing in a university hospital or the number of years of practice had virtually no impact. Our survey, the largest on IE treatment, underscores important heterogeneity in practices for treatment of IE. Nonetheless, physicians who do not follow guidelines can have rational strategies that are based on the literature. These results could inform the revision of future guidelines and identify unmet needs for future studies.

Towards Investigating Global Warming Impact on Human Health Using Derivatives of Photoplethysmogram Signals

Recent clinical studies show that the contour of the photoplethysmogram (PPG) wave contains valuable information for characterizing cardiovascular activity. However, analyzing the PPG wave contour is difficult; therefore, researchers have applied first or higher order derivatives to emphasize and conveniently quantify subtle changes in the filtered PPG contour. Our hypothesis is that analyzing the whole PPG recording rather than each PPG wave contour or on a beat-by-beat basis can detect heat-stressed subjects and that, consequently, we will be able to investigate the impact of global warming on human health. Here, we explore the most suitable derivative order for heat stress assessment based on the energy and entropy of the whole PPG recording. The results of our study indicate that the use of the entropy of the seventh derivative of the filtered PPG signal shows promising results in detecting heat stress using 20-second recordings, with an overall accuracy of 71.6%. Moreover, the combination of the entropy of the seventh derivative of the filtered PPG signal with the root mean square of successive differences, or RMSSD (a traditional heart rate variability index of heat stress), improved the detection of heat stress to 88.9% accuracy.

Isolated native tricuspid valve endocarditis due to group A β-hemolytic Streptococcus without drug addiction

We discuss a case of tricuspid valve endocarditis to group A Streptococcus in a middle-age man without a history of intravenous drug use.

Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association

BACKGROUND

Infective endocarditis is a potentially lethal disease that has undergone major changes in both host and pathogen. The epidemiology of infective endocarditis has become more complex with today's myriad healthcare-associated factors that predispose to infection. Moreover, changes in pathogen prevalence, in particular a more common staphylococcal origin, have affected outcomes, which have not improved despite medical and surgical advances.

METHODS AND RESULTS

This statement updates the 2005 iteration, both of which were developed by the American Heart Association under the auspices of the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease of the Young. It includes an evidence-based system for diagnostic and treatment recommendations used by the American College of Cardiology and the American Heart Association for treatment recommendations.

CONCLUSIONS

Infective endocarditis is a complex disease, and patients with this disease generally require management by a team of physicians and allied health providers with a variety of areas of expertise. The recommendations provided in this document are intended to assist in the management of this uncommon but potentially deadly infection. The clinical variability and complexity in infective endocarditis, however, dictate that these recommendations be used to support and not supplant decisions in individual patient management.

Bartonella endocarditis

Blood culture-negative endocarditis presents a clinical and diagnostic challenge. Here, we describe a patient with a delayed diagnosis of Bartonella henselae endocarditis. <Learning objective: The aim of this report is to highlight the importance of Bartonella species as a cause of culture-negative endocarditis and to illustrate the challenges it poses in diagnosis and treatment.>.

Metagenomic analysis for detecting pathogens in culture-negative infective endocarditis

Pathogen identification is important for proper diagnosis and optimal treatment of infective endocarditis (IE). Blood and valve cultures are the gold standard for detecting pathogens responsible for IE. However, these tests only detect culturable pathogens, and have low sensitivity, especially in patients previously treated with antibiotics. Culture-negative IE is still a major clinical problem and a diagnostic challenge. Recently, metagenomic analysis using next generation sequencing has been used to detect pathogens directly from clinical samples. However, there are very few reports of the use of metagenomic analysis for pathogen identification in culture-negative IE cases and the usefulness of this new method is unknown. Here, we report a case of successful pathogen detection with metagenomic analysis in a patient of culture-negative IE. The patient underwent valve replacement surgery and received antibiotics for 5 weeks and survived. Using metagenomic analysis of resected vegetation, we detected Abiotrophia defectiva, which is often associated with culture-negative IE due to its fastidious growth. This method may be useful for pathogen identification in future cases of culture-negative IE.

