Risk of Infective Endocarditis in Patients with Spinal Surgical Site Infection and Staphylococcus aureus Bacteremia

Context: Surgical site infection (SSI) is responsible for significant morbidity, prolonged hospital stays, and increased costs. Infectious endocarditis (IE) is a rare but serious complication of bacteremia, particularly that resulting from Staphylococcus aureus SSI. The VIRSTA score predicts the risk of IE and determines the priority of transthoracic echocardiography (TTE) in patients with S. aureus bacteremia. The aim of the study was to (1) assess the performance of the VIRSTA score and (2) determine the usefulness of TTE in S. aureus bacteremia related to spinal SSI. Materials and Methods: We carried out a retrospective study of consecutive patients with spinal SSI and S. aureus bacteremia at two university hospitals in France (Bordeaux and Tours) from January 2009 to January 2023. We collected the patients' clinical and surgical characteristics at baseline, VIRSTA score items, TTE results, and medicosurgical management. The associations of these parameters with IE were assessed using the chi-square test and logistic regression models. Results: Of 82 patients with spinal SSI and S. aureus bacteremia, only 1 (1.21%) developed IE. Thirteen patients did not benefit from TTE during hospitalization and were considered free of IE after clinical follow-up. Diabetes mellitus (p < 0.04) and the presence of severe sepsis or septic shock (p < 0.03) were significantly associated with the presence of IE in this population. Conclusions: Incidence of IE in patients with spinal SSI and S. aureus bacteremia is low. The VIRSTA score has high sensitivity but is not accurate for identifying patients at high risk for IE and systematic performance of TTE is complex and not useful in this setting. Level of Evidence: IV.

Prevalence and Mortality of Infective Endocarditis in Community-Acquired and Healthcare-Associated Staphylococcus aureus Bacteremia: A Danish Nationwide Registry-Based Cohort Study

BACKGROUND

Staphylococcus aureus bacteremia (SAB) can be community-acquired or healthcare-associated, and prior small studies have suggested that this mode of acquisition impacts the subsequent prevalence of infective endocarditis (IE) and patient outcomes.

METHODS

First-time SAB was identified from 2010 to 2018 using Danish nationwide registries and categorized into community-acquired (no healthcare contact within 30 days) or healthcare-associated (SAB >48 hours of hospital admission, hospitalization within 30 days, or outpatient hemodialysis). Prevalence of IE (defined from hospital codes) was compared between groups using multivariable adjusted logistic regression analysis. One-year mortality of S aureus IE (SAIE) was compared between groups using multivariable adjusted Cox proportional hazard analysis.

RESULTS

We identified 5549 patients with community-acquired SAB and 7491 with healthcare-associated SAB. The prevalence of IE was 12.1% for community-acquired and 6.6% for healthcare-associated SAB. Community-acquired SAB was associated with a higher odds of IE as compared with healthcare-associated SAB (odds ratio, 2.12 [95% confidence interval {CI}, 1.86-2.41]). No difference in mortality was observed with 0-40 days of follow-up for community-acquired SAIE as compared with healthcare-associated SAIE (HR, 1.07 [95% CI, .83-1.37]), while with 41-365 days of follow-up, community-acquired SAIE was associated with a lower mortality (HR, 0.71 [95% CI, .53-.95]).

CONCLUSIONS

Community-acquired SAB was associated with twice the odds for IE, as compared with healthcare-associated SAB. We identified no significant difference in short-term mortality between community-acquired and healthcare-associated SAIE. Beyond 40 days of survival, community-acquired SAIE was associated with a lower mortality.

Unreliability of Clinical Prediction Rules to Exclude without Echocardiography Infective Endocarditis in Staphylococcus aureus Bacteremia

BACKGROUND

It is unclear whether the use of clinical prediction rules is sufficient to rule out infective endocarditis (IE) in patients with Staphylococcus aureus bacteremia (SAB) without an echocardiogram evaluation, either transthoracic (TTE) and/or transesophageal (TEE). Our primary purpose was to test the usefulness of PREDICT, POSITIVE, and VIRSTA scores to rule out IE without echocardiography. Our secondary purpose was to evaluate whether not performing an echocardiogram evaluation is associated with higher mortality.

METHODS

We conducted a unicentric retrospective cohort including all patients with a first SAB episode from January 2015 to December 2020. IE was defined according to modified Duke criteria. We predefined threshold cutoff points to consider that IE was ruled out by means of the mentioned scores. To assess 30-day mortality, we used a multivariable regression model considering performing an echocardiogram as covariate.

RESULTS

Out of 404 patients, IE was diagnosed in 50 (12.4%). Prevalence of IE within patients with negative PREDICT, POSITIVE, and VIRSTA scores was: 3.6% (95% CI 0.1-6.9%), 4.9% (95% CI 2.2-7.7%), and 2.2% (95% CI 0.2-4.3%), respectively. Patients with negative VIRSTA and negative TTE had an IE prevalence of 0.9% (95% CI 0-2.8%). Performing an echocardiogram was independently associated with lower 30-day mortality (OR 0.24 95% CI 0.10-0.54, p = 0.001).

CONCLUSION

PREDICT and POSITIVE scores were not sufficient to rule out IE without TEE. In patients with negative VIRSTA score, it was doubtful if IE could be discarded with a negative TTE. Not performing an echocardiogram was associated with worse outcomes, which might be related to presence of occult IE. Further studies are needed to assess the usefulness of clinical prediction rules in avoiding echocardiographic evaluation in SAB patients.

The LAUsanne STAPHylococcus aureus ENdocarditis (LAUSTAPHEN) score: A prediction score to estimate initial risk for infective endocarditis in patients with S. aureus bacteremia

Introduction

Infective endocarditis (IE) is a common complication of Staphylococcus aureus bacteremia (SAB). The study aimed to develop and validate a prediction score to determine IE risk among SAB.

Methods

This retrospective study included adults with SAB (2015-2021) and divided them into derivation and validation cohorts. Using the modified 2015 European Society of Cardiology modified Duke Criteria for definite IE, the LAUSTAPHEN score was compared to previous scores.

Results

Among 821 SAB episodes, 419 and 402 were divided into derivation and validation cohorts, respectively. Transthoracic and transoesophageal echocardiography (TOE) were performed in 77.5 and 42.1% of episodes, respectively. Definite IE was diagnosed in 118 episodes (14.4%). Derivation cohort established that cardiac predisposing factors, such as cardiac implantable electronic devices, prolonged bacteremia ≥48 h, and vascular phenomena were independently associated with IE. In addition to those parameters, native bone and joint infections were used to constitute the LAUSTAPHEN score. LAUSTAPHEN and VIRSTA scores misclassified <4% of IE cases as low risk. Misclassification using POSITIVE and PREDICT scores was >10%. The number of TOEs required to safely exclude IE were 66.9 and 51.6% with VIRSTA and LAUSTAPHEN, respectively.

Discussion

LAUSTAPHEN and VIRSTA scores exhibited the lowest misclassification rate of IE cases to the low-risk group. However, the number of patients requiring TOE was higher for VIRSTA than for LAUSTAPHEN.

Comparing Echocardiographic Modalities in Native-Valve Infective Endocarditis Due to Methicillin-Resistant Staphylococcus Aureus in People Who Inject Drugs

Background: Methicillin-resistant Staphylococcus aureus (MRSA) infective endocarditis (IE) is associated with high morbidity and mortality. Current IE guidelines recommend transesophageal echocardiogram (TEE) over transthoracic echocardiogram (TTE) to diagnose infective endocarditis. Management of IE in people who inject drugs (PWID) in many medical centers is mainly conservative with prolonged intravenous antibiotics. Cardiac valve replacement in these patients remains controversial, given the high risk of reinfection. This study’s purpose is to evaluate whether obtaining sequential TEE after TTE in PWID with MRSA native-valve IE changes the management plan in these patients.

Methods: A retrospective cohort of patients who are 18 years of age or older and inject drugs with definite MRSA IE between 2013 and 2019 were studied. Their echocardiographic reports and overall management plans were reviewed.

