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

Calcium polystyrene sulfonate-induced rectal ulcer causing E. coli native-valve infective endocarditis

Escherichia coli-associated native-valve infective endocarditis is a rare disease that affects elderly patients with underlying risk factors such as diabetes mellitus, malignancy, and renal failure. Long-term use of calcium polystyrene sulfonate is a potential risk factor for gastrointestinal mucosal damage or even colorectal ulcers. Herein, we describe a fatal case of a 66-year-old Japanese man with diabetes mellitus and renal failure who was prescribed calcium polystyrene sulfonate (CPS) for 11 years and developed a CPS-induced rectal ulcer, leading to E. coli native-valve infective endocarditis. The patient was admitted to our hospital due to acute-onset impaired consciousness. As a result of the systemic investigation, he was diagnosed with E. coli bacteremia accompanied by multiple cerebral infarctions and an acute hemorrhagic rectal ulcer. Transesophageal echocardiography revealed a 20-mm vegetative structure on the mitral valve, resulting in a final diagnosis of E. coli-associated infective endocarditis. After rectal resection, mitral valve replacement surgery was performed; however, the patient died shortly after surgery. Pathological findings of the resected rectum showed deposition of a basophilic crystalline material suggesting the presence of CPS. Our case highlights the potential risk of colorectal ulcers in a long-term CPS user, which can trigger bacterial translocation and endocarditis as fatal complications.

Escherichia coli: A Rare Cause of Prosthetic Valve Endocarditis

Prosthetic valve endocarditis (PVE) is a complication of valve replacement associated with high morbidity and mortality. Escherichia coli (E. coli) is rarely associated with infective endocarditis (IE), accounting for less than 1% of the cases reported. The low frequency is attributed to the organism's low affinity to adhere to the endocardial endothelium. Risk factors that may play a role in developing IE by E. coli include age above 70, diabetes mellitus, a genitourinary source of infection, female sex, healthcare contact, implanted endovascular devices, and immunosuppression. We present a 70-year-old Hispanic woman who arrived with constitutional symptoms and persistent urinary complaints. She had diabetes mellitus, recurrent urinary tract infections, and native mitral valve IE treated with antibiotic therapy and tissue valve replacement. The valve was replaced with a mechanical valve a second time due to malfunctioning. The patient was found to have E. coli bacteremia and ultimately diagnosed with PVE. She was treated solely with ceftriaxone and gentamicin combination therapy resulting in complete resolution of valve vegetations. Our case represents the 11th report of this uncommon disease and illustrates its epidemiology and associated risk factors. We summarize the previous 10 cases reported and highlight the lack of prospective trial data to define optimal therapy for managing PVE caused by E. coli.

Native Valve Infective Endocarditis Secondary to Acute Cholecystitis in the Setting of Escherichia coli Bacteremia: A Case Report

Infective endocarditis is an infection of the endocardium that affects the heart valves. It is usually caused by bacteremia secondary to distant infections such as urinary tract infections, surgical procedures, or other sources of pathogenic entry into the blood. It often affects damaged native valves, as well as prosthetic valves, and is primarily caused by Gram-positive bacteria, such as Staphylococcus aureus. Infective endocarditis secondary to Escherichia coli is rare, despite E. coli being one of the most common pathogens causing Gram-negative bacteremia. Between 1909 and 2002, 36 cases of native valve infective endocarditis were reported that met Duke criteria. The majority were secondary to urinary tract infections due to E. coli. Infective endocarditis secondary to E. coli bacteremia in the setting of acute cholecystitis is highly uncommon, and this case report aims to highlight this unusual presentation of infective endocarditis.

Escherichia coli prosthetic valve endocarditis from a non-genitourinary source

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E. coli is an infrequent cause of infective endocarditis due to is limited ability to adhere to heart valves.

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There is a notable increase in the share of total cases of E. coli infective endocarditis due to prosthetic valve infections.

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There is an increased recognition of non-genitourinary sources of E. coli prosthetic valve endocarditis.

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The overall mortality rate is declining for E. coli prosthetic valve endocarditis cases.

