Staphylococcus aureus endocarditis in Danish intravenous drug users: high proportion of left-sided endocarditis

Staphylococcus aureus bacteraemia and endocarditis - epidemiology and outcome: a review

PURPOSE

To review the epidemiology of Staphylococcus aureus bacteraemia (SAB) and endocarditis (SAE), and discuss the short- and long-term outcome.  Materials and methods: A literature review of the epidemiology of SAB and SAE.

RESULTS

The reported incidence of SAB in Western countries is 16-41/100,000 person-years. Increasing incidence has been observed in many regions, in Iceland by 27% during 1995-2008. The increase is believed to depend on changes in population risk factors and possibly better and more frequent utilization of diagnostic procedures. S. aureus is now the leading causes of infective endocarditis (IE) in many regions of the world. It accounts for 15-40% of all IE cases, and the majority of cases in people who inject drugs (PWID). Recently, the incidence of SAE in PWID in Stockholm, Sweden, was found to be 2.5/1000 person-years, with an in-hospital mortality of 2.5% in PWID as compared to 15% in non-drug users. The 30-day mortality associated with SAB amounts to 15-25% among adults in Western countries, but is lower in children (0-9%). Mortality associated with SAE is high (generally 20-30% in-hospital mortality), and symptomatic cerebral embolizations are common (12-35%). The 1-year mortality reported after SAB and SAE is 19-62% and reflects deaths from underlying diseases and complications caused by the infection. In a subset of SAE cases, valvular heart surgery is needed (15-45%), but active intravenous drug use seems to be a reason to refrain from surgery. Despite its importance, there are insufficient data on the optimal management of SAB and SAE, especially on the required duration of antibiotic therapy.  Conclusions: The epidemiology of SAB and SAE has been changing in the past decades. They still carry a substantial morbidity and mortality. Intensified studies on treatment are warranted for improving patient outcome.

Patients with Infectious Endocarditis and Drug Dependence Have Worse Clinical Outcomes after Valvular Surgery

BACKGROUND

Patients with infective endocarditis (IE) are at high risk for post-operative morbidity and death, which might be associated with drug abuse. The purpose of this study is to evaluate the impact of drug dependence on outcomes in patients who have IE and undergo valvular surgery (VS).

PATIENTS AND METHODS

The Nationwide/National Inpatient Sample 2001-2012 was queried to select patients with IE who had elective VS using International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis and procedure codes. Among them, patients with drug dependence (PDD) were identified, and their health status and post-operative outcomes were compared with those in patients without drug dependence (control group). Chi-square and Wilcoxon rank sum tests as well as multi-variable regression analysis were used for statistics.

RESULTS

A total of 809 (12.9%) PDD of the 6,264 patients who underwent VS were evaluated. They were younger compared with those in the control group (39.0 ± 10.8 y vs. 54.4 ± 14.8 y; p < 0.0001), had less age-related co-morbidities such as hypertension, diabetes mellitus, congestive heart failure, renal failure, obesity, but greater rates of alcohol abuse, liver disease, and psychoses. Despite the younger age and fewer co-morbidities, PDD compared with control patients were more likely to have post-operative complications develop overall (odds ratio [OR] = 1.6; 95% confidence interval [CI] 1.34-2.01), including infectious complications (OR = 1.5; 95% CI 1.27-1.78), specifically pneumonia (OR = 1.4; 95% CI 1.14-1.74) and sepsis (OR = 1.4; 95% CI 1.16-1.63), renal complications (OR = 1.5; 95% CI 1.23-1.77), and pulmonary embolism (OR = 1.9; 95% CI 1.44-2.52). Further, PDD had 11% longer hospital length of stay than those in the control groups (p < 0.0001). We did not find significant difference in hospital deaths, however, between these groups.

CONCLUSION

Drug dependence is associated with worse post-operative outcomes in patients with infective endocarditis who underwent valvular surgery and lengthens their hospital stay.

