Gram-negative endocarditis

Infective Endocarditis due to Non-HACEK Gram-Negative Bacilli: Clinical Characteristics and Risk Factors from a Prospective Multicenter Brazilian Cohort

Background: Non-HACEK Gram-negative bacilli (NGNB) infective endocarditis (IE) has a growing frequency. We aimed to describe cases of NGNB IE and find associated risk factors. Methods: We conducted a prospective observational study of consecutive patients with definitive IE according to the modified Duke criteria in four institutions in Brazil. Results: Of 1154 adult patients enrolled, 38 (3.29%) had IE due to NGNB. Median age was 57 years, males predominated, accounting for 25/38 (65.8%). Most common etiologies were Pseudomonas aeruginosa and Klebsiella spp. (8 episodes, 21% each). Worsening heart failure occurred in 18/38 (47.4%). Higher prevalence of embolic events was found (55,3%), mostly to the central nervous system 7/38 (18.4%). Vegetations were most commonly on aortic valves 17/38 (44.7%). Recent healthcare exposure was found in 52.6% and a central venous catheter (CVC) in 13/38 (34.2%). Overall mortality was 19/38 (50%). Indwelling CVC (OR 5.93; 95% CI, 1.29 to 27.3; p = 0.017), hemodialysis (OR 16.2; 95% CI, 1.78 to 147; p = 0.008) and chronic kidney disease (OR 4.8; 95% IC, 1.2 to 19.1, p = 0.049) were identified as risk factors for mortality. Conclusions: The rate of IE due to NGNB was similar to that in previous studies. Enterobacterales and P. aeruginosa were the most common etiologies. NGNB IE was associated with central venous catheters, prosthetic valves, intracardiac devices and hemodialysis and had a high mortality rate.

Characteristics of oral microbiome of healthcare workers in different clinical scenarios: a cross-sectional analysis

The environment of healthcare institutes (HCIs) potentially affects the internal microecology of medical workers, which is reflected not only in the well-studied gut microbiome but also in the more susceptible oral microbiome. We conducted a prospective cross-sectional cohort study in four hospital departments in Central China. Oropharyngeal swabs from 65 healthcare workers were collected and analyzed using 16S rRNA gene amplicon sequencing. The oral microbiome of healthcare workers exhibited prominent deviations in diversity, microbial structure, and predicted function. The coronary care unit (CCU) samples exhibited robust features and stability, with significantly higher abundances of genera such as Haemophilus, Fusobacterium, and Streptococcus, and a lower abundance of Prevotella. Functional prediction analysis showed that vitamin, nucleotide, and amino acid metabolisms were significantly different among the four departments. The CCU group was at a potential risk of developing periodontal disease owing to the increased abundance of F. nucleatum. Additionally, oral microbial diversification of healthcare workers was related to seniority. We described the oral microbiome profile of healthcare workers in different clinical scenarios and demonstrated that community diversity, structure, and potential functions differed markedly among departments. Intense modulation of the oral microbiome of healthcare workers occurs because of their original departments, especially in the CCU.

Infective endocarditis by HACEK: a review

Infective endocarditis (IE) is a severe disease that is still associated with high mortality despite recent advances in diagnosis and treatment. HACEK organisms (Haemophilus spp., Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) are gram-negative bacteria that are part of the normal flora of the mouth and upper respiratory tract in humans. These organisms cause a wide range of infections, of which IE is one of the most notable. In order to control and prevent endocarditis caused by HACEK, measures such as oral hygiene and the use of prophylactic drugs should be used for people at risk, including people with underlying heart disease and people with artificial valves. This review is a summary of the main aspects of IE focusing on HACEK organisms.