Escherichia coli (E. coli) is a rare cause of infective endocarditis due to its lack of traditional virulence factors that promote endocardial adherence. Previous case reports of E. coli infective endocarditis demonstrate specific risk factors to include advanced age over 70, female sex, diabetes, immunosuppression, and intravascular or cardiac devices. Antecedent genitourinary infection is the most common source. We present a case of a 55-year-old Honduran man with a recent bioprosthetic mitral valve replacement and tricuspid valve repair who presented with one month of subjective fevers, night sweats, anorexia, and significant weight loss. After extensive work-up, the patient was diagnosed with E. coli infective endocarditis secondary to E. coli growth in blood cultures and a transesophageal echocardiogram (TEE) revealing a vegetation on his prosthetic mitral valve. An indolent gastrointestinal source was suspected to be the source of infection with imaging only notable for mild periappendiceal stranding concerning for a possible site of antecedent inflammation. He was treated with a 6-week course of ceftriaxone and gentamicin inpatient and then discharged on trimethoprim-sulfamethoxazole suppressive therapy with serial echocardiographic follow-up given the persistent small vegetation on repeat echocardiogram. Our case report and review of ten recent cases of prosthetic valve endocarditis described in the literature illustrates several common features of the epidemiology, presentation, and management of E. coli prosthetic valve endocarditis including more commonly reported non-genitourinary sources of bacteremia, a trend towards more frequent surgical interventions, and a declining mortality rate.

Cutaneous Vasculitis and Generalized Lymphadenopathy Associated with Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli Endocarditis: A Rare Case Report

INTRODUCTION

Infective endocarditis (IE) has been known as the great imitator due to variable clinical manifestation, making its diagnosis challenging. A missed diagnosis could lead to inappropriate therapy. We presented a rare case of blood culture-negative infective endocarditis (BCNIE) due to extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli manifest with cutaneous vasculitis and generalized lymphadenopathy. We highlighted its diagnostic challenge and management.

CASE ILLUSTRATION AND DISCUSSION

A 36-year-old male with known asymptomatic ruptured sinus of Valsalva (SOV) presented with fever of unknown origin for six months, fatigue, weight loss with a history of multiple hospitalizations. The physical examination revealed a continuous murmur at Erb's point, cutaneous vasculitis, and bilateral inguinal lymphadenopathy. The laboratory result was leukocytosis and elevated C-Reactive Protein (CRP). Generalized lymphadenopathy was detected from the thorax and abdominal Computed Tomography (CT) Scans. Positive Anti Nuclear Antibody (ANA) Indirect Immunofluorescence (IF) speckled pattern led us to consider an autoimmune as the etiology, but we still considered IE as a differential diagnosis due to history of structural heart disease. Detection of multiple tiny oscillating masses at the tricuspid valve from the echocardiogram and cardiac CT led to possible IE diagnosis. Negative three consecutive blood cultures led the diagnosis to BCNIE. Surgery was performed to evacuate the vegetations, repair the SOV, and tricuspid valve replacement with a bioprosthetic valve. These results in improvement of the patient's condition. ESBL-producing Escherichia coli yielded in tissue culture made the diagnosis of IE became definite.

CONCLUSION

ESBL-producing Escherichia coli should be considered as the etiology of BCNIE. Cutaneous vasculitis and generalized lymphadenopathy as a manifestation of IE could lead to diagnostic confusion. A thorough investigation will help clinician to avoid delay or inappropriate treatment that could be detrimental for the patient.

Successful Resolution of Early-Onset Prosthetic Valve Endocarditis Associated With Extended Spectrum β-Lactamases Producing Escherichia coli With Medical Management

A 74-year-old male with a recent bioprosthetic mitral valve placement presented with dyspnea, chills, and palpitations. Blood cultures on admission grew extended spectrum β-lactamase Escherichia coli. Transthoracic echocardiogram and transesophageal echocardiography were negative for valvular vegetations, but given the recent history of mitral valve replacement and difficulty visualizing valvular vegetations in prosthetic valve, we initiated treatment of our patient with antibiotics for 6 weeks. Repeat blood cultures showed clearance of the organism and on follow-up, and the patient had no signs of recurrence of infection.