Results: One hundred and twenty-six patients met the inclusion criteria. TTE was performed in 121 patients and, of these patients, 69 (57%) had detectable valvular vegetations while 52 (43%) did not. Of the 52 patients with a negative TTE, 44 underwent TEE, 28 (53%) of which showed vegetation. A total of 18 (14%) patients underwent surgery. Of these, six (33%) patients had a positive TTE only, with no subsequent TEE. Ten (56%) patients had both a positive TTE and TEE, and two (11%) patients had a negative TTE but positive TEE.

Conclusion: In this retrospective cohort, obtaining a sequential TEE after a TTE in PWID with proven MRSA native IE by modified Duke’s criteria changed the management plan in two patients. The decision to perform a TEE in these patients needs to be individualized. Larger studies are needed to better evaluate the role of TEE in this patient population.

Role of echocardiography in uncomplicated Staphylococcus aureus catheter-related bloodstream infections

Uncomplicated bacteremia and catheter-related bloodstream infection (CRBSI) are frequently suggested as factors associated with low risk of infective endocarditis in Staphylococcus aureus bacteremia (SAB). Nevertheless, guidelines recommend that echocardiography in all patients with SAB. We evaluated the effects of echocardiography on patient outcomes. Patients with uncomplicated S. aureus CRBSI were retrospectively identified between January 2013 and June 2018 at a 1950-bed, tertiary-care university hospital. Treatment failure was defined as any case of relapse or all-cause death within 90 days. Of 890 SAB patients, 95 with uncomplicated S. aureus CRBSI were included. Thirty-two patients underwent echocardiography within 30 days of their first positive blood culture. Two patients who underwent echocardiography revealed right-sided infective endocarditis. One patient who did not undergo echocardiography experienced recurrent SAB (peripheral CRBSI) 85 days after his first positive blood culture. There were no SAB-related deaths. The Kaplan-Meier curves of treatment failure showed no significant differences between patients who did and did not undergo echocardiography (P = .77). In multivariable analysis, risk factors for treatment failure were liver cirrhosis (hazard ratio: 9.60; 95% confidence interval: 2.13-43.33; P = .003) and other prostheses (hazard ratio: 63.79; 95% confidence interval: 5.05-805.40; P = .001). This study did not verify the putative association between treatment failure and implementation of echocardiography in patients with uncomplicated S. aureus CRBSI. Given the low observed rates of adverse outcomes, routine echocardiography might not be obligatory and could be performed on an individual basis.

Human bite wounds as a portal of entry for infective endocarditis and purulent pericarditis: a very rare association

Human bites are an infrequent cause of emergency department visits and hospital admissions. There are rarely published cases of complicated infection, such as infective endocarditis. We present a rare case of a patient with acute infective endocarditis in a healthy native valve and purulent pericarditis from a human bite. A 40-year-old man with obesity suffered deep human bites by an adult woman, with two deep lesions in the anterior thorax and one superficial lesion in the upper abdomen and admitted in intensive care unit with septic shock and a persistent aortic murmur. Echocardiography described evidence of vegetation, perforation and severe regurgitation of aortic valve. Scanner described moderate pericardial effusion. Cardiac surgery was performed, with evidence of purulent pericardial effusion after pericardiotomy, and subsequently aortic valve replacement with a 25 mm bioprosthesis. The patient showed positive progress.

Validation of VIRSTA and Predicting Risk of Endocarditis Using a Clinical Tool (PREDICT) Scores to Determine the Priority of Echocardiography in Patients With Staphylococcus aureus Bacteremia

Background

Infective endocarditis (IE) secondary to Staphylococcus aureus bacteremia (SAB) has high morbidity and mortality. The systematic use of echocardiography in SAB is controversial. We aimed to validate VIRSTA and Predicting Risk of Endocarditis Using a Clinical Tool (PREDICT) scores for predicting the risk of IE in Colombian patients with SAB and, consequently, to determine the need for echocardiography.

Methods

Cohort of patients hospitalized with SAB in 2 high complexity institutions in Medellin, Colombia, between 2012 and 2018. The diagnosis of IE was established based on the modified Duke criteria. The VIRSTA and PREDICT scores were calculated from the clinical records, and their operational performance was calculated.

Results

The final analysis included 922 patients, 62 (6.7%) of whom were diagnosed with IE. The frequency of IE in patients with a negative VIRSTA scale was 0.44% (2/454). The frequency of IE in patients with a negative PREDICT scale on day 5 was 4.8% (30/622). The sensitivity and negative predictive value (NPV) of the VIRSTA scale was 96.7% and 99.5%, respectively. For the PREDICT scale on day 5, the sensitivity and NPV were 51.6% and 95.1%, respectively. The discrimination, given by the area under the receiver operating characteristic curve, was 0.86 for VIRSTA and 0.64 for PREDICT.

Conclusions

In patients with negative VIRSTA, screening echocardiography may be unnecessary because of the low frequency of IE. In PREDICT-negative patients, despite the low frequency of IE, it is not safe to omit echocardiography.

Forgoing transesophageal echocardiogram in selected patients with complicated Staphylococcus aureus bacteremia

Infective endocarditis (IE) has been increasingly recognized as an important complication of Staphylococcus aureus bacteremia (SAB), leading to a low threshold for echocardiography and extended treatment with anti-staphylococcal agents. However, outside of IE, many indications for prolonged anti-staphylococcal therapy courses are present. We sought to determine the frequency in which findings from a transesophageal echocardiogram (TEE) changed clinical SAB management in a large Canadian health region. Residents (> 18 years) with SAB from 2012 to 2014 who underwent transthoracic echocardiogram (TTE) and TEE were assessed. Patients potentially benefiting from an extended course of anti-staphylococcal agents were defined a priori. Patient demographics, treatment (including surgical), and clinical outcomes were extracted and evaluated. Of the 705 episodes of SAB that underwent a screening echocardiogram, 203 episodes underwent both a TTE and TEE, of which 92.1% (187/203) contained an a priori indication for extended anti-staphylococcal therapy. Regardless of TEE results, actual duration of therapy did not differ in SAB episodes that had ≥ 1 extended anti-staphylococcal therapy criteria (36.7 days, IQR 23.4-48.6 vs. 43.8 days, IQR 33.3-49.5, p = 0.17). Additionally, there were no cases in which TEE was utilized as the sole reason to shorten duration of therapy or proceed to surgery for those with SAB. Routine performance of TEE may be unnecessary in all SAB as many patients have pre-existing indications for extended anti-staphylococcal therapy independent of TEE findings. An algorithm to selectively identify cases of SAB that would benefit from TEE can reduce resource and equipment expenditure and patient risks associated with TEE.

A narrative review of early surgery versus conventional treatment for infective endocarditis: do we have an answer?

The most appropriate strategy and timing for surgery in infective endocarditis (IE) remains an argument of debate. Despite some authors promote the adoption of an early surgical approach (within 48 hours) to limit mortality and complications, no robust randomized trials are available on this argument and the evidence on this subject remain at the "expert opinion" level. Additionally, the different messages promulgated by the American and European guidelines contributed to fuel confusion regarding the relative priority of the surgical over medical therapy in IE. The European Society of Cardiology (ESC) guidelines individuates three level of urgency: emergency surgery, to be performed within 24 hours; urgent surgery, recommended within a few days; elective surgery to be performed after 1-2 weeks of antibiotic therapy. Urgent surgery is recommended for most cases of IE. In the American Heart Association (AHA)'s guidelines define early surgery as "during the initial hospitalization and before completion of a full course of antibiotics." Some of the available evidences showed that are no proven benefits in delaying surgery if a definite diagnosis of IE has been established. However, this argument is controversial across the literature and several factors including the center specific experience can play a role in decision-making. In this review the latest evidences on IE clinical and surgical characteristics along with the current studies on the adoption of an early surgical approach are analyzed to clarify whether enough evidence is available to inform an update of the guidelines.

Early differentiation between uncomplicated and complicated Staphylococcus aureus bacteraemia: Potential value and limitations of a clinical risk score

OBJECTIVE

A cornerstone in the management of Staphylococcus aureus bacteraemia (SAB) is the differentiation between a complicated and an uncomplicated SAB course. The ability to early and accurately identify patients with - and without - complicated bacteraemia may optimise the utility of diagnostics and prevent unnecessary prolonged antibiotic therapy.