Gram-negative endocarditis: disease presentation, diagnosis and treatment

PURPOSE OF REVIEW

Gram-negative bacilli (GNB) cause between 1% and 10% of infective endocarditis (IE). Most episodes are caused by microorganisms of the Haemophilus spp., Aggregatibacter spp. Cardiobacterium spp., Eikenella spp., and Kingella spp (HACEK) group. The frequency of IE caused by non-HACEK (GNB-IE) has increased in recent years. Uncertainties persist regarding its best medical treatment and the appropriateness and timing of surgical treatment. In addition, there are new drugs with activity against multiresistant microorganisms, of which there is little experience in this disease. We review this topic by answering the most frequently asked questions that arise among our colleagues.

RECENT FINDINGS

HACEK microorganisms cause 1.5-2% of IE with only a 2% mortality. In contrast, non-HACEK GNB-IE accounts for 2.5-3% of all IE cases and is associated with nosocomial acquisition, advanced age, solid organ transplantation and 20-30% mortality. Drug addiction is important in areas with epidemic opioid abuse.

SUMMARY

The frequency of IE caused by GNB has been modified in recent years. HACEK episodes are no longer treated with ampicillin and aminoglycosides. In non-HACEK GNB-IE, combination therapy with a beta-lactam and a quinolone or aminoglycoside is recommended. The surgical indication and its value are evident in many patients. Management should rely on a collaborative group with experience in this disease.

Infective endocarditis caused by Enterobacteriaceae: phenotypic and molecular characterization of Escherichia coli and Klebsiella pneumoniae in Rio de Janeiro, Brazil

The etiological agent for infective endocarditis (IE), a life-threatening disease, is usually gram-positive bacteria. However, gram-negative bacteria can rarely cause IE and 4% of cases are associated with morbidity and mortality. This study aimed to characterize Escherichia coli and Klebsiella pneumoniae isolates from the blood of patients with IE. The characteristics of blood isolates were compared with those of urinary isolates from patients with urinary tract infections (UTIs). The results of this study revealed that K. pneumoniae isolates from patients with IE were phylogenetically related to those from patients with UTI. Additionally, the resistance phenotype, resistance gene, virulence gene, and plasmid profiles were similar between the blood and urinary isolates. The isolates belonging to the sequence types (STs) 76, 36, 101 (K. pneumoniae), and 69 (E. coli) are reported to be associated with drug resistance. The Enterobacteriaceae isolates from patients with IE did not produce extended-spectrum β-lactamase or carbapenemase. Additionally, this study investigated the virulence phenotype, biofilm formation ability, and the ability to adhere to the epithelial cells in vitro of the isolates. The isolates from patients with IE exhibited weaker biofilm formation ability than the urinary isolates. All isolates from patients with IE could adhere to the renal epithelial cells. However, three isolates from patients with UTIs could not adhere to the epithelial cells. The closely related K. pneumoniae isolates (648, KP1, KP2, KP3, and KP4) could not form biofilms or adhere to the epithelial cells. In summary, the molecular analysis revealed that the genetic characteristics of IE-causing K. pneumoniae and E. coli were similar to those of UTI-causing isolates. These isolates belonged to the STs that are considered treatable. Genetically similar isolates did not exhibit the same virulence phenotype. Thus, these non-hypervirulent clones must be monitored as they can cause complex infections in susceptible hosts.

Clinical outcomes of combination versus monotherapy for gram negative non-HACEK infective endocarditis

The objective of this single-center, retrospective cohort study was to identify whether combination therapy is associated with a lower rate of adverse outcomes for the treatment of Gram negative non-HACEK IE. The primary endpoint was a composite of 60-day all-cause mortality, readmission, or recurrence of bacteremia. Of the 60 patients included, 56.7% met the primary composite outcome, with 20% overall mortality at 60 days. There was no difference in the primary composite outcome of 60-day readmission, infection recurrence or mortality between groups, with 62% of patients in the monotherapy group and 50% of patients in the combination therapy group experiencing the composite outcome (P = 0.36). Despite the high mortality and complicated nature of non-HACEK Gram negative IE, this study showed no difference in 60-day bacteremia recurrence, readmission or mortality among patients treated with combination therapy or monotherapy, suggesting that monotherapy may lead to similar clinical outcomes.

