Infective endocarditis caused by gram-negative bacteria: a review of the literature, 1945-1977

Non-HACEK gram-negative bacilli endocarditis: a multicentre retrospective case-control study

BACKGROUND

Infective endocarditis (IE) caused by non-HACEK gram-negative bacilli (GNB) is poorly characterised and may be emerging as a consequence of medical progress.

METHODS

We performed an observational retrospective case-control study. Cases were non-HACEK GNB IE, definite or possible (modified Duke criteria), diagnosed in adults between 2007 and 2020 in six French referral hospitals. Two controls were included for each case (IE due to other bacteria, matched by sites and diagnosis date).

RESULTS

Non-HACEK GNB were identified in 2.4% (77/3230) of all IE during the study period, with a mean age of 69.2 ± 14.6 years, and a large male predominance (53/77, 69%). Primary pathogens were Escherichia coli (n = 33), Klebsiella sp. (n = 12) and Serratia marcescens (n = 9), including eight (10%) multidrug-resistant GNB. Compared to controls (n = 154: 43% Streptococcus sp., 41% Staphylococcus sp. and 12% Enterococcus sp.), non-HACEK GNB IE were independently associated with intravenous drug use (IVDU, 8% vs. 2%, p = .003), active neoplasia (15% vs. 6%, p = .009), haemodialysis (9% vs. 3%, p = .007) and healthcare-associated IE (36% vs. 18%, p = .002). Urinary tract was the main source of infection (n = 25, 33%) and recent invasive procedures were reported in 29% of cases. Non-HACEK GNB IE were at lower risk of embolism (31% vs. 47%, p = .002). One-year mortality was high (n = 28, 36%). Comorbidities, particularly malignant hemopathy and cirrhosis, were associated with increased risk of death.

CONCLUSIONS

Non-HACEK GNB are rarely responsible for IE, mostly as healthcare-associated IE in patients with complex comorbidities (end-stage renal disease, neoplasia), or in IVDUs.

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.

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 in Persons Who Use Drugs: Epidemiology, Current Management, and Emerging Treatments

Infective endocarditis associated with injection drug use (IDU-IE) is markedly increasing in the United States and Canada. Long-term outcomes are dismal and stem from insufficient substance use disorder treatment. In this review, we summarize the principles of antimicrobial and surgical management for infective endocarditis associated with injection drug use. We discuss approaches to opioid use disorder care and harm reduction in the inpatient setting and review opportunities to address preventable infections among persons injecting drugs. We highlight barriers to implementing optimal treatment and consider novel approaches that may reshape infective endocarditis associated with injection drug use treatment in coming years.

Expect the Unexpected: A Rare Case of Pseudomonas aeruginosa Endocarditis

Infective endocarditis (IE) caused by Pseudomonas aeruginosa is extremely uncommon. Reported cases have usually been associated with intravenous drug use, prosthetic heart valves, and/or implanted cardiac devices. Traditionally, successful treatment has necessitated a combination of antimicrobial(s) and valve replacement. Yet, P. aeruginosa IE remains difficult to manage, especially in cases where valve replacement may not be an immediate option. We present such a case of P. aeruginosa IE, highlighting that medical management with 2 antipseudomonal synergistic agents may be an alternative to surgery in particularly complicated cases.

Non-nosocomial healthcare-associated left-sided Pseudomonas aeruginosa endocarditis: a case report and literature review

Background

With the development of invasive medical procedures, an increasing number of healthcare-associated infective endocarditis cases have been reported. In particular, non-nosocomial healthcare-associated infective endocarditis in outpatients with recent medical intervention has been increasingly identified.

Case presentation

A 66-year-old man with diabetes mellitus and a recent history of intermittent urethral self-catheterization was admitted due to a high fever. Repeated blood cultures identified Pseudomonas aeruginosa, and transesophageal echocardiography uncovered a new-onset severe aortic regurgitation along with a vegetative valvular structure. The patient underwent emergency aortic valve replacement surgery and was successfully treated with 6 weeks of high-dose meropenem and tobramycin. Historically, most cases of P. aeruginosa endocarditis have occurred in the right side of the heart and in outpatients with a history of intravenous drug abuse. In the case presented, the repeated manipulations of the urethra may have triggered the infection. Our literature review for left-sided P. aeruginosa endocarditis showed that non-nosocomial infection accounted for nearly half of the cases and resulted in fatal outcomes as often as nosocomial cases. A combination therapy with anti-pseudomonal beta-lactams or carbapenems and aminoglycosides may be the preferable treatment. Medical treatment alone may be effective, and surgical treatment should be carefully considered.

