Beta-Hemolytic Streptococcal Infective Endocarditis: Characteristics and Outcomes From a Large, Multinational Cohort

Gerbode defect resulting from Group B Streptococcus infective endocarditis: a case report

BACKGROUND

Gerbode defect is an unusual abnormal communication between the left ventricle and the right atrium and is a serious complication of aortic infective endocarditis. Group B Streptococcus is an uncommon cause of infective endocarditis and has a markedly destructive effect on valvular tissue. Acute fistulation between the left ventricle and the right atrium associated with this form of infective endocarditis is a life-threatening, aggressive complication that often requires urgent surgical intervention. However, the identification of actual communication is often extremely difficult. Herein, we describe an unusual case of Gerbode defect resulting from Group B Streptococcus infective endocarditis and discuss the issues surrounding such a rare cardiac defect and such an infection.

CASE PRESENTATION

A 60-year-old man with underlying uncontrolled diabetes mellitus underwent endoscopic retrograde biliary drainage for acute cholangitis. On the 10th postoperative day, the patient developed multiple acute cerebral embolisms. Transthoracic echocardiography demonstrated severe aortic regurgitation and a large mobile vegetation near the tricuspid annulus. No obvious fistula between the left ventricle and the right atrium could be demonstrated. The blood culture examination was positive for Group B Streptococcus. The patient was diagnosed with Group B Streptococcus infective endocarditis, and antibiotic therapy was initiated. Transesophageal echocardiogram performed after referral to our hospital confirmed detachment of the right coronary cusp of the aortic valve from the annulus and an abnormal cavity immediately below the right coronary cusp. Color Doppler imaging finally revealed systolic blood flows from the left ventricle into the right atrium through the cavity. Therefore, we diagnosed the patient with Gerbode defect resulting from Group B Streptococcus infective endocarditis. In addition to aortic valve replacement, defect closure and left ventricular outflow tract repair were successfully performed urgently for severely complicated and uncommon infective endocarditis. The patient was uneventfully discharged without any complications.

CONCLUSIONS

We reported successful surgical treatment of unusual active IE and Gerbode defect caused by GBS. Careful preoperative echocardiographic work-up is imperative for accurate early diagnosis and successful repair.

Clinical characteristics and mortality rates of bacteremia caused by Streptococcus anginosus group: A retrospective study of 84 cases at a tertiary hospital in South Korea

The Streptococcus anginosus group (SAG) is a subgroup of viridans streptococci comprising three species: S. anginosus, S. constellatus, and S. intermedius. SAG usually resides in the oral cavity and colonizes the throat, and the gastrointestinal and genitourinary tracts. SAG can form abscesses in various parts of the body; however, the clinical features of SAG infection are not clear. Here, we reviewed the medical records of all SAG bacteremia patients aged over 18 years who were diagnosed between January 2010 and December 2021 at a tertiary university hospital. We then compared clinical characteristics, source of infection, need for surgical or interventional treatment, and 28-day mortality rates among each species of SAG. Differences in percentages between groups were compared using a proportion test, and differences between mean values were assessed using the Kruskal-Wallis test with post-hoc Bonferroni correction. In total, 84 cases of SAG bacteremia (40 S. anginosus cases, 31 S. constellatus cases, and 13 S. intermedius cases) were identified. The most common comorbidity was diabetes mellitus (n = 26, 31%), and the most common source was hepatobiliary infection (n = 30, 35.7%). Polymicrobial bacteremia was observed in 22.6% (19/84) of cases. Twenty-eight day mortality due to S. anginosus bacteremia was 12.5%; no deaths were reported in the S. constellatus and S. intermedius groups. However, the difference among the groups was not significant (p = 0.054). Hepatobiliary infection was the most common source of SAG bacteremia. In addition, S. anginosus bacteremia resulted in more severe disease and higher mortality rates than S. constellatus or S. intermedius bacteremia.

Prognosis of prosthetic valve infective endocarditis due to Streptococcus spp., a retrospective multi-site study to assess the impact of antibiotic treatment duration

PURPOSE

The duration of antibiotic treatment for prosthetic valve endocarditis caused by Streptococcus spp. is largely based on clinical observations and expert opinion rather than empirical studies. Here we assess the impact of a shorter antibiotic duration.

