Prognostic role of persistent positive blood cultures after initiation of antibiotic therapy in left-sided infective endocarditis

Comparative effectiveness of empirical antibiotic treatments in methicillin-susceptible Staphylococcus aureus infective endocarditis: A post hoc analysis of a prospective French cohort study

OBJECTIVES

The empirical treatment of infective endocarditis is still debated. The aim of this study was to compare the impact of empirical treatment with antistaphylococcal penicillin (ASP) or cefazolin vs. other treatments in methicillin-susceptible Staphylococcus aureus (MSSA) endocarditis.

METHODS

A post hoc analysis of a prospective cohort study of patients hospitalized in a French reference centre with MSSA endocarditis was conducted between 2013 and 2022. The primary outcome was the duration of bacteraemia under treatment.

RESULTS

Of the 208 patients included, 101 patients (48.6%) were classified in the reference group (ASP or cefazolin) and 107 (52.4%) in the non-reference group. Empirical treatment with ASP/cefazolin was associated with a shorter duration of bacteraemia compared to other treatments (3.6 d vs. 4.6 d, P = 0.01). This difference was not corrected by the addition of an aminoglycoside (3.6 d vs. 4.7 d, P < 0.01). In multivariate analysis, empirical treatment with ASP/cefazolin was associated with a duration of bacteraemia ≤72 h (P = 0.02), whereas endocarditis on native valves (P = 0.01), and intracardiac abscess were associated with longer duration of bacteraemia (P = 0.01).

CONCLUSIONS

Empirical treatment of endocarditis with ASP or Cefazolin is more effective than other treatments in MSSA endocarditis, even when the other treatments are combined with aminoglycosides.

The prevalence of persistent bacteraemia in patients with a non-staphylococcal infective endocarditis, a retrospective cohort study

BACKGROUND

Current guidelines on the management of infective endocarditis (IE) recommend follow-up blood cultures (FUBCs) to identify persistent bacteraemia, as this has prognostic value and guides treatment decisions. While persistent bacteraemia frequently occurs in Staphylococcus aureus bacteraemia and IE, its prevalence and impact in non-staphylococcal IE is largely unknown. We determined prevalence and prognostic value of persistent bacteraemia in non-staphylococcal IE.

METHODS

We conducted a retrospective analysis of all patients diagnosed with definite non-staphylococcal endocarditis according to the modified Duke Criteria in two university hospital endocarditis registries We determined the prevalence and prognostic value of persistent bacteraemia.

RESULTS

Of the included 159 patients 70 (44%) had prosthetic valve endocarditis (PVE). A median number of two [IQR 1-3] FUBCs were taken during the first week, with 134/159 (84%) having at least one FUBC in the first four days. Seven patients (4,4%) had persistent bacteraemia 48 h after start of antibiotic treatment: 5/70 patients (7.1%) with PVE and 2/89 (2.2%) with native valve endocarditis. Among 97 patients with streptococcal IE, nine patients with HACEK IE and six patients with Cutibacterium IE, no persistent bacteraemia was observed. Enterococcus faecalis was the causative microorganism in five patients with persistent bacteraemia, the other two had non-HACEK Gram-negative endocarditis.

CONCLUSION

Persistent bacteraemia in non-staphylococcal endocarditis was rare. It was more frequently observed in PVE and was restricted to more resilient microorganisms such as enterococci and non-HACEK Gram-negative bacteria. Routine collection of FUBCs in patients with streptococcal endocarditis has a low yield and may require re-evaluation.

Iatrogenic Infective Endocarditis in Hemodialysis Patients: A Case Report and Review of the Literature

Foreign bodies such as implanted cardiac devices are susceptible to infections and may be involved in infective endocarditis. Exposure to pathogens, by frequent use of intravascular accesses for hemodialysis (i.e., catheters or fistulas), combined with high rates of degenerative heart valve diseases in hemodialysis patients, both favor the development of infective endocarditis in this population. The mitral and aortic valves are predominantly implicated in endocardial infections. The involvement of both mitral and tricuspid valves is rare in the general population but can occur in hemodialysis patients with implanted cardiac devices. Infective endocarditis is associated with high morbidity and mortality rates among hemodialysis patients, mostly because of the complications of septic emboli. Prevention, prophylaxis, and early diagnosis of endocarditis can be lifesaving in this fragile population. We report a case of right and left heart methicillin-sensitive Staphylococcus aureus endocarditis with cerebral septic emboli in an elderly hemodialysis patient carrier of an arteriovenous fistula and an ipsilateral nonleadless pacemaker.