Conclusions

We presented a rare case of native aortic valve endocarditis caused by P. aeruginosa. This case illustrates the importance of identifying the causative pathogen(s), especially for outpatients with a recent history of medical procedures.

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.

Efficacy of tigecycline-colistin combination in the treatment of carbapenem-resistant Klebsiella pneumoniae endocarditis

Here we discuss the efficacy of colistin-tigecycline combination in the treatment of multidrug-resistant (MDR) Klebsiella pneumoniae infective endocarditis (IE). We report a case of a 67-year-old head-injured patient who developed a carbapenem-resistant K. pneumoniae IE. The patient was treated with colistin-tigecycline combination, with a favourable outcome. In conclusion, colistin-tigecycline combination may be a possible combination in the therapy of IE caused by MDR Enterobacteriaceae.

Brucella endocarditis - a series of five case reports

Endocarditis due to brucellosis is considered a rare occurrence involving native, congenital and prosthetic valves. The diagnosis needs high degree of suspicion in culture negative endocarditis especially in those with history of exposure to farm animals. A positive culture in a susceptible patient confirms the diagnosis with 91% sensitivity. An early diagnosis and prompt treatment with appropriate antibiotics can restore the valve structural integrity with minimal damage. Here we present a series of five cases of culture proven Brucella endocarditis (four native valves, one prosthetic valve) and this report discusses the diagnostic and management issues involved.

Left-sided Pseudomonas aeruginosa endocarditis in patients without injection drug use

We aimed to determine the clinical features, predisposing factors, and outcome of left-sided Pseudomonas aeruginosa endocarditis in persons with no history of injection drug use. We performed a retrospective review of patient medical records from Mayo Clinic (Rochester, MN; Scottsdale, AZ; and Jacksonville, FL) for all cases of left-sided P. aeruginosa endocarditis. We identified 4 cases. We present these cases, as well as a review of the English-language medical literature. Data gathered included the year the case was reported; the valve involved; treatment, including valve replacement surgery; and outcome, if known. Left-sided P. aeruginosa endocarditis in persons without injection drug use is a rare but serious infection, with a history of instrumentation as a common predisposing condition. Valvular surgery is indicated, when possible, for the best chance of survival, along with extended therapy with combination antibiotics for complete recovery.

[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.

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.

Treatment strategies for infective endocarditis

IMPORTANCE OF THE FIELD

Despite significant advances in medical, surgical, and critical care interventions, infective endocarditis (IE) remains a disease associated with considerable morbidity and mortality. Estimates from the American Heart Association place the incidence of IE in the US at 10,000 - 15,000 new cases each year. This may be due to the changing epidemiology of IE, including increasing antimicrobial resistance, increasing heart surgeries, prosthetic valve implantation, and widespread use of intravenous drugs. Furthermore, a new form of the disease, healthcare-associated IE, which is associated with new therapeutic modalities such as intravenous catheters, hyperalimentation lines, pacemakers, and dialysis shunts, has emerged.

AREAS COVERED IN THIS REVIEW

We present the latest therapeutic and preventive strategies for IE caused by a variety of bacterial and fungal pathogens. The general methods employed included an extensive literature search, confined to the last 10 years, using key words such as 'infective endocarditis', 'culture-negative endocarditis', 'treatment guidelines for IE', and 'prophylaxis for IE'.

WHAT THE READER WILL GAIN

Comprehensive information regarding the changing epidemiology of IE is provided. The latest guidelines with respect to therapy and prophylaxis of IE are reviewed.

TAKE HOME MESSAGE

Successful management of IE depends on maintaining a high index of suspicion for the disease and, when IE is diagnosed, close cooperation of medical and surgical disciplines is required. Further research is needed to better understand and provide optimal therapy for complex situations such as multidrug-resistant and polymicrobial IE.

Successful conservative treatment of nontyphoid salmonella endocarditis involving a bioprosthetic valve

We report a first case of Salmonella enteritidis endocarditis involving a bioprosthetic aortic valve. Despite additional native tricuspid valve involvement, the clinical course was favorable using an antibiotic regimen of ciprofloxacin and netilmicin. Although Salmonella prosthetic valve endocarditis is considered an indication for surgical replacement of the prosthesis, this case indicates that prolonged treatment with fluoroquinolones may be an alternative provided that the hemodynamic situation is stable.

