Staphylococcus Aureus Infective Endocarditis Research Articles

Infective Endocarditis Caused by Staphylococcus aureus After Transcatheter Aortic Valve Replacement.

Staphylococcus aureus (SA) has been extensively studied as causative microorganism of surgical prosthetic-valve infective endocarditis (IE). However, scarce evidence exists on SA IE after transcatheter aortic valve replacement (TAVR). Data were obtained from the Infectious Endocarditis After TAVR International Registry, including patients with definite IE after TAVR from 59 centres in 11 countries. Patients were divided into 2 groups according to microbiologic etiology: non-SA IE vs SA IE. SA IE was identified in 141 patients out of 573 (24.6%), methicillin-sensitive SA in most cases (115/141, 81.6%). Self-expanding valves were more common than balloon-expandable valves in patients presenting with early SA IE. Major bleeding and sepsis complicating TAVR, neurologic symptoms or systemic embolism at admission, and IE with cardiac device involvement (other than the TAVR prosthesis) were associated with SA IE (P < 0.05 for all). Among patients with IE after TAVR, the likelihood of SA IE increased from 19% in the absence of those risk factors to 84.6% if ≥ 3 risk factors were present. In-hospital (47.8% vs 26.9%; P < 0.001) and 2-year (71.5% vs 49.6%; P < 0.001) mortality rates were higher among patients with SA IE vs non-SA IE. Surgery at the time of index SA IE episode was associated with lower mortality at follow-up compared with medical therapy alone (adjusted hazard ratio 0.46, 95% CI 0.22-0.96; P= 0.038). SA IE represented approximately 25% of IE cases after TAVR and was associated with very high in-hospital and late mortality. The presence of some features determined a higher likelihood of SA IE and could help to orientate early antibiotic regimen selection. Surgery at index SA IE was associated with improved outcomes, and its role should be evaluated in future studies.

Clinical analysis of Staphylococcus aureus infective endocarditis in children

Objective To describe the clinical characteristics, treatment and outcomes of Staphylococcus aureus infective endocarditis (SAIE) in children. Methods One hundred and fifty-one children with infective endocarditis (IE) and treated in Shanghai Children′s Medical Center of Shanghai Jiaotong University School of Medicine were retrospectively analyzed, from January 2007 to December 2017.There were 88 boys and 63 girls, the age of IE onset ranged from 1 month to 17 years [(6.27±4.80) years]. There were 23 cases (15.2%) with infection of staphyloco-ccus aureus, 128 cases with non-Staphylococcus aureus infective endocarditis (NSAIE). The clinical characteristics, treatment and prognosis of patients between the SAIE group and the NSAIE group were analyzed and compared. Results Among the SAIE group, there were 15 boys and 8 girls, the age of IE onset ranged from 3 months to 16 years [(6.2±5.6) years]; 10 cases of them had no underlying heart disease.There was no significant difference in gender, age and previous cardiac surgery between the SAIE group and the NSAIE group (all P>0.05). The number of patients without underlying heart disease in the SAIE group was more than that in the NSAIE group, and the difference was statistically significant[43.5%(10/23 cases) vs.20.3%(26/128 cases), χ2=5.762, P=0.016]. Compared with the NSAIE group, the SAIE group was associated with significantly higher levels of C-reactive protein [60.0(128.0) mg/L vs.25.0(58.0) mg/L, Z=-2.033, P=0.042], higher erythrocyte sedimentation rate [(59.3±43.2) mm/h vs.(39.4±31.5) mm/h, t=-2.283, P=0.024], and lower levels of serum albumin [30.1(12.7) g/L vs.34.3(8.4) g/L, Z=-2.282, P=0.022]. The proportion of severe sepsis in the SAIE group was also significantly higher than that in the NSAIE group [21.7%(5/23 cases) vs.7.0%(9/128 cases), Z=5.014, P=0.045]. Twelve cases (52.2%) of the SAIE group had systemic embolic events, including cerebral events (6 cases), pulmonary (2 cases), limbs (1 case), splenic (1 case), limbs and mesenteric (1 case), limbs and cerebral events (1 case). Eighteen cases in the SAIE group were treated with antibiotics combined with surgery and 1 case died, while 5 cases were treated with antibiotics alone, 4 cases died and 1 case abandoned.The SAIE patients had a significantly higher systemic embolic rate [52.2%(12/23 cases) vs.20.3%(26/128 cases), χ2=7.978, P=0.016], neurological events rate [30.4%(7/23 cases) vs.10.9%(14/128 cases), χ2=4.669, P=0.031] and in-hospital mortality [21.7%(5/23 cases) vs.6.3%(8/128 cases), χ2=4.139, P=0.042] than those in the NSAIE group. Conclusions SAIE was most common in those without heart disease.Compared with NSAIE, SAIE is characterized by a higher prevalence of severe sepsis, major neurological events, and inpatient mortality.Timely surgery is recommended in these cases, when possible, before the occurrence of complications. Key words: Infective endocarditis; Staphylococcus aureus; Child

