Evolving trends in infective endocarditis

Infective endocarditis: prevention strategy and risk factors in an animal model

INTRODUCTION

Infective endocarditis is a serious infection of the endocardium, especially the heart valves, which is associated with a high mortality rate. It generally occurs in patients with altered and abnormal cardiac architecture combined with exposure to bacteria from trauma and other potentially high-risk activities with transient bacteremia.

Surgical Challenges in Infective Endocarditis: State of the Art

Infective endocarditis (IE) is still a life-threatening disease with frequent lethal outcomes despite the profound changes in its clinical, microbiological, imaging, and therapeutic profiles. Nowadays, the scenario for IE has changed since rheumatic fever has declined, but on the other hand, multiple aspects, such as elderly populations, cardiovascular device implantation procedures, and better use of multiple imaging modalities and multidisciplinary care, have increased, leading to escalations in diagnosis. Since the ESC and AHA Guidelines have been released, specific aspects of diagnostic and therapeutic management have been clarified to provide better and faster diagnosis and prognosis. Surgical treatment is required in approximately half of patients with IE in order to avoid progressive heart failure, irreversible structural damage in the case of uncontrolled infection, and the prevention of embolism. The timing of surgery has been one of the main aspects discussed, identifying cases in which surgery needs to be performed on an emergency (within 24 h) or urgent (within 7 days) basis, irrespective of the duration of antibiotic treatment, or cases where surgery can be postponed to allow a brief period of antibiotic treatment under careful clinical and echocardiographic observation. Mainly, guidelines put emphasis on the importance of an endocarditis team in the handling of systemic complications and how they affect the timing of surgery and perioperative management. Neurological complications, acute renal failure, splenic or musculoskeletal manifestations, or infections determined by multiresistant microorganisms or fungi can affect long-term prognosis and survival. Not to be outdone, anatomical and surgical factors, such as the presence of native or prosthetic valve endocarditis, a repair strategy when feasible, anatomical extension and disruption in the case of an annular abscess (mitral valve annulus, aortic mitral curtain, aortic root, and annulus), and the choice of prosthesis and conduits, can be equally crucial. It can be hard for surgeons to maneuver between correct pre-operative planning and facing unexpected obstacles during intraoperative management. The aim of this review is to provide an overview and analysis of a broad spectrum of specific surgical scenarios and how their challenging management can be essential to ensure better outcomes and prognoses.

Development and validation of a dosing nomogram for continuous infusion cloxacillin in infective endocarditis

BACKGROUND

Cloxacillin is the first-line treatment for methicillin-susceptible staphylococcal infective endocarditis (IE). The recommended dose is 12 g per day regardless of the patient characteristics, despite the importance of renal function on its pharmacokinetics.

OBJECTIVES

We sought to build a population pharmacokinetics model of continuous infusion cloxacillin in IE patients to evaluate the influence of multiple covariates and then develop a nomogram based on significant covariates for individual adaptation.

PATIENTS AND METHODS

We included patients of a local IE cohort who were treated with cloxacillin administered by continuous infusion, excluding those who received intermittent or continuous dialysis, extracorporeal membrane oxygenation or extracorporeal circulation. The population pharmacokinetic analysis was performed using Pmetrics. The influence of weight, ideal weight, height, body mass index, body surface area, glomerular filtration rate (GFR) calculated with the Chronic Kidney Disease Epidemiology Collaboration formula (both expressed in mL/min/1.73 m² and in mL/min) and serum protein level on cloxacillin pharmacokinetics was assessed. Accounting for relevant covariates, a dosing nomogram was developed to determine the optimal daily dose required to achieve a steady-state plasma concentration range of 20-50 mg/L with a probability ≥0.9.

RESULTS

A total of 114 patients (331 plasma concentrations) were included. A one-compartment model including GFR expressed in mL/min as a covariate was chosen. Using the nomogram, achieving the cloxacillin concentration target requires a daily dose ranging from 3.5 to 13.1 g for a GFR ranging from 20 to 125 mL/min.

CONCLUSIONS

This work provided a practical tool for cloxacillin dose adjustment in IE according to renal function.

Case Report: Rare Case of Staphylococcus pasteuri Endocarditis

A 45-year-old woman was admitted with severe pain in the right leg and dyspnea. Her medical history included previous Staphylococcus aureus endocarditis, biological aortic valve replacement, and intravenous drug abuse. She was febrile but did not have any focal signs of infection. Blood tests showed raised infectious markers and troponin levels. Electrocardiogram showed sinus rhythm without signs of ischemia. Ultrasound revealed thrombosis of the right popliteal artery. The leg was not critically ischemic, and therefore, treatment with dalteparin was chosen. Transesophageal echocardiography showed an excrescence on the biological aortic valve. Empiric treatment for endocarditis was started with intravenous vancomycin, gentamicin, and oral rifampicin. Blood cultures subsequently grew Staphylococcus pasteuri. On day 2, treatment was changed to intravenous cloxacillin. Due to the comorbidity, the patient was not a candidate for the surgical treatment. On day 10, the patient developed moderate expressive aphasia and weakness in the right upper limb. Magnetic resonance imaging showed micro-embolic lesions scattered across both hemispheres of the brain. Treatment was changed from cloxacillin to cefuroxime. On day 42, infectious markers were normal, and echocardiography showed regression of the excrescence. Antibiotic treatment was stopped. Follow-up on day 52 did not show any signs of active infection. However, on day 143, the patient was readmitted with cardiogenic shock due to aortic root fistulation to the left atrium. She quickly deteriorated and died.

Long-Term Results of Patch Repair in Destructive Valve Endocarditis

OBJECTIVES

Treatment of destructive endocarditis with abscess formation is a surgical challenge and associated with significant morbidity and mortality. A root replacement is often performed in case of an annular abscess. This retrospective study was designed to assess the long-term outcome of extensive debridement and patch reconstruction as an alternative approach.

METHODS

Between November 2007 and November 2016, a selected group of 79 patients (29.6% of all surgical endocarditis cases) with native valve endocarditis (NVE, 53.2%) or prosthetic valve endocarditis (PVE, 46.8%) valve endocarditis underwent surgical therapy with extensive annular debridement and patch reconstruction. Their postoperative course, freedom from recurrent endocarditis, and survival at 1, 5, and 7 years were evaluated.

RESULTS

About two-thirds of patients were in a stable condition, one-third of patients were in a critical state. The median logistic EuroSCORE I was 17%. Infected tissue was removed, and defect closure was performed, either with autologous pericardium for small defects, or with bovine pericardium for larger defects. Overall, in-hospital mortality was 11.3% (NVE: 9.7%, PVE: 13.2%; p = 0.412). In single valve endocarditis survival at 1, 5, and 7 years was 81, 72, 72%, respectively for NVE, and 80, 57, 57%, respectively for PVE (p = 0.589), whereas in multiple valve endocarditis survival at 1, 5, and 7 years was 82, 82, 82% for NVE, and 61, 61, and 31%, respectively for PVE (p = 0.132). Confirmed late reinfection was very low.

CONCLUSION

Surgical treatment of destructive endocarditis with abscess formation using patch repair techniques offers acceptable early and long-term results. The relapse rate was low. PVE and involvement of multiple valves were associated with worse outcomes.

