Proposal for the use of echocardiography in bloodstream infections due to different streptococcal species

Infective Endocarditis in Patients With Bicuspid Aortic Valves: Unique Clinical and Microbiologic Features

OBJECTIVE

Patients with bicuspid aortic valves (BAV) are at increased risk of infective endocarditis (IE). Information of the clinical presentation and the microbiology of BAV-associated IE, however, is limited. Therefore, our study aimed to characterise the clinical features native valve endocarditis (NVE) in the setting of BAV and compared them to patients with prosthetic valve endocarditis (PVE) following BAV replacement.

METHODS

Adult patients with BAV or history of BAV with aortic valve replacement (AVR) and a definite or possible IE diagnosis within the Mayo Clinic Enterprise (USA) from January 2008 to December 2021, were included. BAV was confirmed by trans-oesophageal echocardiography. IE was defined according to the modified Duke criteria and only an initial episode was included. Statistical analyses were performed to compare clinical characteristics, microbiology, and IE complications.

RESULTS

Overall, 161 patients with BAV and IE (NVE [n=60], 37.3%) and PVE [n=101, 62.7%) were included. Mean age±SD was 56.5±16.1 years, and 139 (86.3%) patients were males. PVE patients were older (p<0.01) and had a higher rate of hypertension (p<0.01), chronic heart failure (p<0.01), chronic kidney disease (p<0.01), and perivalvular abscess (p<0.01). BAV patients with NVE had a higher prevalence of isolated mitral valve IE (p<0.01), moderate to severe aortic valve regurgitation (p<0.01) and combined aortic with mitral valve IE (p<0.01). Streptococcus mitis was the most common pathogen in NVE (30.0%) while Staphylococcus aureus was the most common in PVE (15.8%).

CONCLUSIONS

Patients with BAV are at risk of both NVE and PVE. Each syndrome has unique clinical features, including microbiologic findings, that should be appreciated in IE diagnosis and management.

Evaluation of the HANDOC Score and the 2023 International Society of Cardiovascular Infectious Diseases and European Society of Cardiology Duke Clinical Criteria for the Diagnosis of Infective Endocarditis Among Patients With Streptococcal Bacteremia

BACKGROUND

Streptococci are a common cause of infective endocarditis (IE). We aimed to evaluate the performance of the HANDOC score to identify patients at high risk for IE and the Duke clinical criteria of the European Society of Cardiology (ESC; 2015 and 2023 versions) and the 2023 version from the International Society of Cardiovascular Infectious Diseases (ISCVID) in diagnosing IE among patients with streptococcal bacteremia.

METHODS

This retrospective study included adult patients with streptococcal bacteremia hospitalized at Lausanne University Hospital. Episodes were classified as IE by the Endocarditis Team. A HANDOC score >2 classified patients as high risk for IE.

RESULTS

Among 851 episodes with streptococcal bacteremia, IE was diagnosed in 171 episodes (20%). Among 607 episodes with non-β-hemolytic streptococci, 213 (35%) had HANDOC scores >2 points; 132 (22%) had IE. The sensitivity of the HANDOC score to identify episodes at high risk for IE was 95% (95% confidence interval [CI], 90%-98%), the specificity 82% (95% CI, 78%-85%), and the negative predictive value (NPV) 98% (95% CI, 96%-99%). 2015 Duke-ESC, 2023 Duke-ISCVID, and 2023 Duke-ESC clinical criteria classified 114 (13%), 145 (17%), and 126 (15%) episodes as definite IE, respectively. Sensitivity (95% CI) for the 2015 Duke-ESC, 2023 Duke-ISCVID, and 2023 Duke-ESC clinical criteria was calculated at 65% (57%-72%), 81% (74%-86%), and 73% (65%-79%), respectively, with specificity (95% CI) at 100% (98%-100%), 99% (98%-100%), and 99% (98%-100%), respectively.

CONCLUSIONS

The HANDOC score showed an excellent NPV to identify episodes at high risk for IE. Among the different versions of the Duke criteria, the 2023 Duke-ISCVID version fared better for the diagnosis of IE among streptococcal bacteremia.