Changes in Communication between Muscle Stem Cells and their Environment with Aging

Aging is associated with both muscle weakness and a loss of muscle mass, contributing towards overall frailty in the elderly. Aging skeletal muscle is also characterised by a decreasing efficiency in repair and regeneration, together with a decline in the number of adult stem cells. Commensurate with this are general changes in whole body endocrine signalling, in local muscle secretory environment, as well as in intrinsic properties of the stem cells themselves. The present review discusses the various mechanisms that may be implicated in these age-associated changes, focusing on aspects of cell-cell communication and long-distance signalling factors, such as levels of circulating growth hormone, IL-6, IGF1, sex hormones, and inflammatory cytokines. Changes in the local environment are also discussed, implicating IL-6, IL-4, FGF-2, as well as other myokines, and processes that lead to thickening of the extra-cellular matrix. These factors, involved primarily in communication, can also modulate the intrinsic properties of muscle stem cells, including reduced DNA accessibility and repression of specific genes by methylation. Finally we discuss the decrease in the stem cell pool, particularly the failure of elderly myoblasts to re-quiesce after activation, and the consequences of all these changes on general muscle homeostasis.

Combination antibiotic therapy for the treatment of infective endocarditis due to enterococci

INTRODUCTION

Enterococci are common causes of infective endocarditis (IE) in both health care and community-based setting. Enterococcal IE requires bactericidal therapy for an optimal outcome. For decades, cell-wall-active antimicrobial agents (penicillins or vancomycin) in combination with aminoglycosides were the cornerstone of the treatment; however, the emergence of antibiotic resistance has significantly reduced the efficacy of these regimens.

MATERIALS AND METHODS

Data for this review were identified by searches of MEDLINE and references from relevant articles on antibiotic combination regimens for the treatment of enterococcal IE. Abstracts presented in scientific conferences were not searched for.

CONCLUSION

New effective and safe combination treatments, including double-β-lactam and daptomycin/β-lactam combination, are proving useful for the management of IE due to enterococci.

Neurologic aspects of cardiac emergencies

In this review, cardiac arrest is discussed, with a focus on neuroprognostication and the emerging data, with regard to identifying more accurate predictors of neurologic outcomes in the era of therapeutic hypothermia. Topics discussed include recent controversies with regard to targeted temperature management in comatose survivors of cardiac arrest; neurologic complications associated with surgical disease and procedures, namely aortic dissection, infective endocarditis, left ventricular assist devices, and coronary artery bypass grafting; and the cause, pathogenesis, and management of neurogenic stunned myocardium.

Cardiothoracic surgical emergencies in the intensive care unit

Patients with cardiothoracic surgical emergencies are frequently admitted to the ICU, either prior to operative intervention or after surgery. Recognition and appropriate timing of operative intervention are key factors in improving outcomes. A collaborative team approach with the cardiothoracic service is imperative in managing this patient population.

Endocarditis due to gram-negative bacilli at a French teaching hospital over a 6-year period: clinical characteristics and outcome

BACKGROUND

Infective endocarditis (IE) due to gram-negative bacilli (GNB) is rare. However, several studies described a change in the epidemiological profile of patients within the past few years.

METHODS

We reviewed all cases diagnosed and followed in the infectious diseases ward of a French teaching hospital in Paris between 2009 and 2014, inclusive.

RESULTS

Among the 17 patients with definite GNB-IE (11 male, mean age 54 years), 12 (70%) were due to non-HACEK GNB and 5 (30%) to HACEK group GNB. A prosthetic valve was involved in 10 cases (8 in non-HACEK and 2 in HACEK group). Escherichia coli (4/12 patients) and Pseudomonas aeruginosa (3/12 patients) were the most common pathogens in the first group; all the pathogens in the second group were Haemophilus spp. One-third of the patients with non-HACEK GNB had nosocomial IE, whereas injection drug use-related infections were rare (2/12). All patients with HACEK infection had at least one complication (intracardiac abscess, stroke or other systemic embolization). All patients were treated by antibiotic combination therapy during a median time of 42 days (interquartile range (IQR) = 42-42) and 10 (59%) underwent cardiac surgery. One death at 9 months was observed in the non-HACEK group.

