A 10-year survey of blood culture negative endocarditis in Sweden: Aminoglycoside therapy is important for survival

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.

Comparing Treatment Outcomes of Ampicillin-Sulbactam, Other β-Lactams, and Vancomycin in Blood Culture-Negative Infective Endocarditis

Selection of proper antibiotics for blood culture-negative infective endocarditis (BCNIE) is difficult due to limited data on antibiotic regimens for BCNIE in existing literature. The aim of this study was to compare ampicillin-sulbactam, other β-lactams antibiotics, and vancomycin among patients with BCNIE to determine the proper antibiotic regimens. This retrospective study included adult patients with BCNIE admitted to Severance Hospital from November 2005 to August 2017. Patients were classified into three groups as, treated with ampicillin-sulbactam, other β-lactams, and vancomycin. The primary outcome was 1-year all-cause mortality. A total of 74 cases with BCNIE were enrolled in this study. There were no statistically significant differences in clinical characteristics between the three groups. One-year mortality did not significantly differ between the study groups either. Further, in-hospital mortality, 28-day mortality and overall mortality showed no difference. However, Cox-regression analysis showed nosocomial infective endocarditis as an independent risk factor and a protective effect of surgery on 1-year mortality. This study showed no clear difference in the outcomes of BCNIE as per the antibiotic therapy but suggested the beneficial effect of surgical treatment. With increasing global concern of antimicrobial resistance, it might be reasonable to select ampicillin-sulbactam-based antibiotic therapy while actively considering surgical treatment in BCNIE.

Evaluation of 16S rDNA Heart Tissue PCR as a Complement to Blood Cultures for the Routine Etiological Diagnosis of Infective Endocarditis

Identification of the causative pathogen is required to optimize the effective therapy in infective endocarditis (IE). The aim of this study was to assess a 16S rDNA PCR to identify bacteria from heart valve tissues and to evaluate its usefulness as a complement to blood and removed valves cultures. A total of 266 patients diagnosed with IE from January 2015 to December 2019 were evaluated. Results between 16S rDNA PCR from heart valve tissues were compared with microbiological cultures. Blood cultures were positive in 83.5% of patients diagnosed with IE, while 39.6% and 71.8% of the evaluated heart valve samples were positive by culture and 16S rDNA PCR, respectively. For 32 (12%) patients, 16S rDNA tissue PCR provided valuable information supporting the results of blood cultures in the case of bacteria characteristic from the skin microbiota. Additionally, a microorganism was identified by using 16S rDNA PCR in 36% of blood culture-negative cases. The present study reveals that molecular diagnosis using 16S rDNA tissue PCR provides complementary information for the diagnosis of IE, and it should be recommended in surgical endocarditis, especially when blood cultures are negative.

A changing profile of infective endocarditis at a tertiary hospital in China: a retrospective study from 2001 to 2018

Background

Infective endocarditis (IE) is a lethal disease which has been changing significantly over the past decades; however, information about IE in China remains scarce. This study surveyed the changes in clinical characteristics of IE at a tertiary hospital in south China over a period of nearly 18 years.

Methods

Medical records with IE patients consecutively hospitalized between June 2001 and June 2018 were selected from the electronic medical records system in Nanfang Hospital of Southern Medical University. Data were divided by admission time into two groups equally: early-period group, June 2001 to December 2009 and later-period group, January 2010 to July 2018.

Results

A Total of 313 IE patients were included in our study. Compared with the early-period group, patients in the later-period group included fewer intravenous drug users (IVDUs), older age at onset, reduced development of pulmonary embolism, less renal dysfunction, decreased proportion of Staphylococcus aureus infection and fewer vegetations observed in the right heart by echocardiography. The later-period group also showed a higher proportion of ischemic strokes and higher proportion of positive microbiological findings compared with the early-period group. The in-hospital mortality remained about the same between the two periods and the multivariate analysis identified intravenous drug addicted, prosthetic valve endocarditis, hemorrhagic stroke, acute congestive heart failure, renal insufficiency, left-sided endocarditis, early surgical as independent predictors of in-hospital mortality.

Conclusions

Our study demonstrated a dramatic change in the profile of IE over a period of 18 years at a tertiary hospital in south China and presented several independent predictors of in-hospital mortality. The geographic variations observed in our study will be of important value to profile the clinical feature of China and offer the reference for clinical decisions in our region.

Ruptured mitral valve abscess with mitral incompetence in culture negative infective endocarditis: case report

Introduction

Perivalvular abscess in native valve infective endocarditis (IE) is associated with significantly increased mortality.

Case description

Herein, we report a 29 year old Indian male who presented with culture negative IE with perivalvular abscess and severe mitral regurgitation requiring mitral valve replacement.

Discussion

Initial approach is very difficult in terms of when IE presents as culture negative. This case highlights the important role of echocardiography in the management of culture negative IE.

