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

Pathogens and antimicrobial susceptibility profiles in critically ill patients with bloodstream infections: a descriptive study

BACKGROUND

Surveillance of antimicrobial resistance is vital to guiding empirical treatment of infections. Collating and reporting routine data on clinical isolate testing may offer more timely information about resistance patterns than traditional surveillance network methods.

METHODS

Using routine microbiology testing data collected from the Bacteremia Antibiotic Length Actually Needed for Clinical Effectiveness retrospective cohort study, we conducted a descriptive secondary analysis among critically ill patients in whom bloodstream infections had been diagnosed in 14 intensive care units (ICUs) in Canada. The participating sites were located within tertiary care teaching hospitals and represented 6 provinces and 10 cities. More than 80% of the study population was accrued from 2011-2013. We assessed the epidemiologic features of the infections and corresponding antimicrobial susceptibility profiles. Susceptibility testing was done according to Clinical Laboratory Standards Institute guidelines at accredited laboratories.

RESULTS

A total of 1416 pathogens were isolated from 1202 patients. The most common organisms were Escherichia coli (217 isolates [15.3%]), Staphylococcus aureus (175 [12.4%]), coagulase-negative staphylococci (117 [8.3%]), Klebsiella pneumoniae (86 [6.1%]) and Streptococcus pneumoniae (85 [6.0%]). The contribution of individual pathogens varied by site. For 13 ICUs, gram-negative susceptibility rates were high for carbapenems (95.4%), tobramycin (91.2%) and piperacillin-tazobactam (90.0%); however, the proportion of specimens susceptible to these agents ranged from 75.0%-100%, 66.7%-100% and 75.0%-100%, respectively, across sites. Fewer gram-negative bacteria were susceptible to fluoroquinolones (84.5% [range 64.1%-97.2%]). A total of 145 patients (12.1%) had infections caused by highly resistant microorganisms, with significant intersite variation (range 2.6%-24.0%, χ2 = 57.50, p < 0.001).

INTERPRETATION

We assessed the epidemiologic features of bloodstream infections in a geographically diverse cohort of critically ill Canadian patients using routine pathogen and susceptibility data extracted from readily available microbiology testing databases. Expanding data sharing across more ICUs, with serial measurement and prompt reporting, could provide much-needed guidance for empiric treatment for patients as well as system-wide prevention methods to limit antimicrobial resistance.

[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.

A Case of Infective Endocarditis caused by Abiotrophia defectiva in Korea

Abiotrophia defectiva, a nutritionally variant streptococci can cause bacteremia, brain abscess, septic arthritis and in rare cases, infective endocarditis, which accounts for 5-6% of all cases. A. defectiva is characteristically difficult to diagnose and the mortality, morbidity and complication rates are high. Here, we discuss a case of infective endocarditis caused by A. defectiva. A 62-year-old female had previously undergone prosthetic valve replacement 6 years prior to admission. She developed infective endocarditis after tooth extraction. Her endocarditis was successfully treated with antimicrobial therapy and mitral valve replacement surgery. This is the first case of infective endocarditis caused by A. defectiva reported in Korea. This case shows that A. defectiva could be considered as a causative organism of infective endocarditis in Korea.

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.

Promotion of adhesion and proliferation of endothelial progenitor cells on decellularized valves by covalent incorporation of RGD peptide and VEGF

Tissue engineered heart valve is a promising alternative to current heart valve surgery, for its capability of growth, repair, and remodeling. However, extensive development is needed to ensure tissue compatibility, durability and antithrombotic potential. This study aims to investigate the biological effects of multi-signal composite material of polyethyl glycol-cross-linked decellularized valve on adhesion and proliferation of endothelial progenitor cells. Group A to E was decellularized valve leaflets, composite material of polyethyl glycol-cross-linked decellularized valves leaflets, vascular endothelial growth factor-composite materials, Arg-Gly-Asp peptide-composite materials and multi-signal modified materials of polyethyl glycol-cross-linked decellularized valve leaflets, respectively. The endothelial progenitor cells were seeded for each group, cell adhesion and proliferation were detected and neo-endothelium antithrombotic function of the multi-signal composite materials was evaluated. At 2, 4, and 8 h after the seeding, the cell numbers and 3H-TdR incorporation in group D were the highest. At 2, 4, and 8 days after the seeding, the cell numbers and 3H-TdR incorporation were significantly higher in groups C, D, and E compared with groups A and B (P < 0.05) and cell numbers and the expression of t-PA and eons in the neo-endothelium were quite similar to those in the human umbilical vein endothelial cells at 2, 4, and 8 days after the seeding. The Arg-Gly-Asp- peptides (a sequential peptide composed of arginine (Arg), glycine (Gly) and aspartic acid (Asp)) and VEGF-conjugated onto the composite material of PEG-crosslinked decellularized valve leaflets synergistically promoted the adhesion and proliferation of endothelial progenitor cells on the composite material, which may help in tissue engineering of heart valves.

Bartonella Endocarditis and Pauci-Immune Glomerulonephritis: A Case Report and Review of the Literature

Among culture-negative endocarditis in the United States, Bartonella species are the most common cause, with Bartonella henselae and Bartonella quintana comprising the majority of cases. Kidney manifestations, particularly glomerulonephritis, are common sequelae of infectious endocarditis, with nearly half of all Bartonella patients demonstrating renal involvement. Although a pauci-immune pattern is a frequent finding in infectious endocarditis-associated glomerulonephritis, it is rarely reported in Bartonella endocarditis. Anti-neutrophil cytoplasmic antibody (ANCA) positivity can be seen with many pathogens causing endocarditis and has been previously reported with Bartonella species. In addition, ANCA-associated vasculitis can also present with renal and cardiac involvement, including noninfectious valvular vegetations and pauci-immune glomerulonephritis. Given the overlap in their clinical presentation, it is difficult to differentiate between Bartonella endocarditis and ANCA-associated vasculitis but imperative to do so to guide management decisions. We present a case of ANCA-positive Bartonella endocarditis with associated pauci-immune glomerulonephritis that was successfully treated with medical management alone.