An Unusual Case of Neisseria flavescens/subflava Group Tricuspid Valve Endocarditis in a Patient With Previously Treated Methicillin-Resistant Staphylococcus aureus Endocarditis

Infective endocarditis (IE) is classified as an infection of any cardiac valve or endocardial surface and is often associated with high morbidity and mortality. Certain bacteria such as gram-positive cocci and viridans group streptococci have high predilection for both naïve and damaged cardiac valvular tissues, accounting for the majority of IE cases. In very infrequent instances, gram-negative bacteria (GNB), more specifically non-meningococcal, non-gonococcal GNB, have been shown to cause IE. The following is a case of a young male diagnosed with Neisseria flavescens/subflava tricuspid valve endocarditis after being previously treated for Methicillin-resistant Staphylococcus aureus (MRSA) endocarditis.

[Infective endocarditis due to non-HACEK gram-negative bacilli in a Level III cardiovascular center in Argentina (1998-2016)]

Non-HACEK Gram-negative bacilli are a rare cause of infective endocarditis. Epidemiological, diagnostic and prognostic aspects of this entity are little known, and there is limited experience. The aim of this study was to analyze the clinical, microbiological and in-hospital outcomes of non-HACEK Gram negative bacilli endocarditis and to compare them with those due to other microorganisms.

Risk Factors and Outcomes of Endocarditis Due to Non-HACEK Gram-Negative Bacilli: Data from the Prospective Multicenter Italian Endocarditis Study Cohort

The objective of this study was to investigate predisposing factors and outcomes of infective endocarditis (IE) caused by non-HACEK Gram-negative bacilli (GNB) in a contemporary multicenter cohort. Patients with IE due to GNB, prospectively observed in 26 Italian centers from 2004 to 2011, were analyzed. Using a case-control design, each case was compared to three age- and sex-matched controls with IE due to other etiologies. Logistic regression was performed to identify risk factors for IE due to GNB. Factors associated with early and late mortality were assessed by Cox regression analysis. The study group comprised 58 patients with IE due to GNB. We found that Escherichia coli was the most common pathogen, followed by Pseudomonas aeruginosa and Klebsiella pneumoniae The genitourinary tract as a source of infection (odds ratio [OR], 13.59; 95% confidence interval [CI], 4.63 to 39.93; P < 0.001), immunosuppression (OR, 5.16; 95% CI, 1.60 to 16.24; P = 0.006), and the presence of a cardiac implantable electronic device (CIED) (OR, 3.57; 95% CI, 1.55 to 8.20; P = 0.003) were factors independently associated with IE due to GNB. In-hospital mortality was 13.8%, and mortality rose to 30.6% at 1 year. A multidrug-resistant (MDR) etiology was associated with in-hospital mortality (hazard ratio [HR], 21.849; 95% CI, 2.672 to 178.683; P = 0.004) and 1-year mortality (HR, 4.408; 95% CI, 1.581 to 12.287; P = 0.005). We conclude that the presence of a genitourinary focus, immunosuppressive therapy, and an indwelling CIED are factors associated with IE due to GNB. MDR etiology is the major determinant of in-hospital and long-term mortality.

The relationship between causative microorganisms and cardiac lesions caused by infective endocarditis: New perspectives from the contemporary cohort of patients

BACKGROUND

The etiology of infective endocarditis (IE) is changing. More aggressive forms with multiple IE cardiac lesions have become more frequent. This study sought to explore the relationship between contemporary causative microorganisms and IE cardiac lesions and to analyze the impact of multiple lesions on treatment choice.