Multivalvular Endocarditis: A Rare Condition with Poor Prognosis

Background. Infective endocarditis (IE) is a severe condition. Our aim was to describe the profile and prognosis of patients with multivalvular infective endocarditis (MIE) and compare them to single-valve IE (SIE). Methods. We used a retrospective analysis of the Spanish IE Registry (2008−2020). Results. From 4064 definite cases of valvular IE, 577 (14.2%) had MIE. In patients with MIE, the most common locations were mitral (552, 95.7%) and aortic (550, 95.3%), with mitral-aortic involvement present in 507 patients (87.9%). The most common etiologies were S. viridans (192, 33.3%) and S. aureus (113, 19.6%). MIE involved only native valves in 450 patients (78.0%). Compared with patients with SIE, patients with MIE had a similar age (69 vs. 67 years, respectively, p = 0.27) and similar baseline characteristics, but were more frequently men (67.1% vs. 72.9%, p = 0.005) and had a higher incidence of intracardiac complications (36.2% vs. 50.4%, p < 0.001), heart failure (42.7% vs. 52.9%, p < 0.001), surgical indication (67.7 vs. 85.1%, p < 0.001), surgery (46.3% vs. 56.3%), and in-hospital mortality (26.9% vs. 34.3%, p < 0.001). MIE was an independent predictor of in-hospital mortality (odds ratio (OR) 1.3, 95% confidence interval (CI) 1.1−1.7, p = 0.004) but did not have an independent association with 1-year mortality (OR 1.1, 95% CI 0.9−1.4, p = 0.43). Conclusions. About one-seventh of the valvular IE patients had MIE, mainly due to mitral-aortic involvement. MIE is associated with a poor in-hospital prognosis. An early diagnosis and treatment of IE might avoid its spread to a second valve.

Etiology, clinical characteristics, and outcome of infective endocarditis: 10-year experience from a tertiary care center in Pakistan

This study was conducted to assess the clinical characteristics, causative agents, complications, and outcomes of infective endocarditis (IE) among patients presenting to our tertiary care center over the last decade. This retrospective cohort study included all adult patients admitted to the Aga Khan University Hospital with the diagnosis of IE over a ten-year period from 2010 to 2020.  Outcomes variables included complications during hospitalization, surgical intervention, mortality, and length of stay. We identified a total of 305 cases out of which 176 (58%) were males and 129 (42%) were females. The mean age of the patients was 46.9±18.8 years. 95 (31%) had prosthetic valves in place. Staphylococcus aureus was isolated in 54 (39%) patients followed by coagulase-negative Staphylococcus in 23 (17%). Echocardiography revealed vegetations and abscesses in 236 (77%) and 4 (1%) patients, respectively. The most common valvular complication was mitral valve regurgitation found in 26 (9%) patients, followed by tricuspid valve regurgitation in 13 (4%) patients and aortic valve regurgitation in 11 (3%) patients. Furthermore, 81 (27%) patients suffered from heart failure and 66 (22%) from a stroke during hospitalization. The mean hospital length of stay was 10.4 ± 10.6 days. 64 (21%) patients required surgical repair and the overall mortality rate was 25%. Prosthetic valve endocarditis (OR = 3.74, 95% CI = 2.15-6.50, p<0.001), chronic kidney disease (OR = 2.51, 95% CI = 1.15-5.47, p=0.036), previous stroke (OR = 2.42, 95% CI = 1.18-4.96, p=0.026), and ischemic heart disease (OR = 3.04, 95% CI = 1.50-6.16, p=0.003) were significantly associated with an increased risk of mortality. In conclusion, our study provided valuable data on the clinical characteristics and outcomes of patients with IE in a developing country. S. aureus was the most common causative agent. Heart failure and stroke were the most common complications. The presence of prosthetic valves, history of chronic kidney disease, ischemic heart disease and previous stroke were associated with a significantly increased risk of mortality. Surgical management was not associated with improved outcomes.

Thirty-Day Readmission After Infective Endocarditis: Analysis From a Nationwide Readmission Database

Background

The contemporary incidence of and reasons for early readmission after infective endocarditis (IE) are not well known. Therefore, we analyzed 30‐day readmission demographics after IE from the US Nationwide Readmission Database.

Methods and Results

We examined the 2010 to 2014 Nationwide Readmission Database to identify index admissions for a primary diagnosis of IE with survival at discharge. Incidence, reasons, and independent predictors of 30‐day unplanned readmissions were analyzed. In total, 11 217 patients (24.8%) were nonelectively readmitted within 30 days among the 45 214 index admissions discharged after IE. The most common causes of readmission were IE (20.5%), sepsis (8.7%), complications of device/graft (8.1%), and congestive heart failure (7.6%). In‐hospital mortality and the valvular surgery rates during the readmissions were 8.1% and 9.1%, respectively. Discharge to home or self‐care, undergoing valvular surgery, aged ≥60 years, and having private insurance were independently associated with lower rates of 30‐day readmission. Length of stay of ≥10 days, congestive heart failure, diabetes mellitus, renal failure, chronic pulmonary disease, peripheral artery disease, and depression were associated with higher risk. The total hospital costs of readmission were $48.7 million per year (median, $11 267; interquartile range, $6021–$25 073), which accounted for 38.6% of the total episodes of care (index+readmission).

Conclusions

Almost 1 in 4 patients was readmitted within 30 days of admission for IE. The most common reasons were IE, other infectious causes, and cardiac causes. A multidisciplinary approach to determine the surgical indications and close monitoring are necessary to improve outcomes and reduce complications in in‐hospital and postdischarge settings.

Outcomes of mitral valve repair in acute native mitral valve infective endocarditis

OBJECTIVES

Mitral valve repair (MVR) is considered the treatment of choice for mitral valve (MV) regurgitation. However, MVR in acute native MV infective endocarditis is technically challenging and not commonly performed. Our goal was to report our outcomes of MVR in acute native MV infective endocarditis.

METHODS

Between January 2016 and December 2017, 35 patients presenting with acute native MV infective endocarditis underwent MVR. Primary end points were successful MVR and freedom from recurrent endocarditis. Secondary end point was the postoperative incidence of major adverse events.

RESULTS

The mean age was 58 ± 13 years (74% men) and the median logistic EuroSCORE was 17.1%. Twenty patients underwent isolated MVR; the other 15 patients underwent concomitant procedures. MVR was performed with removal of the vegetation (vegectomy), limited resection of the infected tissue, direct closure of the defect, besides annuloplasty in all patients. Mean intensive care and hospital stays were 5 and 17 days, respectively. All-cause mortality was 11% (4/35) at 30 days and a total of 23% (8/35) within a follow-up period of 10 ± 7.7 months. Endocarditis recurred in 2 patients 15 and 8 months after surgery, respectively. Both underwent successful MV re-repair. Follow-up echocardiography indicated none-to-trace, mild or moderate regurgitation in 15, 10 and 2 patients, respectively.

CONCLUSIONS

Although MVR in acute native MV infective endocarditis is a complex procedure, it offers a treatment option for such patients with acceptable short-term results. Limited resection in addition to annuloplasty is our preferred method of repair. Nevertheless, long-term results in a larger cohort are still mandatory.

The influence of race in older adults with infective endocarditis

BACKGROUND

Age is a risk factor for infective endocarditis, and almost half of diagnosed patients are age ≥ 60 years. Large national studies have not evaluated inpatient mortality and surgical valvular interventions between older White and Black patients hospitalized with infective endocarditis.

METHODS

We used the Nationwide Inpatient Sample database to identify older adults ≥60 years in North America with a principle diagnosis of infective endocarditis. Multivariate logistic regression was used to compare in-hospital mortality and valvular repairs/replacement between older Black and White patients.

RESULTS

Of 10,390 adults, age ≥ 60 years hospitalized for infective endocarditis during 2013 and 2014, 7356 were White and 1089 Black. Blacks were younger (mean age: 70.5 ± 0.5 vs. 73.5 ± 0.2 years, p < 0.01), lived in more zip codes with a median annual income <$39,000/yr. (40.4% vs 18.8%, p < 0.01), and had higher co-morbidity burden (Charlson comorbidity score ≥ 3: 54.6% vs 40.7%, p < 0.01). After multivariate adjustment, Blacks had higher odds for in-hospital mortality (Odds Ratio (OR) = 2.0, [Confidence Interval (CI) 1.1-3.8]; p = 0.020), and lower odds for mitral valve repairs/replacements (OR = 0.53, CI: 0.29-0.99, p = 0.049).

