Current controversies in infective endocarditis

Prophylactic antibiotic use for infective endocarditis: a systematic review and meta-analysis

OBJECTIVES

Infective endocarditis (IE) is a devastating disease with a 50% 1-year mortality rate. In recent years, medical authorities across the globe advised stricter criteria for antibiotic prophylaxis in patients with high risk of IE undergoing dental procedures. Whether such recommendations may increase the risk of IE in at-risk patients must be investigated.

DESIGN

Prospectively registered systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, Scopus and ClinicalTrials.gov were searched through 23 May 2022, together with an updated search on 5 August 2023.

ELIGIBILITY CRITERIA

All primary studies reporting IE within 3 months of dental procedures in adults >18 years of age were included, while conference abstracts, reviews, case reports and case series involving fewer than 10 cases were excluded.

DATA EXTRACTION AND SYNTHESIS

All studies were assessed by two reviewers independently, and any discrepancies were further resolved through a third researcher.

RESULTS

Of the 3771 articles screened, 38 observational studies fit the inclusion criteria and were included in the study for subsequent analysis. Overall, 11% (95% CI 0.08 to 0.16, I2=100%) of IE are associated with recent dental procedures. Streptococcus viridans accounted for 69% (95% CI 0.46 to 0.85) of IE in patients who had undergone recent dental procedures, compared with only 21% (95% CI 0.17 to 0.26) in controls (p=0.003). None of the high-risk patients developed IE across all studies where 100% of the patients were treated with prophylactic antibiotics, and IE patients are 12% more likely to have undergone recent dental manipulation compared with matched controls (95% CI 1.00 to 1.26, p=0.048).

CONCLUSIONS

Although there is a lack of randomised control trials due to logistic difficulties in the literature on this topic, antibiotic prophylaxis are likely of benefit in reducing the incidence of IE in high-risk patients after dental procedures. Further well-designed high-quality case-control studies are required.

TRIAL REGISTRATION NUMBER

CRD42022326664.

Bartonella species as a cause of culture-negative endocarditis in South Africa

Previous reports have highlighted the high prevalence of blood culture negative endocarditis (BCNE) in South Africa. The Tygerberg Endocarditis Cohort (TEC) study is an ongoing prospective cohort study of patients with confirmed or suspected IE presenting to Tygerberg Academic Hospital, Cape Town, South Africa. Current analysis includes patients that presented between November 2019 and August 2020. Forty four (44) patients have been included in this ongoing study. Fourteen of the 44 patients (31.8%) had BCNE. Further analysis of the patients with BCNE identified Bartonella species as the most common causative organism (n=6; 43%). Other causes included Mycoplasma species (n=2). No cause could be identified in 4 of the 44 patients (9%). Bartonella quintana was identified with PCR of valvular tissue as the causative organism in 4 of the 5 patients that underwent urgent surgery. The patients with Bartonella IE (n=6) had an average age of 39 years with equal gender distribution. The common clinical features were clubbing (n=5; 83%), anemia (n=4; 66.6%), haematuria (n=3; 50%), acute on chronic severe regurgitant lesion (n=3; 50%) and acute severe regurgitant lesion (n=2; 33.3%).The aortic valve was involved in 5 of 6 patients. During a mean follow-up period of 251 days after diagnosis, no major adverse events occurred. Bartonella-associated IE is an important cause of BCNE in the Western Cape of South Africa. Imaging findings (in patients with BCNE) of significant valvular destruction with large vegetations on the aortic valve not affected by congenital or rheumatic valve disease should raise the suspicion of Bartonella-associated IE.

Infective endocarditis in South Africa

Infective endocarditis (IE) is defined by infection of either a native or prosthetic heart valve, endocardial surface or any cardiac prosthetic device. It is a disease of both the developed and developing world, although IE has evolved in the developed world to a disease markedly different to the disease encountered in the developing world. IE in developed nations is mainly a disease of older patients with degenerative heart valve disease or cardiac prosthetic material, with virulent Staphylococci the most common causative organism. Data regarding the epidemiology of IE in South Africa, a developing country, is limited. The available data suggest it is still a disease of younger patients with rheumatic heart disease (RHD), associated with penicillin-sensitive Streptococcal infection. Although novel diagnostic techniques and improved therapeutic options has emerged, the 1-year mortality rate has remained high in both the developed and developing world at around 30%.