CONCLUSIONS

Regarding HACEK IE, this report supports the frequent association with vascular complications. Regarding non-HACEK GNB IE, this report supports the increasing proportion of nosocomial infections. We reported a high proportion of surgery in the therapeutic management of both HACEK and non-HACEK groups associated with no in-hospital mortality.

Loss of Antibiotic Tolerance in Sod-Deficient Mutants Is Dependent on the Energy Source and Arginine Catabolism in Enterococci

Enterococci are naturally tolerant to typically bactericidal cell wall-active antibiotics, meaning that their growth is inhibited but they are not killed even when exposed to a high concentration of the drug. The molecular reasons for this extraordinary tolerance are still incompletely understood. Previous work showed that resistance to killing collapsed specifically in mutants affected in superoxide dismutase (Sod) activity, arguing that bactericidal antibiotic treatment led to induction of a superoxide burst. In the present work, we show that loss of antibiotic tolerance in ΔsodA mutants of pathogenic enterococci is dependent on the energy source present during antibiotic treatment. Hexoses induce greater killing than the pentose ribose, and no killing was observed with glycerol as the energy source. These results point to glycolytic reactions as crucial for antibiotic-mediated killing of ΔsodA mutants. A transposon mutant library was constructed in Enterococcus faecalis ΔsodA mutants and screened for restored tolerance of vancomycin. Partially restored tolerance was observed in mutants with transposon integrations into intergenic regions upstream of regulators implicated in arginine catabolism. In these mutants, the arginine deiminase operon was highly upregulated. A model for the action of cell wall-active antibiotics in tolerant and nontolerant bacteria is proposed.

IMPORTANCE

Antibiotic tolerance is a serious clinical concern, since tolerant bacteria have considerably increased abilities to resist killing by bactericidal drugs. Using enterococci as models for highly antibiotic-tolerant pathogens, we showed that tolerance of these bacteria is linked to their superoxide dismutase (Sod), arguing that bactericidal antibiotics induce generation of reactive oxygen species inside cells. Wild-type strains are tolerant because they detoxify these deleterious molecules by the activity of Sod, whereas Sod-deficient strains are killed. This study showed that killing depends on the energy source present during treatment and that an increase in arginine catabolism partially restored tolerance of the Sod mutants. These results are used to propose a mode-of-action model of cell wall-active antibiotics in tolerant and nontolerant bacteria.

Clinical relevance of echocardiogram in patients with cerebral palsy undergoing posterior spinal fusion

BACKGROUND

Spinal deformity is one of the secondary musculoskeletal problems that occur with cerebral palsy (CP). Of the co morbidities associated with CP and spinal deformity, cardiac function is of theoretical concern.

OBJECTIVE

The goal of our study was to determine the clinical relevance of routine preoperative cardiology evaluation via echocardiogram for patients with CP presenting for posterior spine fusion (PSF) surgery.

METHODS

A retrospective chart review was performed of CP patients presenting for scoliosis surgery. The data collected for each patient included: age, sex, height, weight, Cobb angle, and medical history. All patients had a preoperative cardiac evaluation.

RESULTS

Seventy-two patients were included. The mean age was 13.6 ± 3.4 years. Left ventricular systolic function was normal in all patients; the mean shortening fraction was 39.3 ± 6.2%. No patient had more than mild insufficiency of either the semilunar or atrioventricular valve. One patient was diagnosed with aortic root dilation as well as aortic valve insufficiency. All patients had PSF surgery without changes in anesthetic or surgical plans, and no patient experienced complications attributable to a cardiac origin.