Native valve infective endocarditis due to ampicillin-resistant Escherichia coli in the postoperative period of a right radical nephrectomy due to xanthogranulomatous pyelonephritis

Infective endocarditis (IE) due to Escherichia coli is a rare disease, although increasingly frequent. Persistent fever in septic patients despite adequate treatment raises the need to consider IE as a differential diagnosis. We present the case of a 36-year-old male patient who underwent a radical right nephrectomy as a result of diagnosis of xanthogranulomatous pyelonephritis, presenting in the postoperative period a state of septic shock with persistent fever of 41°C. Given the finding of a new-onset murmur, he was diagnosed with a mitroaortic IE by means of a transesophageal echocardiogram (TEE), having to undergo cardiac surgery for valve replacement. After multiple postoperative complications, he is successfully discharged.

E. coli endocarditis of the tricuspid valve

Infective endocarditis (IE) is a focus of infection which effects the endocardium, specifically the heart valves or intra-cardiac devices.

A 64-year-old male with gastric carcinoma and no prior cardiac history presented to the emergency room with altered mental status. Initial investigations showed the patient had a leukocytosis with a left shift. Blood cultures taken upon arrival eventually grew Esherichia coli, thought to be from the urinary tract, although initial urinalysis was delayed until after initiation of antibiotics. Electrocardiogram showed sinus bradycardia with frequent premature atrial contractions. Chest X-Ray showed bilateral pleural effusions, which were eventually drained and found to be growing E. coli. Transthoracic echocardiogram was done which showed moderate-sized tricuspid valve vegetation with severe tricuspid regurgitation.

IE has been increasing in incidence throughout the years. In prior decades IE was a disease primarily affecting patients with known rheumatic heart disease, prosthetic heart valves, and intravenous drug abusers however more commonly it is becoming healthcare acquired. E. coli is not often seen to be a culprit of IE. We present a rare case of E. coli endocarditis of a native tricuspid valve.

Escherichia coli Endocarditis Presenting With Septic Shock in an Immunocompetent Female Patient

Escherichia coli (E. coli) is a rare cause of infective endocarditis, despite being a common cause of bacteremia. E. coli endocarditis affects most frequently immunocompromised elderly women, especially those with diabetes mellitus. We present a case of a 78-year-old female immunocompetent patient, presenting with septic shock and multiple organ dysfunction syndrome. E. coli was isolated in all sets of blood cultures and in urine culture and a contrast-enhanced abdominal computed tomography (CT) scan revealed spleen and left kidney infracts. Transthoracic echocardiography revealed a large (> 15 mm) mobile mass on the atrial side of the posterior mitral valve leaflet. The patient was initially treated with intravenous ceftriaxone and ciprofloxacin for 2 weeks with successful clinical response and clearance of bacteremia, was then subjected to valve replacement (with isolation of E. coli from replaced valve cultures) and continued antibiotic therapy for additional 4 weeks postoperatively. E. coli has emerged in recent years as an important cause of bacteremia, especially in the elderly. In selected patients, as those with persistent Gram-negative bacteremia or severe sepsis/septic shock, echocardiography is of paramount importance for the diagnosis of Gram-negative endocarditis and should be included in our diagnostic algorithm of patient's evaluation.

Culture-dependent and metagenomic analysis of lesser horseshoe bats' gut microbiome revealing unique bacterial diversity and signatures of potential human pathogens

Bats are highly diverse and ecologically important mammals. They harbor various bacteria, viruses, and fungal communities that are either beneficial or potentially pathogenic. Extensive metagenomic studies in bats are limited, particularly for the gut, and to date, there are no reports on the bacterial diversity of Rhinolophus monoceros from Meghalaya, India. There are limited studies on the isolation of potential harmful or beneficial bacteria and their interactions with the environment through culture-dependent approaches. Therefore, high-throughput screening was used to understand the population structure, genetic diversity, and ecological role of the microorganisms. High-throughput sequencing of the 16S rRNA marker for gene mapping showed that the gut samples constitute a diverse group of bacteria that is dominated by Proteobacteria, followed by Firmicutes. The bacterial genera Corynebacterium and Mycobacterium were also observed in the Illumina dataset. Illumina sequencing revealed eight bacterial phyla composed of 112 genera. The metagenomic analysis of the OTUs from the gut revealed diverse bacterial communities as well as zoonotic and human pathogens. There were differences in the bacterial communities between the two methods used in this study, which could be related to host specificity, diet, and habitat. The culture-dependent technique resulted in the isolation of 35 bacterial isolates, of which Bacillus cereus and B. anthracis are well-known bacterial pathogens that show virulent traits including hemolytic and proteolytic activities. Pseudomonas stutzeri is an opportunistic human pathogen that was also isolated and showed similar traits. Antibiotic sensitivity tests were performed on all 35 isolates, and different antibiotics were used for Gram-positive and -negative bacteria. The result showed that some isolates are resistant to antibiotics such as penicillin G and Cefoxitin. This report on gut bacterial communities could attract interest in the possibility of isolating and characterizing bacteria for the production of antibiotics, enzymes, plant growth promoters, and probiotics. However, the presence of potential pathogenic bacteria that may impose health hazards cannot be ignored and needs to be studied further.