Native-valve infective endocarditis caused by Enterobacteriaceae: report on 9 cases and literature review

Although the demographic characteristics of patients who develop infective endocarditis (IE) have changed over the last few decades, Enterobacteriaceae remain rarely responsible. We report the clinical and epidemiological characteristics of 9 patients with native-valve Enterobacteriaceae IE from 6 French medical intensive care units over a 10-y period and have identified 29 additional cases in the literature. Nearly a third of the 38 patients were immunocompromised and/or had previously known valvular heart disease. Salmonella spp. and Yersinia spp. were the most frequently isolated microorganisms reported in the literature. The overall mortality rate was 24% (9/38) and was lower for operated patients (10% (1/10)) compared to those who did not undergo valve surgery (31% (8/26)). Our results confirmed the rarity of native-valve endocarditis caused by Enterobacteriaceae, pathogens frequently responsible for nosocomial and community-acquired bacteraemias. This paradox may be explained by susceptibility to the bactericidal action of serum and the inability of these bacteria to colonize the endocardium.

Escherichia coli native valve endocarditis

Among 36 cases of Escherichia coli native valve endocarditis (NVE) that met Duke criteria (31 cases in the literature between 1909 and 2002, and five cases seen in Paris, France), the urinary tract was the most common portal of entry. The majority (72.2%) of cases developed in elderly females. Overall, the proportion of patients aged > 70 years rose from 5.3% in 1982 to 22.9% in 2002. Persistent E. coli bacteraemia in the elderly in the absence of cardiac risk-factors may be a sign of NVE and should prompt an investigation by echocardiography.

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

BACKGROUND

Despite advances in medical, surgical, and critical care interventions, infective endocarditis remains a disease that is associated with considerable morbidity and mortality. The continuing evolution of antimicrobial resistance among common pathogens that cause infective endocarditis creates additional therapeutic issues for physicians to manage in this potentially life-threatening illness.

METHODS AND RESULTS

This work represents the third iteration of an infective endocarditis "treatment" document 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 updates recommendations for diagnosis, treatment, and management of complications of infective endocarditis. A multidisciplinary committee of experts drafted this document to assist physicians in the evolving care of patients with infective endocarditis in the new millennium. This extensive document is accompanied by an executive summary that covers the key points of the diagnosis, antimicrobial therapy, and management of infective endocarditis. For the first time, an evidence-based scoring system that is used by the American College of Cardiology and the American Heart Association was applied to treatment recommendations. Tables also have been included that provide input on the use of echocardiography during diagnosis and treatment of infective endocarditis, evaluation and treatment of culture-negative endocarditis, and short-term and long-term management of patients during and after completion of antimicrobial treatment. To assist physicians who care for children, pediatric dosing was added to each treatment regimen.

CONCLUSIONS

The recommendations outlined in this update should assist physicians in all aspects of patient care in the diagnosis, medical and surgical treatment, and follow-up of infective endocarditis, as well as management of associated complications. Clinical variability and complexity in infective endocarditis, however, dictate that these guidelines be used to support and not supplant physician-directed decisions in individual patient management.

Escherichia coli endocarditis: seven new cases in adults and review of the literature

Described here are seven new cases of infective endocarditis due to Escherichia coli, including four involving prosthetic valves, followed by a review of similar cases in the literature. The review identified cases according to the modified Duke's criteria and revealed 16 cases reported before 1960, 5 between 1960 and 1980, and 11 after 1980. Currently, patients diagnosed with E. coli endocarditis are older than the patients diagnosed before 1960 (p<0.05), and they are often diabetic with underlying heart disease. Prosthetic valves are frequently involved (p<0.05), and the principal source of infection is the urinary tract. Surgery is often necessary. The mortality rate associated with this type of infection has decreased since 1960, but it remains high, with 17% calculated for the present series of seven new cases. The data presented here suggest that elderly patients with prior valve disease or prosthetic valve and E. coli urinary tract infection should be examined for endocarditis.