Evaluation of empirical treatment for blood culture-negative endocarditis

OBJECTIVES

Much progress has been made in understanding the main causes of blood culture-negative endocarditis (BCNE). Few studies concerning BCNE treatment (due to previous antibiotics used or fastidious pathogens) are available. We performed this study to evaluate the effectiveness of our therapeutic protocol in BCNE, based on compliance with the protocol, outcome and 1 year mortality.

PATIENTS AND METHODS

We collected prospectively and analysed retrospectively cases of BCNE between 2002 and 2014, using a simplified and standardized protocol developed by our multidisciplinary team. We apply two kinds of protocols to treat BCNE, which include only four intravenous antimicrobial agents: amoxicillin, vancomycin, gentamicin and amphotericin B.

RESULTS

We had 177 patients with definite BCNE. There were 154 (87.0%) patients treated with both appropriate antimicrobial agents and appropriate duration of treatment. We analysed the causes of inappropriate treatment in 13 (7.3%) cases and inappropriate duration in 10 (5.6%) cases. The treatment changes were justified in all cases except one of discharge against medical advice. The fatality rate was 5.1% (nine cases) and all deaths occurred in the group of patients who were treated with appropriate treatment; however, four deaths were not attributable to empirical treatment failure. Concerning the other deaths, the lack of surgical management, in association with empirical treatment, could explain our protocol's failure, such as poorly tolerated surgery.

CONCLUSIONS

Our protocol is efficient and our mortality rate was low, compared with the literature review. This may result from a strategy that uses a sampling procedure and a standardized protocol at the same time.

Diagnosis of blood culture-negative endocarditis and clinical comparison between blood culture-negative and blood culture-positive cases

PURPOSE

To analyze the clinical characteristics of blood culture-negative endocarditis (BCNE) and how it compares to those of blood culture-positive endocarditis (BCPE) cases and show how molecular tools helped establish the etiology in BCNE.

METHODS

Adult patients with definite infective endocarditis (IE) and having valve surgery were included. Valves were studied by polymerase chain reaction (PCR). Statistical analysis compared BCNE and BCPE.

RESULTS

One hundred and thirty-one patients were included; 53 (40 %) had BCNE. The mean age was 45 ± 16 years; 33 (62 %) were male. BCNE was community-acquired in 41 (79 %). Most patients were referred from other hospitals (38, 73 %). Presentation was subacute in 34 (65 %), with fever in 47/53 (90 %) and a new regurgitant murmur in 34/42 (81 %). Native valves were affected in 74 %, mostly left-sided. All echocardiograms showed major criteria for IE. Antibiotics were used prior to BC collection in 31/42 (74 %). Definite histological diagnosis was established for 35/50 (70 %) valves. PCR showed oralis group streptococci in 21 (54 %), S. aureus in 3 (7.7 %), gallolyticus group streptococci in 2 (5.1 %), Coxiella burnetii in 1 (2.5 %) and Rhizobium sp. in 1 (2.5 %). In-hospital mortality was 9/53 (17 %). Fever (p = 0.06, OR 4.7, CI 0.91-24.38) and embolic complications (p = 0.003, OR 3.3, CI 1.55-6.82) were more frequent in BCPE cases, while new acute regurgitation (p = 0.05, OR 0.3, CI 0.098-0.996) and heart failure (p = 0.02, OR 0.3, CI 0.13-0.79) were less so.

CONCLUSIONS

BCNE resulted mostly from prior antibiotics and was associated with severe hemodynamic compromise. Valve histopathology and PCR were useful in confirming the diagnosis and pointing to the etiology of BCNE.

Infective endocarditis: does a new 16S rDNA set of primers improve the microbiological diagnosis?

BACKGROUND

In infective endocarditis (IE), blood cultures are negative in 2.5-31% of cases because of a previously prescribed antimicrobial treatment. Molecular methods may represent an alternative to conventional microbiological techniques to identify the causative agent. The aim of this prospective study was to evaluate the performance of a new primer pair (341F/785R) for 16S rDNA amplification in heart valves compared with primers 91E/13BS already used for the diagnosis of IE. The primer pair 341F/785R was previously selected in silico to allow 16S rDNA amplification for a large coverage of bacterial species.

RESULTS

A total of 74 patients suspected of having IE were included in this study. IE was diagnosed in 55 of these patients using the modified Duke criteria, which was the gold standard here. 91E/13BS primers were more sensitive than 341F/785R primers: 38/55 (69.1%) samples were positive using 91E/13BS primers against 28/55 (50.9%) with 341F/785R (p = 0.013). When at least one of the two molecular methods was positive, the sensitivity and specificity of 16S rDNA amplification was 72.7% and 94.7%, respectively.

CONCLUSION

Even if the new primer pair 341F/785R seemed promising in silico, it was less sensitive for 16S rDNA amplification in heart valves than the 91E/13BS pair already used. This study underlines a lack of standardization for 16S rDNA amplification for clinical samples.