Staphylococcus Aureus Endocarditis associated with Injecting New Psychoactive Substances

Background

Staphylococcus aureus infective endocarditis (IE) associated with injection of new psychoactive substances (NPS) in Edinburgh from 2014 to 2016 was observed. We compared these infections with a series of S. aureus IE cases in a non-injecting population within Edinburgh.

Methods

NPS-associated S. aureus IE diagnosed between 1 January 2014 and 31 May 2016 in persons who inject drugs (PWID) were compared with a series of S. aureus IE cases from non-PWID.

Results

There was a fourfold increase in the annual incidence of S. aureus IE, mainly due to NPS use in PWID. A larger vegetation diameter was seen on echocardiogram in PWID vs non-PWID (median 1.7 cm vs 0.65 cm; p = 0.009) with more embolic complications in PWID (15 PWID vs 1 non-PWID; p = 2.1 x 10-7) but no difference in 90-day mortality (2 PWID vs 4 non-PWID; p = 0.39).

Conclusions

NPS-associated S. aureus IE correlated with complications, such as deep organ embolic abscesses, that were different from non-PWID S. aureus IE. The alarming increase in incidence resolved with targeted public health and legislative measures.

The road less traveled - defining molecular commensalism with Streptococcus sanguinis

The commensal oral microbial flora has evolved with the human host to support colonization of the various intraoral sites without triggering a significant immune response. In exchange, the commensal microbes provide critical protection against invading pathogens. The intrinsic ability of the oral flora to create a symbiotic microbial community with the host can be disturbed, selecting for the overgrowth of a dysbiotic community that can result in dental diseases, such as caries and periodontitis. Although the mechanisms of molecular pathogenesis in oral diseases are well characterized, much less is known about the molecular mechanisms used by the commensal flora to maintain oral health. Here we focus on the commensal species Streptococcus sanguinis, which is found in abundance in the early oral biofilm and is strongly correlated with oral health. Streptococcus sanguinis exhibits a variety of features that make it ideally suited as a model organism to explore the molecular basis for commensalism. As such, this review will describe our current mechanistic understanding of S. sanguinis commensalism and speculate upon its molecular traits that may be exploitable to maintain or restore oral health under conditions that would otherwise lead to disease.

The prognosis of infective endocarditis treated with biological valves versus mechanical valves: A meta-analysis

OBJECTIVE

Surgery remains the primary form of treatment for infective endocarditis (IE). However, it is not clear what type of prosthetic valve provides a better prognosis. We conducted a meta-analysis to compare the prognosis of infective endocarditis treated with biological valves to cases treated with mechanical valves.

METHODS

Pubmed, Embase and Cochrane databases were searched from January 1960 to November 2016.Randomized controlled trials, retrospective cohorts and prospective studies comparing outcomes between biological valve and mechanical valve management for infective endocarditis were analyzed. The Newcastle-Ottawa Scale(NOS) was used to evaluate the quality of the literature and extracted data, and Stata 12.0 software was used for the meta-analysis.

RESULTS

A total of 11 publications were included; 10,754 cases were selected, involving 6776 cases of biological valves and 3,978 cases of mechanical valves. The all-cause mortality risk of the biological valve group was higher than that of the mechanical valve group (HR = 1.22, 95% CI 1.03 to 1.44, P = 0.023), as was early mortality (RR = 1.21, 95% CI 1.02 to 1.43, P = 0.033). The recurrence of endocarditis (HR = 1.75, 95% CI 1.26 to 2.42, P = 0.001), as well as the risk of reoperation (HR = 1.79, 95% CI 1.15 to 2.80, P = 0.010) were more likely to occur in the biological valve group. The incidence of postoperative embolism was less in the biological valve group than in the mechanical valve group, but this difference was not statistically significant (RR = 0.90, 95% CI 0.76 to 1.07, P = 0.245). For patients with prosthetic valve endocarditis (PVE), there was no significant difference in survival rates between the biological valve group and the mechanical valve group (HR = 0.91, 95% CI 0.68 to 1.21, P = 0.520).

CONCLUSION

The results of our meta-analysis suggest that mechanical valves can provide a significantly better prognosis in patients with infective endocarditis. There were significant differences in the clinical features of patients receiving a biological valve compared to patients receiving a mechanical valve. A large, multicenter retrospective study included in our meta-analysis suggested that any mortality risk of the biological valve group was significant higher than that of the mechanical valve group. However, the risk was no different after risk was adjusted. So, we thought the reason for this result may be related to the characteristics of the patient rather than valve dysfunction. It is still necessary to future randomized studies to verify this conclusion.