Implantation of mitral, aortic, and tricuspid bioprostheses due to infective endocarditis with necessary reimplantation of the bioprosthetic aortic valve

The patient was admitted to the Department of Cardiac Surgery of the J. Struś City Hospital in Poznan due to infective endocarditis involving the aortic, mitral, and tricuspid valves. Implantation of three biological valve prostheses proceeded without complications. Starting on day 23, the patient's general condition deteriorated, with high fever. Despite postoperative antibiotic therapy, transesophageal echocardiography revealed the presence of vegetation on the bioprosthetic aortic valve. On the 46th day after the initial surgery, the patient required replacement of the aortic bioprosthesis, which exhibited the presence of numerous vegetations. The bioprosthetic mitral and tricuspid valves were not affected by the degenerative process. On the 12th day after the reimplantation of the bioprosthetic aortic valve, the patient was discharged from the hospital in good general condition.

Role of Echinocandins in Fungal Biofilm-Related Disease: Vascular Catheter-Related Infections, Immunomodulation, and Mucosal Surfaces

Biofilm-related infections have become an increasingly important clinical problem. Many of these infections occur in patients with multiple comorbidities or with impaired immunity. Echinocandins (caspofungin, micafungin, and anidulafungin) exert their fungicidal activity by inhibition of the synthesis of the (1→3)-β-d-glucan. They are active among in vitro and in vivo model systems against a number of Candida species and filamentous fungi in their planktonic and biofilm phenotype. Their superior activity against biofilms poses them in an advantageous position among the antifungal armamentarium. However, additional studies are warranted to expand our knowledge on the role of echinocandins against biofilm-related infections.

Prediction of Symptomatic Embolism in Filipinos With Infective Endocarditis Using the Embolic Risk French Calculator

BACKGROUND

Cardioembolic events are life-threatening complications of infective endocarditis (IE). The embolic risk French calculator estimates the embolic risk in IE computed on admission. Variables in this tool include age, diabetes, atrial fibrillation, prior embolism, vegetation length, and Staphylococcus aureus on culture. A computed risk of > 7% was considered high in the development of this tool. Knowledge of this risk applied in our local setting is important to guide clinicians in preventing such catastrophic complications. Among patients with IE, we aim to determine the efficacy of the embolic risk French calculator, using a computed score of > 7%, in predicting major embolic events.

METHODS

All adults admitted from 2013 to 2016 with definite IE were included. The risk for embolic events was computed on admission. All were monitored for the duration of admission for the occurrence of the primary outcome (any major embolic event: arterial emboli, intracranial hemorrhage, pulmonary infarcts, or aneurysms). Secondary outcomes were: 1) composite of death and embolic events; and 2) death from any cause.

RESULTS

Eighty-seven adults with definite IE were included. Majority had a valvular heart disease and preserved ejection fraction (EF). The mitral valve was most commonly involved. Embolic events occurred in 25 (29%). Multivariate analysis identified a high embolic score > 7% (relative risk (RR): 15.12, P < 0.001), vegetation area ≥ 18 mm2 (RR: 6.39, P < 0.01), and a prior embolism (RR: 5.18, P = 0.018) to be independent predictors of embolic events. For the composite of embolic events and death, independent predictors include a high score of > 7% (RR: 13.56, P < 0.001) and a prior embolus (RR: 13.75, P = 0.002). Independent predictors of death were a high score > 7% (RR: 6.20, P = 0.003) and EF ≤ 45% (RR: 9.91, P = 0.004).

CONCLUSION

Cardioembolic events are more prevalent in our study compared to previous data. The embolic risk French calculator is a useful tool to estimate and predict risk for embolic events and in-hospital mortality. The risk of developing embolic events should be weighed against the risks of early preventive cardiac surgery, as to institute timely and appropriate management.

Cefazolin versus Nafcillin for Methicillin-Sensitive Staphylococcus aureus Bloodstream Infection in a California Tertiary Medical Center

Recent observational studies have suggested possible reductions in mortality in patients receiving cefazolin versus antistaphylococcal penicillins. We examined 90-day mortality in patients receiving cefazolin compared to nafcillin for methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infection (BSI). We identified persons with MSSA BSI admitted to San Francisco General Hospital from January 2008 to July 2013 through a hospital-wide infection surveillance system and confirmed 90-day mortality using U.S. national vital registries. We included persons receiving cefazolin or nafcillin as the predominant intravenous antimicrobial agent; all participants received inpatient Infectious Diseases service consultation. We estimated the association between receipt of cefazolin and 90-day risk of death by multivariate logistic regression, including a propensity score for receiving cefazolin as the second predictor. Of 230 MSSA BSI cases, 30 received nafcillin and 70 received cefazolin as the predominant antimicrobial; 10 died within 90 days, 5 from each group. Unadjusted analysis showed substantial but not statistically significant reduced odds of death in those receiving cefazolin (odds ratio, 0.38; 95% confidence interval [CI], 0.10 to 1.44). Multivariate analysis with propensity scores found a similar adjusted odds ratio (0.40; 95% CI, 0.09 to 1.74; P = 0.22). We found a large reduction in 90-day mortality in those receiving cefazolin compared to nafcillin for MSSA BSI, but this finding was not statistically significant. The magnitude of effect seen in this and other studies justifies further study.

Obturator internus pyomyositis manifested as sciatica in a patient with subacute bacterial endocarditis: A rare case report

Pyomyositis is a pyogenic infection of the skeletal muscles causing myalgia and fever in patients. Hematogenous seeding engendered by persistent bacteremia and septic embolism is usually the underlying cause of the disease. Trauma, intravenous drug use, and immunodeficiency are the main predisposing factors.Obturator internus pyomyositis with sciatica has not previously been reported. We report a rare case of a patient with subacute bacterial endocarditis presenting with left buttock pain and sciatica.Computed tomography confirmed the diagnosis of obturator internus pyomyositis. The patient was discharged uneventfully after successful antibiotic treatment.The mortality rate of patients who have pyomyositis comorbid with another condition or disease is extremely high. Early diagnosis and aggressive management are imperative.