Escherichia coli endocarditis of a native mitral valve

Escherichia coli (E.coli) is a rare cause of endocarditis, although is a common causative agent of bacteremia. An 89-year-old woman presented with recurrent episodes of fever and persistent E. coli bacteremia with 3-month duration, despite antimicrobial therapy. At first, a urinary tract infection was diagnosed and later a mycotic aneurysm of the abdominal aorta was found and required an endovascular repair. The persistence of fever and the evidence of a systolic murmur at the mitral focus raised the suspicion of endocarditis. A transesophageal echocardiogram and a cardiac Magnetic Resonance Imaging (MRI) confirmed the presence of a vegetation at the mitral valve and the patient was treated with ceftriaxone. The presence of comorbid conditions and certain bacterial virulence factors predispose to this rare condition. A high level of suspicion is important to early diagnosis and prompt therapy.

Native valve endocarditis due to Escherichia coli infection: a case report and review of the literature

Background

Infective endocarditis due to Escherichia coli is a rare disease but is increasing in frequency, especially among older women. In addition, its mortality rate is higher than that of endocarditis due to the HACEK-group gram-negative bacteria (Haemophilus spp., Aggregatibacter spp., Cardiobacterium hominis, Eikenella corrodens, and Kingela spp.).

Case presentation

A 58-year-old Japanese woman with a history of alcohol abuse was admitted to our hospital because of a fever. She was diagnosed with infective endocarditis due to E. coli based on repeated blood cultures and transthoracic echocardiography, which revealed vegetations attached to the anterior leaflet and chordae tendineae of the mitral valve. Despite administration of sulbactam/ampicillin and gentamycin, she developed purulent spondylitis during hospitalization and required treatment with meropenem administration for 6 weeks, leading to resolution of the endocarditis. She took oral levofloxacin for 2 months, and the spondylitis was completely cured 7 months after discharge.

Conclusion

Escherichia coli affects native valves without degenerative valvulopathy rather than prosthetic valves, especially in patients with risk factors such as an immunosuppressive status, excessive alcohol consumption, or treatment with hemodialysis. Peripheral embolization, congestive heart failure, and valve-ring abscesses are major complications of E. coli endocarditis; notably, infective myocarditis can also occur. The mortality and surgical intervention rates are 21% and 42%, respectively. Physicians should be cognizant of the necessity of surgical intervention when E. coli endocarditis is resistant to antibiotic therapy.

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.

Emphysematous endocarditis caused by AmpC beta-lactamase-producing Escherichia coli: A case report

RATIONALE

Infective endocarditis (IE) is a life-threatening disease, mostly caused by gram-positive bacteria. Gram-negative bacteria were identified as a causative organism in relatively small number of cases. Although, antibiotic-resistant Escherichia coli is common cause of gram-negative endocarditis, AmpC beta-lactamase (BL)-harboring E coli is very rare cause of IE. Furthermore, emphysematous endocarditis is also a very rare manifestation of E coli infection.

PATIENT CONCERNS

We report a case of 80-year-old female patient presenting with dizziness, fever, and altered mental status, who was finally diagnosed with emphysematous endocarditis caused by E coli harboring an AmpC BL gene.

DIAGNOSIS

Her chest computed tomography revealed air bubbles surrounding the annulus of a mitral valve and a transesophageal echocardiogram revealed a hyperechogenic mass fixed on the posteromedial side of the mitral annulus with 2 eccentric mitral regurgitation jets. Blood cultures grew E coli which harbored the DHA-type AmpC BL. The organism belonged to a B2 phylogenic group, and multilocus sequence typing analyses revealed that the strains were of ST-95.