CONCLUSIONS

Blacks age ≥ 60 years hospitalized in North America with infective endocarditis are less likely to undergo mitral valvular repairs/replacement and had higher in-hospital mortality compared to White patients.

Prevalence of mupirocin and chlorhexidine resistance among methicillin-resistant coagulase-negative staphylococci isolated during methicillin-resistant Staphylococcus aureus decolonization strategies

BACKGROUND

The widespread of methicillin-resistant Staphylococcus aureus (MRSA) antimicrobial decolonization in the clinical setting may lead to an increase in the prevalence of multiresistance to coagulase-negative staphylococci (CoNS) owing to their selection. This study aimed to investigate the impact of MRSA decolonization strategies, using mupirocin and chlorhexidine, on their CoNS susceptibility.

METHODS

A total of 312 CoNS isolates were collected before starting the decolonization protocols "baseline strains" (BLS) group, 330 isolates were collected after application of the targeted decolonization protocol "targeted decolonization strains" group, and 355 isolates were collected after application of the universal decolonization protocol "universal decolonization strains" group. Methicillin-resistant CoNS (MR-CoNS) were identified and tested for mupirocin and chlorhexidine susceptibilities. Heptaplex polymerase chain reaction assay was applied for simultaneous screening for chlorhexidine (CHX-R) and mupirocin resistance (Mu-R) genes.

RESULTS

Mu-R prevalence of MR-CoNS among the BLS group was considered moderate (9.1%); however, CHX-R in the BLS group was 5.8%, the rate of which significantly increased among the universal decolonization strains group.

DISCUSSION

Both MRSA decolonization strategies have an additional benefit in reducing the prevalence of MR-CoNS. The prevalence Mu-R rate didn't change significantly during either of the MRSA decolonization practices that may be due to the local nature of mupirocin application on the nasal mucosa only. In contrast CHX-R that was found to be significantly higher among the UDS group.

CONCLUSIONS

Our findings indicate that both MRSA decolonization strategies have an additional benefit in reducing the prevalence of MR-CoNS. Although the universal MRSA decolonization has superior efficacy in decolonization of CoNS, it may increase the risk of selecting CHX-R and Mu-R. In addition, other potential resistance genes should be studied.

Bacteremia after professional mechanical plaque removal in patients with chronic periodontitis

OBJECTIVE

The aim of this study was to investigate the characteristics of bacteremia caused by professional mechanical plaque removal (PMPR) in two groups of patients with generalized moderate chronic periodontitis.

MATERIALS AND METHODS

Venous blood samples were taken at multiple time points for one hour following PMPR in fifty patients with generalized moderate chronic periodontitis. Subjects consisted of two groups, one group was receiving supportive periodontal therapy (SPT, n = 25) and the other group was receiving initial periodontal therapy (IPT, n = 25). Blood samples were processed and analyzed for cultivable microflora. Pertinent clinical parameters were recorded for each patient in both groups.

RESULTS

Bacteremia was detected in 10 of 25 SPT and 8 of 25 IPT patients (p = 0.796). In both groups, the prevalence of bacteremia was dependent on the time of blood sampling and varied in magnitude between <10²  CFU/ml and 10⁶  CFU/ml. Sixteen different bacterial species were identified in both groups, mostly Actinomyces naeslundii (SPT n = 3, IPT n = 4) and Streptococcus spp. (SPT n = 6, IPT n = 2). In regression models, Grade II furcation involvement (p = 0.004) and Gingival Bleeding Index (p = 0.036) had affected the occurrence of bacteremia but in the SPT group only.

CONCLUSION

Professional mechanical plaque removal was associated with bacteremia regardless of whether a patient was receiving SPT or IPT.

Staphylococcus capitis Osteomyelitis: Case Report

This case report describes an unusual invasive infection with Staphylococcus capitis, in a child with a history of repaired congenital heart disease and an acute presentation of osteomyelitis. Coagulase-negative staphylococci are rare causes of osteomyelitis without an implanted device in the bone and, as such, should prompt evaluation for associated infections that may be contributing to the unusual presentation. Additionally, this case highlights the importance of considering methicillin heteroresistance in staphylococcal infections when the clinical course is not proceeding as expected.

Twenty-Year Secular Trends in Infective Endocarditis in a Teaching Hospital

Background

The purpose of this study was to analyze the secular trends of infective endocarditis in a teaching hospital between January 1996 and December 2015.

Methods

We report on a single-center retrospective study of patients with left-side valve infective endocarditis. We performed an analysis of secular trends in the main epidemiological and etiological aspects, as well as clinical outcomes, in 5 successive 4-year periods (P1 to P5).

Results

In total, 595 episodes of infective endocarditis were included, of which 76% were community-acquired and 31.3% involved prosthetic valves. Among the cases, 70% occurred in men, and the mean age (SD) was 64.1 (14.3) years. A significant increase in older patients (age ≥70 years) between P1 (15.332%) and P5 (51.9%; P < .001) was observed. The rate of infective endocarditis on biological prostheses also increased in the prosthetic group, accounting for 30% in P1 and 67.3% in P5 (P < .001). By contrast, there were significant decreases in vascular and immunological phenomena over the study period, with decreases in the presence of moderate to severe valvular insufficiency (75.9% in P1 to 52.6% in P5; P < .001) and valvular surgery (43% in P1 vs 29.6% in P5; P = .006). Finally, overall mortality was 23.9%, and although it was highest in P1, it subsequently remained stable through P2 to P5 (38% in P1 to 20% in P5; P = .004).

Conclusions

There has been a significant increase in infective endocarditis in older patients. The decrease in moderate to severe valve regurgitation at diagnosis could explain the stable mortality despite the increase in the mean age of patients over time.

Paradoxical Embolism in a Patient with Aortic Valve Endocarditis: A Case Report

This report describes a case of aortic valve endocarditis with systemic and paradoxical pulmonary embolism in a patient with congenital interventricular communication. The patient underwent cardiac surgery and did not have a favorable outcome, presenting refractory cardiogenic shock and subsequently dying while in the hospital. This is an extremely rare case of paradoxical embolism in a patient with infective endocarditis; only four similar cases have been reported in the literature.

A retrospective epidemiologic study to define risk factors, microbiology, and clinical outcomes of infective endocarditis in a large tertiary-care teaching hospital

Objective:

This study aims to define risk factors as well as their association with microbiology and clinical outcomes in a large US infective endocarditis population.

Methods:

Hospital records were searched for appropriate infective endocarditis–related ICD codes from 16 July 2007 to 13 August 2015. A total of 363 cases were retrospectively identified that met definite Modified Duke Criteria for infective endocarditis and were analyzed by age group, causative organism, and associated risk factors for use of valvular surgical intervention, 30/90/180-day mortality after admission, and embolic phenomena.

Results:

Chronic hemodialysis was the most common risk factor (26.7% of cases). Of all age groups, those aged 78+ years had the lowest 30-day mortality but those aged 58–77 years had the highest mortality (p = 0.039). Staphylococcus aureus was the most prevalent causative organism. Those aged 78–97 years were more likely to have enterococcal infective endocarditis than those aged 18–27 years (p = 0.0144). Chronic hemodialysis associated infective endocarditis was more likely to be caused by coagulase-negative staphylococcus (p = 0.0121) and have a higher 30-day mortality (p = 0.141) than intravenous drug use associated infective endocarditis. Intravenous drug use and chronic hemodialysis were similarly likely to be caused by S. aureus. Intravenous drug use associated infective endocarditis was more likely to be caused by viridans group streptococci (p = 0.0001). Fungal infective endocarditis was most likely to embolize. Chronic hemodialysis patients were less likely to undergo valvular surgery (p = 0.001) and those with chronic hemodialysis who did had lower mortality than those only managed medically that did not reach statistical significance (p = 0.2991). Infective endocarditis caused by coagulase-negative staphylococci had the greatest 30-day mortality at 31.3% but did not reach statistical significance over all other causative organisms (p = 0.060).