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

The BSAC Guidelines on Endocarditis were last published in 1998. The Guidelines presented here have been updated and extended to reflect changes in both the antibiotic resistance characteristics of causative organisms and the availability of new antibiotics. 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. The Guidelines cover diagnosis and laboratory testing, suitable antibiotic regimens and causative organisms. Special emphasis is placed on common causes of endocarditis, such as streptococci and staphylococci, however, other bacterial causes (such as enterococci, HACEK organisms, Coxiella and Bartonella) and fungi are considered. The special circumstances of prosthetic endocarditis are discussed.

The spectrum of cardiovascular infections due to Salmonella enterica: a review of clinical features and factors determining outcome

Cardiovascular infections due to Salmonella enterica are infrequently reported, so their clinical features, prognosis, and optimal treatment are not completely known. Mortality associated with aortitis and endocarditis caused by nontyphoidal Salmonella remains exceedingly high. In this review of cases of cardiovascular infections due to Salmonella enterica studied in 2 hospitals in Madrid, we tried to assess the clinical manifestations and the procedures leading to diagnosis in addition to treatment and outcome. To complete the spectrum of infections related to cardiovascular surgery, cases of postoperative mediastinitis, pericarditis, and infections associated with cardiac devices were also included.Twenty-three patients were reviewed: 11 had mycotic aneurysms; 7 had endocarditis; 2 had device-related infections; and 3 had pericarditis, mediastinitis, and infection of an arteriovenous fistula, respectively. The risk of endovascular infection in patients older than 60 years with bacteremia due to nontyphoidal Salmonella was 23%. Most patients with aortitis had risk factors for atherosclerosis, and 6 had preexisting atherosclerotic aortic aneurysms. All except 1 patient with endocarditis had underlying cardiac disorders. Acquired immunodeficiency disease (AIDS) was a major risk factor for salmonella bacteremia in 1 patient with aortitis and 1 with endocarditis. Fever, unremitting sepsis, "breakthrough" and relapsing bacteremia were the most common clinical findings. In addition, abdominal or thoracic pain and cardiac failure and pericarditis were common features in patients with aortitis and endocarditis respectively. Computed tomography (CT) scan, arteriography, and echocardiography were the main diagnostic tools. Mortality associated with mycotic aneurysms and endocarditis due to S. enterica was 45% and 28%, respectively. Thoracic aneurysms, rupture, and shock at the time of diagnosis were associated with increased mortality in patients with aortitis. In situ bypass grafting was successfully performed in most cases. After surgery, antimicrobial therapy was continued for 4-9 weeks. No relapses were observed after a mean follow-up of 64 months. Antimicrobial therapy alone or combined with valve replacement or excision of a ventricular aneurysm was successful treatment for most patients with salmonella endocarditis. Combined medical and surgical treatment was required for patients with mediastinitis and pericarditis, and patients with device-related infections needed removal of the complete device. Diagnosis of aortitis due to nontyphoidal Salmonella should be established as early as possible to reduce mortality. Patients older than 60 years who have positive blood cultures for Salmonella along with fever and back, abdominal, or chest pain should have an extensive workup for infective aortitis. Immediate bactericidal antimicrobial therapy should be started and a CT scan should be performed on an emergency basis. If a mycotic aneurysm is found, surgical resection should follow as soon as possible. Resection of the aneurysm with in situ bypass grafting is the procedure of choice. Postoperative antimicrobial therapy for 6-8 weeks seems enough to avoid relapses. Optimal treatment of patients with endocarditis occurring on ventricular aneurysms must include resection of the aneurysmal sac. Salmonella endocarditis can be successfully treated with antimicrobials alone. Valve replacement should be reserved for patients with cardiac failure or persisting sepsis, and for those who relapse after discontinuation of antimicrobial therapy.

Cardiac infections in the immunosuppressed patient

This article presents the various manifestations of cardiac infections found in the immunosuppressed host. Emphasis is placed on the correlation between specific impairments of host defenses and the occurrence of certain types of pathogens. The effect of immunosuppression on the clinical manifestations of these infections is discussed. Finally, appropriate diagnostic modalities are presented for the major types of infections.

Monotherapy versus combination therapy for bacterial infections

The authors discuss the latest findings regarding the use of one or more antimicrobial drugs for a variety of infections. They offer suggestions for treatment based on a host of considerations, including the synergy and antagonism of specific drugs, type of infection, potential toxicities, and cost.