Community-acquired Staphylococcus aureus bacteriuria: a warning microbiological marker for infective endocarditis?

BackgroundUrinary tract infection (UTI) is frequently diagnosed in the Emergency Department (ED). Staphylococcus aureus (SA) is an uncommon isolate in urine cultures (0.5–6% of positive urine cultures), except in patients with risk factors for urinary tract colonization. In the absence of risk factors, community-acquired SA bacteriuria may be related to deep-seated SA infection including infective endocarditis. We hypothesized that SA bacteriuria could be a warning microbiological marker of unsuspected infective endocarditis in the ED.MethodsThis is a retrospective chart review of consecutive adult patients between December 2005 and February 2018. All patients admitted in the ED with both SA bacteriuria (104 CFU/ml SA isolated from a single urine sample) and SA bacteremia, without risk factors for UT colonization (i.e., < 1 month UT surgery, UT catheterization) were analyzed. Diagnosis of infective endocarditis was based on the Duke criteria.ResultsDuring the study period, 27 patients (18 men; median age: 61 [IQR: 52–73] years) were diagnosed with community-acquired SA bacteriuria and had subsequently documented bacteremia and SA infective endocarditis. Only 5 patients (18%) had symptoms related to UT infection. Median delay between ED admission and SA bacteriuria identification was significantly shorter than that between ED admission and the diagnosis of infective endocarditis (1.4 ± 0.8 vs. 4.3 ± 4.2 days: p = 0.01). Mitral and aortic valves were most frequently involved by infective endocarditis (93%). Mortality on day 60 reached 56%.ConclusionsThis study suggests that community-acquired SA bacteriuria should warn the emergency physician about a potentially associated left-sided infective endocarditis in ED patients without risk factors for UT colonization.

Investigating the Impact of Early Valve Surgery on Survival in Staphylococcus aureus Infective Endocarditis Using a Marginal Structural Model Approach: Results of a Large, Prospectively Evaluated Cohort

The impact of valve surgery on outcomes of Staphylococcus aureus infective endocarditis (SAIE) remains controversial. We tested the hypothesis that early valve surgery (EVS) improves survival by using a novel approach that allows for inclusion of major confounders in a time-dependent way. EVS was defined as valve surgery within 60 days. Univariable and multivariable Cox regression analyses were performed. To account for treatment selection bias, we additionally used a weighted Cox model (marginal structural model) that accounts for time-dynamic imbalances between treatment groups. To address survivor bias, EVS was included as a time-dependent variable. Follow-up of patients was 1 year. Two hundred and three patients were included in the analysis; 50 underwent EVS. All-cause mortality at day 30 was 26%. In the conventional multivariable Cox regression model, the effect of EVS on the death hazard was 0.85 (95% confidence interval [CI], .47-1.52). Using the weighted Cox model, the death hazard rate (HR) of EVS was 0.71 (95% CI, .34-1.49). In subgroup analyses, no survival benefit was observed in patients with septic shock (HR, 0.80 [CI, .26-2.46]), in NVIE (HR, 0.76 [CI, .33-1.71]) or PVIE (HR, 1.02 [CI, .29-3.54]), or in patients with EVS within 14 days (HR, 0.97 [CI, .46-2.07]). Using both a conventional Cox regression model and a weighted Cox model, we did not find a survival benefit for patients who underwent EVS in our cohort. Until results of randomized controlled trials are available, EVS in SAIE should be based on individualized decisions of an experienced multidisciplinary team. German Clinical Trials registry (DRKS00005045).