METHODS

Development and validation of a prediction score in SAB using demographic, clinical, and laboratory data from two independent Dutch cohorts; estimating the risk of complicated disease at the time of the first positive blood culture. Models were developed using logistic regression and evaluated by c-statistics, ie area under the ROC-curve, and negative predictive values (NPV).

RESULTS

The development- and validation cohorts included 150 and 183 patients, respectively. The most optimal prediction model included: mean arterial pressure, signs of metastatic infection on physical examination, leucocyte count, urea level and time to positivity of blood cultures (c-statistic 0.82, 95% CI 0.74-0.89). In the validation cohort, the c-statistic of the prediction score was 0,77 (95% CI 0.69-0.84). The NPV for complicated disease for patients with a score of ≤2 was 0.83 (95% CI 0.68-0.92), with a negative likelihood ratio of 0.14 (95% CI 0.06-0.31).

CONCLUSION

The early SAB risk score helps to identify patients with high probability of uncomplicated SAB. However, the risk score's lacked absolute discriminative power to guide decisions on the management of all patients with SAB on its own. The heterogenicity of the disease and inconsistency in definitions of complicated SAB are important challenges in the development of clinical rules to guide the management of SAB.

Prevalence of infective endocarditis in patients with positive blood cultures: a Danish nationwide study

AIMS

Increasing attention has been given to the risk of infective endocarditis (IE) in patients with certain blood stream infections (BSIs). Previous studies have been conducted on selected patient cohorts, yet unselected data are sparse. We aimed to investigate the prevalence of IE in BSIs with bacteria typically associated with IE.

METHODS AND RESULTS

By crosslinking nationwide registries from 2010 to 2017, we identified patients with BSIs typically associated with IE: Enterococcus faecalis (E. faecalis), Staphylococcus aureus (S. aureus), Streptococcus spp., and coagulase negative staphylococci (CoNS) and examined the concurrent IE prevalence. A trend test was used to examine temporal changes in the prevalence of IE. In total 69 021, distributed with 15 350, 16 726, 19 251, and 17 694 BSIs were identified in the periods of 2010-2011, 2012-2013, 2014-2015, and 2016-2017, respectively. Patients with E. faecalis had the highest prevalence of IE (16.7%) followed by S. aureus (10.1%), Streptococcus spp. (7.3%), and CoNS (1.6%). Throughout the study period, the prevalence of IE among patients with E. faecalis and Streptococcus spp. increased significantly (P = 0.0005 and P = 0.03, respectively). Male patients had a higher prevalence of IE for E. faecalis, Streptococcus spp., and CoNS compared with females. A significant increase in the prevalence of IE was seen for E. faecalis, Streptococcus spp., and CoNS with increasing age.

CONCLUSION

For E. faecalis BSI, 1 in 6 had IE, for S. aureus BSI 1 in 10 had IE, and for Streptococcus spp. 1 in 14 had IE. Our results suggest that screening for IE seems reasonable in patients with E. faecalis BSI, S. aureus BSI, or Streptococcus spp. BSI.

Assessing the impact of a 'bundle of care' approach to Staphylococcus aureus bacteraemia in a tertiary hospital

Background

Staphylococcus aureus bacteraemia is associated with significant morbidity and mortality. There is evidence that standardised care bundle implementation may improve the rates of appropriate investigations and improve overall management. A S. aureus bacteraemia care bundle was introduced at Christchurch Hospital, New Zealand in early 2014. We assessed the impact of the intervention on the management and outcome of S. aureus bacteraemia.

Methods

A cohort study of cases of S. aureus bacteraemia was conducted following standardised care bundle introduction. Prospective enrolment of post-intervention patients occurred from 1^st January 2014 to 30^th June 2015, with retrospective review of pre-intervention cases from 1^st January 2009 to 31^st December 2013.

Results

In the pre-intervention period 447 patients had at least one episode of S. aureus bacteraemia compared to 151 patients in the post-intervention period. The two groups were similar by gender, ethnicity, and age. Significant increases in Infectious Diseases consultation rate (86.6% vs 94.8%; p=0.009), echocardiography (76.3% vs 96.3%; p<0.001), urine culture (74.0% vs 91.9%; p<0.001), follow up blood cultures (44.2% vs 83.0%; p<0.001), and at least 2 weeks of parenteral therapy (83.5% vs 92.9%; p=0.014) were observed after introduction of the bundle. There were no significant differences in rates 30-day mortality (18.6% vs. 20.5%; p=0.596), but there was a reduction in episodes of relapsed infection in the post-intervention cohort (7.4% vs 1.3%; p=0.004).

Conclusion

An integrated care bundle for the management of S. aureus bacteraemia resulted in increased use of quality of care indicators and infectious diseases review and improved patient outcome.

Expert consensus-based clinical practice guidelines management of intravascular catheters in the intensive care unit

The French Society of Intensive Care Medicine (SRLF), jointly with the French-Speaking Group of Paediatric Emergency Rooms and Intensive Care Units (GFRUP) and the French-Speaking Association of Paediatric Surgical Intensivists (ADARPEF), worked out guidelines for the management of central venous catheters (CVC), arterial catheters and dialysis catheters in intensive care unit. For adult patients: Using GRADE methodology, 36 recommendations for an improved catheter management were produced by the 22 experts. Recommendations regarding catheter-related infections’ prevention included the preferential use of subclavian central vein (GRADE 1), a one-step skin disinfection(GRADE 1) using 2% chlorhexidine (CHG)-alcohol (GRADE 1), and the implementation of a quality of care improvement program. Antiseptic- or antibiotic-impregnated CVC should likely not be used (GRADE 2, for children and adults). Catheter dressings should likely not be changed before the 7th day, except when the dressing gets detached, soiled or impregnated with blood (GRADE 2− adults). CHG dressings should likely be used (GRADE 2+). For adults and children, ultrasound guidance should be used to reduce mechanical complications in case of internal jugular access (GRADE 1), subclavian access (Grade 2) and femoral venous, arterial radial and femoral access (Expert opinion). For children, an ultrasound-guided supraclavicular approach of the brachiocephalic vein was recommended to reduce the number of attempts for cannulation and mechanical complications. Based on scarce publications on diagnostic and therapeutic strategies and on their experience (expert opinion), the panel proposed definitions, and therapeutic strategies.

A Narrative Review of Early Oral Stepdown Therapy for the Treatment of Uncomplicated Staphylococcus aureus Bacteremia: Yay or Nay?

Historically, intravenous (IV) antibiotics have been the cornerstone of treatment for uncomplicated Staphylococcus aureus bacteremia (SAB). However, IV antibiotics are expensive, increase the rates of hospital readmission, and can be associated with catheter-related complications. As a result, the potential role of oral antibiotics in the treatment of uncomplicated SAB has become a subject of interest. This narrative review article aims to summarize key arguments for and against the use of oral antibiotics to complete treatment of uncomplicated SAB and evaluates the available evidence for specific oral regimens. We conclude that evidence suggests that oral step-down therapy can be an alternative for select patients who meet the criteria for uncomplicated SAB and will comply with medical treatment and outpatient follow-up. Of the currently studied regimens discussed in this article, linezolid has the most support, followed by fluoroquinolone plus rifampin.

Clinical utility of echocardiography for the diagnosis of native valve infective endocarditis in Staphylococcus aureus bacteremia

BACKGROUND

The incidence of Staphylococcus aureus infective endocarditis (IE) is steadily rising due to advances in health care delivery. Routine echocardiography is essential in the management of Staphylococcus aureus bacteremia (SAB). The aim of this retrospective cohort study was to characterize the real-world use of echocardiography in adult patients with SAB and native valve S aureus IE.

METHODS

Using an academic hospital microbiological database, all cases of SAB in adults between 2010 and 2016 were identified. Demographic, echocardiographic, and clinical features were recorded.

RESULTS

A total of 738 episodes of SAB were identified, of which 504 (68%) patients underwent transthoracic echocardiography (TTE) within 30 days. Of 73 patients with definite IE, 46 (63%) patients had definite IE diagnosed on the initial TTE. An additional 14 (19%) patients had definite IE diagnosed on repeat TTE, 6 (8%) on transesophageal echocardiography (TEE), and 7 (10%) were diagnosed without fulfilling Duke echocardiographic criteria. The yield of repeat TTE was comparable to that of TEE for identifying new vegetations not identified on the initial TTE (17% vs 21%, P = .78).