OBJECTIVES

To assess the impact of antibiotic treatment duration for streptococcal prosthetic valve endocarditis on 12-month mortality as well as subsequent morbidity resulting in additional cardiac surgical interventions, and rates of relapse and reinfection.

METHODS

This retrospective multisite (N= 3) study examines two decades of data on patients with streptococcal prosthetic valve endocarditis receiving either 4 or 6 weeks of antibiotics. Overall mortality, relapse, and reinfection rates were also assessed for the entire available follow-up period.

RESULTS

The sample includes 121 patients (median age 72 years, IQR [53; 81]). The majority (74%, 89/121) received a ß-lactam antibiotic combined with aminoglycoside in 74% (89/121, median bi-therapy 5 days [1; 14]). Twenty-eight patients underwent surgery guided by ESC-guidelines (23%). The 12-month mortality rate was not significantly affected by antibiotic duration (4/40, 10% in the 4-week group vs 3/81, 3.7% in the 6-week group, p=0.34) or aminoglycoside usage (p=0.1). Similarly, there were no significant differences between the 2 treatment groups for secondary surgical procedures (7/40 vs 21/81, p=0.42), relapse or reinfection (1/40 vs 2/81 and 2/40 vs 5/81 respectively).

CONCLUSIONS

Our study found no increased adverse outcomes associated with a 4-week antibiotic duration compared to the recommended 6-week regimen. Further randomized trials are needed to ascertain the optimal duration of treatment for streptococcal endocarditis.

Impact of Intermediate Susceptibility to Penicillin on Antimicrobial Treatment and Outcomes of Endocarditis Caused by Viridans and Gallolyticus Group Streptococci

BACKGROUND

Evidence supporting combination treatment with a beta-lactam plus an aminoglycoside (C-BA) for endocarditis caused by viridans and gallolyticus group streptococci (VGS-GGS) with intermediate susceptibility to penicillin (PENI-I) is lacking. We assessed the clinical characteristics and outcomes of PEN-I VGS-GGS endocarditis and compared the effectiveness and safety of C-BA with third-generation cephalosporin monotherapy.

METHODS

Retrospective analysis of prospectively collected data of a cohort of definite endocarditis caused by penicillin-susceptible and PENI-I VGS-GGS (penicillin minimum inhibitory concentration ranging from 0.25 to 2 mg/L) between 2008 and 2018 in 40 Spanish hospitals. We compared cases treated with monotherapy or with C-BA and performed multivariable analyses of risk factors for in-hospital and 1-year mortality.

RESULTS

A total of 914 consecutive cases of definite endocarditis caused by VGS-GGS with complete or intermediate susceptibility to penicillin were included. A total of 688 (75.3%) were susceptible to penicillin and 226 (24.7%) were PENI-I. Monotherapy was used in 415 (45.4%) cases (cephalosporin in 331 cases) and 499 (54.6%) cases received C-BA. In-hospital mortality was 11.9%, and 190 (20.9%) patients developed acute kidney injury. Heart failure (odds ratio [OR]: 6.06; 95% confidence interval [CI]: 1.37-26.87; P = .018), central nervous system emboli (OR: 9.83; 95% CI: 2.17-44.49; P = .003) and intracardiac abscess (OR: 13.47; 95% CI: 2.24-81.08; P = .004) were independently associated with in-hospital mortality among PEN-I VGS-GGS cases, while monotherapy was not (OR: 1.01; 95% CI: .26-3.96; P = .982).

CONCLUSIONS

Our findings support the use of cephalosporin monotherapy in PEN-I VGS-GGS endocarditis in order to avoid nephrotoxicity without adversely affecting patient outcomes.

Impact of routine brain imaging on the prognosis of patients with left-sided valve infective endocarditis without neurological manifestations

BACKGROUND

There are limited data on the impact of routine use of brain magnetic resonance imaging (MRI) on the prognosis of neurologically asymptomatic patients with left-sided infective endocarditis (IE).

METHODS

Among patients diagnosed with possible or definite IE in two tertiary referral centers between January 2005 and March 2019, we identified 527 left-sided IE patients without neurological symptoms or signs at the time of diagnosis. Patients who underwent brain MRI within 1 week after the IE diagnosis were classified as the routine brain imaging group (n = 216), and the rest were categorized as the control group (n = 311). All-cause mortality at 3 months, attributable mortality (defined as death directly related to IE), and fatal neurological events compared after adjustment using inverse probability of treatment weighting (IPTW).