METHODS

In 246 patients hospitalized for IE between 2008 and 2015, cardiac lesions caused by IE were analyzed by echocardiography, classified according to the 2015 European Society of Cardiology guidelines and correlated with microbiological data. We defined a new parameter, the Echo IE Sum, to summarize all IE cardiac lesions in a single patient, enabling comprehensive comparisons between different etiologies and treatment strategies.

RESULTS

Staphylococcus aureus was associated with the development of large vegetation (OR 2.442; 95% CI 1.220-4.889; p=0.012), non-HACEK bacteria with large vegetation (OR 13.662; 95% CI 2.801-66.639; p=0.001), perivalvular abscess or perivalvular pseudoaneurysm (OR 5.283; 95% CI 1.069-26.096; p=0.041), and coagulase-negative staphylococci (CoNS) with leaflet abscess or aneurysm (OR 3.451; 95% CI 1.285-9.266, p=0.014), and perivalvular abscess or perivalvular pseudoaneurysm (OR 4.290; 95% CI 1.583-11.627; p=0.004). The Echo IE Sum significantly differed between different etiologies (p<0.001), with the highest value in non-HACEK and the lowest in streptococcal endocarditis. Patients operated for IE had a significantly higher Echo IE Sum vs those who were medically treated (p<0.001).

CONCLUSION

None of the IE cardiac lesions is microorganism-specific. However, more severe lesions were caused by S. aureus, CoNS, and non-HACEK bacteria. The highest propensity to develop multiple lesions was shown by the non-HACEK group. Higher Echo IE Sum in patients sent to surgery emphasized the importance of multiple IE cardiac lesions on treatment choice and potential usage of Echo IE Sum in patient 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.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Infective endocarditis due to multidrug resistant gram-negative bacilli: single centre experience over 5 years

BACKGROUND

Infective endocarditis (IE) due to gram-negative (GN) bacilli is uncommon. Although multi- and extensively-drug resistant (MDR/XDR) GN infections are emerging, very few data are available on IE due to these microrganisms.

METHODS

In this study, we describe the clinical characteristics, course and outcome of five contemporary, definite, MDR/XDR GNIE cases seen at our centre.

RESULTS

All patients had been admitted to a hospital during the 6months before IE onset, 2 were on hemodialysis and 3 on intravenous medications. Three of the 5 cases were hospital-acquired. Intracardiac prosthetic devices were present in all cases (3 central venous lines, 2 prosthetic heart valves, 2 pacemakers). Mean Charlson comorbidity index was 5.8. Causative pathogens were XDR Pseudomonas aeruginosa (2 cases), XDR Acinetobacter baumannii, MDR Burkolderia cepacia and MDR Escherichia coli (1 case each). Concomitant pathogens with a MDR/XDR phenotype were isolated in 4 patients. Both valves and intracardiac devices and left and right sides of the heart were involved. The rate of complications was high. Antibiotic treatment hinged on the use of colistin, a carbapenem or both. Cardiovascular surgical procedures were performed in 3 patients. Despite aggressive therapeutic regimens, outcomes were poor. Clearance of bacteremia was obtained in 3 patients, in-hospital death occurred in 3 patients, only 1 patient survived during follow up.

CONCLUSIONS

MDR/XDR GN are emerging as a cause of IE in carriers of intracardiac prostheses with extensive healthcare contacts and multiple comorbidities. Resistant GNIE has a complicated course and shows a dismal prognosis.

Community-acquired multidrug-resistant Gram-negative bacterial infective endocarditis

We describe two cases of bacterial endocarditis secondary to multidrug-resistant Gram-negative organisms. In both cases, the diagnosis was made in accordance with the modified Duke's criteria and confirmed by histopathological analysis. Furthermore, in both instances there were no identifiable sources of bacteraemia and no history of contact with hospital or other medical services prior to the onset of symptoms. The patients were managed in similar fashion with prolonged broad-spectrum antibiotic therapy and surgical intervention and made complete recoveries. These cases highlight Gram-negative organisms as potential agents for endocarditis, as well as expose the dissemination of such multidrug-resistant bacteria into the community. The application of an integrated medical and surgical approach and therapeutic dilemmas encountered in managing these cases are described.