CONCLUSIONS

Most cases of IE in SAB were identified using TTE alone, with repeat TTE improving the diagnostic yield in the setting of clinical decompensation.

Trends in the use of echocardiography in patients with Staphylococcus aureus bacteremia: an analysis using the Nationwide Inpatient Sample data

BACKGROUND

Infective endocarditis occurs in approximately 10%-30% of patients with Staphylococcus aureus bacteremia (SaB). Guidelines recommend echocardiography in patients with SaB and risk factors for infective endocarditis in the absence of any obvious source of infection. Herein, we explored the trends in the use of echocardiography in patients with SaB and its relationship to outcomes using a large national database.

METHOD

All patients with a principal discharge diagnosis of SaB were identified using the National Inpatient Sample database from 2001 to 2014. Procedure code 88.72 was used to identify echocardiography. Logistic regression models were estimated to identify the year-over-year trends in echocardiogram, predictors of use, and association with mortality.

RESULTS

From 2001 to 2014, there were 668 423 hospitalizations with SaB diagnosis and 86 387 (12.9%) had echocardiogram. The rate of echocardiography increased from 10.7% in 2001 to 15.2% in 2014 (p_trend  < 0.001). Major predictors of echocardiogram usage were younger age, male gender, presence of sepsis, valvular or congenital heart disease, prosthetic heart valve (PHV), cardiac implantable electronic device (CIED), hemodialysis, and drug abuse. The adjusted rates of echocardiography increased from approximately 10% to 15% in hospitalizations without risk factors for IE while for high-risk groups like PHV and CIED it remained constant at 30% and 19%, respectively. Echocardiography was associated with 31% lower odds of in-hospital mortality.

CONCLUSION

The increase in echocardiography rate was largely attributable to increased use in those without risk factors while usage in those with PHV and CIED remained much lower than expected. Echocardiography use was associated with lower risk-adjusted mortality. These findings require further study and confirmation.

Diagnosis and treatment of catheter-related bloodstream infection: Clinical guidelines of the Spanish Society of Infectious Diseases and Clinical Microbiology and (SEIMC) and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC)

Catheter-related bloodstream infections (CRBSI) constitute an important cause of hospital-acquired infection associated with morbidity, mortality, and cost. The aim of these guidelines is to provide updated recommendations for the diagnosis and management of CRBSI in adults. Prevention of CRBSI is excluded. Experts in the field were designated by the two participating Societies (the Spanish Society of Infectious Diseases and Clinical Microbiology and [SEIMC] and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units [SEMICYUC]). Short-term peripheral venous catheters, non-tunneled and long-term central venous catheters, tunneled catheters and hemodialysis catheters are covered by these guidelines. The panel identified 39 key topics that were formulated in accordance with the PICO format. The strength of the recommendations and quality of the evidence were graded in accordance with ESCMID guidelines. Recommendations are made for the diagnosis of CRBSI with and without catheter removal and of tunnel infection. The document establishes the clinical situations in which a conservative diagnosis of CRBSI (diagnosis without catheter removal) is feasible. Recommendations are also made regarding empirical therapy, pathogen-specific treatment (coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus spp., Gram-negative bacilli, and Candida spp.), antibiotic lock therapy, diagnosis and management of suppurative thrombophlebitis and local complications.

Benefit of Echocardiography in Patients With Staphylococcus aureus Bacteremia at Low Risk of Endocarditis

Background

The risk of endocarditis among patients with Staphylococcus aureus bacteremia is not uniform, and a number of different scores have been developed to identify patients whose risk is less than 5%. The optimal echocardiography strategy for these patients is uncertain.

Methods

We used decision analysis and Monte Carlo simulation using input parameters taken from the existing literature. The model examined patients with S aureus bacteremia whose risk of endocarditis is less than 5%, generally those with nosocomial or healthcare-acquired bacteremia, no intracardiac prosthetic devices, and a brief duration of bacteremia. We examined 6 echocardiography strategies, including the use of transesophageal echocardiography, transthoracic echocardiography, both modalities, and neither. The outcome of the model was 90-day survival.

Results

The optimal echocardiography strategy varied with the risk of endocarditis and the procedural mortality associated with transesophageal echocardiography. No echocardiography strategy offered an absolute benefit in 90-day survival of more than 0.5% compared with the strategy of not performing echocardiography and treating with short-course therapy. Strategies using transesophageal echocardiography were never preferred if the mortality of this procedure was greater than 0.5%.

Conclusions

In patients identified to be at low risk of endocarditis, the choice of echocardiography strategy appears to exert a very small influence on 90-day survival. This finding may render test-treatment trials unfeasible and should prompt clinicians to focus on other, more important, management considerations in these patients.

Impact on mortality of adherence to evidence-based interventions in patients with catheter-related bloodstream infection due to methicillin-sensitive Staphylococcus aureus

BACKGROUND

Recent studies have demonstrated improved survival when the management of Staphylococcus aureus bloodstream infection (BSI) is compliant with evidence-based therapeutic interventions. Whether this effect extends to low-risk sources, such as catheter-related BSI, remains unclear.

METHODS

We retrospectively included 225 episodes of methicillin-sensitive S. aureus catheter-related BSI diagnosed in our centre during two non-consecutive periods: 2002-2004 (first period (101 episodes)) and 2009-2013 (second period (124 episodes)). We evaluated the adherence (percentage of compliance = (no. of interventions performed/no. of interventions recommended) × 100) to the following bundle: early catheter removal (≤72 hours), early initiation of appropriate antibiotic therapy, adequate sampling of follow-up blood cultures, transthoracic echocardiography (TTE) during hospitalization and adequate duration of therapy.

RESULTS

Patients in the second period had a higher burden of comorbidities and more severe underlying conditions. All-cause 30-day mortality was 9.3%, with a significant difference between the first and second periods (13.9% versus 5.6%; p value = .035). Bundle adherence was significantly higher in the second period, particularly for follow-up blood cultures (26.7% versus 48.4%; p value = .001), performance of TTE (45.5% versus 84.7%; p value < .001) and appropriate duration of therapy (34.7% versus 50.0%; p value = .022). Bundle adherence ≥ 55% was associated with lower 30-day mortality (hazard ratio: 0.31; 95% confidence interval: 0.13-0.76). This effect remained significant across propensity score-based models adjusted for septic shock, study period and underlying conditions.

CONCLUSIONS

There was a survival benefit in adhering to a bundle of evidence-based interventions in the specific setting of catheter-related BSI due to methicillin-sensitive S. aureus.

Methicillin-sensible Staphylococcus aureus causing endocarditis, with cerebral and orthopaedic complications, in a 17-month-old child with no risk factor

We report a case of Staphylococcus aureus endocarditis, with large vegetation, in a 17-month-old male infant, complicated with meningitis, ischaemic strokes and osteoarthritis leading to haemorrhagic stroke by aneurysm rupture. He did not present any risk factor for endocarditis. The final course was favourable through, after valve replacement. The strain was sensible to methicillin and belongs to complex clonal 398, with accessory gene regulator I. We did not found immunodeficiency.

Infectious endocarditis: An update for emergency clinicians

INTRODUCTION

Infectious endocarditis (IE) is a potentially deadly disease without therapy and can cause a wide number of findings and symptoms, often resembling a flu-like illness, which makes diagnosis difficult.

OBJECTIVE

This narrative review evaluates the presentation, evaluation, and management of infective endocarditis in the emergency department, based on the most current literature.

DISCUSSION

IE is due to infection of the endocardial surface, most commonly cardiac valves. Major risk factors include prior endocarditis (the most common risk factor), structural heart damage, IV drug use (IVDU), poor immune function (vasculitis, HIV, diabetes, malignancy), nosocomial (surgical hardware placement, poor surgical technique, hematoma development), and poor oral hygiene, and a wide variety of organisms can cause IE. Patients typically present with flu-like illness. Though fever and murmur occur in the majority of cases, they may not be present at the time of initial presentation. Other findings such as Roth spots, Janeway lesions, Osler nodes, etc. are not common. An important component is consideration of risk factors. A patient with IVDU (past or current use) and fever should trigger consideration of IE. Other keys are multiple sites of infection, poor dentition, and abnormal culture results with atypical organisms. If endocarditis is likely based on history and examination, admission for further evaluation is recommended. Blood cultures and echocardiogram are key diagnostic tests.