Reassessment of vegetation size as a sole indication for surgery in left-sided infective endocarditis

BACKGROUND

Guidelines recommend surgery in left-sided infective endocarditis (LSIE) associated with large vegetations. Given that most patients who undergo surgery also have other indications (heart failure and/or uncontrolled infection), it is not settled whether surgery should be routinely recommended in patients with large vegetations but no other predictors of poor outcome.

METHODS

A total of 726 patients with definitive LSIE were included in our analysis. Mean age was 64.9 years, 61% were male. Multivariate analysis of all patients was performed to determine if vegetation size is related to death in LSIE. Then, patients were divided in two groups according to vegetation size: Group A (>10 mm, n=420) and group B (≤10 mm, n=306). Univariate and multivariate analyses of group A patients were carried out to identify the variables related to death in this group. Impact of surgery on mortality of group A patients without heart failure or uncontrolled local infection (n=139) was assessed.

RESULTS

Age, Staphylococcus aureus, perivalvular complications, heart failure, kidney failure and septic shock, but not vegetation size, were associated with death. Patients with large vegetations showed increased mortality (31.7% in group A vs 24.8% in group B, p=0.045). Group A had more valve rupture and valve regurgitation than group B, but heart failure (55% vs 53%, p=0.678), stroke (22% vs 17.0%, p=0.091), systemic embolism (39% vs 32%, p=0.074), perivalvular complication (28% vs 28%, p=0.865) or septic shock (15% vs 13%, p=0.288) were similar in both groups. In patients from group A without heart failure or uncontrolled infection mortality was similar with and without surgery (n=139; n=70 with surgery, n=69 without surgery; mortality 18.6% vs 11.6% respectively, p=0.251).

CONCLUSIONS

large vegetations identify patients with poor outcome in LSIE. However, surgery is not associated with a better prognosis in patients with large vegetations if they do not present with another predictor of poor outcome such as heart failure or uncontrolled infection. These findings challenge whether vegetation size alone should be an indication for surgery in LSIE.

Daptomycin Plus Fosfomycin Versus Daptomycin Alone for Methicillin-resistant Staphylococcus aureus Bacteremia and Endocarditis: A Randomized Clinical Trial

BACKGROUND

We aimed to determine whether daptomycin plus fosfomycin provides higher treatment success than daptomycin alone for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia and endocarditis.

METHODS

A randomized (1:1) phase 3 superiority, open-label, and parallel group clinical trial of adult inpatients with MRSA bacteremia was conducted at 18 Spanish hospitals. Patients were randomly assigned to receive either 10 mg/kg of daptomycin intravenously daily plus 2 g of fosfomycin intravenously every 6 hours, or 10 mg/kg of daptomycin intravenously daily. Primary endpoint was treatment success 6 weeks after the end of therapy.

RESULTS

Of 167 patients randomized, 155 completed the trial and were assessed for the primary endpoint. Treatment success at 6 weeks after the end of therapy was achieved in 40 of 74 patients who received daptomycin plus fosfomycin and in 34 of 81 patients who were given daptomycin alone (54.1% vs 42.0%; relative risk, 1.29 [95% confidence interval, .93-1.8]; P = .135). At 6 weeks, daptomycin plus fosfomycin was associated with lower microbiologic failure (0 vs 9 patients; P = .003) and lower complicated bacteremia (16.2% vs 32.1%; P = .022). Adverse events leading to treatment discontinuation occurred in 13 of 74 patients (17.6%) receiving daptomycin plus fosfomycin, and in 4 of 81 patients (4.9%) receiving daptomycin alone (P = .018).