INTERVENTIONS

She was treated with meropenem following the resistant profiles, and surgery was recommended by the healthcare professional, but denied by the patient's guardians. She was transferred to another hospital due to a refusal for further treatment.

LESSONS

Emphysematous endocarditis is an uncommon complication of E coli bacteremia. Certain phylogenetic groups may be associated with development of E coli endocarditis.

Infective endocarditis following urinary tract infection caused by Globicatella sanguinis

We report the first case of infective endocarditis following urinary tract infection (UTI) caused by Globicatella sanguinis in an 87-year-old Japanese woman with recurrent episodes of UTI. We identified the pathogen using the Rapid ID32 Strep system. Accurate identification of this infection is important and essential for the effective antimicrobial coverage to this pathogen.

Microbiome analysis reveals the abundance of bacterial pathogens in Rousettus leschenaultii guano

Bats are crucial for proper functioning of an ecosystem. They provide various important services to ecosystem and environment. While, bats are well-known carrier of pathogenic viruses, their possible role as a potential carrier of pathogenic bacteria is under-explored. Here, using culture-based approach, employing multiple bacteriological media, over thousand bacteria were cultivated and identified from Rousettus leschenaultii (a frugivorous bat species), the majority of which were from the family Enterobacteriaceae and putative pathogens. Next, pathogenic potential of most frequently cultivated component of microbiome i.e. Escherichia coli was assessed to identify its known pathotypes which revealed the presence of virulent factors in many cultivated E. coli isolates. Applying in-depth bacterial community analysis using high-throughput 16 S rRNA gene sequencing, a high inter-individual variation was observed among the studied guano samples. Interestingly, a higher diversity of bacterial communities was observed in decaying guano representative. The search against human pathogenic bacteria database at 97% identity, a small proportion of sequences were found associated to well-known human pathogens. The present study thus indicates that this bat species may carry potential bacterial pathogens and advice to study the effect of these pathogens on bats itself and the probable mode of transmission to humans and other animals.

Practice variation in treatment of suspected asymptomatic bacteriuria prior to cardiac surgery: are there differences in postoperative outcome? A retrospective cohort study

OBJECTIVES

It is unclear whether postoperative infections can be prevented by treating asymptomatic bacteriuria, or whether, on the other hand, such treatment will increase the risk of more serious infection by pathogenic bacteria different from the ones causing bacteriuria. This study aimed to support future treatment decisions for preoperative cardiothoracic surgery patients with asymptomatic bacteriuria, by examining current preoperative practice, in relation to postoperative outcome.

METHODS

A retrospective cohort study was conducted. All patients who underwent cardiothoracic surgery in 2011-2013 using extracorporeal circulation in St. Antonius Hospital Nieuwegein, and who preoperatively had nitrituria and/or leucocyturia were included. Exclusion criteria were C-reactive protein level higher than 10 mg/l, emergency surgery, critical preoperative state and/or antibiotic treatment because of other infections. Outcomes were postoperative infections and length of stay. Furthermore, we compared culture results of preoperative urine with postoperative infection sites in order to study the hypothesis of haematogenous spread.

RESULTS

One thousand and two patients with leucocyturia or nitrituria were eligible, of whom 3.9% had been treated with antibiotics preoperatively (AB+). Of the 96.1% of patients who had not been treated (AB-), 8.3% had an infection postoperatively, compared with 5.1% in the treatment (AB+) group. This was not statistically significant {odds ratio, corrected for EuroSCORE, 0.53 [95% confidence interval (CI) 0.12-2.24, P = 0.39]}. Length of stay, corrected for EuroSCORE, between the treated (AB+) and the non-treated (AB-) group did not differ, with a hazard ratio of 1.05 (95% CI 0.63-1.75, P = 0.85). As regards bacterial culture results, none of patients not treated with antibiotics preoperatively (AB-) seemed to have a postoperative infection due to haematogenous spread of bacteria from the urinary tract present preoperatively.

CONCLUSIONS

The risk of haematogenous spread of bacteria seems to be non-existent in this large cohort of non-treated patients, under our local clinical practice. Based on this current, best available evidence, it seems therefore safe not to treat patients with asymptomatic bacteriuria prior to cardiothoracic surgery. This could also imply that it is safe not to perform routine preoperative urine testing.