Low mortality but increasing incidence of Staphylococcus aureus endocarditis in people who inject drugs: Experience from a Swedish referral hospital

Staphylococcus aureus is a leading cause of infective endocarditis in people who inject drugs (PWID). The management of S aureus endocarditis (SAE) in PWID can be problematic. The objective of this retrospective observational study was to assess the epidemiology, clinical characteristics, and mortality of S aureus endocarditis (SAE) in PWID in Stockholm, Sweden.The Department of Infectious Diseases at the Karolinska University Hospital serves as a regional referral center for drug users with severe infections. Patients with active intravenous drug use treated for SAE at the department between January 2004 and December 2013 were retrospectively identified. Clinical and microbiological data were obtained from medical records and the diagnosis verified according to the modified Duke criteria.In total, 120 SAE episodes related to intravenous drug use were identified. Its incidence in Stockholm was 0.76/100,000 adult person-years for the entire period, increasing from 0.52/100,000 person-years in 2004 to 2008 to 0.99 in 2009 to 2013 (P = 0.02). The SAE incidence among PWID specifically was 249 (range 153-649) /100,000 person-years. Forty-two (35%) episodes were left-sided, and multiple valves were involved in 26 (22%). Cardiac valve surgery was performed in 10 (8%) episodes, all left-sided. The in-hospital and 1-year mortality rates were 2.5% (3 deaths) and 8.0% (9 deaths), respectively.We noted a high and increasing incidence over time of SAE related to intravenous drug use in Stockholm. The increased incidence partly reflects a rising number of PWID during the study period. The low mortality noted, despite a substantial proportion with left-sided endocarditis, probably in part reflects the quality of care obtained at a large and specialized referral center for drug users with severe infections.

Evaluating treatment options for patients with infective endocarditis: when is it the right time for surgery?

Infective endocarditis remains a life-threatening condition with an unchanging incidence and mortality of nearly 30% at 1 year. Surgery is required in 25–50% of acute infections and 20–40% of patients during convalescence. Operative procedures are often technically challenging and high-risk, often due to coexistent multisystem disease. However, international guidelines provide clear indications for surgical intervention, which are applicable for the majority of patients. These are not, however, supported by particularly robust clinical evidence and decision-making often needs to be tailored to the advancing age of the overall patient cohort, the presence of multisystem disease, comorbidities, prior antibiotic therapy of varying duration and the availability of surgical expertise. Native valve endocarditis will be the initial focus of this article, along with subgroups including prosthetic valve endocarditis. We present the treatment options for patients with infective endocarditis, evaluate the evidence-base that supports current clinical practice and attempt to provide an insight and subsequent recommendations for the timing of surgery.

Clinical manifestations and outcome in Staphylococcus aureus endocarditis among injection drug users and nonaddicts: a prospective study of 74 patients

BACKGROUND

Endocarditis is a common complication in Staphylococcus aureus bacteremia (SAB). We compared risk factors, clinical manifestations, and outcome in a large, prospective cohort of patients with S. aureus endocarditis in injection drug users (IDUs) and in nonaddicts.

METHODS

Four hundred and thirty consecutive adult patients with SAB were prospectively followed up for 3 months. Definite or possible endocarditis by modified Duke criteria was found in 74 patients: 20 patients were IDUs and 54 nonaddicts.

RESULTS

Endocarditis was more common in SAB among drug abusers (46%) than in nonaddicts (14%) (odds ratio [OR], 5.12; 95% confidence interval [CI], 2.65-9.91; P < 0.001). IDUs were significantly younger (27 +/- 15 vs 65 +/- 15 years, P < 0.001), had less ultimately or rapidly fatal underlying diseases (0% vs 37%, P < 0.001) or predisposing heart diseases (20% vs 50%, P = 0.03), and their SAB was more often community-acquired (95% vs 39%, P < 0.001). Right-sided endocarditis was observed in 60% of IDUs whereas 93% of nonaddicts had left-sided involvement (P < 0.001). An extracardiac deep infection was found in 85% of IDUs and in 89% of nonaddicts (P = 0.70). Arterial thromboembolic events and severe sepsis were also equally common in both groups. There was no difference in mortality between the groups at 7 days, but at 3 months it was lower among IDUs (10%) compared with nonaddicts (39%) (OR, 5.73; 95% CI, 1.20-27.25; P = 0.02).

CONCLUSION

S. aureus endocarditis in IDUs was associated with as high complication rates including extracardiac deep infections, thromboembolic events, or severe sepsis as in nonaddicts. Injection drug abuse in accordance with younger age and lack of underlying diseases were associated with lower mortality, but after adjusting by age and underlying diseases injection drug abuse was not significantly associated with mortality.