CONCLUSIONS

Emergency physicians should consider IE in the patient with flu-like symptoms and risk factors. Appropriate evaluation and management can significantly reduce disease morbidity and mortality.

What risk of endocarditis is low enough to justify the omission of transoesophageal echocardiography in Staphylococcus aureus bacteraemia? A narrative review

BACKGROUND

Recent criteria which can identify patients with Staphylococcus aureus bacteraemia (SAB) who are at very low risk of endocarditis raise the question of whether transoesophageal echocardiography (TOE) is appropriate for these patients.

AIMS

To estimate the probability of occult endocarditis complicating SAB below which a TOE-guided treatment strategy no longer offers the best 180-day survival, and to examine the key uncertainties affecting this result.

SOURCES

Estimates of the parameters required to calculate the Pauker-Kassirer testing threshold were identified from studies published prior to 1 June 2017 using a composite search strategy that involved a systematic search for relevant controlled trials and guidelines, followed by a non-systematic iterative search of the observational literature.

CONTENT

Estimates of the necessary parameters were generally consistent across the literature with the exception of the procedural mortality of TOE. In our base-case scenario (TOE mortality 0.1%), the testing threshold for TOE in apparently uncomplicated SAB was a 1.1% probability of occult endocarditis. Sensitivity analyses revealed that the procedural mortality of TOE was a key uncertainty affecting estimates of the testing threshold.

IMPLICATIONS

None of the available clinical tools can place patients with SAB below this probability of endocarditis with 95% confidence. Future work in this area should concentrate on improving the precision of these tools and on exploring the value of alternative echocardiography strategies. In addition, a better understanding of the harms of TOE is required to ensure that recommendations regarding the role of this investigation in the management of patients with SAB are appropriate.

Echocardiography has low utility in cancer patients with Staphylococcus aureus bacteraemia: findings from a retrospective study

AIM

To describe the incidence of infective endocarditis (IE) detected on echocardiography in cancer patients with confirmed Staphylococcus aureus bacteraemia (SAB).

METHODS

We retrospectively identified 95 cases of SAB in cancer patients from January 2007-March 2016. Echocardiography was ordered at the discretion of the treating team, and positive findings defined according to the Modified Duke Criteria. Complicated bacteraemia was defined by prolonged bacteraemia, presence of intracardiac device/prosthetic valve, or signs of metastatic infection.

RESULTS

Major predisposing risk factors for IE (intracardiac device, prosthetic valve, valvular disease, diabetes mellitus, renal dialysis) were present in 27% of cases. Fifty-one of 95 (54%) had a central venous catheter and 17 (18%) patients had complicated bacteraemia. Echocardiography was performed in 75/95 (79%) episodes, with transthoracic echocardiography (TTE) alone in 56, transoesophageal echocardiography (TOE) alone in 4 and both in 15. Echocardiography was diagnostic for IE in 2 patients (1 TTE, 1 TOE), including one result that led to the diagnosis of IE in a clinically unsuspected case. Four further cases of IE were diagnosed on clinical findings, resulting in an overall rate of IE of 6% (6/95). Five of these cases occurred in patients with complicated bacteraemia or ≥ 1 risk factor for IE. No patient was readmitted due to IE.

CONCLUSION

IE is infrequent in cancer patients with uncomplicated SAB and no risk factors for IE. Performing echocardiography routinely in all cancer patients with SAB rarely alters diagnosis or affects antibiotic management and therefore should be reserved for patients with specific risk factors.

Criteria for Identifying Patients With Staphylococcus aureus Bacteremia Who Are at Low Risk of Endocarditis: A Systematic Review

This systematic review examines the methods and results of recent studies reporting clinical criteria able to identify patients with Staphylococcus aureus bacteremia who are at very low risk of endocarditis. We searched PubMed, EMBASE, and the Cochrane Collaboration CENTRAL database for articles published after March 1994 using a combination of MeSH and free text search terms for S. aureus AND bacteremia AND endocarditis. Studies were included if they presented a combination of clinical and microbiological criteria with a negative likelihood ratio of ≤0.20 for endocarditis. We found 8 studies employing various criteria and reference standards whose criteria were associated with negative likelihood ratios between 0.00 and 0.19 (corresponding to 0%-5% risk of endocarditis at 20% background prevalence). The benefit of echocardiography for patients fulfilling these criteria is uncertain.

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

PURPOSE

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

RESULTS

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

Risk assessment for infected endocarditis in Staphylococcus aureus bacteremia patients: When is transesophageal echocardiography needed?

Aims:

Echocardiography is the main technique for the diagnosis of endocarditis in patients with Staphylococcus aureus bacteremia (SAB), but a consensus about performing transthoracic echocardiography or transesophageal echocardiography (TEE) as first-line tests is currently lacking. Recently, a new scoring system has been proposed by Palraj et al. to guide the use of TEE in this population. Our aim was to validate this scoring system or modify it, if necessary.

Methods and results:

Data from SAB patients admitted from 2012 to 2014 were collected. We tested the Palraj scores to stratify patients’ risk for endocarditis. Moreover, we analyzed our population to identify any other possible clinical predictors of endocarditis not included in the score. Endocarditis was diagnosed in 38 of 205 patients (18.5%). Palraj’s score was effective in the detection of patients at high risk of endocarditis. In addition, we identified the presence of cardiac devices, prolonged bacteremia and intravenous drug abuse (IVDA) as elements strongly correlated with endocarditis. Two scoring systems (Day-1 and Day-5) were derived including IVDA as a variable. Using a Day-1 cut-off value ≥5 and a Day-5 cut-off value ≥2, the ‘modified Palraj’s score’ showed sensitivities of 42.1% and 97.0% and specificities of 88.6% and 32.0% for Day-1 and Day-5 scores, respectively.

Conclusion:

We modify and expand upon an effective scoring system to identify SAB patients at high risk for endocarditis in order to guide use of TEE. The inclusion of IVDA in the criteria for the calculation of the scores improves its effectiveness.

Clinical predictors and clinical prediction rules to estimate initial patient risk for infective endocarditis in Staphylococcus aureus bacteraemia: a systematic review and meta-analysis

OBJECTIVES

We conducted a meta-analysis to summarize diagnostic properties of risk factors and clinical prediction rules for diagnosing infective endocarditis (IE) in Staphylococcus aureus bacteraemia (SAB).

METHODS

We searched MEDLINE, Embase, and the Cochrane Database from inception to 6 January 2016 to identify studies evaluating risk factors and clinical prediction rules for IE in SAB patients. Pooled estimates of diagnostic properties for main risk factors were calculated using a bivariate random effects model.

RESULTS

Of 962 articles identified, 30 studies were included. These involved 16 538 SAB patients including 1572 IE cases. Risk factors with positive likelihood ratio (PLR) greater than 5 included embolic events (PLR 12.7, 95% CI 9.2-17.7), pacemakers (PLR 9.7, 95% CI 3.7-21.2), history of previous IE (PLR 8.2, 95% CI 3.1-22.0), prosthetic valves (PLR 5.7, 95% CI 3.2-9.5), and intravenous drug use (PLR 5.2, 95% CI 3.8-6.9). The only clinical factor with negative likelihood ratio (NLR) less than 0.5 was documented clearance of bacteraemia within 72 hours (NLR range 0.32-0.35). Of the nine published clinical prediction rules for ruling out IE, five had an NLR below 0.1.

CONCLUSIONS

SAB patients with high-risk features (embolic events, pacemakers, prosthetic valves, previous IE, or intravenous drug use) should undergo a trans-esophageal echocardiography (TEE) for IE. Clinical prediction rules show promise in safely ruling out endocarditis, but require validation in future studies.