Tropheryma whipplei endocarditis in Spain: Case reports of 17 prospective cases

Tropheryma whipplei endocarditis is an uncommon condition with very few series and <90 cases reported in the literature. The aim of the study was to analyze the epidemiological, clinical, and outcome characteristics of 17 cases of T. whipplei endocarditis recruited in our country from a multicentric cohort from 25 Spanish hospitals from the Spanish Collaboration on Endocarditis-Grupo de Apoyo al Manejo de la Endocarditis infecciosa en España.From a total of 3165 cases included in the cohort, 14.2% were diagnosed of blood culture negative endocarditis (BCNE) and 3.5% of these had T. whipplei endocarditis. This condition was more frequent in men. The average age was 60.3 years. Previous cardiac condition was present in 35.3% of the cases. The main clinical manifestation was cardiac failure (76.5%) while fever was only present in the 35.3%. Ecocardiography showed vegetations in 64.7% of patients. Surgery was performed in all but 1 cases and it allowed the diagnosis when molecular assays were performed. A broad range rRNA 16S polymerase chain reaction was used for first instance in all laboratories and different specific targets for T. whipplei were employed for confirmation. A concomitant Whipple disease was diagnosed in 11.9% of patients. All patients received specific antimicrobial treatment for at least 1 year, with no relapse and complete recovery.T. whipplei endocarditis is an uncommon condition with an atypical presentation that must be considered in the diagnosis of BCNE. The prognosis is very good when an appropriate surgical management and antimicrobial-specific treatment is given.

Over 20 years experience with aortic homograft in aortic valve replacement during acute infective endocarditis

OBJECTIVES

Despite the controversy, the aortic homograft is supposedly the best option in acute infective endocarditis (AIE), due to its resistance to reinfection. However, the technical complexity and the risk of structural deterioration over time have limited its utilization. The aim of this study was to evaluate the long-term results of aortic homograft for the treatment of infective endocarditis in our institution with particular attention to predictors of survival and homograft reoperation.

METHODS

The cohort includes 112 patients who underwent aortic valve replacement with an aortic homograft for AIE between January 1990 and December 2014.

RESULTS

Fifteen patients (13.4%) died during the first 30 days after the operation. Two patients were lost to follow-up after discharge from the hospital; therefore, 95 patients were available for long-term analysis. The median duration of follow-up was 7.8 years (IQR 4.7-17.6). Five patients (5.3%) suffered a recurrence of infective endocarditis (1 relapse and 4 new episodes). Sixteen patients (16.8%) were reoperated for structural valve degeneration (SVD; n = 14, 87.5%) or for infection recurrence (n = 2, 12.5%). Freedom from homograft reoperation for infective endocarditis or structural homograft degeneration at 10 and 15 years postoperatively was 86.3 ± 5.5 and 47.3 ± 11.0%, respectively. For patients requiring homograft reoperation, the median interval to reintervention was 11.6 years (IQR 8.3-14.5). Long-term survival was 63.6% (95% CI 52.4-72.8%) and 53.8% (95% CI 40.6-65.3%) at 10 and 15 years, respectively.

CONCLUSIONS

The use of aortic homograft in acute aortic valve endocarditis is associated with a remarkably low risk of relapsing infection and very acceptable long-term survival. The risk of reoperation due to SVD is significant after one decade especially in young patients. The aortic homograft seems to be ideally suited for reconstruction of the aortic valve and cardiac structures damaged by the infective process especially in early surgery.

Rare case of simultaneous enterococcal endocarditis and prosthetic joint infection

A 59-year-old man was admitted with a 3-month history of daily fevers as well as bilateral knee pain and swelling. Medical history was significant for bilateral knee arthroplasties 4 years prior to admission. Two sets of peripheral blood cultures as well as bilateral knee synovial fluid grew Enterococcus faecalis within 10 hours. Transoesophageal echocardiography revealed aortic and mitral valve vegetations suggestive of infectious endocarditis, with severe regurgitation secondary to large size. The patient's hospitalisation was complicated by acute heart failure, necessitating emergent mitral valve repair and aortic valve replacement, followed shortly thereafter by bilateral total knee arthroplasty resection with placement of antibiotic spacers. He was treated with intravenous penicillin and gentamicin for 4 months and recovered fully. He underwent repeat bilateral knee arthroplasties and was placed on amoxicillin for 6 months postoperatively, with no further evidence of infection.

HACEK endocarditis: a review

INTRODUCTION

The HACEK group, referring to Haemophilus spp., Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae, is a rare cause of infective endocarditis (IE). It causes the majority of Gram-negative endocarditis cases and has an excellent prognosis and simple management if properly identified. However, delay in diagnosis and associated complications can render the infection fatal.

AREAS COVERED

Over the past few decades, there have been tremendous advancements in understanding the manifestations and progression of HACEK endocarditis (HE). This review tackles the epidemiology of HE, the microbiological characteristics of each organism in the HACEK group, the methods used to diagnose HE, the clinical manifestations, complications, and mortality of patients with HE, as well as the recommended treatment and preventive methods. Expert Commentary: The lack of robust randomized controlled trials in diagnosis and treatment of HE makes it difficult to determine the optimal management of such infections. Nevertheless, advancements in culturing methods have shown progress in isolating and identifying these fastidious organisms. Positive blood cultures for any of the HACEK organisms in the setting of no definite focus of infection is highly suggestive of HE. In such cases, treatment with ceftriaxone or a fluoroquinolone, even without obtaining antibiotic susceptibilities, should be initiated. Moreover, the decision to proceed with surgical intervention should be individualized. As is the case for other IE, HE requires the collaboration of a multidisciplinary team consisting of the infectious disease specialist, cardiologist, cardiothoracic surgeon, and the microbiologist.