Global and regional burden of infective endocarditis, 1990-2010: a systematic review of the literature

Infective endocarditis (IE) is a life-threatening disease associated with serious complications. The GBD 2010 (Global Burden of Disease, Injuries, and Risk Factors) study IE expert group conducted a systematic review of IE epidemiology literature to inform estimates of the burden on IE in 21 world regions in 1990 and 2010. The disease model of IE for the GBD 2010 study included IE death and 2 sequelae: stroke and valve surgery. Several medical and science databases were searched for IE epidemiology studies in GBD high-, low-, and middle-income regions published between 1980 and 2008. The epidemiologic parameters of interest were IE incidence, proportions of IE patients who developed stroke or underwent valve surgery, and case fatality. Literature searches yielded 1,975 unique papers, of which 115 published in 10 languages were included in the systematic review. Eligible studies were population-based (17%), multicenter hospital-based (11%), and single-center hospital-based studies (71%). Population-based studies were reported from only 6 world regions. Data were missing or sparse in many low- and middle-income regions. The crude incidence of IE ranged between 1.5 and 11.6 cases per 100,000 people and was reported from 10 countries. The overall mean proportion of IE patients that developed stroke was 0.158 ± 0.091, and the mean proportion of patients that underwent valve surgery was 0.324 ± 0.188. The mean case fatality risk was 0.211 ± 0.104. A systematic review for the GBD 2010 study provided IE epidemiology estimates for many world regions, but highlighted the lack of information about IE in low- and middle-income regions. More complete knowledge of the global burden of IE will require improved IE surveillance in all world regions.

PCR-electrospray ionization time-of-flight mass spectrometry: a new tool for the diagnosis of infective endocarditis from heart valves

A polymerase chain reaction with an injection of the amplicons in an electrospray ionization mass spectrometry (PCR-ESI-MS) technique was evaluated for the diagnosis of bacterial and yeast pathogens on 13 cardiac valves with suspected endocarditis. At the moment of surgery, 3/13 PCR-ESI-MS results matched with microbiological documentation. Nine PCR-ESI-MS results correlated with Duke's criteria, leukocytes, C-reactive protein and blood cultures before surgery. The PCR-ESI-MS result of the last valve failed to confirm the blood culture result obtained fifteen days before. With speed and accuracy, this method may be useful to assert microbiological identification and adapt treatment.

Transthoracic and transesophageal echocardiography for the indication of suspected infective endocarditis: vegetations, blood cultures and imaging

BACKGROUND

The aim of this study was to investigate the ability of transthoracic echocardiography (TTE) to detect vegetations and the relationship between blood cultures and transesophageal echocardiography (TEE).

METHODS

Five hundred eleven TTE and TEE pairs performed to evaluate endocarditis were retrospectively analyzed. Vegetation on TTE, prosthetic valve, change in regurgitation, and blood cultures were correlated with vegetation on TEE.

RESULTS

TTE detected 45% of vegetations seen on TEE. There was no difference for prosthetic valves. Prosthetic valves (odds ratio, 1.7; P = .03) and increased regurgitation (odds ratio, 1.7; P = .01) were associated with vegetations on TEE; staphylococcal bacteremia and fungemia were not. Negative blood cultures were associated with negative results on TEE (P < .0001), but 27% of patients with prosthetic valves had culture-negative endocarditis or nonbacterial thrombotic endocarditis, and 6% had abscesses missed by TTE.

CONCLUSION

This study demonstrates a limited capacity of TTE to detect vegetations. TEE may be an appropriate initial study to evaluate prosthetic valves. TEE for culture-negative endocarditis deserves further study.

Infective endocarditis--prophylaxis, diagnostic criteria, and treatment

BACKGROUND

Despite important medical advances, infective endocarditis (IE) is still a disease with high morbidity and mortality. Its prophylaxis, diagnosis, and treatment are still a major challenge in clinical practice.

METHODS

Selective literature review based on the current German and European guidelines and a PubMed search from 2004 onward.

RESULTS

Essential requirements for the rapid diagnosis and specific treatment of IE are the echocardiographic demonstration of endocardial disease and the identification of the causative organism by blood culture. The modified Duke criteria have made the diagnosis more objective but are not a replacement for clinical judgement. It should be borne in mind, when the initial empirical treatment is chosen, that Staphylococcus aureus is currently the most common causative organism. If diagnostic criteria are met that suggest a methicillin-resistant S. aureus infection, then glycopeptide antibiotics are still the standard treatment. Newer agents such as daptomycin can be considered as an alternative, as suggested by recent studies and in view of the increasing frequency of impaired vancomycin susceptibility. Early surgical treatment should be considered for patients who are likely to encounter further complications along their clinical course. According to the current recommendations, antibiotics should be given for endocarditis prophylaxis only to patients about to undergo one of a small number of explicitly defined procedures, who would otherwise be at a high risk of major illness or death. The purpose of this restriction is to make prophylaxis more efficient.

CONCLUSION

IE remains a potentially lethal infectious disease that can be treated effectively only by physicians from multiple disciplines working in collaboration.