Clinical Risk Factors for Infective Endocarditis in Staphylococcus aureus Bacteremia

Crucial to the management of staphylococcal bacteremia is an accurate evaluation of associated endocarditis, which has both therapeutic and prognostic implications. Because the clinical presentation of endocarditis can be nonspecific, the judicious use of echocardiography is important in distinguishing patients at high risk of developing endocarditis. In the presence of high-risk clinical features, an early transesophageal echocardiogram is warranted without prior transthoracic echocardiography. The purpose of this study was to investigate the clinical risk factors for staphylococcal infective endocarditis that might warrant earlier transesophageal echocardiography and to describe the incidence of endocarditis in cases of methicillin-resistant and methicillin-sensitive Staphylococcus aureus bacteremia. A retrospective case-control study was conducted by means of chart review of 91 patients consecutively admitted to a community hospital from January 2009 through January 2013. Clinical risk factors of patients with staphylococcal bacteremia were compared with risk factors of patients who had definite diagnoses of infective endocarditis. There were 69 patients with bacteremia alone (76%) and 22 patients with endocarditis (24%), as verified by echocardiography. Univariate analysis showed that diabetes mellitus (P=0.024), the presence of an automatic implantable cardioverter-defibrillator/pacemaker (P=0.006) or a prosthetic heart valve (P=0.003), and recent hospitalization (P=0.048) were significantly associated with developing infective endocarditis in patients with S. aureus bacteremia. The incidence of methicillin-resistant and methicillin-sensitive S. aureus bacteremia was similar in the bacteremia and infective-endocarditis groups (P=0.437). In conclusion, identified high-risk clinical factors in the presence of bacteremia can suggest infective endocarditis. Early evaluation with transesophageal echocardiography might well be warranted.

Low rates of endocarditis in healthcare-associated Staphylococcus aureus bacteremia suggest that echocardiography might not always be required

Healthcare-associated Staphylococcus aureus bacteremia (HA-SAB) is an increasingly frequently observed complication of medical treatment. Current guidelines recommend evaluation with echocardiography and preferably transesophageal echocardiography for the exclusion of infectious endocarditis (IE). We performed a retrospective analysis of all patients with HA-SAB between 1 January 2007 and 31 July 2012. Patients were divided into those with a high degree of clinical suspicion of IE (prosthetic intracardiac device, hemodialysis or positive blood cultures for 4 days or more) or those with a low degree of clinical suspicion of IE (absence of high-risk features based on previous literature as strong indicators of endocarditis). Three hundred and fifty-eight patients with HA-SAB were evaluated to determine the prevalence of IE, including 298 (83 %) who had echocardiography. Fourteen patients (4 %) had a final diagnosis of IE after echocardiography. In the group with a high degree of clinical suspicion 11 out of 84 patients (13 %) had IE. In the group with a low degree of clinical suspicion group 3 out 274 patients (1.1 %) had IE. HA-SAB has a low rate of IE, especially in the absence of high-risk features such as prolonged bacteremia, intracardiac prosthetic devices, and hemodialysis. Echocardiographic imaging in this low-risk population of patients is rarely helpful and may generally be avoided, although careful clinical follow-up is warranted. Patients with HA-SAB who have mechanical valves, intracardiac devices, prolonged bacteremia or dialysis dependency have a high incidence of IE and should be evaluated thoroughly using echocardiography.

Infective endocarditis

Infective endocarditis (IE) is a rare, life-threatening disease that has long-lasting effects even among patients who survive and are cured. IE disproportionately affects those with underlying structural heart disease and is increasingly associated with health care contact, particularly in patients who have intravascular prosthetic material. In the setting of bacteraemia with a pathogenic organism, an infected vegetation may form as the end result of complex interactions between invading microorganisms and the host immune system. Once established, IE can involve almost any organ system in the body. The diagnosis of IE may be difficult to establish and a strategy that combines clinical, microbiological and echocardiography results has been codified in the modified Duke criteria. In cases of blood culture-negative IE, the diagnosis may be especially challenging, and novel microbiological and imaging techniques have been developed to establish its presence. Once diagnosed, IE is best managed by a multidisciplinary team with expertise in infectious diseases, cardiology and cardiac surgery. Antibiotic prophylaxis for the prevention of IE remains controversial. Efforts to develop a vaccine that targets common bacterial causes of IE are ongoing, but have not yet yielded a commercially available product.

Clinical prediction rules in Staphylococcus aureus bacteremia demonstrate the usefulness of reporting likelihood ratios in infectious diseases

Infectious diseases specialists often use diagnostic tests to assess the probability of a disease based on knowledge of the diagnostic properties. It has become standard for published studies on diagnostic tests to report sensitivity, specificity and predictive values. Likelihood ratios are often omitted. We compared published clinical prediction rules in Staphylococcus aureus bacteremia to illustrate the importance of likelihood ratios. We performed a narrative review comparing published clinical prediction rules used for excluding endocarditis in S. aureus bacteremia. Of nine published clinical prediction rules, only three studies reported likelihood ratios. Many studies concluded that the clinical prediction rule could safely exclude endocarditis based on high sensitivity and high negative predictive value. Of the studies with similar high sensitivity and high negative predictive value, calculated negative likelihood ratios were able to differentiate and identify the best clinical prediction rule for excluding endocarditis. Compared to sensitivity, specificity and predictive values, likelihood ratios can be more directly used to interpret diagnostic test results to assist in ruling in or ruling out a disease. Therefore, a new standard should be set to include likelihood ratios in reporting of diagnostic tests in infectious diseases research.

An Approach to Improve the Negative Predictive Value and Clinical Utility of Transthoracic Echocardiography in Suspected Native Valve Infective Endocarditis

BACKGROUND

In patients with suspected native valve infective endocarditis, current guidelines recommend initial transthoracic echocardiography (TTE) followed by transesophageal echocardiography (TEE) if clinical suspicion remains. The guidelines do not account for the quality of initial TTE or other findings that may alter the study's diagnostic characteristics. This may lead to unnecessary TEE when initial TTE was sufficient to rule out vegetation.

METHODS

The objective of this study was to determine if the use of a strict definition of negative results on TTE would improve the performance characteristics of TTE sufficiently to exclude vegetation. A retrospective analysis of patients at a single institution with suspected native valve endocarditis who underwent TTE followed by TEE within 7 days between January 1, 2007, and February 28, 2014, was performed. Negative results on TTE for vegetation were defined by either the standard approach (no evidence of vegetation seen on TTE) or by applying a set of strict negative criteria incorporating other findings on TTE. Using TEE as the gold standard for the presence of vegetation, the diagnostic performance of the two transthoracic approaches was compared.

RESULTS

In total, 790 pairs of TTE and TEE were identified. With the standard approach, 661 of the transthoracic studies had negative findings (no vegetation seen), compared with 104 studies with negative findings using the strict negative approach (meeting all strict negative criteria). The sensitivity and negative predictive value of TTE for detecting vegetation were substantially improved using the strict negative approach (sensitivity, 98% [95% CI, 95%-99%] vs 43% [95% CI, 36%-51%]; negative predictive value, 97% [95% CI, 92%-99%] vs 87% [95% CI, 84%-89%]).

CONCLUSIONS

The ability of TTE to exclude vegetation in patients is excellent when strict criteria for negative results are applied. In patients at low to intermediate risk with strict negative results on TTE, follow-up TEE may be unnecessary.

Infective endocarditis

Infective endocarditis occurs worldwide, and is defined by infection of a native or prosthetic heart valve, the endocardial surface, or an indwelling cardiac device. The causes and epidemiology of the disease have evolved in recent decades with a doubling of the average patient age and an increased prevalence in patients with indwelling cardiac devices. The microbiology of the disease has also changed, and staphylococci, most often associated with health-care contact and invasive procedures, have overtaken streptococci as the most common cause of the disease. Although novel diagnostic and therapeutic strategies have emerged, 1 year mortality has not improved and remains at 30%, which is worse than for many cancers. Logistical barriers and an absence of randomised trials hinder clinical management, and longstanding controversies such as use of antibiotic prophylaxis remain unresolved. In this Seminar, we discuss clinical practice, controversies, and strategies needed to target this potentially devastating disease.

The VIRSTA score, a prediction score to estimate risk of infective endocarditis and determine priority for echocardiography in patients with Staphylococcus aureus bacteremia

OBJECTIVES

To develop and validate a prediction score, to quantify, within 48 h of Staphylococcus aureus bacteremia (SAB) diagnosis, the risk of IE, and therefore determine priority for urgent echocardiography.