CONCLUSIONS

Daptomycin plus fosfomycin provided 12% higher rate of treatment success than daptomycin alone, but this difference did not reach statistical significance. This antibiotic combination prevented microbiological failure and complicated bacteremia, but it was more often associated with adverse events.

CLINICAL TRIALS REGISTRATION

NCT01898338.

Optimal Timing of Surgery for Patients with Active Infective Endocarditis

Infective endocarditis (IE) is a rare but serious condition with a dismal prognosis. One of the keys to improving outcomes is the prompt identification of high-risk patients who have intracardiac and extracardiac (systemic and neurologic) complications. However, as cardiac and extracardiac complications indicating surgery add to the surgical risk for active IE, controversies surround the optimal indication and timing for surgery, especially in patients presenting neurologic complications. This article reviews the necessary evaluation for patients with suspected IE and proposes a state-of-the-art patient flow chart for evaluation of suspected IE.

Transcatheter Aortic Valve Replacement for Residual Lesion of the Aortic Valve Following "Healed" Infective Endocarditis

OBJECTIVES

This study aimed to evaluate the safety and mid-term efficacy of transcatheter aortic valve replacement (TAVR) in the setting of aortic valve (AV) infective endocarditis (IE) with residual lesion despite successful antibiotic treatment.

BACKGROUND

Patients with AV-IE presenting residual lesion despite successful antibiotic treatment are often rejected for cardiac surgery due to high-risk. The use of TAVR following IE is not recommended.

METHODS

This was a multicenter retrospective study across 10 centers, gathering baseline, in-hospital, and 1-year follow-up characteristics of patients with healed AV-IE treated with TAVR. Matched comparison according to sex, EuroSCORE, chronic kidney disease, left ventricular function, prosthesis type, and valve-in-valve procedure was performed with a cohort of patients free of prior IE treated with TAVR (46 pairs).

RESULTS

Among 2,920 patients treated with TAVR, 54 (1.8%) presented with prior AV-IE with residual valvular lesion and healed infection. They had a higher rate of multivalvular disease and greater surgical risk scores. A previous valvular prosthesis was more frequent than a native valve (50% vs. 7.5%; p < 0.001). The in-hospital and 1-year mortality rates were 5.6% and 11.1%, respectively, comparable to the control cohort. After matching, the 1-year III to IV aortic regurgitation rate was 27.9% (vs. 10%; p = 0.08) and was independently associated with higher mortality. There was only 1 case of IE relapse (1.8%); however, 18% of patients were complicated with sepsis, and 43% were readmitted due to heart failure.

CONCLUSIONS

TAVR is a safe therapeutic alternative for residual valvular lesion after successfully healed AV-IE. At 1-year follow-up, the risk of IE relapse was low and mortality rate did not differ from TAVR patients free of prior IE, but one-fourth presented with significant aortic regurgitation and >50% required re-admission.

2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the valvular heart disease guideline provides recommendations for clinicians to diagnose and manage valvular heart disease as well as supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from January 1, 2010, to March 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, Cochrane, Agency for Healthcare Research and Quality Reports, and other selected database relevant to this guideline. Structure: Many recommendations from the earlier valvular heart disease guidelines have been updated with new evidence and provides newer options for diagnosis and treatment of valvular heart disease. This summary includes only the recommendations from the full guideline which focus on diagnostic work-up, the timing and choice of surgical and catheter interventions, and recommendations for medical therapy. The reader is referred to the full guideline for graphical flow charts, text, and tables with additional details about the rationale for and implementation of each recommendation, and the evidence tables detailing the data considered in developing these guidelines.

Antifungal Efficacy of Amphotericin B in Candida Albicans Endocarditis Therapy: Systematic Review

INTRODUCTION

Although it is the most common agent among the fungal causes of endocarditis, Candida albicans endocarditis is rare.

OBJECTIVE

To evaluate the efficacy of amphotericin B in the treatment of C. albicans endocarditis beyond a systematic review.