RESULTS

During a median follow-up of 57 months, the routine brain imaging group had a similar risk of 3-month all-cause mortality to the control group in the multivariate analysis (hazard ratio [HR], 0.53; 95% confidence interval [CI], 0.24-1.14) and IPTW-adjusted cohort (HR, 0.59; 95% CI, 0.25-1.42). The risks of attributable mortality and fatal neurological events were also similar between the two groups in the multivariable analysis and IPTW-adjusted cohort. In the subgroup analysis, the routine brain imaging group showed more favorable outcomes in cases of large vegetation (> 10 mm) or acute-onset microorganisms.

CONCLUSIONS

Routine use of brain MRI in left-sided IE patients without neurological manifestations is not associated with improved clinical outcomes. However, routine brain imaging in appropriate clinical settings could improve clinical outcomes.

Not so uncommon, yet neglected 'Severe Streptococcus pyogenes infections at a tertiary care center in south India

Streptococcus pyogenes (SP) causes uncomplicated infections of throat & skin to severe life-threatening invasive diseases and poststreptococcal sequelae. Despite being common, it hasn't been studied much in recent times. Data of 93 adult patients >18 years, culture proven (SP) infections from 2016 to 2019 was studied in south India. Irrespective of comorbidities, SSTI were most common followed by surgical site infections& bacteremia. Isolates were susceptible to penicillin, cephalosporins but 23% were resistant to clindamycin. Timely surgical interventions and appropriate antibiotics reduced morbidity& limb salvage by 9 times. Larger studies, worldwide, to see the current trend of SP need to be conducted.

Streptococcal infective endocarditis: clinical features and outcomes according to species

PURPOSE

Infective endocarditis (IE) is frequently caused by streptococcal species, yet clinical features and mortality are poorly investigated. Our aim was to examine patients with streptococcal IE to describe clinical features and outcomes according to streptococcal species.

METHODS

From 2002 to 2012, we investigated patients with IE admitted to two tertiary Danish heart centres. Adult patients with left-sided streptococcal IE were included. Adjusted multivariable logistic regression analyses were performed, to assess the association between streptococcal species and heart valve surgery or 1-year mortality.

RESULTS

Among 915 patients with IE, 284 (31%) patients with streptococcal IE were included [mean age 63.5 years (SD 14.1), 69% men]. The most frequent species were S. mitis/oralis (21%) and S. gallolyticus (17%). Fever (86%) and heart murmur (81%) were common symptoms, while dyspnoea was observed in 46%. Further, 18% of all cases were complicated by a cardiac abscess/pseudoaneurysm and 25% by an embolic event. Heart valve surgery during admission was performed in 55% of all patients, and S. gallolyticus (OR 0.28 [95% CI 0.11-0.69]) was associated with less surgery compared with S. mitis/oralis. In-hospital mortality was 7% and 1-year mortality 15%, without any difference between species.

CONCLUSION

S. mitis/oralis and S. gallolyticus were the most frequent streptococcal species causing IE. Further, S. gallolyticus IE was associated with less heart valve surgery during admission compared with S. mitis/oralis IE. Being aware of specific symptoms, clinical findings, and complications related to different streptococcal species, may help the clinicians in expecting different outcomes.

Infective Endocarditis: New Challenges in a Classic Disease

Infective endocarditis is a relatively rare, but deadly infection, with an overall mortality of around 20% in most series. Clinical manifestations have evolved in response to significant epidemiological shifts in industrialized nations, with a move toward a nosocomial or health-care-related pattern, in older patients, with more episodes associated with prostheses and/or intravascular electronic devices and a predominance of staphylococcal and enterococcal etiology.Diagnosis is often challenging and is based on the conjunction of clinical, microbiological, and imaging information, with notable progress in recent years in the accuracy of echocardiographic data, coupled with the recent emergence of other useful imaging techniques such as cardiac computed tomography (CT) and nuclear medicine tools, particularly ¹⁸F-fluorodeoxyglucose positron emission/CT.The choice of an appropriate treatment for each specific case is complex, both in terms of the selection of the appropriate agent and doses and durations of therapy as well as the possibility of using combined bactericidal antibiotic regimens in the initial phase and finalizing treatment at home in patients with good evolution with outpatient oral or parenteral antimicrobial therapies programs. A relevant proportion of patients will also require valve surgery during the active phase of treatment, the timing of which is extremely difficult to define. For all the above, the management of infective endocarditis requires a close collaboration of multidisciplinary endocarditis teams.