METHODS

Consecutive adult patients with SAB in 8 French university hospitals between 2009 and 2011 were prospectively enrolled and followed-up 3 months. A predictive model was developed and internally validated using bootstrap procedures.

RESULTS

Among the 2008 patients enrolled, 221 (11.0%) had definite IE of whom 39 (17.6%) underwent valve surgery, 25% of them within 6 days of SAB diagnosis. Ten predictors independently associated with IE were used to build up the prediction score: intracardiac device or previous IE, native valve disease, intravenous drug use, community or non-nosocomial-acquisition, cerebral or extracerebral emboli, vertebral osteomyelitis, severe sepsis, meningitis, C-reactive protein above 190 mg/L, and H48-persistent bacteremia. Patients with a score ≤2 (n = 792, 39.4%) were at low IE-risk (1.1%; negative predictive value: 98.8% (95% CI, 98.4-99.4)) compared to those ≥3 who were at higher risk (17.4%).

CONCLUSIONS

Physicians must be strongly encouraged to urgently perform echocardiography in SAB patients with a score ≥3 to establish IE diagnosis, to orient antimicrobial therapy and to help determine the need for valvular surgery.

Use of Transthoracic Echocardiography in the Management of Low-Risk Staphylococcus aureus Bacteremia: Results From a Retrospective Multicenter Cohort Study

OBJECTIVES

The aim of this study was to develop a prediction model to identify patients with low-risk Staphylococcus aureus bacteremia (SAB), in whom infective endocarditis (IE) can be ruled out based on transthoracic echocardiogram (TTE).

BACKGROUND

S. aureus is a major cause of bacteremia and often leads to IE. Current guidelines recommend performing transesophageal echocardiography on all patients or treating all patients empirically with prolonged intravenous antibiotics; however, this approach is resource intensive, many physicians do not adhere to guidelines, and recent studies suggest that low-risk patients may not require transesophageal echocardiography.

METHODS

We conducted a retrospective cohort study of 833 consecutive hospitalized patients with SAB from 7 academic and community hospitals in Toronto, Canada, over a 3-year period (2007 to 2010). Patients who received a TTE within 28 days of bacteremia (n = 536) were randomly divided into derivation and validation cohorts. Multivariable logistic regression analysis was used to determine high-risk criteria for IE in the derivation cohort, and criteria were then applied to the validation cohort to determine diagnostic properties.

RESULTS

Four high-risk criteria predicted IE: indeterminate or positive TTE (p < 0.001), community-acquired bacteremia (p = 0.034), intravenous drug use (p < 0.001), and high-risk cardiac condition (p < 0.004). In the validation cohort, the presence of any 1 of the high-risk criteria had 97% sensitivity (95% confidence interval [CI]: 87% to 100%) and 99% negative predictive value (95% CI: 96% to 100%) for IE. The negative likelihood ratio was 0.05 (95% CI: 0.007 to 0.35).

CONCLUSIONS

A normal TTE ruled out IE in patients without community-acquired SAB, high-risk cardiac conditions, and intravenous drug use. This study provides evidence that clinical risk stratification combined with a normal TTE may be adequate to rule out IE in most patients with SAB.

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.

Staphylococcus aureus Bloodstream Infection and Endocarditis--A Prospective Cohort Study

OBJECTIVES

To update the epidemiology of S. aureus bloodstream infection (SAB) in a high-income country and its link with infective endocarditis (IE).

METHODS

All consecutive adult patients with incident SAB (n = 2008) were prospectively enrolled between 2009 and 2011 in 8 university hospitals in France.

RESULTS

SAB was nosocomial in 54%, non-nosocomial healthcare related in 18% and community-acquired in 26%. Methicillin resistance was present in 19% of isolates. SAB Incidence of nosocomial SAB was 0.159/1000 patients-days of hospitalization (95% confidence interval [CI] 0.111-0.219). A deep focus of infection was detected in 37%, the two most frequent were IE (11%) and pneumonia (8%). The higher rates of IE were observed in injecting drug users (IE: 38%) and patients with prosthetic (IE: 33%) or native valve disease (IE: 20%) but 40% of IE occurred in patients without heart disease nor injecting drug use. IE was more frequent in case of community-acquired (IE: 21%, adjusted odds-ratio (aOR) = 2.9, CI = 2.0-4.3) or non-nosocomial healthcare-related SAB (IE: 12%, aOR = 2.3, CI = 1.4-3.5). S. aureus meningitis (IE: 59%), persistent bacteremia at 48 hours (IE: 25%) and C-reactive protein > 190 mg/L (IE: 15%) were also independently associated with IE. Criteria for severe sepsis or septic shock were met in 30% of SAB without IE (overall in hospital mortality rate 24%) and in 51% of IE (overall in hospital mortality rate 35%).

CONCLUSION

SAB is still a severe disease, mostly related to healthcare in a high-income country. IE is the most frequent complication and occurs frequently in patients without known predisposing conditions.

Diagnosis and treatment of bacteremia and endocarditis due to Staphylococcus aureus. A clinical guideline from the Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC)

Both bacteremia and infective endocarditis caused by Staphylococcus aureus are common and severe diseases. The prognosis may darken not infrequently, especially in the presence of intracardiac devices or methicillin-resistance. Indeed, the optimization of the antimicrobial therapy is a key step in the outcome of these infections. The high rates of treatment failure and the increasing interest in the influence of vancomycin susceptibility in the outcome of infections caused by both methicillin-susceptible and -resistant isolates has led to the research of novel therapeutic schemes. Specifically, the interest raised in recent years on the new antimicrobials with activity against methicillin-resistant staphylococci has been also extended to infections caused by susceptible strains, which still carry the most important burden of infection. Recent clinical and experimental research has focused in the activity of new combinations of antimicrobials, their indication and role still being debatable. Also, the impact of an appropriate empirical antimicrobial treatment has acquired relevance in recent years. Finally, it is noteworthy the impact of the implementation of a systematic bundle of measures for improving the outcome. The aim of this clinical guideline is to provide an ensemble of recommendations in order to improve the treatment and prognosis of bacteremia and infective endocarditis caused by S. aureus, in accordance to the latest evidence published.

Predicting Risk of Endocarditis Using a Clinical Tool (PREDICT): Scoring System to Guide Use of Echocardiography in the Management of Staphylococcus aureus Bacteremia

BACKGROUND

Infective endocarditis (IE) is a serious complication of Staphylococcus aureus bacteremia (SAB). There is limited clinical evidence to guide use of echocardiography in the management of SAB cases.

METHODS

Baseline and 12-week follow-up data of all adults hospitalized at our institution with SAB from 2006 to 2011 were reviewed. Clinical predictors of IE were identified using multivariable logistic regression analysis.

RESULTS

Of the 757 patients screened, 678 individuals with SAB (24% community acquired, 56% healthcare associated, and 20% nosocomial) met study criteria. Eighty-five patients (13%) were diagnosed with definite IE within the 12 weeks of initial presentation based on modified Duke criteria. The proportion of patients with IE was 22% (36/166) in community-acquired SAB, 11% (40/378) in community-onset healthcare-associated SAB, and 7% (9/136) in nosocomial SAB. Community-acquired SAB, presence of cardiac device, and prolonged bacteremia (≥ 72 hours) were identified as independent predictors of IE in multivariable analysis. Two scoring systems, day 1 (SAB diagnosis day) and day 5 (when day 3 culture results are known), were derived based on the presence of these risk factors, weighted in magnitude by the corresponding regression coefficients. A score of ≥ 4 for day 1 model had a specificity of 96% and sensitivity of 21%, whereas a score of <2 for day 5 model had a sensitivity of 98.8% and negative predictive value of 98.5%.

CONCLUSIONS

We propose 2 novel scoring systems to guide use of echocardiography in SAB cases. Larger prospective studies are needed to validate the classification performance of these scoring systems.