Current best practices and guidelines. Indications for surgical intervention in infective endocarditis

Optimal diagnosis and management of patients with infective endocarditis requires sound clinical judgment based on extensive experience. This is especially important in regard to the indications and timing for surgery. To achieve the best possible outcomes, surgical intervention during treatment is required in 25% to 30% of patients with infective endocarditis. Heart failure and progressive left-sided valvular dysfunction are the most common indications for operation. Valve repair should be considered as an alternative to valve replacement whenever feasible, especially in younger patients. Successful management of perivalvular abscesses and prosthetic valve infections requires radical removal of infected tissue followed by reconstructive procedures performed by experienced surgeons. Emergency or urgent surgery should seldom be delayed.

Current best practices and guidelines indications for surgical intervention in infective endocarditis

Optimal diagnosis and management of patients with infective endocarditis requires sound clinical judgment based on extensive experience. This is especially important in regard to the indications and timing for surgery. To achieve the best possible outcomes, surgical intervention during treatment is required in 25% to 30% of patients with infective endocarditis. Heart failure and progressive left-sided valvular dysfunction are the most common indications for operation. Valve repair should be considered as an alternative to valve replacement whenever feasible, especially in younger patients. Successful management of perivalvular abscesses and prosthetic valve infections requires radical removal of infected tissue followed by reconstructive procedures performed by experienced surgeons. Emergency or urgent surgery should seldom be delayed.

Neurologic manifestations in Staphylococcus aureus endocarditis: a review of 260 bacteremic cases in nondrug addicts

PURPOSE

To investigate the neurologic manifestations of infective endocarditis caused by Staphylococcus aureus in a population of nondrug addicts with special emphasis on the clinical presentation, epidemiology, and mortality.

PATIENTS AND METHODS

During the period from 1982 to 1991 a total of 8,514 cases of bacteremia with S aureus were reported to the Staphylococcus Laboratory, Copenhagen, Denmark. The medical records of cases of suspected infective endocarditis were retrospectively reviewed and classified according to the new diagnostic criteria for endocarditis proposed by Durack.

RESULTS

A total of 260 cases from 63 hospitals fulfilled the diagnostic criteria. Overall, 91 patients (35%) experienced neurologic manifestations. Sixty-one presented with neurologic symptoms, whereas 30 patients developed neurologic complications at various intervals (median: 10 days) after the debut of the disease. The most frequent neurologic manifestation was unilateral hemiparesis, which occurred in 41 patients (45%). Forty-two percent of the females had neurologic manifestations compared to only 30% of the males (P = 0.06). Cases with native mitral valve infection had a significantly higher frequency of neurologic manifestations compared with all other valvular involvement (44% versus 29%, P = 0.02) but the frequency of neurologic complications was only nonsignificantly higher in those patients with native mitral valve infection than in those patients with native aortic valve infection (44% versus 31%, P = 0.10). Only two of the patients with tricuspid valve infection and none of those with congenital heart disorder experienced neurologic manifestations. A neurologic manifestation occurred in 22 (35%) of the 63 episodes in which vegetations were detected on the echocardiograms, compared with 17 (26%) of the 65 episodes without vegetations (P = 0.38). The mortality was 74% in patients with major neurologic manifestations and 56% in patients without neurologic manifestations (P = 0.008). In patients with neurologic complications the mortality was significantly higher among those treated with antibiotics alone as compared with those treated surgically (65 of 81, 80% versus 2 of 10, 20%; P = 0.0003).

CONCLUSIONS

In a population of nondrug addicts with infective endocarditis caused by S aureus the following main conclusions can be drawn: neurologic manifestations occur with a higher frequency in patients with native mitral valve infection. The presence of vegetations on echocardiograms is not a risk factor for developing neurologic complications but this conclusion is based on the results of transthoracic echocardiograms performed in only one half of the patients. The majority of the neurologic manifestations occur on presentation or shortly thereafter and the risk of recurrent embolism is low. Mortality is increased in patients with neurologic manifestations. A neurologic event per se may constitute an indication for surgical treatment.