Necrotizing fasciitis and infective endocarditis caused by Escherichia coli in a hemodialysis patient

Patients with uremia are often immunocompromised and uremia patients undergoing maintenance dialysis are often vulnerable to uncommon infections. We report a 40-year-old man who was undergoing maintenance hemodialysis and was initially diagnosed with monomicrobal necrotizing fasciitis of the lower limbs, based on blood and pus cultures that yielded Escherichia coli. His condition improved after surgical debridement and antibiotic therapy. However, he eventually died of intracranial hemorrhage related to septic emboli. Concurrent infective endocarditis was diagnosed based on an echocardiogram that indicated vegetation in the left ventricular region. Escherichia coli-related necrotizing fasciitis and infective endocarditis is rarely seen in clinical practice. There should be a high index of suspicion for multiple infections when a hemodialysis patient presents with an uncommon infection.

Infective endocarditis in the Lao PDR: clinical characteristics and outcomes in a developing country

INTRODUCTION

Data on infective endocarditis (IE) in Southeast Asia are scarce.

OBJECTIVES

To describe the clinical epidemiology of IE in Lao PDR, a lower middle-income country.

METHODS

A single centre retrospective study at Mahosot Hospital, Vientiane. Patients aged over 1year of age admitted 2006-2012 to Mahosot Hospital with definite or possible IE by modified Duke criteria were included.

RESULTS

Thirty-six patients fulfilled the inclusion criteria; 33 (91.7%) had left-sided IE. Eleven (30.6%) had definite IE and 25 (69.4%) possible left-sided IE. Median age was 25years old [IQR 18-42]. Fifteen patients (41.7%) were males. Underlying heart diseases included: rheumatic valve disease in 12 (33.3%), congenital heart disease in 7 (19.4%), degenerative valve disease in 3 (8.3%), and of unknown origin in 14 (38.9%) patients. Native valve IE was present in 30 patients (83.3%), and prosthetic valve IE in 6 patients (16.7%). The most frequent pathogens were Streptococcus spp. in 7 (19.4%). Blood cultures were negative in 22 patients (61.1%). Complications included: heart failure in 11 (30.6%), severe valve regurgitation in 7 (19.4%); neurological event in 7 (19.4%); septic shock or severe sepsis in 5 (13.9%); and cardiogenic shock in 3 patients (8.3%). No patient underwent heart surgery. Fourteen (38.9%) had died by follow-up after a median of 2.1years [IQR 1-3.2]; and 3 (8.3%) were lost to follow-up.

CONCLUSIONS

Infective endocarditis, a disease especially of young adults and mainly caused by Streptococcus spp., was associated with rheumatic heart disease and had high mortality in Laos.

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.

An Unusual Case of Early Onset Persistent Escherichia coli Septicemia Associated with Endocarditis

Escherichia coli infection is very common cause of early onset septicemia especially in very low-birth-weight newborns, but E. coli endocarditis has not been described in newborns. E. coli endocarditis, even in the adult population, is a rare and not well-characterized disease and is associated with high mortality. We report a very unusual presentation of persistent E. coli infection associated with endocarditis.

Complete heart block associated with tricuspid valve endocarditis due to extended spectrum β-lactamase-producing Escherichia coli

We report a case of complete heart block associated with tricuspid endocarditis due to extended-spectrum β-lactamase-producing Escherichia coli (ESBL E. coli) following a transrectal prostate biopsy. This is the first report of complete heart block associated with tricuspid native valve endocarditis. In addition, this is also the first reported case of ESBL E. coli causing endocarditis of any kind. Prompt antibiotic therapy resulted in a downgrading of the high-grade conduction block and eventual cure of an associated complication, vertebral osteomyelitis, and discitis. The anatomy and microbiology of endocarditis in the context of heart block are presented and discussed.