Conclusion:

In our infective endocarditis population, S. aureus is the predominant causative organism. Chronic hemodialysis is the most common risk factor present in infective endocarditis populations and has greater association with coagulase-negative staphylococci and 30-day mortality. Intravenous drug use had the lowest mortality among risk factors with a similar proportion of S. aureus infective endocarditis compared to chronic hemodialysis but a higher proportion of viridans group streptococci infective endocarditis cases. Further study will need to be performed on prevention and treatment of infective endocarditis in chronic hemodialysis patients.

Successful treatment of acute renal failure secondary to complicated infective endocarditis by peritoneal dialysis: a case report

BACKGROUND

Infective endocarditis is one of the most common infections among intravenous drug addicts. Its complications can affect many systems, and these can include acute renal failure. There is a scarcity of cases in the literature related to acute renal failure secondary to infective endocarditis treated with peritoneal dialysis. In this paper, the case of a 48-year-old Saudi male is reported, who presented with features suggestive of infective endocarditis and who developed acute kidney injury that was treated successfully with high tidal volume automated peritoneal dialysis. To our knowledge, this is the second report of such an association in the literature.

CASE PRESENTATION

A 48-year-old Saudi gentleman diagnosed to have a glucose-6-phosphate dehydrogenase deficiency and hepatitis C infection for the last 9 years, presented to the emergency department with a history of fever of 2 days' duration. On examination: his temperature = 41 °C, there was clubbing of the fingers bilaterally and a pansystolic murmur in the left parasternal area. The results of the blood cultures and echocardiogram were supportive of the diagnosis of infective endocarditis, and the patient subsequently developed acute kidney injury, and his creatinine reached 5.2 mg/dl, a level for which dialysis is essential for the patient to survive.

CONCLUSION

High tidal volume automated peritoneal dialysis is highly effective as a renal replacement therapy in acute renal failure secondary to infective endocarditis if no contraindication is present.

Systematic overdosing of oxa- and cloxacillin in severe infections treated in ICU: risk factors and side effects

Background

Oxacillin and cloxacillin are the most frequently used penicillins for the treatment of severe methicillin-susceptible Staphylococcus aureus infections in intensive care units (ICUs), especially endocarditis. International recommendations do not suggest any adaptation of the dosage in case of renal impairment. We wanted to assess the risk factors for overdosing in ICU and the related observed side effects.

Methods

All patients with a therapeutic drug monitoring of oxa- or cloxacillin between 2008 and 2014 were included. The target range of trough concentration for total antibiotic activity was considered to be 20–50 mg/L. Data concerning the infection, the given treatment, the renal function, and the attributed side effects of overdosing were collected. A logistic regression model was used to compute the measured trough concentrations.

Results

Sixty-two patients were included in this study. We found a median trough plasma concentration of 134.3 mg/L (IQR 65.3–201 mg/L). Ten patients (16.1%) reached the target concentration; all other patients (83.9%) were overdosed. Eleven patients (17.7%) experienced neurological side effects attributed to a high antibiotic concentration, i.e. persistent coma and delirium. When adjusted on the dosage used, the risk of overdosing was significantly associated with a creatinine clearance <10 mL/min (with or without hemodialysis).

Conclusion

With the suggested dose of 12 g/day for cloxacillin treatment in case of endocarditis and severe infections occurring in ICU, 83.9% of patients are largely overdosed. Considering the observed side effects, doses should be accurately monitored and reduced, particularly when renal replacement therapy is needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-017-0255-8) contains supplementary material, which is available to authorized users.

High readmission rates and mental distress after infective endocarditis - Results from the national population-based CopenHeart IE survey

BACKGROUND

Infective endocarditis (IE) is a severe disease requiring lengthy hospitalisation. Little is known about patients' recovery after IE. The aims of this study in IE patients were; (i) to describe mortality, readmission, self-reported health and rehabilitation up to 1year post-discharge, (ii) to examine associations between self-reported health and readmission, and (iii) to investigate predictors of readmission and mortality.

METHODS

All adults treated for IE in Denmark, January-June 2011 (N=347), were followed in registers. Eligible individuals (n=209) were invited to participate in a questionnaire survey (responders n=122). Responses were compared with those of a background reference population and a heart valve surgery population. Mortality and readmission data from registers 12months post-discharge were investigated.

RESULTS

Patients discharged after treatment for IE had a mortality of 18% (95% confidence interval (CI): 14%-23%) one year post-discharge and 65% (95% CI: 59%-71%) had been readmitted, the majority (82%) acutely. Patients had lower self-reported health compared to the background population (physical component scale (PCS); mean (standard deviation (SD)): 42.2 (11.1) vs. 47.1 (12.1), (p=0.0004), mental component scale (MCS); 50.1 (11.7) vs. 53.8 (9.2), (p=0.006), and more were sedentary (29 vs. 15%), (p=0.002). Large proportions had clinical signs of anxiety and depression, 25% and 22% respectively, exceeding a hospital anxiety and depression scale (HADS) cut-off score of 8. Almost half (47%) had not been offered cardiac rehabilitation (CR).

CONCLUSIONS

After IE, mortality and readmission rates were high and self-reported physical and mental health poor. These findings call for changes in in-hospital and post-discharge management.

Infective endocarditis: a review for nurses

Infective endocarditis (IE) is a relatively uncommon condition that can present with a variety of noncardiac symptoms, making diagnosis of this condition challenging. Although IE is no longer uniformly fatal as it was in the preantibiotic era, it still has a high mortality rate. The major risk factor for IE, rheumatic fever, has decreased significantly in the industrialized west, but the incidence of IE remains as high as it was in the preantibiotic era. Today, IE has changed from a disease primarily of the young to one of the elderly. The increase in frequency of IE seems to be related to the fact that individuals are now living longer with chronic heart diseases and are having invasive medical procedures performed more often. The 2 main approaches to treating IE are the use of antibiotics and cardiac surgery. This article provides an overview of IE, epidemiology, pathogenesis, clinical manifestations, diagnosis criteria, and treatment options for IE.

Infective Endocarditis and Cancer Risk: A Population-Based Cohort Study

This study investigated the possible relationship between endocarditis and overall and individual cancer risk among study participants in Taiwan.We used data from the National Health Insurance program of Taiwan to conduct a population-based, observational, and retrospective cohort study. The case group consisted of 14,534 patients who were diagnosed with endocarditis between January 1, 2000 and December 31, 2010. For the control group, 4 patients without endocarditis were frequency matched to each endocarditis patient according to age, sex, and index year. Competing risks regression analysis was conducted to determine the effect of endocarditis on cancer risk.A large difference was noted in Charlson comorbidity index between endocarditis and nonendocarditis patients. In patients with endocarditis, the risk for developing overall cancer was significant and 119% higher than in patients without endocarditis (adjusted subhazard ratio = 2.19, 95% confidence interval = 1.98-2.42). Regarding individual cancers, in addition to head and neck, uterus, female breast and hematological malignancies, the risks of developing colorectal cancer, and some digestive tract cancers were significantly higher. Additional analyses determined that the association of cancer with endocarditis is stronger within the 1st 5 years after endocarditis diagnosis.This population-based cohort study found that patients with endocarditis are at a higher risk for colorectal cancer and other cancers in Taiwan. The risk was even higher within the 1st 5 years after endocarditis diagnosis. It suggested that endocarditis is an early marker of colorectal cancer and other cancers. The underlying mechanisms must still be explored and may account for a shared risk factor of infection in both endocarditis and malignancy.