DATA SEARCH

Articles in English, Spanish and Portuguese, conducted in the following databases: MEDLINE, LILACS, IBECS and SciELO, in humans and published in the last 25 years.

STUDY SELECTION

Observational studies, clinical trials, and case series providing data on the amphotericin B use in patients with a C. albicans endocarditis diagnosis without age limitations.

DATA SYNTHESIS

From the initial search (n=79), 25 articles were fully evaluated, of which 19 were excluded for meeting one or more exclusion criteria, remaining five articles (two observational studies and three case series). Patients using amphotericin B demonstrated improvement in survival rates, and its main use was in association with the surgical method as well as with caspofungin association.

CONCLUSION

Literature lacks evidence to conclude about efficacy and safety of amphotericin B in the treatment of fungal endocarditis. Randomized clinical trials are necessary to provide better evidence on the subject.

Comparative outcomes of cefazolin versus antistaphylococcal penicillins in methicillin-susceptible Staphylococcus aureus infective endocarditis: a post hoc analysis of a prospective multicentre French cohort study

OBJECTIVES

Current guidelines recommend cefazolin as an alternative to antistaphylococcal penicillins (ASPs) in methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis despite the lack of comparative study. The objective of this study was to evaluate the comparative outcomes of cefazolin vs. ASPs in MSSA infective endocarditis.

METHODS

This was a retrospective analysis of an observational multicentre cohort study using prospectively collected data from patients with MSSA endocarditis confirmed by endocarditis team and treated either with cefazolin or ASPs between July 2013 and December 2018. Patients were excluded if they received both treatments. The primary outcome was 90-day all-cause mortality.

RESULTS

Of 210 patients included, 53 patients (25.2%) received cefazolin and 157 (74.8%) received ASPs. The overall 90-day mortality rate was 27.6% (58/210 patients), 24.5% (13/53) in the cefazolin group vs. 28.7% (45/157) in the ASP group (p 0.561). Premature antimicrobial discontinuation due to adverse events occurred less frequently with cefazolin than with ASPs (0/53 vs. 13/157 patients; p 0.042). In multivariate analysis, there was no difference in 90-day mortality between cefazolin and ASPs (adjusted odds ratio (aOR), 1.2; 95% confidence interval (CI), 0.49-2.91; p 0.681), while age (aOR, 1.06; 95% CI, 1.03-1.09; p < 0.001), Charlson comorbidity index (aOR, 1.18; 95% CI, 1.02-1.36 p 0.023), cerebral embolism (aOR, 2.83; 95% CI, 1.33-6.14; p 0.007) and intensive care unit admission (aOR, 4.16; 95% CI, 1.89-9.59; p 0.001) were factors significantly associated with higher mortality.

CONCLUSIONS

Cefazolin seems to be a possible alternative to ASPs in MSSA endocarditis. More studies are needed to confirm these results and determine which treatment should be recommended as first-line therapy.

Infective endocarditis: innovations in the management of an old disease

The annual incidence of infective endocarditis (IE) is estimated to be between 15 and 80 cases per million persons in population-based studies. The incidence of IE is markedly increased in patients with valve prostheses (>4 per 1,000) or with prior IE (>10 per 1,000). The interaction between platelets, microorganisms and diseased valvular endothelium is the cause of vegetations and valvular or perivalvular tissue destruction. Owing to its complexity, the diagnosis of IE is facilitated by the use of the standardized Duke-Li classification, which combines two major criteria (microbiology and imaging) with five minor criteria. However, the sensitivity of the Duke-Li classification is suboptimal, particularly in prosthetic IE, and can be improved by the use of PET or radiolabelled leukocyte scintigraphy. Prolonged antibiotic therapy is mandatory. Indications for surgery during acute IE depend on the presence of haemodynamic, septic and embolic complications. The most urgent indications for surgery are related to heart failure. In the past decade, the prevention of IE has been reoriented, with indications for antibiotic prophylaxis now limited to patients at high risk of IE undergoing dental procedures. Guidelines now emphasize the importance of nonspecific oral and cutaneous hygiene in individual patients and during health-care procedures.