The Effect of Inadequate Initial Empiric Antimicrobial Treatment on Mortality in Critically Ill Patients with Bloodstream Infections: A Multi-Centre Retrospective Cohort Study

Hospital mortality rates are elevated in critically ill patients with bloodstream infections. Given that mortality may be even higher if appropriate treatment is delayed, we sought to determine the effect of inadequate initial empiric treatment on mortality in these patients. A retrospective cohort study was conducted across 13 intensive care units in Canada. We defined inadequate initial empiric treatment as not receiving at least one dose of an antimicrobial to which the causative pathogen(s) was susceptible within one day of initial blood culture. We evaluated the association between inadequate initial treatment and hospital mortality using a random effects multivariable logistic regression model. Among 1,190 patients (1,097 had bacteremia and 93 had candidemia), 476 (40%) died and 266 (22%) received inadequate initial treatment. Candidemic patients more often had inadequate initial empiric therapy (64.5% versus 18.8%), as well as longer delays to final culture results (4 vs 3 days) and appropriate therapy (2 vs 0 days). After adjustment, there was no detectable association between inadequate initial treatment and mortality among bacteremic patients (Odds Ratio (OR): 1.02, 95% Confidence Interval (CI) 0.70-1.48); however, candidemic patients receiving inadequate treatment had nearly three times the odds of death (OR: 2.89, 95% CI: 1.05-7.99). Inadequate initial empiric antimicrobial treatment was not associated with increased mortality in bacteremic patients, but was an important risk factor in the subgroup of candidemic patients. Further research is warranted to improve early diagnostic and risk prediction methods in candidemic patients.

Ampicillin in Combination with Ceftaroline, Cefepime, or Ceftriaxone Demonstrates Equivalent Activities in a High-Inoculum Enterococcus faecalis Infection Model

Ampicillin-ceftriaxone combination therapy has become a predominant treatment for serious Enterococcus faecalis infections, such as endocarditis. Unfortunately, ceftriaxone use is associated with future vancomycin-resistant enterococcus colonization. We evaluated E. faecalis in an in vitro pharmacodynamic model against simulated human concentration-time profiles of ampicillin plus ceftaroline, cefepime, ceftriaxone, or gentamicin. Ampicillin-cefepime and ampicillin-ceftaroline demonstrated activities similar to those of ampicillin-ceftriaxone against E. faecalis.

Marvelous but Morbid: Infective endocarditis due to Serratia marcescens

A 46-year-old man with HIV infection and active intravenous drug use presented with approximately two weeks of fevers and body aches. On physical examination he was somnolent, had a new systolic murmur, bilateral conjunctival hemorrhages, diffuse petechiae, and left-sided arm weakness. Echocardiography revealed a large mitral valve vegetation and brain imaging demonstrated numerous embolic infarctions. Blood cultures grew Serratia marcescens. Despite aggressive treatment with meropenem the patient died due to intracranial hemorrhage complicated by herniation. Serratia marcescens is an uncommon cause of infective endocarditis. While this disease has historically been associated with intravenous drug use, more recent reports suggest that it is now largely a consequence of opportunistic infections of the chronically ill. Our case highlights several characteristic features of this infection, including isolation of a non-pigmented strain of the organism, an antibiotic susceptibility profile suggestive of AmpC β-lactamase production, and rapid clinical deterioration with multiple embolic complications resulting in death. In this review we discuss the history, epidemiology, and management of endovascular infections due to Serratia spp., emphasizing the continued importance of considering this organism in the differential diagnosis of endocarditis among intravenous drug users and as a potential indication for surgical therapy.

Involvement of NADH Oxidase in Competition and Endocarditis Virulence in Streptococcus sanguinis

Here, we report for the first time that the Streptococcus sanguinis nox gene encoding NADH oxidase is involved in both competition with Streptococcus mutans and virulence for infective endocarditis. An S. sanguinis nox mutant was found to fail to inhibit the growth of Streptococcus mutans under microaerobic conditions. In the presence of oxygen, the recombinant Nox protein of S. sanguinis could reduce oxygen to water and oxidize NADH to NAD(+) The oxidation of NADH to NAD(+) was diminished in the nox mutant. The nox mutant exhibited decreased levels of extracellular H2O2; however, the intracellular level of H2O2 in the mutant was increased. Furthermore, the virulence of the nox mutant was attenuated in a rabbit endocarditis model. The nox mutant also was shown to be more sensitive to blood killing, oxidative and acid stresses, and reduced growth in serum. Thus, NADH oxidase contributes to multiple phenotypes related to competitiveness in the oral cavity and systemic virulence.

A comparison of different antibiotic regimens for the treatment of infective endocarditis

BACKGROUND

Infective endocarditis is a microbial infection of the endocardial surface of the heart. Antibiotics are the cornerstone of treatment, but their use is not standardised, due to the differences in presentation, populations affected and the wide variety of micro-organisms that can be responsible.

OBJECTIVES

To assess the existing evidence about the clinical benefits and harms of different antibiotics regimens used to treat people with infective endocarditis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE Classic and EMBASE, LILACS, CINAHL and the Conference Proceedings Citation Index on 30 April 2015. We also searched three trials registers and handsearched the reference lists of included papers. We applied no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of antibiotic regimens for treating possible infective endocarditis diagnosed according to modified Duke's criteria. We considered all-cause mortality, cure rates and adverse events as the primary outcomes. We excluded people with possible infective endocarditis and pregnant women.

DATA COLLECTION AND ANALYSIS

Three review authors independently performed study selection, 'Risk of bias' assessment and data extraction in duplicate. We constructed 'Summary of findings' tables and used GRADE methodology to assess the quality of studies. We described the included studies narratively.

MAIN RESULTS

Four small randomised controlled trials involving 728 allocated/224 analysed participants met our inclusion criteria. These trials had a high risk of bias. Drug companies sponsored two of the trials. We were unable to pool the data due to the heterogeneity in outcome definitions and the different antibiotics used.The included trials compared the following antibiotic schedules. The first trial compared quinolone (levofloxacin) plus standard treatment (anti-staphylococcal penicillin (cloxacillin or dicloxacillin), aminoglycoside (tobramycin or netilmicin) and rifampicin) versus standard treatment alone reporting uncertain effects on all-cause mortality (8/31 (26%) with levofloxacin plus standard treatment versus 9/39 (23%) with standard treatment alone; RR 1.12, 95% CI 0.49 to 2.56, very low quality evidence). The second trial compared daptomycin versus low-dose gentamicin plus an anti-staphylococcal penicillin (nafcillin, oxacillin or flucloxacillin) or vancomycin. This showed uncertain effects in terms of cure rates (9/28 (32.1%) with daptomycin versus 9/25 (36%) with low-dose gentamicin plus anti-staphylococcal penicillin or vancomycin, RR 0.89 95% CI 0.42 to 1.89; very low quality evidence). The third trial compared cloxacillin plus gentamicin with a glycopeptide (vancomycin or teicoplanin) plus gentamicin. In participants receiving gentamycin plus glycopeptide only 13/23 (56%) were cured versus 11/11 (100%) receiving cloxacillin plus gentamicin (RR 0.59, 95% CI 0.40 to 0.85; very low quality evidence). The fourth trial compared ceftriaxone plus gentamicin versus ceftriaxone alone and found no conclusive differences in terms of cure (15/34 (44%) with ceftriaxone plus gentamicin versus 21/33 (64%) with ceftriaxone alone, RR 0.69, 95% CI 0.44 to 1.10; very low quality evidence).The trials reported adverse events, need for cardiac surgical interventions, uncontrolled infection and relapse of endocarditis and found no conclusive differences between comparison groups (very low quality evidence). No trials assessed septic emboli or quality of life.