Coagulase-negative staphylococci

The definition of the heterogeneous group of coagulase-negative staphylococci (CoNS) is still based on diagnostic procedures that fulfill the clinical need to differentiate between Staphylococcus aureus and those staphylococci classified historically as being less or nonpathogenic. Due to patient- and procedure-related changes, CoNS now represent one of the major nosocomial pathogens, with S. epidermidis and S. haemolyticus being the most significant species. They account substantially for foreign body-related infections and infections in preterm newborns. While S. saprophyticus has been associated with acute urethritis, S. lugdunensis has a unique status, in some aspects resembling S. aureus in causing infectious endocarditis. In addition to CoNS found as food-associated saprophytes, many other CoNS species colonize the skin and mucous membranes of humans and animals and are less frequently involved in clinically manifested infections. This blurred gradation in terms of pathogenicity is reflected by species- and strain-specific virulence factors and the development of different host-defending strategies. Clearly, CoNS possess fewer virulence properties than S. aureus, with a respectively different disease spectrum. In this regard, host susceptibility is much more important. Therapeutically, CoNS are challenging due to the large proportion of methicillin-resistant strains and increasing numbers of isolates with less susceptibility to glycopeptides.

Surgical experience with infective endocarditis and aortic root abscess

PURPOSE

This study was conducted to evaluate the surgical outcomes of active infective endocarditis with aortic root abscess formation.

MATERIALS AND METHODS

Between February 1999 and June 2012, 49 patients underwent surgery for active endocarditis with aortic root abscess. The infected valve was native in 29 patients and prosthetic in 20 patients. The patients' mean age was 50±14 years, and 36 patients were male. Surgery was urgent/emergent in 15 patients (31%). The abscess involved the aortic annulus (11), left ventricular outflow tract (18), fibrous trigone (16), and mitral annulus (4). In all patients, wide debridement of abscess and aortic valve replacement with or without patch reconstruction of aortic root or annulus was performed.

RESULTS

There were 6 (12%) operative deaths. Causes of early mortality were sepsis (2) and multi-organ failure (4). On postoperative echocardiogram, there was significant improvement of left ventricular dimension (LVEDD, from 58.8±11.8 mm to 52.6±8.2 mm, p<0.001); however, LV ejection fraction was significantly decreased (from 61.4±12.0% to 49.8±16.5%, p<0.001). The mean follow-up duration was 68.7±40.4 months. There was no late death or recurrent endocarditis during follow up. New York Heart Association functional class significantly improved from 3.2±0.7 to 1.2±0.4 (p<0.001). Kaplan-Meier estimated survival at 10 years was 87.2%.

CONCLUSION

Surgical treatment for active endocarditis with aortic root abscess is still challenging, and was associated with high operative mortality. Nevertheless, long-term survival was excellent with good functional capacity after recovery from the early postoperative period.

Biodegradable materials for surgical management of infective endocarditis: new solution or a dead end street?

Background

One third of patients with infective endocarditis will require operative intervention. Given the superiority of valve repair over valve replacement in many indications other than endocarditis, there has been increasing interest and an increasing number of reports of excellent results of valve repair in acute infective endocarditis. The theoretically ideal material for valve repair in this setting is non-permanent, “vanishing” material, not at risk of seeding or colonization. The goal of this contribution is to review currently available data on biodegradable materials for valve repair in infective endocarditis.

Discussion

Rigorous electronic and manual literature searches were conducted to identify reports of biodegradable materials for valve repair in infective endocarditis. Articles were identified in electronic database searches of Medline, Embase and the Cochrane Library, using a predetermined search strategy. 49 manuscripts were included in the review. Prosthetic materials needed for valve repair can be summarized into annuloplasty rings to remodel the mitral or tricuspid annulus, and patch materials to replace resected valvar tissue. The commercially available biodegradable annuloplasty ring has shown interesting clinical results in a single-center experience; however further data is required for validation and longer follow-up. Unmodified extra-cellular matrix patches, such as small intestinal submucosa, have had promising initial experimental and clinical results in non-infected valve repair, although in valve repair for endocarditis has been reported in only one patient, and concerns have been raised regarding their mechanical stability in an infected field.

Summary

These evolving biodegradable devices offer the potential for valve repair with degradable materials replaced with autologous tissue, which could further improve the results of valve repair for infective endocarditis. This is an evolving field with promising experimental or initial clinical results, however long-term outcomes are lacking and further data is necessary to validate this theoretically interesting approach to infective endocarditis.

Epidemiology of infective endocarditis in a large Belgian non-referral hospital

OBJECTIVES

Guidelines for diagnosis of infective endocarditis are largely based upon epidemiological studies in referral hospitals. Referral bias, however, might impair the validity of guidelines in non-referral hospitals. Recent studies in non-referral care centres on infective endocarditis are sparse. We conducted a retrospective epidemiological study on infective endocarditis in a large non-referral hospital in a Belgian city (Kortrijk).

METHODS

The medical record system was searched for all cases tagged with a putative diagnosis of infective endocarditis in the period 2003-2010. The cases that fulfilled the modified Duke criteria for probable or definite infective endocarditis were included.

RESULTS

Compared to referral centres, an older population with infective endocarditis, and fewer predisposing cardiac factors and catheter-related infective endocarditis is seen in our population. Our patients have fewer prosthetic valve endocarditis as well as fewer staphylococcal endocarditis. Our patients undergo less surgery, although mortality rate seems to be highly comparable with referral centres, with nosocomial infective endocarditis as an independent predictor of mortality.

CONCLUSION

The present study suggests that characteristics of infective endocarditis as well as associative factors might differ among non-referral hospitals and referral hospitals.

Treatment ofPseudomonas aeruginosainfection in critically ill patients

Critically ill patients are on the increase in the present clinical setting. Aging of our population and increasingly aggressive medical and therapeutic interventions, including implanted foreign bodies, organ transplantation and advances in the chemotherapy of malignant diseases, have created a cohort of particularly vulnerable patients. Pseudomonas aeruginosa is one of the leading gram-negative organisms associated with nosocomial infections. This organism is frequently feared because it causes severe hospital-acquired infections, especially in immunocompromised hosts, and is often antibiotic resistant, complicating the choice of therapy. The epidemiology, microbiology, mechanisms of resistance and currently available and future treatment options for the most relevant infections caused by P. aeruginosa are reviewed.

Changing pattern of infective endocarditis in Iran: A 16 years survey

OBJECTIVES

To investigate the changes in characteristics of patients with infective endocarditis in Iran and comparing the results with the changing profiles of Infection Endocarditis (IE) in other countries.

METHODOLOGY

We studied all patients with definite or possible IE seen at four referral teaching hospitals in Iran from Jan. 1995 to Dec. 2010. The data was analyzed both collectively and separately in two consecutive eight-year periods, i.e. 1995-2003 and 2004-2010.

RESULTS

A total of 286 episodes of IE, 172 males and 114 females, were reviewed from which 162 ones were in the first eight-year time period and 124 episodes in the second one. Mean age of the patients was significantly increased in the second eight-year period (24.2±11 vs 39.4±15 years old, p value = 0.01). Increase in the episodes caused by Staphylococcus aureus was significant (40.7% vs 22.8%, p value = 0.01). The mean size of the vegetation was noticeably higher among IDUs than non-IDUs (1.53±0.1cm vs 0.76±0.2cm, p value < 0.001). As well as extra cardiac complications, mortality rate was noticeably higher among the patients with vegetation size ≥ 1cm (34.4% vs 16.3%, p value = 0.003). There was not a significant difference regarding the mortality rate between the conservatively and surgically treated patients (20.7% vs 22.9%, p value = 0.07).