Human Genetic Susceptibility to Native Valve Staphylococcus aureus Endocarditis in Patients With S. aureus Bacteremia: Genome-Wide Association Study

Staphylococcus aureus infective endocarditis (SaIE) is a severe complication of S. aureus bacteremia (SAB) occurring in up to 22% of patients. Bacterial genetic factors and host conditions for SaIE have been intensely studied before; however, to date no study has focused on predisposing host genetic factors to SaIE. The present study aimed to identify genetic polymorphisms associated with SaIE by a Genome-Wide Association Study (GWAS) of 67 patients with definite native valve SaIE (cases) and 72 matched native valve patients with SAB but without IE (controls). All patients were enrolled in the VIRSTA cohort (Le Moing et al., 2015) study. Four single nucleotide polymorphisms (SNPs) located on chromosome 3 were associated with SaIE (P < 1 × 10-5) without reaching conventional genome-wide significance. For all, the frequency of the minor allele was lower in cases than in controls, suggesting a protective effect of the minor allele against SaIE. The same association was observed using an independent Danish verification cohort of SAB with (n = 57) and without (n = 123) IE. Ex vivo analysis of aortic valve tissues revealed that SaIE associated SNPs mentioned above were associated with significantly higher mRNA expression levels of SLC7A14, a predicted cationic amino acid transporter protein. Taken together, our results suggest an IE-protective effect of SNPs on chromosome 3 during the course of SAB. The effects of protective minor alleles may be mediated by increasing expression levels of SLC7A14 in valve tissues. We conclude that occurrence of SaIE may be the combination of a well-adapted bacterial genotype to a susceptible host.

Influence of Staphylococcus aureus on Outcomes after Valvular Surgery for Infective Endocarditis

BackgroundAs Staphylococcus aureus (SA) remains one of the leading cause of infective endocarditis (IE), this study evaluates whether S. aureus is associated with more severe infections or worsened outcomes compared to non-S. aureus (NSA) organisms.MethodsAll patients undergoing valve surgery for bacterial IE between 1995 and 2013 at our institution were included in this study (n = 323). Clinical data were retrospectively collected from the chart review. Patients were stratified according to the causative organism; SA (n = 85) and NSA (n = 238). Propensity score matched pairs (n = 64) of SA versus NSA were used in the analysis.ResultsSA patients presented with more severe IE compared to NSA patients, with higher rates of preoperative vascular complications, preoperative septic shock, preoperative embolic events, preoperative stroke, and annular abscess. Among the matched pairs, there were no significant differences in 30-day (9.4% SA vs. 7.8% NSA, OR = 1.20, p = 0.76) or 1-year mortality (20.3% SA vs. 14.1% NSA, OR = 1.57, p = 0.35) groups, though late survival was significantly worse in SA patients. There was also no significant difference in postoperative morbidity between the two matched groups.ConclusionsSA IE is associated with a more severe clinical presentation than IE caused by other organisms. Despite the clearly increased preoperative risk, valvular surgery may benefit SA IE patients by moderating the post-operative mortality and morbidity.