Guidelines for the diagnosis and antibiotic treatment of endocarditis in adults: a report of the Working Party of the British Society for Antimicrobial Chemotherapy

The BSAC guidelines on treatment of infectious endocarditis (IE) were last published in 2004. The guidelines presented here have been updated and extended to reflect developments in diagnostics, new trial data and the availability of new antibiotics. The aim of these guidelines, which cover both native valve and prosthetic valve endocarditis, is to standardize the initial investigation and treatment of IE. An extensive review of the literature using a number of different search criteria has been carried out and cited publications used to support any changes we have made to the existing guidelines. Publications referring to in vitro or animal models have only been cited if appropriate clinical data are not available. Randomized, controlled trials suitable for the development of evidenced-based guidelines in this area are still lacking and therefore a consensus approach has again been adopted for most recommendations; however, we have attempted to grade the evidence, where possible. The guidelines have also been extended by the inclusion of sections on clinical diagnosis, echocardiography and surgery.

[Left-sided endocarditis due to gram-negative bacilli: epidemiology and clinical characteristics]

INTRODUCTION

The aim of this study is to describe the epidemiological, clinical characteristics, and outcome of patients with left-side endocarditis caused by gram-negative bacteria.

METHOD

Prospective multicenter study of left-sided infective endocarditis reported in the Andalusian Cohort for the Study of Cardiovascular Infections between 1984 and 2008.

RESULTS

Among the 961 endocarditis, 24 (2.5%) were caused by gram-negative bacilli. The most common pathogens were Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica. Native valves (85.7%) were mainly affected, most of them with previous valve damage (57%). Comorbidity was greater (90% vs 39%; P=.05) than in endocarditis due to other microorganism, the most frequent being, diabetes, hepatic cirrhosis and neoplasm. A previous manipulation was found in 47.6% of the cases, and 37% were considered hospital-acquired. Renal failure (41%), central nervous system involvement (33%) and ventricular dysfunction (45%) were the most frequent complications. Five cases (21%) required cardiac surgery, mostly due to ventricular dysfunction. More than 50% of cases were treated with aminoglycosides, but this did not lead to a better outcome or prognosis. Mortality (10 patients) was higher than that reported with other microorganisms (41% vs 35%; P=.05).

CONCLUSIONS

Left-sided endocarditis due to gram-negative bacilli is a rare disease, which affects patients with major morbidities and often with a previous history of hospital manipulations. Cardiac, neurological and renal complications are frequent and associated with a high mortality. The association of aminoglycosides in the antimicrobial treatment did not involve a better outcome or prognosis.

Management of Gram-negative and fungal endocarditis

Infective endocarditis is infrequently caused by Gram-negative bacteria or fungi. Gram-negative organisms are responsible for <4% of cases, whilst fungal endocarditis accounts for <1.5% of culture-positive cases worldwide. Endocarditis due to Gram-negative organisms or fungi is a rare but severe disease. It often has a nosocomial origin, is caused by virulent and often resistant organisms and presents a high rate of complications and high mortality. In this article we present the most recent literature data and address the current management of Gram-negative and fungal infective endocarditis. We also discuss the major challenges of antimicrobial treatment and discuss some issues related to surgical decision-making in difficult-to-manage cases. We finally present our centre's experience with Gram-negative infective endocarditis, with a special focus on the demanding issues that the management of these complex and severely ill patients raise.