CONCLUSION

The most important changing characteristic of IE which influences the outcome of the disease seems to be vegetation size which can account for as the outcome predictor.

Profile of infective endocarditis observed from 2003 - 2010 in a single center in Italy

Background

This study aimed to provide a contemporary picture of the epidemiologic, clinical, microbiologic characteristics and in-hospital outcome of infective endocarditis (IE) observed in a single center in Italy.

Methods

We performed a retrospective study of patients with definite or probable IE observed at the “L. Sacco” Hospital in Milan, Italy, from January 1, 2003 through December 31, 2010.

Results

189 episodes of IE in 166 patients were included. The mean number of incident IE in the study period was of 1.27 (range 0.59-1.76) cases per 1000 patients admitted. The median age of the cohort was 57 (interquartile range, 43-72) years, 63% were male and 62.5% had native valve IE. Twenty-six percent were active intravenous drug users (IVDU), 29% had a health care-associated IE and 5% chronic rheumatic disease. Twenty-nine percent of the cases occurred in patients affected by chronic liver disease and 19% in HIV positive subjects. Staphylococcus aureus was the most common pathogen (30%), followed by streptococci. The mitral (34%) and aortic (31%) valves were involved most frequently. The following complications were common: stroke (19%), non-stroke embolizations (25%), heart failure (26%) and intracardiac abscess (9%). Surgical treatment was frequently employed (52%) but in hospital mortality remained high (17%). Health care-associated IE and complications were independently associated with an increased risk of in-hospital death, while surgery was associated with decreased mortality.

Conclusion

S. aureus emerged as the leading causative organism of IE in a University hospital in northern Italy. Our study confirmed the high in-hospital mortality of IE, particularly if health care associated, and the protective role of surgery.

Comparative epidemiology of bacteremia due to methicillin-resistant Staphylococcus aureus between older and younger adults: a propensity score analysis

OBJECTIVE

We evaluated the clinical and molecular epidemiology of bloodstream infections (BSIs) due to methicillin-resistant Staphylococcus aureus (MRSA) in older versus younger patients treated with vancomycin, determining the independent effect of increased age on outcomes.

DESIGN

Observational retrospective cohort study.

SETTING

Detroit Medical Center, level I trauma center.

PATIENTS

Adult older (65 years and older) and younger (younger than 65 years) patients with documented BSIs due to MRSA treated with vancomycin (2005-2010).

METHODS

Collected demographics, comorbidities, microbiology, treatment, outcomes. Multivariable model used to generate propensity score for each patient on the basis of the probability of being 65 years of age or older.

RESULTS

Three hundred twenty patients were eligible (69 patients 65 years and older; 251 patients younger than 65 years). Catheter-related infections and endocarditis were the most common sites of infection for older (20.3%) and younger (19.1%) adults, respectively. Median first total 24-hour vancomycin dose (1,000 vs 2,000 mg; [Formula: see text]) and initial trough (13.1 vs 15.0 mg/L; [Formula: see text]) was significantly lower in older versus younger patients. Vancomycin treatment failure rates were similar among older and younger patients (49.3% vs 53.4%; [Formula: see text]). In multivariable analysis of outcomes, after controlling for predictors of older age, there was no difference in clinical outcomes between older and younger adults.

CONCLUSIONS

After accounting for confounders associated with increased age, failure rate of patients with BSIs due to MRSA treated with vancomycin was similar between older and younger patients. Older adults were less likely to have optimal vancomycin dosing and initial trough levels than younger patients. Efforts should be made to optimize dosing of medications such as vancomycin in older adults.

Extending the scope of mitral valve repair in active endocarditis

OBJECTIVE

During the last 2 decades, we have applied a repair-oriented surgical approach to patients with active mitral valve endocarditis. We retrospectively analyzed the long-term outcomes with this repair-oriented approach.

METHOD

Between 1991 and 2010, 137 patients underwent operation for active mitral valve endocarditis; of these, 109 patients (80%) had mitral valve repair and represent the study cohort. Repair techniques without patch extension (no-patch techniques) include triangular or quadrangular resection (n = 49), sliding plasty (n = 24), neochordae (n = 18), chordal transfer (n = 12), and others (n = 5). Repair techniques using patch extension (patch techniques) included pericardium (n = 42), tricuspid autograft (n = 8), flip-over technique (n = 7), and partial mitral valve homograft (n = 5). Patches were used in 67 patients (61%). Ring annuloplasty was performed in 60 patients, and a pericardial band was used in 13 patients. Clinical and echocardiographic follow-up were performed. Median follow-up was 48 months.

RESULTS

Hospital mortality was 16%. At 8 years, overall survival was 62% ± 10% with no differences between patients with or without patch repair (P = .5). Freedom from mitral valve repair failure was 81% ± 14% in patients with patch repair and 90% ± 10% in patients without patch repair (P = .09). The rate of thromboembolic or bleeding event was 1% per patient-year, and the rate of endocarditis recurrence was 0.3% per patient-year. Univariable predictors of mortality were age more than 70 years (P < .0001), perivalvular abscess (P = .002), diabetes mellitus (P = .0002), and renal failure (P = .04). Predictors of repair failure were renal failure (P = .035) and perivalvular abscess (P = .033).

CONCLUSIONS

In active mitral valve endocarditis, a repair-oriented surgical approach achieves a reparability rate of 80% with acceptable morbidity and good long-term results. The use of patch techniques offers a durability rate that approximates the rate obtained with the no-patch techniques.

A randomised clinical trial of comprehensive cardiac rehabilitation versus usual care for patients treated for infective endocarditis--the CopenHeartIE trial protocol

INTRODUCTION

Infective endocarditis (IE) is among the most serious infectious diseases in the western world. Treatment requires lengthy hospitalisation, high-dosage antibiotic therapy and possible valve replacement surgery. Despite advances in treatment, the 1-year mortality remains at 20-40%. Studies indicate that patients experience persisting physical symptoms, diminished quality of life and difficulties returning to work up to a year postdischarge. No studies investigating the effects of rehabilitation have been published. We present the rationale and design of the CopenHeart(IE) trial, which investigates the effect of comprehensive cardiac rehabilitation versus usual care for patients treated for IE.

METHODS AND ANALYSIS

We will conduct a randomised clinical trial to investigate the effects of comprehensive cardiac rehabilitation versus usual care on the physical and psychosocial functioning of patients treated for IE. The trial is a multicentre, parallel design trial with 1 : 1 individual randomisation to either the intervention or control group. The intervention consists of five psychoeducational consultations provided by specialised nurses and a 12-week exercise training programme. The primary outcome is mental health (MH) measured by the standardised Short Form 36 (SF-36). The secondary outcome is peak oxygen uptake measured by the bicycle ergospirometry test. Furthermore, a number of exploratory analyses will be performed. Based on sample size calculation, 150 patients treated for left-sided (native or prosthetic valve) or cardiac device endocarditis will be included in the trial. A qualitative and a survey-based complementary study will be undertaken, to investigate postdischarge experiences of the patients. A qualitative postintervention study will explore rehabilitation participation experiences.

ETHICS AND DISSEMINATION

The study complies with the Declaration of Helsinki and was approved by the regional research ethics committee (no H-1-2011-129) and the Danish Data Protection Agency (no 2007-58-0015). Study findings will be disseminated widely through peer-reviewed publications and conference presentations.

REGISTRATION

Clinicaltrials.gov identifier: NCT01512615.