Aortic valve endocarditis caused by Salmonella species

We report a case of aortic valve endocarditis caused by an uncommon pathogen, Salmonella species. Transthoracic echocardiography proved to be inadequate to show the valvular destruction. Transesophageal echocardiography was instrumental in establishing the diagnosis of endocarditis by documenting aortic vegetations with attendant tissue damage extending beyond the valve leaflets (i.e., subvalvular and perivalvular damage). The findings were anatomically confirmed at surgery, which also revealed an aortic root-right ventricular fistula and several aortic ring abscesses. Early implementation of transesophageal echocardiography is strongly recommended in patients with suspected endocarditis.

[Brucellosis with fatal endotoxic shock]

BACKGROUND

Brucellosis is a zoonosis with good prognosis in cases of early diagnosis. To make the diagnosis is still a problem today.

CASE REPORT

A 60-year-old butcher was admitted with undulating fever, sweats, arthralgia and weight loss. Further examination revealed hepatosplenomegaly with laboratory findings of a hepatitis and multiple focal liver lesions shown by abdominal ultrasound and CT. Histologically, these lesions corresponded to caseous granulomas. Diagnosis of brucellosis was confirmed by detection of brucella species in prolonged incubation in blood culture. After the beginning of antibiotic resistance-tested therapy with tetracycline and quinolones, an endotoxic shock occurred during the first 24 hours of treatment and the patient died after multiorgan failure with disseminated intravascular coagulation.

CONCLUSION

In cases of undulating fever with liver involvement, a brucellosis should be considered. Good teamwork of the internal, pathological and microbiological departments is necessary for early and correct diagnosis. This is the first report of human brucellosis in association with lethal endotoxic shock.

Isolated tricuspid valve endocarditis in nonaddicted patients: a diagnostic challenge

Isolated native nonrheumatic tricuspid valve endocarditis rarely is described in the absence of intravenous drug use, intracardiac catheters, or cardiac anomalies. We diagnosed tricuspid valve endocarditis in two elderly nonaddicted patients with recurrent pulmonary infiltrates, anemia, and microscopic hematuria that occurred during several months and was caused by Gemella morbillorum and Candida glabrata, respectively. We have reviewed 27 other cases of nonaddicted patients with tricuspid valve endocarditis from the literature and discussed etiology, clinical characteristics, and outcome. Mean age was 53.5 years (range, 22 to 74 years old), and 72% had underlying medical conditions. Staphylococcus oureus, Streptococcus bovis, and candida species were the causative organisms in 70% of the cases. Average duration of infection before diagnosis was 9.3 months. We conclude that isolated tricuspid valve endocarditis in nonaddicted patients occurs mainly in the middle-aged and older persons, mimicking chronic illness and community-acquired pneumonia. In the absence of a history of intravenous drug use, diagnostic delays are common. We suggest that right-sided endocarditis must be considered in any patient with the "Tricuspid Syndrome," consisting of recurrent pulmonary events, anemia, and microscopic hematuria. Careful evaluation of prior medical records and clinical course can be very helpful. Echocardiography and serial blood cultures provide the key to diagnosis.

Clinical approach to infective endocarditis

The epidemiology of IE has evolved over the past 50 years. Mitral valve prolapse and degenerative valvular disease have replaced rheumatic heart disease as the most common predisposing conditions. The average age of patients with IE has increased, and nosocomially acquired cases are becoming more common. Although viridans streptococci are currently responsible for a smaller proportion of cases than previously, this group of bacteria remains the most common cause of prosthetic value and native valve endocarditis. Staphylococci are the most important cause in some community hospitals, in nosocomial IE, and in IVDUs. IE is a multisystem disease, and patients may present with diverse clinical features. In the absence of direct histopathologic and microbiologic examination of valvular vegetations, the diagnosis of IE depends on the detection of endocardial abnormalities and the isolation of a pathogen from blood. Blood culture remains the most important laboratory test and yields the causative microorganism in 95% of patients. Echocardiography has become an important tool for detecting endocardial lesions. The clinical features of IE in IVDUs are somewhat different than those in other populations. The microbiology is distinctive, and right-sided involvement with septic pulmonary emboli is the most common clinical scenario in this group.

Advances in medical and antibiotic management of infective endocarditis

Infective endocarditis remains a serious medical problem despite advancements in laboratory detection, echocardiographic techniques, and newer antibiotic agents. This article summarizes the microbial agents in infective endocarditis, in addition to developments in medical and antibiotic management.