Gram-negative bacterial endocarditis in adults: state-of-the-heart

Gram-negative endocarditis due to HACEK bacteria (Haemophilus species, Actinobacillus, Cardiobacterium, Eikenella and Kingella species) and non-HACEK organisms is an infrequent occurrence but is associated with significant morbidity and mortality. Traditionally, non-HACEK Gram-negative endocarditis has been associated with injection drug use. However, emerging data from more contemporary cohorts suggest changing epidemiology and risk factors for Gram-negative endocarditis, necessitating an updated review of this subject. Moreover, optimal management, including the need for surgical intervention, and strategies for the prevention of Gram-negative endocarditis need to be revisited.

Resurgence of Pseudomonas endocarditis in Detroit, 2006-2008

A resurgence of endocarditis due to Pseudomonas aeruginosa was seen in 10 injection drug users (IDUs) in Detroit between 2006 and 2008 (6 men, 4 women; mean age, 48.1 yr). All patients tested negative for the human immunodeficiency virus (HIV). Five patients had left-sided endocarditis of the mitral valve and/or the aortic valve; 3 of 5 patients had prosthetic valve endocarditis. Four of 10 patients had right-sided endocarditis of the tricuspid valve alone. One patient had bilateral involvement of the aortic and tricuspid valves. Nine patients had Pseudomonas endocarditis (PsE); 1 patient had mixed endocarditis with P. aeruginosa and Candida parapsilosis. Seven of 10 patients were treated with a combination of intravenous cefepime, 4-6 g/d, plus high-dose tobramycin (HDT) for at least 6 weeks. Tobramycin, 8 mg/kg per day, was given as a single daily dose intravenously, aiming for peak serum levels of 18-22 microg/mL and trough levels of <1 microg/mL. The patient with mixed endocarditis was also treated with fluconazole. Two patients initially treated with other antipseudomonal regimens, including cefepime alone and piperacillin/tazobactam plus tobramycin, failed treatment and were switched to cefepime and HDT. A third patient was switched to cefepime and ciprofloxacin because of nephrotoxicity. Two patients developed nephrotoxicity to tobramycin; 1 patient developed ototoxicity. The overall medical cure rate for both left-sided and right-sided disease was 80% (4/5). All 5 patients who required surgery survived (5/5; 100%). Overall outcome was 90% (9/10). Indications for valve replacement were recurrent Pseudomonas bacteremia (n = 3), recurrent bacteremia and congestive heart failure (n = 1), and persistent bacteremia and fungemia (n = 1). Tricuspid valvulectomy with valve replacement was successful in 2 patients and in a third patient who had successful replacement of both the tricuspid and the aortic valve for recurrent bacteremia and congestive heart failure. Two patients with pure left-sided prosthetic valve endocarditis underwent successful repeat valve replacements. Although this is a small series, the overall mortality rate (1/10; 10%) was low. The patient who did not survive had left-sided involvement of the aortic valve and could not undergo surgery because of a large embolic cerebral infarct. The mortality rate of left-sided disease in the current series was 16.7% (1/6 including the patient with tricuspid and aortic valve PsE) compared to 60% in a series of 15 patients reported in 1990.Our current antimicrobial regimen for PsE consists of a combination of cefepime, 6 g/d, in 3 divided doses, plus HDT, 8 mg/kg per day, given as a single daily dose for 6 weeks. For cefepime-resistant Pseudomonas, imipenem, 4-6 g/d, or meropenem, 6 g/d, plus HDT has been successful. For right-sided disease refractory to medical therapy, surgical intervention is recommended if Pseudomonas bacteremia persists for 2 weeks on appropriate antimicrobial therapy or if bacteremia recurs after a 6-week course of treatment. Tricuspid repair/reconstruction or valvulectomy with valve replacement plus combined antipseudomonal regimen may be the optimal therapy for refractory right-sided endocarditis. This approach not only may prevent the development of severe and permanent impairment of right ventricular function, which is a complication of valvulectomy alone without valve replacement, but also may cure the infection. For left-sided disease, surgery is recommended if blood cultures remain positive for 7 days on appropriate antimicrobial therapy or if Pseudomonas bacteremia recurs after completion of a 6-week course of the combined regimen.