CONCLUSION

The results suggest that routine preoperative cardiology evaluation via echocardiogram for children with CP in the absence of clinical history or physical examination findings suggestive of cardiac disease is not necessary.

Vancomycin-resistant enterococcal infections: epidemiology, clinical manifestations, and optimal management

Since its discovery in England and France in 1986, vancomycin-resistant Enterococcus has increasingly become a major nosocomial pathogen worldwide. Enterococci are prolific colonizers, with tremendous genome plasticity and a propensity for persistence in hospital environments, allowing for increased transmission and the dissemination of resistance elements. Infections typically present in immunosuppressed patients who have received multiple courses of antibiotics in the past. Virulence is variable, and typical clinical manifestations include bacteremia, endocarditis, intra-abdominal and pelvic infections, urinary tract infections, skin and skin structure infections, and, rarely, central nervous system infections. As enterococci are common colonizers, careful consideration is needed before initiating targeted therapy, and source control is first priority. Current treatment options including linezolid, daptomycin, quinupristin/dalfopristin, and tigecycline have shown favorable activity against various vancomycin-resistant Enterococcus infections, but there is a lack of randomized controlled trials assessing their efficacy. Clearer distinctions in preferred therapies can be made based on adverse effects, drug interactions, and pharmacokinetic profiles. Although combination therapies and newer agents such as tedizolid, telavancin, dalbavancin, and oritavancin hold promise for the future treatment of vancomycin-resistant Enterococcus infections, further studies are needed to assess their possible clinical impact, especially in the treatment of serious infections.

The cefazolin inoculum effect in methicillin-susceptible Staphylococcus aureus blood isolates: their association with dysfunctional accessory gene regulator (agr)

We evaluated the clinical significance of the cefazolin inoculum effect (CIE) in methicillin-susceptible Staphylococcus aureus (MSSA) isolates. In total, 146 isolates were recovered from patients with MSSA bacteremia at 9 hospitals in Korea. The CIE was observed in 16 MSSA isolates, and while type A was the only detected β-lactamase in MSSA isolates exhibiting the CIE, no strains expressing type B, C, or D β-lactamases exhibited this effect. The CIE was only observed in agr group III and I isolates and was significantly more common in isolates with agr dysfunction than in those with functional agr (P<0.001). Even among isolates producing type A β-lactamase, the CIE was also prevalent in isolates with dysfunctional agr than in isolates with functional agr (P=0.025). This study demonstrates an association between the CIE of MSSA isolates and agr dysfunction, in addition to those between the CIE and type A β-lactamase.

Healthcare-associated prosthetic heart valve, aortic vascular graft, and disseminated Mycobacterium chimaera infections subsequent to open heart surgery

AIMS

We identified 10 patients with disseminated Mycobacterium chimaera infections subsequent to open-heart surgery at three European Hospitals. Infections originated from the heater-cooler unit of the heart-lung machine. Here we describe clinical aspects and treatment course of this novel clinical entity.

METHODS AND RESULTS

Interdisciplinary care and follow-up of all patients was documented by the study team. Patients' characteristics, clinical manifestations, microbiological findings, and therapeutic measures including surgical reinterventions were reviewed and treatment outcomes are described. The 10 patients comprise a 1-year-old child and nine adults with a median age of 61 years (range 36-76 years). The median duration from cardiac surgery to diagnosis was 21 (range 5-40) months. All patients had prosthetic material-associated infections with either prosthetic valve endocarditis, aortic graft infection, myocarditis, or infection of the prosthetic material following banding of the pulmonary artery. Extracardiac manifestations preceded cardiovascular disease in some cases. Despite targeted antimicrobial therapy, M. chimaera infection required cardiosurgical reinterventions in eight patients. Six out of 10 patients experienced breakthrough infections, of which four were fatal. Three patients are in a post-treatment monitoring period.