Getting to the heart of rectal bleeding: subacute bacterial endocarditis presenting as anaemia and a GI bleed

In this case report, the authors demonstrate a case of subacute bacterial endocarditis presenting with anaemia. It is the first of its kind to describe a delay in diagnosis due to an initial patient investigation for a bleed rather than a cardiac evaluation. Astute clinicians need to be aware of the causes of anaemia in patients with endocarditis and consider that in Streptococcus bovis (S bovis) infection can be related to gastrointestinal polyps or malignancy resulting in bleeding. Although patients with S bovis endocarditis should undergo full gastrointestinal investigation after endocarditis is diagnosed, it should not delay medical treatment. In this article, the authors discuss the consequences of failing to achieve timely recognition of endocarditis along with common systemic complications. The authors also outline current recommendations for surgical intervention as heart valve replacement surgery was warranted in the patient to prevent fatal outcome.

Detection of microbial diversity in endocarditis using cultivation-independent molecular techniques

BACKGROUND

The aim of this study was to investigate whether the diagnosis of infective endocarditis (IE) could be improved using molecular tools in addition to standard microscopy and cultivation methods.

METHODS

Cultivation was performed on blood or tissue samples as recommended in the modified Duke criteria. The molecular tools included a broad-range polymerase chain reaction (PCR)-based denaturant gradient gel electrophoresis and a more detailed identification by constructing clone libraries followed by sequencing.

RESULTS

Of 14 patients, 12 were positive by blood or tissue cultivation and all were monomicrobial. Molecular methods showed the presence of DNA from multiple bacterial species in 6 of the samples and indicated a larger variety of bacteria in the different samples than identified by cultivation. For 8 of the patients there was a good correlation between the results of cultivation and molecular methods, and for these samples the identified bacteria are known to be frequently involved with IE. Many of the additional bacteria only identified by the molecular methods are not reported as common causes of IE.

CONCLUSIONS

Application of molecular tools in addition to cultivation indicated that polymicrobial infections might be of importance in IE. However, the significance of the more unknown microorganisms needs to be investigated further.

Multiple-valve infective endocarditis: clinical, microbiologic, echocardiographic, and prognostic profile

Whether infection in more than 1 valve worsens the prognosis for endocarditis remains untested. We conducted the current study to determine the profile of multiple-valve endocarditis, compare multiple-valve endocarditis with single-valve endocarditis, and determine predictors of outcome. We conducted a prospective and observational study including 680 episodes of infective endocarditis consecutively diagnosed at 3 tertiary centers. Multiple valve involvement was present in 115 episodes (17%), and single valve involvement in 530 (78%). In the remaining 35 cases, valvular involvement could not be documented. Mean age of patients with multiple valve endocarditis was 58 years. Clinical complications were frequent (heart failure 65%, renal failure 44%, systemic embolisms 24%). The microorganism most frequently isolated was Staphylococcus aureus (22%).Factors predictive of in-hospital mortality in the univariate analysis were septic shock, prosthetic endocarditis, heart failure, and persistent infection. In the multivariate analysis, we detected heart failure (odds ratios [OR], 4.7; 95% confidence interval [CI], 1.6-13.8) and persistent infection (OR, 4.3; 95% CI, 1.7-10.8) as predictors of in-hospital mortality. Compared to single-valve endocarditis, multiple-valve disease was associated more frequently with heart failure (65% vs. 50%, p = 0.03), perivalvular complications (41% vs. 21%, p < 0.001), and heart surgery (70% vs. 54%, p = 0.002). Despite these differences, in-hospital mortality was similar (28% vs. 30%, p = 0.647). In conclusion, multiple-valve endocarditis has a poor clinical course. Mortality is similar to that of single-valve endocarditis, probably in relation with aggressive therapy including surgery in many patients. Heart failure and persistent infection are independent predictors of death.

Bactericidal activity of oxacillin and glycopeptides against Staphylococcus aureus in patients with endocarditis: looking for a relationship between tolerance and outcome

Background

There is no clear relationship between in vitro bactericidal activity tests and clinical outcome. We studied bactericidal activity of oxacillin, vancomycin and teicoplanin against Staphylococcus aureus isolates in patients with endocarditis and then we sought to determine if there was a relationship between in vitro bactericidal activity and clinical outcome.

Methods

Minimal bacteriostatic and minimal bactericidal concentrations were determined for Staphylococcus aureus strains isolated from patients with endocarditis following standardized methods. Medical records were reviewed retrospectively to collect data on antimicrobial susceptibility at admission, antimicrobial therapy, need for surgery, embolic events and outcome.

Results and Discussion

Sixty-two Staphylococcus aureus strains were studied in 62 patients with endocarditis. Overall, 91.9% definite, 21% methicillin resistant and 72.6% cured. Surgery was performed in 32.3% and embolic events were documented in 64.5%. Tolerance to oxacillin and teicoplanin was more common than vancomycin tolerance among methicillin susceptible Staphylococcus aureus. Among methicillin resistant Staphylococcus aureus teicoplanin was shown to have a higher rate of tolerance than vancomycin. No statistically significant differences on clinical outcome between oxacillin tolerant and oxacillin non tolerant Staphylococcus aureus infections were observed. Tolerance to oxacillin did not adversely affect clinical outcomes of patients with methicillin susceptible Staphylococcus aureus endocarditis treated with a combination of antimicrobials including oxacillin. The cure rate was significantly lower among patients with methicillin resistant Staphylococcus aureus endocarditis.

Conclusions

In vitro bactericidal test results were not valid predictors of clinical outcome. Physicians need to use additional parameters when treating patients with staphylococcal endocarditis.

The collagen-binding protein Cnm is required for Streptococcus mutans adherence to and intracellular invasion of human coronary artery endothelial cells

Streptococcus mutans is considered the primary etiologic agent of dental caries, a global health problem that affects 60 to 90% of the population, and a leading causative agent of infective endocarditis. It can be divided into four different serotypes (c, e, f, and k), with serotype c strains being the most common in the oral cavity. In this study, we demonstrate that in addition to OMZ175 and B14, three other strains (NCTC11060, LM7, and OM50E) of the less prevalent serotypes e and f are able to invade primary human coronary artery endothelial cells (HCAEC). Invasive strains were also significantly more virulent than noninvasive strains in the Galleria mellonella (greater wax worm) model of systemic disease. Interestingly, the invasive strains carried an additional gene, cnm, which was previously shown to bind to collagen and laminin in vitro. Inactivation of cnm rendered the organisms unable to invade HCAEC and attenuated their virulence in G. mellonella. Notably, the cnm knockout strains did not adhere to HCAEC as efficiently as the parental strains did, indicating that the loss of the invasion phenotype observed for the mutants was linked to an adhesion defect. Comparisons of the invasive strains and their respective cnm mutants did not support a correlation between biofilm formation and invasion. Thus, Cnm is required for S. mutans invasion of endothelial cells and possibly represents an important virulence factor of S. mutans that may contribute to cardiovascular infections and pathologies.

Enterococcus hirae-associated endocarditis outbreaks in broiler flocks: clinical and pathological characteristics and molecular epidemiology

BACKGROUND

Enterococcus hirae-associated endocarditis, characterized by a peak in mortality during the second week of the grow-out, and occasionally lameness, was diagnosed at Dutch broiler farms.

OBJECTIVES

Field cases were studied to increase knowledge on clinical and pathological characteristics, pathogenesis and epidemiology of these infections.

ANIMALS AND METHODS

In total, 1266 birds of 25 flocks from 12 farms were examined. Post-mortem examinations, bacteriology, histopathology, PCR and DNA fingerprinting was carried out. Six flocks were followed longitudinally (n = 1017 birds).