AUTHORS' CONCLUSIONS

Limited and very low quality evidence suggested that there were no conclusive differences between antibiotic regimens in terms of cure rates or other relevant clinical outcomes. However, because of the very low quality evidence, this needs confirmation. The conclusion of this Cochrane review was based on randomised controlled trials with high risk of bias. Accordingly, current evidence does not support or reject any regimen of antibiotic therapy for treatment of infective endocarditis.

A cost-effectiveness analysis of two different antimicrobial stewardship programs

There is a lack of formal economic analysis to assess the efficiency of antimicrobial stewardship programs. Herein, we conducted a cost-effectiveness study to assess two different strategies of Antimicrobial Stewardship Programs. A 30-day Markov model was developed to analyze how cost-effective was a Bundled Antimicrobial Stewardship implemented in a university hospital in Brazil. Clinical data derived from a historical cohort that compared two different strategies of antimicrobial stewardship programs and had 30-day mortality as main outcome. Selected costs included: workload, cost of defined daily doses, length of stay, laboratory and imaging resources used to diagnose infections. Data were analyzed by deterministic and probabilistic sensitivity analysis to assess model's robustness, tornado diagram and Cost-Effectiveness Acceptability Curve. Bundled Strategy was more expensive (Cost difference US$ 2119.70), however, it was more efficient (US$ 27,549.15 vs 29,011.46). Deterministic and probabilistic sensitivity analysis suggested that critical variables did not alter final Incremental Cost-Effectiveness Ratio. Bundled Strategy had higher probabilities of being cost-effective, which was endorsed by cost-effectiveness acceptability curve. As health systems claim for efficient technologies, this study conclude that Bundled Antimicrobial Stewardship Program was more cost-effective, which means that stewardship strategies with such characteristics would be of special interest in a societal and clinical perspective.

Integrating Antimicrobial Therapy with Host Immunity to Fight Drug-Resistant Infections: Classical vs. Adaptive Treatment

Antimicrobial resistance of infectious agents is a growing problem worldwide. To prevent the continuing selection and spread of drug resistance, rational design of antibiotic treatment is needed, and the question of aggressive vs. moderate therapies is currently heatedly debated. Host immunity is an important, but often-overlooked factor in the clearance of drug-resistant infections. In this work, we compare aggressive and moderate antibiotic treatment, accounting for host immunity effects. We use mathematical modelling of within-host infection dynamics to study the interplay between pathogen-dependent host immune responses and antibiotic treatment. We compare classical (fixed dose and duration) and adaptive (coupled to pathogen load) treatment regimes, exploring systematically infection outcomes such as time to clearance, immunopathology, host immunization, and selection of resistant bacteria. Our analysis and simulations uncover effective treatment strategies that promote synergy between the host immune system and the antimicrobial drug in clearing infection. Both in classical and adaptive treatment, we quantify how treatment timing and the strength of the immune response determine the success of moderate therapies. We explain key parameters and dimensions, where an adaptive regime differs from classical treatment, bringing new insight into the ongoing debate of resistance management. Emphasizing the sensitivity of treatment outcomes to the balance between external antibiotic intervention and endogenous natural defenses, our study calls for more empirical attention to host immunity processes.

Prosthetic valve endocarditis 7 months after transcatheter aortic valve implantation diagnosed with 3D TEE

Transcatheter aortic valve implantation (TAVI) was introduced as an alternative treatment for patients with severe symptomatic aortic stenosis for whom surgery would be high-risk. Prosthetic aortic valve endocarditis is a serious complication of surgical AVR (SAVR) with high morbidity and mortality. According to recent cases, post-TAVI prosthetic valve endocarditis (PVE) seems to occur very rarely. We present the case of a 75-year-old woman who underwent TAVI (Edwards Saphien XT) with an uneventful postoperative stay. She was diagnosed with endocarditis using three dimensional (3D) echocardiography on the TAVI device 7 months later and she subsequently underwent surgical aortic valve replacement. Little experience of the interpretation of transoesophageal echocardiography (TEE) and the clinical course and effectiveness of treatment strategies in post-TAVI endocarditis exists. We report a case of PVE in a TAVI patient which was diagnosed with three-dimensional transoesophageal echocardiography (3DTEE).

Sinus of Valsalva Pseudoaneurysm as a Sequela to Infective Endocarditis

Pseudoaneurysm is an uncommon sequela of infective endocarditis. We treated a 44-year-old man who had an active case of group B streptococcal infective endocarditis of the aortic valve despite no evidence of valvular dysfunction or vegetation on his initial transesophageal echocardiogram. After completing 6 weeks of intravenous antibiotic therapy, the patient developed a sinus of Valsalva pseudoaneurysm and severe aortic regurgitation caused by partial detachment of the left coronary cusp. We used a pericardial patch to close the pseudoaneurysm and repair the coronary cusp. This case shows the importance of routine clinical follow-up evaluation in infective endocarditis, even after completion of antibiotic therapy. Late sequelae associated with infective endocarditis or its therapy include recurrent infection, heart failure caused by valvular dysfunction (albeit delayed), and antibiotic toxicity such as aminoglycoside-induced nephropathy and vestibular toxicity.

Population pharmacokinetic analysis and dosing regimen optimization of penicillin G in patients with infective endocarditis

BACKGROUND

This study was designed to evaluate the population pharmacokinetics (popPK) of penicillin G in patients with infective endocarditis and establish a dosage regimen based on pharmacokinetic data and clinical outcome.