Long-term prognosis of left-sided native-valve Staphylococcus aureus endocarditis

Staphylococcus aureus infective endocarditis (SAIE) is a serious and common disease. To assess the clinical and echocardiographic characteristics and prognostic factors of left-sided native-valve SAIE, and to compare these characteristics between two periods (1990-2000 vs. 2001-2010). This was a retrospective analysis of 162 cases of left-sided native-valve SAIE among 1254 patients hospitalized for infective endocarditis (IE) between 1990 and 2010. SAIE represented 18.1% of all cases of IE and 22.9% of cases of native-valve IE. Complications included heart failure in 44.7% of cases, acute renal failure in 23.3%, sepsis in 28.5%, neurological events in 35.8%, systemic embolic events in 54.9% and in-hospital mortality in 25.3%. Factors associated with in-hospital mortality were heart failure (odds ratio [OR] 2.5; P=0.04) and sepsis (OR 5.3; P=0.001). Long-term 5-year survival was 49.6±4.9%. Factors associated with long-term mortality were heart failure (OR 1.7; P=0.032), sepsis (OR 3; P=0.0001) and delayed surgery (OR 0.43; P=0.003). Comparison of the two periods revealed a significant increase in bivalvular involvement, valvular incompetence and acute renal failure from 2001 to 2010. No significant difference was observed in terms of in-hospital mortality rates (28.1% vs. 23.5%; P=0.58) and long-term 5-year survival (45.0±6.6% vs. 57.1±6.4%; P=0.33). Mortality as a result of left-sided native-valve SAIE remains high. Factors associated with in-hospital mortality are heart failure and sepsis. Factors associated with long-term mortality are heart failure, sepsis and delayed surgery. Despite progress in surgical techniques, in-hospital mortality and long-term mortality have not decreased significantly between the two periods.

0031 : Left-sided native valve staphylococcus aureus infective endocarditis – evolution of prognosis

Staphylococcus Aureus infective endocarditis (SAIE) remains a serious disease. Our objective is to study the epidemiological, clinical and echographic characteristics and prognostic factors of left-sided native valve SAIE, and compare these characterisctics between 2 periods (1990-2000 vs 2001-2010). It is a retrospective analysis of 162 left-sided native valve SAIE in 1254 patients hospitalized for infective endocarditis (IE) at University Hospitals in Amiens and Marseille between 1990 and 2010. SAIE represents 18% of IE and 22.8% of native valve IE. Complications include heart failure in 44.7% of the cases, acute renal failure in 23.3%, sepsis in 28.5%, neurological events in 35.8%, systemic embolic event in 54.9% and hospital mortality in 25.3%. Factors associated with hospital mortality are comorbidity index (OR=1.2, p=0.04), heart failure (OR=2.5, p=0.04) and sepsis (OR=5.3, p=0.001). Overall mortality is 45.4%±7.2% at 48 months. Factors associated with overall mortality are comorbidity index (OR=1.1, p=0.017), heart failure (OR=1.7, p=0.032), sepsis (OR=3, p=0.0001) and delayed surgery (OR=0.43, p=0.003). The comparison of the 2 periods shows a significant increase in acute renal failure, bivalvular involvement and valvular insufficiency from 2001 to 2010. There was also a non-significant increase in early surgery (39.1% vs 50%, p=0.2). There was no significant difference in hospital mortality rates (28.1% vs 23.5%, p=0.58), in overall mortality at 48 months (48.8% vs 42.9%, p=0.241), and in delayed mortality at 48 months (28.2% vs 23.5%, p=0.225). The mortality due to left-sided native valve SAIE remains elevated. Factors associated with hospital mortality are comorbidity index, heart failure and sepsis. Factors associated with overall mortality are comorbidity index, heart failure, sepsis and delayed surgery. Despite surgical progress, there is no significant decrease in hospital mortality, overall mortality and delayed mortality between the 2 periods.