Diagnostic tools in surgically treated patients with infective valve endocarditis

Background

Infective valve endocarditis (IE) is associated with significant mortality and complication rates. The diagnosis impacts not only the prognosis but also the management of the disease. The aim of this article is to show the findings obtained from the implementation of our most important diagnostic tools and discuss our standard diagnostic process for patients with IE who underwent surgical treatment between 1994 and 2017.

Methods

Between December 1994 and January 2017 a total of 2,458 patients with IE underwent surgery at our institution. We analyzed clinical, microbiological, echocardiographic, and multi slice computer tomographic (MSCT) features in this group.

Results

The most often isolated involved valve was the aortic valve (59%). Prosthetic valve endocarditis (PVE) was present in almost one third of all cases. The most common valve failures were mitral valve insufficiency (MI) and aortic valve insufficiency (AI) (65% and 57% respectively). Almost one half of the aortic insufficiencies were severe. 63% of all vegetations assessed by echocardiography were larger than 1 cm. We detected a septic embolism in 44% of patients and the most common target organ was the spleen (25%). The most common isolated pathogen was Staphylococcus aureus (26%) and affected patients had a significant correlation with in-hospital mortality (P=0.004).

Conclusions

Echocardiography offers valuable information and is the most important diagnostic method in patients with IE. Preoperative MSCT contributes to the entire perioperative decision-making process. Microbiological diagnosis is mandatory in choosing and adjusting antibiotic therapy and also has prognostic value.

Early Surgery in Valvular Heart Disease

The burden of valvular heart disease (VHD) is increasing with age, and the elderly patients with moderate or severe VHD are notably common. When to operate in asymptomatic patients with VHD remains controversial. The controversy is whether early surgical intervention should be preferred, or a watchful waiting approach should be followed. The beneficial effects of early surgery should be balanced against operative mortality and long-term results. Indications of early surgery in each of the VHD will be discussed in this review on the basis of the latest American and European guidelines.

[Infective endocarditis : New ESC guidelines 2015]

Infective endocarditis is an endovascular infection usually caused by bacteria. Mortality rate is still approximately 20 %. To improve patients' prognosis by implementation of current diagnostic and therapeutic evidence, the European Society of Cardiology published an updated version of the guidelines for management of infective endocarditis in 2015. It strengthens the role of imaging modalities like PET/CT for detection of infectious foci when echocardiography remains negative and highlights the use of modern tests for identification of possible pathogens. New diagnostic criteria were introduced to integrate these methods for improved diagnostic sensitivity. Complicated cases should be treated in reference centers with on-site cardiac surgery. The antibiotic and early surgical management should be discussed in a multidisciplinary endocarditis team. A few years ago, the indication for endocarditis prophylaxis was limited to high-risk patients. These recommendations were confirmed in current guidelines.

[Which patients with infective endocarditis require emergency surgery?]

Half of patients with infectious endocarditis have surgery during the active phase of infective endocarditis (before the end of antibiotic therapy). The American Heart Association and the European Society of Cardiology, independently from each other, have published guidelines in September 2015. As regards surgical indications, these guidelines are similar. The surgical indication must be a common decision of a multidisciplinary team of experts in cardiology, cardiac surgery, imaging and infectious diseases. The main indications are heart failure, non-infectious process control and prevention of embolisms.

Penicillin G Treatment in Infective Endocarditis Patients - Does Standard Dosing Result in Therapeutic Plasma Concentrations?