Staphylococcus spp., Enterobacteriaceae and Pseudomonadaceae oral isolates from Brazilian HIV-positive patients. Correlation with CD4 cell counts and viral load

The aim was to evaluate the presence of Staphylococcus spp., Enterobacteriaceae and Pseudomonadaceae in the oral cavities of HIV-positive patients. Forty-five individuals diagnosed as HIV-positive by ELISA and Western-blot, and under anti-retroviral therapy for at least 1 year, were included in the study. The control group constituted 45 systemically healthy individuals matched to the HIV patients to gender, age and oral conditions. Oral rinses were collected and isolates were identified by API system. Counts of microorganisms from HIV and control groups were compared statistically by a Mann-Whitney test (α=5%). The percentages of individuals positive for staphylococci were similar between the groups (p=0.764), whereas for Gram-negative rods, a higher percentage was observed amongst HIV-positive (p=0.001). There was no difference in Staphylococcus counts between HIV and control groups (p=0.1008). Counts were lower in the oral cavities of patients with low viral load (p=0.021), and no difference was observed in relation to CD4 counts (p=0.929). Staphylococcus aureus was the most frequently isolated species in HIV group, and Staphylococcus epidermidis was the prevalent species in the control group. Significantly higher numbers of enteric bacteria and pseudomonas were detected in the oral cavities of the HIV group than in the control (p=0.0001). Enterobacter cloacae was the most frequently isolated species in both groups. Counts of enteric bacteria and pseudomonas were significantly lower in patients with low CD4 counts (p=0.011); however, there was no difference relating to viral load. It may be concluded that HIV group showed greater species diversity and a higher prevalence of Enterobacteriaceae/Pseudomonadaceae.

[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.

Multi-resistant Escherichia coli and mycotic aneurysm: two case reports

INTRODUCTION

Mycotic aneurysms account for a small proportion of all aneurysms. Escherichia coli a gram-negative organism, is recognised as a rare cause of aortic aneurysm. We report two cases of mycotic aneurysm caused by the same strain of multi-resistant Escherichia coli. The purpose of this case report is to highlight the possibility that this strain may be associated with an increased risk of endovascular infection especially in extra-aortic sites. These aneurysms can be difficult to detect and can have serious consequences.

CASE PRESENTATION

In case one, the patient presented with symptoms and signs of septicaemia secondary to a urinary tract infection. Despite adequate treatment the patient continued with pyrexia and raised inflammatory markers, therefore a series of CT scans of the abdomen and thorax were performed, which revealed two intra-thoracic pseudo-aneurysms with associated haematomas. In case two, the patient also developed Escherichia coli septicaemia. On day 44 he developed a swelling on the right side of his neck. An ultrasound scan showed a pseudoaneurysm of the right common carotid artery.

CONCLUSIONS

Whilst a case report cannot prove that a heightened risk exists, we suggest that it is an area worthy of further surveillance. We recommend when older patients with atheromatosis develop prolonged Escherichia coli septicaemia, the possibility of an infected aneurysm should be borne in mind.

Evaluation of the relationship between causative organisms and clinical characteristics of infective endocarditis in dogs: 71 cases (1992-2005)

OBJECTIVE

To evaluate microbiologic findings in dogs with infective endocarditis (IE) and determine whether there were differences in clinical features of disease caused by different groups of infective agents.

DESIGN

Retrospective case series.

ANIMALS

71 dogs with suspected or definite IE.

PROCEDURES

Medical records were reviewed for results of bacterial culture and susceptibility testing, serologic assays for vector-borne disease, and PCR testing on vegetative growths. Cases were grouped by causative organism and relationships among infectious agent group, and various hematologic, biochemical, and clinical variables were determined. Survival analyses were used to determine associations between infecting organisms and outcome.

RESULTS

Causative bacteria were identified in 41 of 71 (58%) dogs. Gram-positive cocci were the causative agents in most (21/41; 51%) infections, with Streptococcus canis associated with 24% of infections. Gram-negative organisms were detected in 9 of the 41 (22%) dogs. Infection with Bartonella spp was detected in 6 of 31 (19%) dogs with negative results for microbial growth on blood culture. Aortic valve involvement and congestive heart failure were more frequent in dogs with endocarditis from Bartonella spp infection, and those dogs were more likely to be afebrile. Infection with Bartonella spp was negatively correlated with survival. Mitral valve involvement and polyarthritis were more frequent in dogs with streptococcal endocarditis.

CONCLUSIONS AND CLINICAL RELEVANCE

Streptococci were the most common cause of IE and were more likely to infect the mitral valve and be associated with polyarthritis. Dogs with IE secondary to Bartonella spp infection were often afebrile, more likely to develop congestive heart failure, rarely had mitral valve involvement, and had shorter survival times.