METHOD

Forty-six serum penicillin G samples from 25 individuals were analyzed using a nonlinear mixed-effects model. popPK were estimated using a one-compartment model. We created a receiver operating characteristic (ROC) curve for penicillin G efficacy and the ratio of its minimum concentration (Cmin)/minimum inhibitory concentration (MIC). Simulations were used to optimize the penicillin G dosage regimen using this ratio.

RESULT

Estimated popPK were: CL (L/h) = 0.21 × creatinine clearance (CLcr) (mL/min), Vd (L) = 28.9. The areas under the ROC curves were 0.87 for clinical efficacy. The cut-off value of penicillin G Cmin/MIC was 60. The continuous administration of 1 million IU penicillin G/h was necessary to achieve a positive outcome for patients with normal renal function (CLcr ≥ 60 mL/min).

CONCLUSION

Our findings suggest that population-based parameters are useful for evaluating penicillin G pharmacokinetics and that an individualized dosage should be determined based on a described dosage regimen.

Infective endocarditis due to Abiotrophia defectiva and Granulicatella spp. complicated by infectious intracranial cerebral aneurysms: a report of three cases and review of the literature

Nutritionally variant streptococci, now classified as Abiotrophia defectivaor Granulicatella spp., are thought to account for 2 % of all infective endocarditis cases but estimates of their frequency are complicated by changes in nomenclature and difficulties in obtaining positive microbiology cultures. Their growth characteristics and difficulty undertaking antibiotic susceptibility testing may impede optimal antibiotic treatment decisions. We describe three patients with definite infective endocarditis due to these organisms seen at our hospital between 2005 and 2010, all of whom presented with neurological symptoms due to infectious intracranial cerebral aneurysms. We recommend that, for patients with left-sided infective endocarditis due to A. defictiva and Granulicatella spp., clinicians should consider imaging the central nervous system.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pilot Screening to Determine Antimicrobial Synergies in a Multidrug-Resistant Bacterial Strain Library

With the rise in multidrug-resistant (MDR) bacterial infections, there has been increasing interest in combinations of ≥2 antimicrobial agents with synergistic effects. We established an MDR bacterial strain library to screen for in vitro antimicrobial synergy by using a broth microdilution checkerboard method and high-throughput luciferase-based bacterial cell viability assay. In total, 39 MDR bacterial strains, including 23 carbapenem-resistant gram-negative bacteria, 9 vancomycin-intermediate Staphylococcus aureus, and 7 vancomycin-resistant Enterococcus faecalis, were used to screen for potential antimicrobial synergies. Synergies were more frequently identified with combinations of imipenem plus trimethoprim-sulfamethoxazole for carbapenem-resistant Acinetobacter baumannii in the library. To verify this finding, we tested 34 A. baumannii clinical isolates resistant to both imipenem and trimethoprim-sulfamethoxazole by the checkerboard method. The imipenem plus trimethoprim-sulfamethoxazole combination showed synergy in the treatment of 21 (62%) of the clinical isolates. The results indicate that pilot screening for antimicrobial synergy in the MDR bacterial strain library could be valuable in the selection of combination therapeutic regimens to treat MDR bacterial infections. Further studies are warranted to determine whether this screening system can be useful to screen for the combined effects of conventional antimicrobials and new-generation antimicrobials or nonantimicrobials.

Acute kidney injury induced by antimicrobial agents in the elderly: awareness and mitigation strategies

The use of antimicrobial agents has increased in recent years as treatments have diversified and resistant bacteria have appeared. With increased use of antimicrobial agents, elderly patients are prone to adverse drug reactions (ADRs) as a result of factors such as drug-drug interactions, polypharmacy, long-term use, and over- or under-dosage. In particular, elderly patients using antimicrobials are at increased risk to develop drug-induced acute kidney injury (AKI), which is the most common severe ADR in such patients. AKI is a serious problem that is associated with mortality amongst hospitalized patients. Antimicrobial-induced AKI can be classified into three different types: acute tubular necrosis (ATN), acute interstitial nephritis (AIN), and renal tubule lumen obstruction. AKI can generally be prevented by proper maintenance of fluid balance. To design dosage regimens that ensure efficient drug excretion via the kidney, it is necessary to accurately estimate renal function; however, the kidney undergoes age-dependent structural and functional alterations over time. Therefore, proper management of antimicrobial agents by an antimicrobial stewardship team may lead to decreased incidence of AKI. This article reviews antimicrobial-induced AKI and discusses potential strategies for increasing awareness of AKI and mitigating its clinical effects.

Staphylococcus lugdunensis Endocarditis in a 35-Year-Old Woman in Her 24th Week of Pregnancy

Background. Infective endocarditis is associated with considerable morbidity and mortality. Guidelines addressing prophylaxis and management of infective endocarditis do not extensively deal with concomitant pregnancy, and case reports on infective endocarditis are scarce. This is the first published report of infective endocarditis by Staphylococcus lugdunensis in a pregnant woman. Case Presentation. We report a single case of a 35-year-old woman in her 24th week of pregnancy who was admitted to our intensive care unit with fever and suspected infectious endocarditis. Blood culture detected Staphylococcus lugdunensis. A vegetation and severe mitral regurgitation due to complete destruction of the valve confirmed the diagnosis. An interdisciplinary panel of cardiologists, maternal-fetal medicine specialists, cardiac and plastic surgeons, infectiologists, anesthesiologists, and neonatologists was formed to determine the best therapeutic strategy. Conclusions. Timing and indications for surgical intervention to prevent embolic complications in infective endocarditis remain controversial. This original case report illustrates how managing infective endocarditis by Staphylococcus lugdunensis particularly in the 24th week of pregnancy can represent a therapeutic challenge to a broad section of specialties across medicine. Critical cases like this require a thorough weighing of risks and benefits followed by swift action to protect the mother and her unborn child.

Mycotic Aneurysm Treated with Aneurysm Trapping. Case Report

The authors describe a rare case of mycotic aneurysm (MA) associated with subarachnoid hemorrhage treated with aneurysm trapping. The literature on management and the surgical techniques are controversial due to lack of randomize trials.