Streptococcus dysgalactiae subsp. equisimilis infection and its intersection with Streptococcus pyogenes

SUMMARYStreptococcus dysgalactiae subsp. equisimilis (SDSE) is an increasingly recognized cause of disease in humans. Disease manifestations range from non-invasive superficial skin and soft tissue infections to life-threatening streptococcal toxic shock syndrome and necrotizing fasciitis. Invasive disease is usually associated with co-morbidities, immunosuppression, and advancing age. The crude incidence of invasive disease approaches that of the closely related pathogen, Streptococcus pyogenes. Genomic epidemiology using whole-genome sequencing has revealed important insights into global SDSE population dynamics including emerging lineages and spread of anti-microbial resistance. It has also complemented observations of overlapping pathobiology between SDSE and S. pyogenes, including shared virulence factors and mobile gene content, potentially underlying shared pathogen phenotypes. This review provides an overview of the clinical and genomic epidemiology, disease manifestations, treatment, and virulence determinants of human infections with SDSE with a particular focus on its overlap with S. pyogenes. In doing so, we highlight the importance of understanding the overlap of SDSE and S. pyogenes to inform surveillance and disease control strategies.

Performance of the 2023 Duke-International Society of Cardiovascular Infectious Diseases Diagnostic Criteria for Infective Endocarditis in Relation to the Modified Duke Criteria and to Clinical Management-Reanalysis of Retrospective Bacteremia Cohorts

BACKGROUND

Revised diagnostic criteria for infective endocarditis (IE), the 2023 Duke-ISCVID criteria, were recently presented and need validation. Here, we compare the 2000 modified Duke criteria for IE with Duke-ISCVID among patients with bacteremia and relate the diagnostic classification to IE treatment.

METHODS

We reanalyzed patient cohorts with Staphylococcus aureus, Staphylococcus lugdunensis, non-β-hemolytic streptococci, Streptococcus-like bacteria, Streptococcus dysgalactiae, Enterococcus faecalis, and HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella) bacteremia. Episodes were classified as definite, possible, or rejected IE with the modified Duke and Duke-ISCVID criteria. Reclassification included the microbiology criteria, positron emission tomography-computed tomography, and cardiac implanted electronic devices. To calculate sensitivity, patients treated for IE were considered as having IE.

RESULTS

In 4050 episodes of bacteremia, the modified Duke criteria assigned 307 episodes (7.6%) as definite IE, 1190 (29%) as possible IE, and 2553 (63%) as rejected IE. Using the Duke-ISCVID criteria, 13 episodes (0.3%) were reclassified from possible to definite IE, and 475 episodes (12%) were reclassified from rejected to possible IE. With the modified Duke criteria, 79 episodes that were treated as IE were classified as possible IE, and 11 of these episodes were reclassified to definite IE with Duke-ISCVID. Applying the decision to treat for IE as a reference standard, the sensitivity of the Duke-ISCVID criteria was 80%. None of the 475 episodes reclassified to possible IE were treated as IE.

CONCLUSIONS

The Duke-ISCVID criteria reclassified a small proportion of episodes to definite IE at the expense of more episodes of possible IE. Future criteria should minimize the possible IE group while keeping or improving sensitivity.

Bacteraemia with gram-positive bacteria-when and how do I need to look for endocarditis?

BACKGROUND

Patients with bacteraemia caused by gram-positive bacteria are at risk for infective endocarditis (IE). Because IE needs long antibiotic treatment and sometimes heart valve surgery, it is very important to identify patients with IE.

OBJECTIVES

In this narrative review we present and discuss how to determine which investigations to detect IE that are needed in individual patients with gram-positive bacteraemia.

SOURCES

Published original studies and previous reviews in English, within the relevant field are used.

CONTENT

First, the different qualities of the bacteraemia in relation to IE risk are discussed. The risk for IE in bacteraemia is related to the species of the bacterium but also to monomicrobial bacteraemia and the number of positive cultures. Second, patient-related factors for IE risk in bacteraemia are presented. Next, the risk stratification systems to determine the risk for IE in gram-positive bacteraemia caused by Staphylococcus aureus, viridans streptococci, and Enterococcus faecalis are presented and their use is discussed. In the last part of the review, an account for the different modalities of IE-investigations is given. The main focus is on echocardiography, which is the cornerstone of IE-investigations. Furthermore, 18F-fluorodesoxyglucose positron emission tomography/computed tomography and cardiac computed tomography are presented and their use is also discussed. A brief account for investigations used to identify embolic phenomena in IE is also given. Finally, we present a flowchart suggesting which investigations to perform in relation to IE in patients with gram-positive bacteraemia.