Penicillin G is frequently used to treat infective endocarditis (IE) caused by streptococci, penicillin-susceptible staphylococci and enterococci. Appropriate antibiotic exposure is essential for survival and reduces the risk of complications and drug resistance development. We determined penicillin G plasma concentration [p-penicillin] once weekly in 46 IE patients. The aim was to evaluate whether penicillin G 3 g every 6 hr (q6 h) resulted in therapeutic concentrations and to analyse potential factors that influence inter- and intra-individual variability, using linear regression and a random coefficient model. [P-penicillin] at 3 hr and at 6 hr was compared with the minimal inhibitory concentration (MIC) of the bacteria isolated from blood cultures to evaluate the following PK/PD targets: 50% fT > MIC and 100% fT > MIC. [P-penicillin] varied notably between patients and was associated with age, weight, p-creatinine and estimated creatinine clearance (eCLcr). Additionally, an increase in [p-penicillin] during the treatment period showed strong correlation with age, a low eCLcr, a low weight and a low p-albumin. Of the 46 patients, 96% had [p-penicillin] that resulted in 50% fT > MIC, while 71% had [p-penicillin] resulting in 100% fT > MIC. The majority of patients not achieving the 100% fT > MIC target were infected with enterococci. Streptococci and staphylococci isolated from blood cultures were highly susceptible to penicillin G. Our results suggest that penicillin G 3 g q6 h is suitable to treat IE caused by streptococci and penicillin-susceptible staphylococci, but caution must be taken when the infection is caused by enterococci. When treating enterococci, therapeutic drug monitoring should be applied to optimize penicillin G dosing and exposure.

Haemophilus parainfluenzae endocarditis with systemic embolisation following maxillary sinusitis

The authors present a case of a man with Haemophilus parainfluenzae endocarditis complicated with embolisation to the central nervous system. The patient had no evidence of endocarditis by transoesophageal and transthoracic echocardiograms at baseline, but shortly after developed large mitral valve vegetations with valve rupture. The case highlights how rapidly structural valve damage can ensue despite good clinical and laboratorial antibiotic response.

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.

Clinical classification and prognosis of isolated right-sided infective endocarditis

From an epidemiologic point of view, right-sided infective endocarditis (RSIE) affects different types of patients: intravenous drug users (IDUs), cardiac device carriers (pacemakers and implantable automatic defibrillators), and the "3 noes" endocarditis group: no left-sided, no IDUs, no cardiac devices. Our objective is to describe and compare the clinical profile and outcome of these groups of patients. Every episode of infective endocarditis (IE) consecutively diagnosed in 3 tertiary centers from 1996 to 2012 was included in an ongoing multipurpose database. We assessed 85 epidemiologic, clinical, echocardiographic, and outcome variables in patients with isolated RSIE. A bivariated comparative analysis between the 3 groups was conducted.Among 866 IE episodes, 121 were classified as isolated RSIE (14%): 36 IDUs (30%), 65 cardiac device carriers (54%), and 20 "3 noes" group (16%). IDUs were mainly young men (36 ± 7 years) without previous heart disease, few comorbidities, and frequent previous endocarditis episodes (28%). Human immunodeficiency virus infection was frequent (69%). Cardiac device carriers were older (66 ± 15 years) and had less comorbidities (34%). Removal of the infected device was performed in 91% of the patients without any death. The "3 noes" endocarditis group was composed mainly by middle-age men (56 ± 18 years), health care related infections (50%), and had many comorbidities (75%). Whereas Staphylococcus aureus were the most frequent cause in IDUs (72% vs 34% in device carriers and 34% in the "3 noes" group, P = 0.001), coagulase negative Staphylococci predominated in the device carriers (58% vs 11% in drug users and 35% in the "3 noes", P < 0.001). Significant differences in mortality were found (17% in drug users, 3% in device carriers, and 30% in the "3 noes" group; P < 0.001). These results suggest that RSIE should be separated into 3 groups (IDUs, cardiac device carriers, and the "3 noes") and considered as independent entities as there are relevant epidemiologic, clinical, microbiological, echocardiographic, and prognostic differences among them.

Efficacy and safety of fosfomycin plus imipenem as rescue therapy for complicated bacteremia and endocarditis due to methicillin-resistant Staphylococcus aureus: a multicenter clinical trial

BACKGROUND

There is an urgent need for alternative rescue therapies in invasive infections caused by methicillin-resistant Staphylococcus aureus (MRSA). We assessed the clinical efficacy and safety of the combination of fosfomycin and imipenem as rescue therapy for MRSA infective endocarditis and complicated bacteremia.