Reduced valve replacement surgery and complication rate in Staphylococcus aureus endocarditis patients receiving acetyl-salicylic acid

To assess the influence of acetyl-salicylic acid (ASA) on clinical outcomes in Staphylococcus aureus infective endocarditis (SA-IE). The International Collaboration on Endocarditis - Prospective Cohort Study database was used in this observational study. Multivariable analysis of the SA-IE cohort compared outcomes in patients with and without ASA use, adjusting for other predictive variables, including: age, diabetes, hemodialysis, cancer, pacemaker, intracardiac defibrillator and methicillin resistance. Data were analysed from 670 patients, 132 of whom were taking ASA at the time of SA-IE diagnosis. On multivariable analysis, ASA usage was associated with a significantly decreased overall rate of acute valve replacement surgery (OR 0.58 [95% CI 0.35-0.97]; p<0.04), particularly where valvular regurgitation, congestive heart failure or periannular abscess was the indication for such surgery (OR 0.46 [0.25-0.86]; p<0.02). There was no reduction in the overall rates of clinically apparent embolism with prior ASA usage, and no increase in hemorrhagic strokes in ASA-treated patients. In this multinational prospective observational cohort, recent ASA usage was associated with a reduced occurrence of acute valve replacement surgery in SA-IE patients. Future investigations should focus on ASA's prophylactic and therapeutic use in high-risk and newly diagnosed patients with SA bacteremia and SA-IE, respectively.

Risk Factors for Infective Endocarditis and Outcome of Patients With Staphylococcus aureus Bacteremia

To investigate the risk factors for Staphylococcus aureus infective endocarditis (SAIE) and 6-month mortality in patients with S aureus bacteremia (SAB). This study consisted of patients who were diagnosed as having nosocomial or community-acquired SAB or SAIE between June 1, 2000, and December 31, 2005. Clinical characteristics of patients with SAB were compared with those of patients with SAIE, and predictors of mortality in patients with SAB were analyzed. The median age of the 132 randomly selected patients with SAB and the 66 patients with SAIE was 66 and 68 years, respectively. Univariable analysis showed that unknown origin of SAB, a valvular prosthesis, a pacemaker, persistent fever, and persistent bacteremia were significantly associated with SAIE. In multivariable analysis, unknown origin of SAB (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.9-9.3; P=.001), a valvular prosthesis (OR, 9.2; 95% CI, 3.2-26.2; P<.001), persistent fever (OR, 3.1; 95% CI, 1.0-9.0; P=.04), and persistent bacteremia (OR, 6.8; 95% CI, 2.3-20.2- P=.001) were independently associated with SAIE. Six- month mortality was 8% in patients with SAB vs 35% in patients with SAIE (OR, 6.5; 95% CI, 2.9- 14.8; P<.001). In univariable analysis, methicillin- resistant S aureus (OR, 7.2; 95% CI, 1.7 - 29.4; P=.005) was significantly associated with 6-month mortality in patients with SAB. Unknown origin of SAB, a valvular prosthesis, persistent fever, and persistent bacteremia were independently associated with SAIE in patients with SAB. In univariable analysis, methicillin-resistant S aureus was associated with 6-month mortality in patients with SAB. S aureus infective endocarditis had a significantly higher mortality than SAB. The optimal management of SAB and SAIE deserves further study.

Impact of Methicillin Resistance on Clinical Features and Outcomes of Infective Endocarditis Due to Staphylococcus aureus

This study sought to determine the impact of methicillin resistance on clinical features and outcomes in patients with Staphylococcus aureus (SA) infective endocarditis (IE). Retrospective chart review. Univariate and forward stepwise logistic regressions were conducted to determine which factors significantly affected death and systemic embolism. From October 1995 to April 2002, 57 patients with a definite diagnosis of IE caused by SA were included: 28 cases of methicillin-sensitive SA infection and 29 methicillin-resistant SA (MRSA) infection. Patients with MRSA infection are more likely to have old age, underlying diseases, history of hospitalization within the last 6 months, nosocomial infection, and antibiotic use within the last 3 months. Patients with MRSA infection had clinical presentation of less systemic embolism and more sepsis and had a higher 3-month mortality rate. Methicillin resistance is an independent positive predictor of death and a negative predictor of systemic embolism. MRSA became a dominant cause of SA IE. Although it caused a lower incidence of systemic embolism, MRSA infection had a higher mortality rate because of sepsis.