IMPLICATIONS

For the individual patient as well as the healthcare system, it is important both to diagnose IE and to decide when to stop looking for IE. This review might be helpful in finding that balance.

Infective Endocarditis Due to Kingella kingae

Infective endocarditis due to Kingella kingae is a rare but serious invasive infection that occurs mostly in children. Recent advances in nucleic acid amplification testing as well as in cardiac imaging have enabled more accurate diagnosis. A good understanding of the epidemiology and virulence factors remains crucial to guide the therapeutic approach. Here, we synthesize the current state of knowledge on epidemiological features, pathophysiological insights, complications, and therapy regarding Kingella kingae endocarditis in children and adults. Finally, throughout this comprehensive review, knowledge gaps and areas for future research are also identified.

Species designation of streptococci causing infective endocarditis in patients with mitral valve prolapse

OBJECTIVES

Viridans group streptococci (VGS) have been previously linked to infective endocarditis (IE) in patients with mitral valve prolapse (MVP). The species identification of VGS is now available in clinical laboratories; however, it has not been examined in MVP IE. Therefore, we detailed the clinical profile, species designations, and antibiotic susceptibility of VGS isolates from patients with MVP IE.

METHODS

We retrospectively queried all adults with MVP and a definite or possible IE diagnosis seen at medical centers of the Mayo Clinic Enterprise from January 2009 to December 2021. Data, including clinical characteristics, comorbidities, microbiology, and outcomes, were extracted from electronic health records. VGS isolates from patients with MVP and IE were subclassified into mutans, salivarius, anginosus, sanguinis, and mitis groups.

RESULTS

A total of 38 patients with MVP with IE due to streptococcal species were included. Overall, median age was 62.4 years and 32% of patients were females. The most prevalent comorbidities were diabetes mellitus (26%), hypertension (21%), heart failure (16%), and malignancy (16%). A total of (37%) patients presented with an embolic event at the time of their IE diagnosis, 27 (66%) required valve surgery, and no patient died within the hospital stay. The Streptococcus mitis group was the predominant (n = 17, 45%) species designation; S. anginosus and S. sanguinis were identified in three (8%) each; S. mutans in two (5%); and S. salivarius in one (3%). Non-VGS streptococcal pathogens included S. agalactiae in three patients (8%), S. equi in two (5%), and S. dysgalactiae and S. bovis in one each (3%). VGS were identified in five (13%) patients, but species designation was not done. No penicillin resistance was identified among the isolates.

CONCLUSION

The S. mitis group was the predominant species in our investigation. Continued evaluation of VGS species should be considered to profile the IE risk based on species identification.

Time to blood culture positivity- an independent predictor of mortality in Streptococcus pyogenes bacteraemia

Background

Streptococcus pyogenes bacteremia is a severe condition with high mortality. Time to blood culture positivity (TTP) is known to predict the outcome in bacteremia with other pathogens. This study aimed to determine the association between TTP and outcome in S pyogenes bacteremia.

Methods

This retrospective observational cohort study comprised adults with S pyogenes bacteremia, identified through the laboratory database between 2015 and 2018, in the Region of Skåne, Sweden. Correlations between TTP and outcomes were investigated. Primary outcome was death within 30 days, and secondary outcomes were presence of sepsis or disease deterioration within the first 48 hours.

Results

A total of 347 episodes of S pyogenes bacteremia were identified, of which 61 were excluded, resulting in 286 included episodes. Median TTP was 10.4 (interquartile range, 8.4–11.4) hours. Thirty-day mortality was 10%. Median TTP was shorter in patients who died within 30 days compared to survivors (8.6 vs 10.4 hours; P < .001). In a multivariable logistic regression, shorter TTP was associated with 30-day mortality when adjusting for age, Charlson Comorbidity Index, and focus of infection (odds ratio, 3.7 [95% confidence interval, 1.2–11.3]; P = .02). There was no statistically significant difference in TTP between patients with sepsis within 48 hours and those who did not have sepsis. Additionally, there was no statistically significant difference in TTP between patients with disease deterioration compared to those who did not deteriorate.

Conclusions

Knowledge on TTP might be a tool to determine the prognosis of a given patient with S pyogenes bacteremia.