Expanded Gram-Negative Antimicrobial Prophylaxis Reduces Surgical Site Infections in Hip Arthroplasty

BACKGROUND

A first-generation cephalosporin is the recommended antibiotic prophylaxis for implants. However, this standard does not address the increasing prevalence and virulence of gram-negative pathogens infecting patients. We found that gram-negative bacilli caused 30% of our surgical site infections (SSIs) following hip procedures, whereas only 10% of knee SSIs were caused by gram-negative bacilli. To address this, we instituted Expanded Gram-Negative Antimicrobial Prophylaxis (EGNAP) for our hip arthroplasty patients. The purpose of this study is to measure the effect of EGNAP on the SSI rates following primary total hip arthroplasty.

METHODS

The study consisted of 10,084 total patients. Before July 2012, all patients were administered 1 g of cefazolin. After July 2012, our protocol was adjusted by adding the EGNAP with either gentamicin or aztreonam to hip patients (group 1) and not to the knee arthroplasty patients (group 2).

RESULTS

Group 1 consisted of the 5389 primary hip arthroplasty patients. Of these patients, 4122 (before July 2012) did not receive weight-based high-dose gentamicin and 1267 (after July 2012) did. Before the introduction of EGNAP, group 1 SSI rate was 1.19% (49/4122). After July 2012 when EGNAP was added, the overall group 1 SSI rate decreased to 0.55% (7/1267) (P = .05). During the study period, there was not a significant difference in SSI rate of knee arthroplasty (group 2): 1.08% vs 1.02% (P = .999).

CONCLUSIONS

The addition of EGNAP for hip arthroplasty is a safe and effective method to decrease SSIs.

LEVEL OF EVIDENCE

III. Case-control study.

Granulicatella elegans endocarditis: a diagnostic and therapeutic challenge

A 63-year-old man with a history of non-ischaemic cardiomyopathy presented with acute worsening of heart failure and septic shock. Echocardiogram revealed a large aortic valve vegetation with new onset severe aortic incompetence. Blood cultures grew Granulicatella elegans, for which antimicrobial sensitivities could not be carried out in our lab. Despite antibiotic therapy and aggressive care, the patient's clinical condition worsened and he died. G. elegans, previously grouped under nutrient variant streptococci (NVS), is an extremely rare cause for bacterial infective endocarditis (IE). Unlike with the Viridans group, IE caused by NVS has a very poor outcome and higher mortality rate. The difficulty in isolation of the bacteria in culture, inability to reliably measure antibiotic susceptibility in vitro, frequent treatment failure and complications such as multivalvular involvement, make this an extremely challenging infection to treat. Early detection of the organism, appropriate antibiotics and early surgical management when indicated, are key to management.

Steak tartare endocarditis

This report describes a case of Campylobacter fetus prosthetic valve infective endocarditis and discusses the subsequent management. Although C. fetus has a tropism for vascular endothelium, infective endocarditis has rarely been reported. In this patient, despite initial optimal antimicrobial therapy, valve replacement was ultimately required due to ongoing infectious emboli to the brain in the setting of evidence of vegetation enlargement on echocardiogram. The prosthetic valve was replaced, the patient completed a 6-week course of parenteral antibiotics after surgical intervention and he made a full recovery with no long-term neurological sequelae. This case highlights the fact that despite the relatively low prevalence of C. fetus endocarditis, it is associated with a high degree of mortality and valve replacement is often indicated.

A successful percutaneous mechanical vegetation debulking used as a bridge to surgery in acute tricuspid valve endocarditis

Timing of surgical management of acute infective endocarditis is a major challenge, with respect to surgical complications, risks of recurrences and optimal valve repair or replacement. We present a case of a 24-year-old male with a history of intravenous drug abuse, who was referred to our center after 10 days of medical management of acute infective endocarditis. Upon arrival he was in septic shock, multi-organ failure, and mobile vegetations on the tricuspid valve with severe tricuspid regurgitation. He also had bilateral pulmonary infarcts and an ischemic stroke in the right parietal lobe. A successful percutaneous transcatheter mechanical vegetation debulking was performed followed by surgical valve replacement seven days later. This case introduces a new option in the management of right-sided endocarditis in critically ill patient, and demonstrates the technical feasibility of a debulking procedure in this setting, which led subsequently to a significant improvement in patient's condition, and he was ultimately able to undergo definitive surgery.

Can radiological characteristics of preoperative cerebral lesions predict postoperative intracranial haemorrhage in endocarditis patients?

OBJECTIVES

Infective endocarditis (IE) is associated with high mortality (20-40%) and neurological complications (20-50%). Postoperative intracranial haemorrhage (ICH) is a feared complication especially in patients with preoperative cerebral infarcts. The aim of this study was to determine the radiological characteristics of cerebral lesions that could predict the occurrence of postoperative ICH in IE patients.

METHODS

We retrospectively reviewed all charts, brain imaging and follow-up data from patients operated for left-sided endocarditis between January 2007 and April 2013.

RESULTS

A total of 308 patients (age 62.0 ± 13.9) underwent surgery for IE. Preoperative cerebrovascular complications were present in 122 patients (39.6%), representing stroke in 87, silent cerebral infarctions in 31 patients and transient ischaemic attacks in 4 patients. Among 118 patients with cerebral lesions, the aetiological classification of the lesions was ischaemic in 63.6%, ischaemic with haemorrhagic transformation (HT) in 17.8%, ischaemic with concomitant microbleeds in 16.1% and intracerebral bleeding in 2.5%. Postoperative ICH occurred in 17 patients and its incidence was slightly higher in patients with preoperative cerebral infarcts compared with those without preoperative cerebral infarcts [7.6 vs 4.2%, respectively, odds ratio (OR) 1.88, 95% confidence interval (CI) 0.70-5.02, P = 0.21]. However, the difference was not statistically significant. Similarly, the incidence of postoperative ICH was higher in cases of HT of ischaemic infarcts than in cases of ischaemic infarcts not complicated with HT (19.0 vs 5.3%). However, the difference was not statistically significant (P = 0.24). The radiological pattern of preoperative cerebral lesions was single in 35.6% and multiple in 60.0% of cases. Multiple cerebral lesions were associated with a non-significantly lower incidence of postoperative ICH than single lesions (5.6 vs 11.9%, respectively, OR: 0.44, CI: 0.11-1.73, P = 0.29).