CONCLUSION

Healthcare-associated infections due to M. chimaera occurred in patients subsequent to cardiac surgery with extracorporeal circulation and implantation of prosthetic material. Infections became clinically apparent after a time lag of months to years. Mycobacterium chimaera infections are easily missed by routine bacterial diagnostics and outcome is poor despite long-term antimycobacterial therapy, probably because biofilm formation hinders eradication of pathogens.

Optimizing therapy for vancomycin-resistant enterococcal bacteremia in children

PURPOSE OF REVIEW

Uncertainties exist regarding the optimal treatment for vancomycin-resistant enterococcal (VRE) bloodstream infections, particularly in settings in which ampicillin cannot be used.

RECENT FINDINGS

Quinupristin-dalfopristin, linezolid, and daptomycin, all approved between 1999 and 2003, represent the mainstays of therapy for VRE bacteremia, although only linezolid has been specifically approved by the United States Food and Drug Administration for this indication. The main objective of this review is to compare the relative efficacies, dosing strategies, and side-effect profiles of quinupristin-dalfopristin, linezolid, and daptomycin for VRE bacteremia in the pediatric population. A brief description of recently approved broad-spectrum Gram-positive agents that may have a role in the management of VRE bacteremia in upcoming years is also provided.

SUMMARY

Linezolid, despite its bacteriostatic activity against VRE, may be the most versatile of the available drugs. It has activity against both Enterococcus faecalis and E. faecium, can be administered orally, and resistance appears to be less of a concern with linezolid compared with the other agents. Additionally, the results of two recent meta-analyses demonstrate more favorable outcomes with linezolid compared with daptomycin for the treatment of VRE bacteremia. The clinical pharmacokinetics of linezolid have been well described in children. The most notable concern with linezolid, however, is toxicities associated with prolonged use. Until more prospective data are available, we favor linezolid as first-line therapy for the treatment of VRE bacteremia in children.

Kingella kingae infections in children

BACKGROUND

Improvements in culture techniques and molecular detection methods have led to findings indicating that, particularly in infants and young children, Kingella kingae is a significantly more important pathogen than previously thought. However, despite this, the pediatric community is still largely unaware of the existence of this organism. The aim of this review is therefore to summarise current knowledge of the epidemiology, transmission, clinical presentation, diagnosis and treatment of K. kingae infections in children.

DISCUSSION

K. kingae is a common coloniser of the oropharynx, can be transmitted from child to child, and can cause outbreaks of infection. Invasive infections almost exclusively occur in children aged between six months and four years of age, and involve mainly joints and bone, less frequently the endocardium, and very rarely other localisations. With the exception of bacteremia and endocarditis, which can be followed by severe complications, the diseases due to K. kingae are usually accompanied by mild to moderate clinical signs and symptoms, and only slightly altered laboratory data. Moreover, they generally respond to widely used antibiotics, although resistant strains are reported. However, the mild symptoms and limited increase in the levels of acute phase reactants create problems because K. kingae disease may be confused with other clinical conditions that have a similar clinical picture.

CONCLUSIONS

Although K. kingae was identified more than 50 years ago, it is poorly known by pediatricians and is not systematically sought in laboratories. Education is therefore necessary in order to reduce the risk of outbreaks, permit the early identification of K. kingae infections, and allow the prompt prescription of adequate therapeutic regimens capable of avoiding the risk of a negative evolution in those cases in which this elusive pathogen can cause significant clinical problems.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

Endovascular repair of a mycotic thoracic aortic aneurysm in a patient with aortic coarctation

This report describes the management of a 28-year-old female patient who presented with septicemia and mediastinal mass-effect secondary to a proximal mycotic aneurysm of the descending aorta. The patient had an infected bicuspid aortic valve, aortic coarctation, and a left vertebral artery arising directly from the aortic arch. Evidence of disseminated embolization affecting her posterior cerebral circulation, the left axillary, and the superior mesenteric arteries was noted. The patient had a considerably small aorta. An urgent thoracic endovascular aortic repair was performed successfully with a chimney stent to the left vertebral artery. The report discusses the planning and technique used in managing this complex case.