RESULTS

Average mortality was 4.1% for the entire grow-out, of which 36% was attributed to endocarditis. Fibrinous thromboendocarditis of the right atrioventricular (AV) valve was found in 24% of hearts, compared to 7% and 4% with lesions of left and both AV valves, respectively. Thrombotic lesions were found in 24% (n = 432) of lungs, but only in larger branches of the Arteria pulmonalis. Occasionally, thrombi were found in the Arteria ischiadica externa and in liver and brain vessels. Enterococcus was cultured from 54% (n = 176) of heart and in 75% (n = 28), 62% (n = 106) and 31% (n = 16) of liver, bone marrow and lung samples, respectively. Further identification, using the Rapid ID Strep 32 API system and a PCR targeting mur-2 and mur-2(ed) genes was carried out on a subset of Enterococcus positive isolates (n = 65): both techniques identified the isolates as Enterococcus hirae. Pulsed-field gel electrophoresis did not indicate evidence of clonality between farms and flocks.

CONCLUSIONS

The relevance of these findings for pathogenesis and epidemiology of E. hirae infections is discussed. CLINICAL IMPORTANCE. This study may facilitate diagnosis of field cases and may contribute to the design of further research and development of control measures.

Increasing incidence and mortality of infective endocarditis: a population-based study through a record-linkage system

Background

Few population-based studies provide epidemiological data on infective endocarditis (IE). Aim of the study is to analyze incidence and outcomes of IE in the Veneto Region (North-Eastern Italy).

Methods

Residents with a first hospitalization for IE in 2000-2008 were extracted from discharge data and linked to mortality records to estimate 365-days survival. Etiology was retrieved in subsets of this cohort by discharge codes and by linkage to a microbiological database. Risk factors for mortality were assessed through logistic regression.

Results

1,863 subjects were hospitalized for IE, with a corresponding crude rate of 4.4 per 100,000 person-years, increasing from 4.1 in 2000-2002 to 4.9 in 2006-2008 (p = 0.003). Median age was 68 years; 39% of subjects were hospitalized in the three preceding months. 23% of patients underwent a cardiac valve procedure in the index admission or in the following year. Inhospital mortality was 14% (19% including hospital transfers); 90-days and 365-days mortality rose through the study years. Mortality increased with age and the Charlson comorbidity index, in subjects with previous hospitalizations for heart failure, and (in the subcohort with microbiological data) in IE due to Staphylococci (40% of IE).

Conclusions

The study demonstrates an increasing incidence and mortality for IE over the last decade. Analyses of electronic archives provide a region-wide picture of IE, overcoming referral biases affecting single clinic or multicentric studies, and therefore represent a first fundamental step to detect critical issues related to IE.

Prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) is associated with a high mortality during the early and midterm follow-up despite diagnostic and therapeutic improvements; its incidence is increasing and reaches 20-30% of all infective endocarditis episodes. In this review, changes in epidemiology, microbiology, diagnosis and therapy that have evolved in the past few years are analyzed. Staphylococci (both Staphylococcus aureus and coagulase-negative Staphylococcus) have emerged as the most common cause of PVE and are associated with a severe prognosis. Moreover, diagnosis may often be difficult because of its complications and extracardiac manifestations; thus, a comprehensive assessment of the clinical, echocardiographic and laboratory data must be performed. Early PVE, comorbidity, severe heart failure and new prosthetic dehiscence are predictors of mortality. Therapy is not indicated by evidence-based recommendations but mostly on identification of the high-risk conditions. A PVE is a common indication for surgery, whereas medical treatment alone may be achieved in a few instances. Systematic prophylaxis should be used to prevent this severe complication of cardiac valve replacement.

Evidence for subpopulations of Listeria monocytogenes with enhanced invasion of cardiac cells

Cardiac infections caused by the foodborne bacterium Listeria monocytogenes represent a significant but poorly studied facet of disease. It is not known whether L. monocytogenes cardiac infections stem solely from host susceptibility, or whether bacterial isolates exist that exhibit a tropism for cardiac tissue. Here we examine the cardio-invasive capacity of a recent L. monocytogenes cardiac case strain (07PF0776) as well as nine additional outbreak and clinical isolates. Mice infected with the cardiac isolate 07PF0776 had 10-fold more bacteria recovered from heart tissue than those infected with L. monocytogenes strain 10403S, a well-characterized clinical isolate originally obtained from a human skin lesion. Additional L. monocytogenes isolates exhibited varied capacities to colonize the hearts of mice; however, those with the highest efficiency of mouse cardiac invasion also demonstrated the highest levels of bacterial invasion in cultured myoblast cells. Our findings strongly suggest that subpopulations of L. monocytogenes strains have acquired an enhanced ability to target and invade the myocardium.

Surgical treatment of active infective endocarditis: A single center experience

OBJECTIVE

This study was undertaken to examine the outcomes of surgery for active infective endocarditis.

METHODS

Fifty consecutive patients underwent surgery for active infective endocarditis in a tertiary care center between January 2000 and June 2003. Modified Duke Criteria was used to include the patients in the study.

RESULTS

Mean age of the patients was 55.72 years (range 18-89 years). Underlying heart disease was the most common cause of acute infection, accounting for 30 % of all the cases. 16 % patients had a recent dental procedure and 10 % had a recent surgical procedure. The most common infective organism was staphylococcus aureus (24%), followed by streptococcus viridians (20%). The most common indications for surgery were congestive heart failure (CHF) (52%), embolic phenomenon (18%) and septic shock (10%). Most common postoperative complication was respiratory failure (30%) followed by renal failure (24%) pacemaker implantation 22%; stroke 18%, bleeding 16% and GI bleeding 2 %. Seven out of 50 patients died during hospital course that accounts for 14% of the motility rate.

CONCLUSIONS

Surgery for endocarditis continues to be challenging and associated with high operative mortality and morbidity. Age, shock, prosthetic valve endocarditis, impaired ventricular function, and recurrent infections adversely affect long-term survival.

Staphylococcus aureus host cell invasion and virulence in sepsis is facilitated by the multiple repeats within FnBPA

Entry of Staphylococcus aureus into the bloodstream can lead to metastatic abscess formation and infective endocarditis. Crucial to the development of both these conditions is the interaction of S. aureus with endothelial cells. In vivo and in vitro studies have shown that the staphylococcal invasin FnBPA triggers bacterial invasion of endothelial cells via a process that involves fibronectin (Fn) bridging to alpha(5)beta(1) integrins. The Fn-binding region of FnBPA usually contains 11 non-identical repeats (FnBRs) with differing affinities for Fn, which facilitate the binding of multiple Fn molecules and may promote integrin clustering. We thus hypothesized that multiple repeats are necessary to trigger the invasion of endothelial cells by S. aureus. To test this we constructed variants of fnbA containing various combinations of FnBRs. In vitro assays revealed that endothelial cell invasion can be facilitated by a single high-affinity, but not low-affinity FnBR. Studies using a nisin-inducible system that controlled surface expression of FnBPA revealed that variants encoding fewer FnBRs required higher levels of surface expression to mediate invasion. High expression levels of FnBPA bearing a single low affinity FnBR bound Fn but did not invade, suggesting that FnBPA affinity for Fn is crucial for triggering internalization. In addition, multiple FnBRs increased the speed of internalization, as did higher expression levels of FnBPA, without altering the uptake mechanism. The relevance of these findings to pathogenesis was demonstrated using a murine sepsis model, which showed that multiple FnBRs were required for virulence. In conclusion, multiple FnBRs within FnBPA facilitate efficient Fn adhesion, trigger rapid bacterial uptake and are required for pathogenesis.

Cardiac complications of infective endocarditis

Cardiac complications caused by infective endocarditis (IE) are varied and frequently life-threatening. This article focuses on new data related to several complications, and summarizes the indications, timing, and type of valve surgery recommended in the management of IE. Several recent studies using propensity score techniques have resulted in disparate conclusions and underscore the need for randomized prospective studies to better address whether and when surgery should be performed in patients with IE. Mitral valve repair is an exciting new development in surgical methodology and probably will have increased application over the next two decades. Excellent reviews related to periannular abscesses, fistulae, acute coronary syndrome, and pericarditis have been published recently and are also summarized.