CONCLUSIONS

The results suggest that the incidence of postoperative ICH in IE patients was slightly higher in the presence of preoperative cerebral infarcts. In addition, preoperative cerebral ischaemic infarcts complicated with HT tended to have a higher incidence of postoperative ICH than those not complicated with HT. However, the difference was not statistically significant. Multiple preoperative cerebral infarcts were not associated with higher incidence of postoperative ICH compared with single cerebral infarcts.

[In vitro activity of ampicillin-ceftriaxone against Enterococcus faecalis isolates recovered from invasive infections]

In vitro activity of the combination of ampicillin- ceftriaxone against 30 Enterococcus faecalis isolates recovered from invasive infections in patients admitted to Hospital de Clínicas José de San Martin in the city of Buenos Aires was assessed. Ampicillin- ceftriaxone synergies were determined by microdilution in Müeller-Hinton (MH) broth with and without subinhibitory concentrations of ceftriaxone. Synergy was detected in 22/30 isolates. A decrease in both minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was observed in 14/30 isolates, whereas in 6/30 isolates the decrease was observed in the MIC value and only in the MBC value in the 2 remaining isolates. The bactericidal activity of the combination showed to be higher at low concentrations of ampicillin (< 1 μg/ml). We detected in vitro synergy using the ampicillin-ceftriaxone combination and thus, its efficacy was confirmed in the treatment of severe infections by E. faecalis.

Quality Improvement of Staphylococcus aureus Bacteremia Management and Predictors of Relapse-free Survival

PURPOSE

The purpose of this study is to improve the quality of care and patient outcomes for Staphylococcus aureus bacteremia.

METHODS

A quasi-experimental pre- and postintervention study design was used to compare process and clinical endpoints before and after a quality-improvement initiative. All inpatients >18 years of age with a positive blood culture for S. aureus during the specified pre- and postintervention period with clinical information available in the electronic medical record were included. An institutional protocol for the care of patients with S. aureus bacteremia was developed, formalized, and distributed to providers using a pocket card, an electronic order set, and targeted lectures over a 9-month period.

RESULTS

There were 167 episodes of S. aureus bacteremia (160 patients) identified in the preintervention period, and 127 episodes (123 patients) in the postintervention period. Guideline adherence improved in the postintervention period for usage of transesophageal echocardiogram (43.9% vs 20.2%, P <.01) and adequate duration of intravenous therapy (71% vs 60%, P = .05). In a multivariate Cox proportional hazard model, the variables associated with increased relapse-free survival were postintervention period (hazard ratio [HR] 0.48; confidence interval [CI], 0.24-0.95; P .035) and appropriate source control (HR 0.53; CI, 0.24-0.92; P .027). Regardless of intervention, presence of cancer was associated with an increased risk of relapse or mortality at 90 days (HR 2.88; P <.0001; CI, 1.35-5.01).

CONCLUSION

A bundled educational intervention to promote adherence to published guidelines for the treatment of S. aureus bacteremia resulted in a significant improvement in provider adherence to guidelines as well as increased 90-day relapse-free survival.

Arteriovenous fistula of the groin in a drug abuser with endocarditis

Intravenous drug abusers commonly develop endocarditis due to injection of particulate matter that can cause endothelial damage to the valves. The frequent need to access the venous system can result in vascular traumas with potential complications including arteriovenous (AV) fistulas. Here, we present the case of an intravenous drug abuser with endocarditis and an unusually large AV fistula in the groin. The patient was successfully operated for endocarditis. However, the AV fistula was at the time not acknowledged. The combination of ileofemoral vein thrombosis and a large AV fistula led to pulmonary septic embolism and life-threating, right-sided heart failure. Computed tomography scan did not reveal the AV fistula, but suspicion was raised. Ultrasound diagnosed and revealed the magnitude of the AV fistula, and the patient was treated with a minimally invasive percutaneous technique.

Aspergillus mediastinitis after cardiac surgery

BACKGROUND

Mediastinitis is a serious complication after cardiac surgery. While bacteria are the more common pathogens, fungal infections are rare. In particular, several cases of postoperative Aspergillus mediastinitis have been reported, the majority of which had an extremely poor outcome.

METHODS

A case of mediastinitis in a 42-year-old patient due to Aspergillus fumigatus after cardiac surgery is described. Two main risk factors were found: cardiogenic shock requiring veno-arterial extracorporeal life support and failure of primary closure of the sternum. A full recovery was attained after surgical drainage and antifungal therapy with liposomal amphotericin B, followed by a combination of voriconazole and caspofungin. The patient was followed for 18 months without relapse.

RESULTS

This is an extremely rare case of postoperative Aspergillus mediastinitis exhibiting a favourable outcome. Based on a systematic review of the literature, previous cases were examined with a focus on risk factors, antifungal therapies, and outcomes.

CONCLUSION

The clinical features of postoperative Aspergillus mediastinitis may be paucisymptomatic, emphasizing the need for a low index of suspicion in cases of culture-negative mediastinitis or in indolent wound infections. In addition to surgical debridement, the central component of antifungal therapy should include amphotericin B or voriconazole.

Dose Timing of Aminoglycosides in Hemodialysis Patients: A Pharmacology View

Aminoglycosides for patients undergoing intermittent hemodialysis (IHD) have traditionally been dosed at half the normal dose administered at the end of a hemodialysis session. Several investigations have suggested that administering higher doses preceding or with the initiation of dialysis would more readily optimize pharmacodynamic parameters. However, the selection of an optimal aminoglycoside dosing strategy in patients receiving IHD is complex and requires consideration of numerous factors, precluding a singular approach. By reviewing aminoglycoside pharmacokinetics, pharmacodynamics, risks for toxicity and resistance development, and practical considerations, we derive indication- and setting- specific recommendations. We identify some areas (definitive therapy of gram-negative infections in patients receiving predictable hemodialysis sessions, for example) where dosing preceding or with the initiation of dialysis is optimal and feasible, and others (gram-positive synergy, unstable patients with poor/unpredictable vascular access) where postdialysis dosing remains preferred. Finally, given the dearth of data exploring the pharmacodynamics and clinical outcomes of IHD patients receiving aminoglycoside therapy, we identify several key questions in need of investigation.