Streptococcus agalactiae infective endocarditis in Canada: a multicenter retrospective nested case control analysis

Background

Infective endocarditis (IE) caused by Streptococcus agalactiae (GBS) is increasingly reported and associated with an aggressive course and high mortality rate. Existing literature on GBS IE is limited to case series; we compared the characteristics of patients with GBS IE to patients with GBS bacteremia without IE to identify risk factors for development of IE.

Methods

A nested case–control study in a cohort of adult patients with GBS bacteremia over a 18-year period was conducted across seven centres in three Canadian cities. A chart review identified patients with possible or definite IE (per Modified Duke Criteria) and patients with IE were matched to those without endocarditis in a 1:3 fashion. Multivariate analyses were completed using logistic regression.

Results

Of 520 patients with GBS bacteremia, 28 cases of possible or definite IE were identified (5.4%). 68% (19/28) met criteria for definite IE, surgery was performed in 29% (8/28), and the overall in-hospital mortality rate was 29% (8/28). Multivariate analysis demonstrated that IE was associated with injection drug use (OR = 19.6, 95% CI = 3.39–111.11, p = 0.001), prosthetic valve (OR = 11.5, 95% CI = 1.73–76.92, p = 0.011) and lack of identified source of bacteremia (OR = 3.81, 95% CI = 1.24–11.65, p = 0.019).

Conclusions

GBS bacteremia, especially amongst people who inject drugs, those with prosthetic valves, and those with no apparent source of infection, should increase clinical suspicion for IE.

Multiple mycotic aneurysms with infective endocarditis: A case report

Mycotic aneurysms are sometimes seen in patients with infective endocarditis. We report a case of infective endocarditis with multiple mycotic aneurysms. Although antibiotics were effective, mycotic aneurysms appeared in the cerebral, hepatic, and gastroepiploic arteries. A 55-year-old man presented with mitral valve endocarditis due to Streptococcus oralis. Surgical treatment was deferred because of cerebral hemorrhage. After antibiotic initiation, his fever and C-reactive protein levels declined, and blood culture was negative. However, he experienced repeated cerebral hemorrhage and the number of cerebral mycotic aneurysms increased. Additionally, his spleen ruptured and the number of mycotic aneurysms in the hepatic and gastroepiploic arteries increased. After embolization for mycotic aneurysm and mitral valve replacement, no mycotic aneurysms appeared. Regardless of whether laboratory data improve or not, multiple mycotic aneurysms sometimes appear, and cardiac surgery for infection control should be considered in the early phase.

Clinical Features and Outcomes of Streptococcus anginosus Group Infective Endocarditis: A Multicenter Matched Cohort Study

Background

Although Streptococcus anginosus group (SAG) endocarditis is considered a severe disease associated with abscess formation and embolic events, there is limited evidence to support this assumption.

Methods

We performed a retrospective analysis of prospectively collected data from consecutive patients with definite SAG endocarditis in 28 centers in Spain and Italy. A comparison between cases due to SAG endocarditis and viridans group streptococci (VGS) or Streptococcus gallolyticus group (SGG) was performed in a 1:2 matched analysis.

Results

Of 5336 consecutive cases of definite endocarditis, 72 (1.4%) were due to SAG and matched with 144 cases due to VGS/SGG. SAG endocarditis was community acquired in 64 (88.9%) cases and affected aortic native valve in 29 (40.3%). When comparing SAG and VGS/SGG endocarditis, no significant differences were found in septic shock (8.3% vs 3.5%, P = .116); valve disorder, including perforation (22.2% vs 18.1%, P = .584), pseudoaneurysm (16.7% vs 8.3%, P = .108), or prosthesis dehiscence (1.4% vs 6.3%, P = .170); paravalvular complications, including abscess (25% vs 18.8%, P = .264) and intracardiac fistula (5.6% vs 3.5%, P = .485); heart failure (34.7% vs 38.9%, P = .655); or embolic events (41.7% vs 32.6%, P = .248). Indications for surgery (70.8% vs 70.8%; P = 1) and mortality (13.9% vs 16.7%; P = .741) were similar between groups.

Conclusions

SAG endocarditis is an infrequent but serious condition that presents a prognosis similar to that of VGS/SGG.