Bacteremia, Sepsis, and Infective Endocarditis Associated with Staphylococcus aureus

Bacteremia and infective endocarditis (IE) are important causes of morbidity and mortality associated with Staphylococcus aureus infections. Increasing exposure to healthcare, invasive procedures, and prosthetic implants has been associated with a rising incidence of S. aureus bacteremia (SAB) and IE since the late twentieth century. S. aureus is now the most common cause of bacteremia and IE in industrialized nations worldwide and is associated with excess mortality when compared to other pathogens. Central tenets of management include identification of complicated bacteremia, eradicating foci of infection, and, for many, prolonged antimicrobial therapy. Evolving multidrug resistance and limited therapeutic options highlight the many unanswered clinical questions and urgent need for further high-quality clinical research.

Guidelines for the diagnosis, prevention and management of implantable cardiac electronic device infection. Report of a joint Working Party project on behalf of the British Society for Antimicrobial Chemotherapy (BSAC, host organization), British Heart Rhythm Society (BHRS), British Cardiovascular Society (BCS), British Heart Valve Society (BHVS) and British Society for Echocardiography (BSE)

Infections related to implantable cardiac electronic devices (ICEDs), including pacemakers, implantable cardiac defibrillators and cardiac resynchronization therapy devices, are increasing in incidence in the USA and are likely to increase in the UK, because more devices are being implanted. These devices have both intravascular and extravascular components and infection can involve the generator, device leads and native cardiac structures or various combinations. ICED infections can be life-threatening, particularly when associated with endocardial infection, and all-cause mortality of up to 35% has been reported. Like infective endocarditis, ICED infections can be difficult to diagnose and manage. This guideline aims to (i) improve the quality of care provided to patients with ICEDs, (ii) provide an educational resource for all relevant healthcare professionals, (iii) encourage a multidisciplinary approach to ICED infection management, (iv) promote a standardized approach to the diagnosis, management, surveillance and prevention of ICED infection through pragmatic evidence-rated recommendations, and (v) advise on future research projects/audit. The guideline is intended to assist in the clinical care of patients with suspected or confirmed ICED infection in the UK, to inform local infection prevention and treatment policies and guidelines and to be used in the development of educational and training material by the relevant professional societies. The questions covered by the guideline are presented at the beginning of each section.

Clinical management of Staphylococcus aureus bacteremia: a review

IMPORTANCE

Several management strategies may improve outcomes in patients with Staphylococcus aureus bacteremia.

OBJECTIVES

To review evidence of management strategies for S. aureus bacteremia to determine whether transesophageal echocardiography is necessary in all adult cases and what is the optimal antibiotic therapy for methicillin-resistant S. aureus (MRSA) bacteremia.

EVIDENCE REVIEW

A PubMed search from inception through May 2014 was performed to identify studies addressing the role of transesophageal echocardiography in S. aureus bacteremia. A second search of PubMed, EMBASE, and the Cochrane Library from January 1990 through May 2014 was performed to find studies addressing antibiotic treatment for MRSA bacteremia. Studies reporting outcomes from antibiotic therapy for MRSA bacteremia were included. All searches, which were limited to English and focused on adults, were augmented by review of bibliographic references from included studies. The quality of evidence was assessed using the Grades of Recommendation, Assessment, Development and Evaluation system with consensus of independent evaluations by at least 2 of the authors.

FINDINGS

In 9 studies with a total of 4050 patients, use of transesophageal echocardiography was associated with higher rates of a diagnosis of endocarditis (14%-28%) compared with transthoracic echocardiography (2%-15%). In 4 studies, clinical or transthoracic echocardiography findings did not predict subsequent transesophageal echocardiography findings of endocarditis. Five studies identified clinical or transthoracic echocardiography characteristics associated with low risk of endocarditis (negative predictive values from 93% to 100%). Characteristics associated with a low risk of endocarditis include absence of a permanent intracardiac device, sterile follow-up blood cultures within 4 days after the initial set, no hemodialysis dependence, nosocomial acquisition of S. aureus bacteremia, absence of secondary foci of infection, and no clinical signs of infective endocarditis. Of 81 studies of antibiotic therapy for MRSA bacteremia, only 1 high-quality trial was identified. In that study of 246 patients with S. aureus bacteremia, daptomycin was not inferior to vancomycin or an antistaphylococcal penicillin, each in combination with low-dose, short-course gentamicin (clinical success rate, 44.2% [53/120] vs 41.7% [48/115]; absolute difference, 2.4% [95% CI, -10.2% to 15.1%]).

CONCLUSIONS AND RELEVANCE

All adult patients with S. aureus bacteremia should undergo echocardiography. Characteristics of low-risk patients with S. aureus bacteremia for whom transesophageal echocardiography can be safely avoided have been identified. Vancomycin and daptomycin are the first-line antibiotic choices for MRSA bacteremia. Well-designed studies to address the management of S. aureus bacteremia are needed.

Staphylococcus aureus bacteraemia in a UK tertiary referral centre: a 'transoesophageal echocardiogram for all' policy

OBJECTIVES

Infective endocarditis (IE) is a feared complication in up to 38% of cases of Staphylococcus aureus bacteraemia (SAB). BSAC guidelines recommend echocardiography in all cases of SAB. The aim of this study was to determine the incidence of IE in SAB using transoesophageal echocardiography (TOE) as the first step in diagnostic imaging. This study also sought to identify clinical predictors that could improve stratification of those with and without IE.

METHODS

A guideline was implemented that any SAB resulted in the microbiology department (i) recommending that the patient be referred for TOE and (ii) notifying the echocardiography department, resulting in streamlined listing of the patient for TOE. All cases of SAB were then assessed prospectively at University Hospitals Birmingham NHS Foundation Trust between September 2011 and October 2012. Previously identified risk factors for complicated S. aureus bacteraemia were recorded.

RESULTS

There were 98 SAB episodes in total. TOE was performed in 58 (59%) with a further 22 episodes imaged by transthoracic echocardiography alone. IE was diagnosed overall in 13 (16%) cases investigated with echocardiography. No risk factor for IE other than presence of a cardiac device was detected in this group (P = 0.013).

CONCLUSIONS

The rate of IE found in SAB is high when TOE is performed first line. There are no clear risk factors to improve yield or the type of echocardiography to be performed. Echocardiography should be performed in all cases and TOE should be considered where it is expected to influence management, as long as local resources allow.

Characteristics of invasive Staphylococcus aureus infections in three regions of Korea, 2009-2011: a multi-center cohort study

BACKGROUND

Despite the importance of invasive Staphylococcus aureus (ISA) infection, its overall burden in non-selected populations has only been defined in a small number of studies in Europe and North America. To define the characteristics of ISA infections in Korea, we conducted a multi-center cohort study to estimate population-based incidence rates.

METHODS

We conducted a multicenter prospective cohort study at nine university-affiliated active-surveillance core centers (ASCs) in three regions of Korea. To cover all available clinical microbiologic laboratories, we classified the laboratories in these regions into three groups according to their clinical environment as: 1) Nine ASCs, 2) Five major commercial laboratories and 3) Forty-four acute-care hospital-affiliated microbiology laboratories. We requested all the laboratories to report prospectively their numbers of cases of S. aureus isolated from normally sterile sites. Detailed clinical information was collected about the cases in the nine ASCs.

RESULTS

From 1 July 2009 to 30 June 2011, a total of 1,198 cases of ISA infection were identified at the nine ASCs, including 748 (62%) methicillin-resistant S. aureus (MRSA) infections. Most (81%) ISA infections were healthcare-associated (HCA): 653 (55%) hospital-onset and 322 (27%) community-onset. 223 (19%) were community-associated infections. The most common primary diagnosis was catheter-associated infection (225 cases, 19%). Respiratory tract infection (160, 13%), skin & soft tissue (152, 13%) and bone & joint infections (120, 10%) were also common. 30-day and 12-week mortality rates were 25.6% (262/1,024) and 36.5% (314/860), respectively. Complications, including metastatic infection within 12 weeks, occurred in 17.8% of ISA infections. The most common site of metastatic infection was the lung (9.8%, 84/860). Based on the total of 2,806 observed cases of ISA infection, estimated annual rates of ISA and invasive MRSA infections were 43.3 and 27.7 per 100,000 populations, respectively.

CONCLUSIONS

Our data provide important information about the clinical characteristics of ISA infections. We estimate that over 21,000 ISA infections and 13,000 invasive MRSA infections occurred in Korea in 2010.