METHODS

The trial was conducted between 2001 and 2010 in 3 Spanish hospitals. Adult patients with complicated MRSA bacteremia or endocarditis requiring rescue therapy were eligible for the study. Treatment with fosfomycin (2 g/6 hours IV) plus imipenem (1 g/6 hours IV) was started and monitored. The primary efficacy endpoints were percentage of sterile blood cultures at 72 hours and clinical success rate assessed at the test-of-cure visit (45 days after the end of therapy).

RESULTS

The combination was administered in 12 patients with endocarditis, 2 with vascular graft infection, and 2 with complicated bacteremia. Therapy had previously failed with vancomycin in 9 patients, daptomycin in 2, and sequential antibiotics in 5. Blood cultures were negative 72 hours after the first dose of the combination in all cases. The success rate was 69%, and only 1 of 5 deaths was related to the MRSA infection. Although the combination was safe in most patients (94%), a patient with liver cirrhosis died of multiorgan failure secondary to sodium overload. There were no episodes of breakthrough bacteremia or relapse.

CONCLUSIONS

Fosfomycin plus imipenem was an effective and safe combination when used as rescue therapy for complicated MRSA bloodstream infections and deserves further clinical evaluation as initial therapy in these infections.

My paper 10 years later: infective endocarditis in the intensive care unit

INTRODUCTION

Although the recent literature contains plenty of studies concerning all aspects of infective endocarditis (IE), very few focus on severe IE requiring admission to the ICU.

RESULTS

In 2004, we published a report on the clinical spectrum and prognostic factors in 228 consecutive critically ill patients with IE. Septic shock, neurological complications and immunocompromised state were independently associated with in-hospital mortality. Cardiac surgery during the acute phase of EI was associated with better survival. A lot of information has been accumulated during the past 10 years on management of IE. Although three sets of blood cultures allow the identification of about 90% of cases, culture-negative IE still remains a diagnostic challenge. Blood-polymerase chain reaction in valve tissue may yield a microbiologic diagnosis. New imaging techniques such as positron emission tomography computed tomography (PET-CT) have shown additive value in patients with an intracardiac device or valvular prosthesis. Systematic cerebral magnetic resonance imaging can lead to modification of therapeutic plans. The decision to operate and the timing of cardiac surgery should take into account the presence of congestive heart failure, neurological complications, renal failure and multiorgan dysfunction syndrome. In 2011 and 2013, we published the results of a multicentre prospective observational study of 198 ICU patients with left-sided IE and confirmed that cardiac surgery was associated with better outcome. The strongest independent predictor of post-operative mortality was the pre-operative multiorgan failure score. Neurological failure also represented a major determinant of mortality, regardless of the mechanism of neurological complication.

CONCLUSION

In the present paper, we propose algorithms to optimize the medico-surgical approach.

Effect of electrical stimulus parameters on the development and propagation of action potentials in short excitable fibres

Intracellular action potentials (IAPs) produced by short fibres in response to their electrical stimulation were analysed. IAPs were calculated on the basis of the Hodgkin-Huxley (1952) model by the method described by Joyner et al. (1978). Principal differences were found in processes of activation of short (semilength L less than 5 lambda) and long fibres under near-threshold stimulation. The shorter the fibre, the lower was the threshold value (Ithr). Dependence of the latency on the stimulus strength (Ist) was substantially non-linear and was affected by the fibre length. Both fibre length and stimulus strength influenced the IAP amplitude, the instantaneous propagation velocity (IPV) and the site of the first origin of the IAP (and, consequently, excitability of the short fibre membrane). With L less than or equal to 2 lambda and Ithr less than or equal to Ist less than or equal to 1.1Ithr, IPV could reach either very high values (so that all the fibre membrane fired practically simultaneously) or even negative values. The latter corresponded to the first origin of the propagated IAP, not at the site of stimulation but at the fibre termination or at a midpoint. The characters of all the above dependencies were unchanged irrespective of the manner of approaching threshold (variation of stimulus duration or its strength). Reasons for differences in processes of activation of short and long fibres are discussed in terms of electrical load and latency. Applications of the results to explain an increased jitter, velocity recovery function and velocity-diameter relationship are also discussed.