Low-dose Gentamicin for Uncomplicated Enterococcus faecalis Bacteremia May be Nephrotoxic in Children

BACKGROUND

Uncertainty exists regarding the role of synergistic gentamicin for uncomplicated Enterococcus faecalis bacteremia in children.

METHODS

We conducted a retrospective, observational study comparing clinical outcomes of children with E. faecalis bacteremia without endocarditis receiving ampicillin monotherapy with those receiving ampicillin along with low-dose gentamicin therapy. To account for nonrandom assignment of combination therapy, propensity score weighting was combined with multivariable regression to estimate the effect of combination therapy on duration of bacteremia, bacteremic relapse, and acute kidney injury (AKI).

RESULTS

One hundred sixty-three (52%) patients received ampicillin with low-dose gentamicin, and 150 (48%) patients received ampicillin monotherapy. Incorporating propensity-score weighting with additional adjustment for source control measures, patients receiving combination therapy experienced bacterial clearance 10 hours faster than children receiving ampicillin monotherapy (adjusted mean difference 0.42; confidence interval (CI), .02 to .82; P = .04). Bacteremic relapse was similar between the two groups (17% vs 18%); adjusted hazards ratio (aHR) 1.12; 95% CI, .65 to 1.92. Children receiving low-dose gentamicin had approximately twice the risk of developing AKI compared to children not receiving this agent, adjusting for the receipt of additional nephrotoxins (aHR 1.94; 95% CI, 1.48-2.97).

CONCLUSIONS

Our study suggests that for children with uncomplicated E. faecalis bacteremia, the addition of low-dose gentamicin may decrease the time to bacterial clearance by 10 hours but without any impact on recurrent bacteremia. However, with this potential benefit comes the increased likelihood of AKI. Low-dose gentamicin for the treatment of uncomplicated enterococcal bacteremia may pose harm to children with limited benefit.

Treatment outcomes with cefazolin versus oxacillin for deep-seated methicillin-susceptible Staphylococcus aureus bloodstream infections

Clinical preference for a semisynthetic penicillin (oxacillin or nafcillin) over cefazolin for deep-seated methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections (BSI) perseveres despite limited data to support this approach. A retrospective cohort study of patients treated for MSSA BSI with either oxacillin or cefazolin was performed across two medical centers in Chicago, IL. The outcome measures included documented in-hospital treatment failure, all-cause in-hospital mortality, duration of MSSA BSI, and incidence of documented adverse events. Of 161 patients with MSSA BSI, 103 (64%) received cefazolin, and 58 (36%) received oxacillin. The identified sources of BSI were central line (37.9%), osteoarticular (18%), and skin and soft tissue (17.4%). Patients with endocarditis (29/52 [44.2%]) and other deep-seated infections (23/52 [55.8%]) were classified under the subset of deep-seated infections (52/161 [32.3%]). Multivariate models found deep-seated infection (adjusted odds ratio [aOR], 4.52; 95% confidence interval [CI], 1.23 to 16.6; P = 0.023), metastatic disease (aOR, 4.21; 95% CI, 1.13 to 15.7; P = 0.033), and intensive care unit (ICU) onset of infection (aOR, 4.80; 95% CI, 1.26 to 18.4; P = 0.022) to be independent risk factors for in-hospital treatment failure. Treatment group was not an independent predictor of failure (aOR, 3.76; 95% CI, 0.98 to 14.4; P = 0.053). The rates of treatment failure were similar among cefazolin-treated (5/32 [15.6%]) and oxacillin-treated (4/20 [20.0%]) patients (P = 0.72) in the subset of deep-seated infections. Mortality was observed in 1 (1%) and 3 (5.2%) cases of cefazolin- and oxacillin-treated patients, respectively (P = 0.13). Cefazolin was not associated with higher rates of treatment failure and appears to be an effective alternative to oxacillin for treatment of deep-seated MSSA BSI.