Infective endocarditis

IE is a fascinating disease that continues to challenge the clinicians. Over the last several decades, there have been marked changes in its presentation. The morbidity and mortality have markedly improved by early diagnosis and prompt treatment using highly effective antibiotic regimens and early valve replacement surgery whenever necessary. Early diagnosis is possible by improvement in blood culture techniques and advances in transthoracic and transesophageal echocardiographic approaches. This article has reviewed the pathogenesis, microbiology, clinical presentation, diagnostic methodology, treatment, and prevention of IE.

Ciprofloxacin resistant Serratia marcescens endocarditis as a complication of non-Hodgkin's lymphoma

We report a case of endocarditis caused by a ciprofloxacin-resistant strain of Serratia marcescens in a 50-year-old female neutropenic patient with non-Hodgkin's lymphoma which occurred while receiving ciprofloxacin prophylaxis. She made poor progress on first line therapy with azlocillin and gentamicin by bolus injection t.d.s. The infection was finally eliminated by a regimen of continuous infusion of azlocillin and once daily gentamicin.

Prevotella bivia as an unusual cause of endocarditis

A case of monomicrobial endocarditis due to Prevotella bivia in a 60-year-old man without previous cardiac lesions is reported. The extremely indolent course with multiple systemic emboli as the only clinical manifestation occurring at least seven months before diagnosis and the persistently negative blood cultures were remarkable features of this case. The incidence, clinical characteristics, treatment and outcome of published cases of infective endocarditis due to anaerobic bacteria are briefly reviewed.

Serious Infections Caused by Pseudomonas Aeruginosa

Over the last 3 decades, Pseudomonas aeruginosa has become a leading cause of infectious morbidity and mortality in certain predisposed patient populations. It primarily affects those with impaired host defenses, and its prevalence in the hospital environment makes it an important nosocomial pathogen. Infection with this organism may result in a broad spectrum of clinical manifestations, many of which may be seen in the intensive care setting. This review focuses on epidemiology, clinical presentations, nad treatment of serious Pseudomonas infections.

Endocarditis caused by Brucella melitensis

OBJECTIVE

To describe the management of an uncommon but serious infection in Australia.

CLINICAL FEATURES

A 25-year-old woman developed endocarditis after residence in Turkey and consumption of goat dairy products. Brucella melitensis was isolated from blood cultures.

INTERVENTION AND OUTCOME

The valve remained infected after prolonged intravenous administration of trimethoprim-sulfamethoxazole, gentamicin and rifampicin. Uncontrolled sepsis and worsening haemodynamic function necessitated valve replacement. To date the patient remains well while taking trimethoprim-sulfamethoxazole and rifampicin.

CONCLUSION

Endocarditis due to Brucella spp. is uncommon in Australia. This infection is difficult to cure with antimicrobial therapy alone and early surgical intervention is advisable.

Salmonella prosthetic valve endocarditis

Four cases of Salmonella prosthetic valve endocarditis have been reported previously in the English medical literature (Fraser et al. 1967; Yamamoto et al., 1974; Shanson et al., 1977; Bassa et al., 1989). This report describes a fifth case in a 62-year-old woman who developed tricuspid valve endocarditis after an episode of Salmonella gastroenteritis, and reviews prior cases of Salmonella prosthetic valve endocarditis.

Enterobacter endocarditis

Endocarditis due to Enterobacter species is very rare. We recently cared for a patient who developed E. cloacae endocarditis following mitral valve replacement with a porcine heterograft, and was successfully treated with antibiotic therapy alone. A review of the literature disclosed an additional 17 well-described cases of enterobacter endocarditis. Two-thirds of the patients had underlying cardiac disease. The mitral valve was most frequently involved (10/16 cases) with 4 of the patients having concomitant aortic valve involvement. The overall mortality rate was 44.4%. Antibiotic therapy of enterobacter endocarditis should consist of the combination of a beta-lactam antibiotic and an aminoglycoside with careful monitoring of blood cultures to assure the adequacy of therapy. Resistance of enterobacter to previously susceptible antibiotics may occur during therapy due to induction of a chromosomally-mediated beta-lactamase, necessitating a change in antimicrobial therapy. Valvular surgery is indicated for patients failing medical management.