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Biomedical subjects

V G Fowler

Publications and source records attributed to V G Fowler.

At least 19 recordsLinked to original sources
PubMed2006

Prosthetic valve endocarditis due to coagulase-negative staphylococci: findings from the International Collaboration on Endocarditis Merged Database.

Infective endocarditis due to coagulase-negative staphylococci is increasingly recognized as a difficult-to-treat disease associated with poor outcome. The aim of this report is to describe the characteristics and outcome of patients with prosthetic valve endocarditis (PVE) due to coagulase-negative staphylococci versus those of patients with PVE due to Staphylococcus aureus and viridans streptococci. Patients were identified through the International Collaboration on Endocarditis Merged Database. A total of 54 cases of coagulase-negative staphylococci PVE, 58 cases of S. aureus PVE, and 63 cases of viridans-streptococci-related PVE were available for analysis. There was no difference between the three groups with respect to the type of valve involved or the rate of embolization. However, heart failure was encountered more frequently with coagulase-negative staphylococci (54%) than with either S. aureus (33%; p=0.03) or viridans streptococci (32%; p=0.02). In addition, valvular abscesses complicated 39% of infections due to coagulase-negative staphylococci compared with 22% of those due to S. aureus (p=0.06) and 6% of those due to viridans streptococci (p<0.001). Mortality was highest in patients with S. aureus and coagulase-negative staphylococcal endocarditis (47 and 36%, respectively; p=0.22) and was considerably lower in patients with viridans streptococcal endocarditis (p=0.002 compared to patients with coagulase-negative staphylococcal endocarditis). The results of this analysis demonstrate the aggressive nature of coagulase-negative staphylococcal PVE and the substantially greater morbidity and mortality associated with this infection compared to PVE caused by other pathogens.

Aged↗
PubMed2005

Enterococcal prosthetic valve infective endocarditis: report of 45 episodes from the International Collaboration on Endocarditis-merged database.

Enterococcal prosthetic valve infective endocarditis (PVE) is an incompletely understood disease. In the present study, patients with enterococcal PVE were compared to patients with enterococcal native valve endocarditis (NVE) and other types of PVE to determine differences in basic clinical characteristics and outcomes using a large multicenter, international database of patients with definite endocarditis. Forty-five of 159 (29%) cases of definite enterococcal endocarditis were PVE. Patients with enterococcal PVE were demographically similar to patients with enterococcal NVE but had more intracardiac abscesses (20% vs. 6%; p=0.009), fewer valve vegetations (51% vs. 79%; p<0.001), and fewer cases of new valvular regurgitation (12% vs. 45%; p=0.01). Patients with either enterococcal PVE or NVE were elderly (median age, 73 vs. 69; p=0.06). Rates of in-hospital mortality, surgical intervention, heart failure, peripheral embolization, and stroke were similar in both groups. Patients with enterococcal PVE were also demographically similar to patients with other types of PVE, but mortality may be lower (14% vs. 26%; p=0.08). Notably, 93% of patients with enterococcal PVE came from European centers, as compared with only 79% of patients with enterococcal NVE (p=0.03). Thus, patients with enterococcal PVE have higher rates of myocardial abscess formation and lower rates of new regurgitation compared to patients with enterococcal NVE, but there are no differences between the groups with regard to surgical or mortality rates. In contrast, though patients with enterococcal PVE and patients with other types of PVE share similar characteristics, mortality is higher in the latter group. Importantly, the prevalence of enterococcal PVE was higher in the European centers in this study.

Aged↗
PubMed2005

Enterococcal endocarditis: 107 cases from the international collaboration on endocarditis merged database.

PURPOSE: To describe clinical features and outcomes of enterococcal left-sided native valve endocarditis and to compare it to endocarditis caused by other pathogens. SUBJECTS AND METHODS: Patients in the International Collaboration on Endocarditis-Merged Database were included if they had left-sided native valve endocarditis. Demographic characteristics, clinical features, and outcomes were analyzed. Multivariable analysis evaluated enterococcus as a predictor of mortality. RESULTS: Of 1285 patients with left-sided native valve endocarditis, 107 had enterococcal endocarditis. Enterococcal endocarditis was most frequently seen in elderly men, frequently involved the aortic valve, tended to produce heart failure rather than embolic events, and had relatively low short-term mortality. Compared to patients with non-enterococcal endocarditis, patients with enterococcal endocarditis had similar rates of nosocomial acquisition, heart failure, embolization, surgery, and mortality. Compared to patients with streptococcal endocarditis, patients with enterococcal endocarditis were more likely to be nosocomially acquired (9 of 59 [15%] vs 2 of 400 [1%]; P <.0001) and have heart failure (49 of 107 [46%] vs 234 of 666 [35%]; P = 0.03). Compared to patients with S. aureus endocarditis, patients with enterococcal endocarditis were less likely to embolize (28 of 107 [26%] vs 155 of 314 [49%]; P <.0001) and less likely to die (12 of 107 [11%] vs 83 of 313 [27%]; P = 0.001). Multivariable analysis of all patients with left-sided native valve endocarditis showed that enterococcal endocarditis was associated with lower mortality (odds ratio [OR] 0.49; 95% confidence interval [CI] 0.24 to 0.97). CONCLUSIONS: Enterococcal native valve endocarditis has a distinctive clinical picture with a good prognosis.

Aged↗
PubMed2004

Risk factors for postoperative mediastinitis due to methicillin-resistant Staphylococcus aureus.

Risk factors for developing postoperative mediastinitis (POM) due to methicillin-resistant Staphylococcus aureus (MRSA) were analyzed in a case-case control study of patients who underwent median sternotomy during the period from 1994 through 2000. Three patient groups were studied. The first consisted of 64 patients with POM due to MRSA; the second consisted of 79 patients with POM due to methicillin-susceptible S. aureus (MSSA); and the third consisted of 80 uninfected control patients. In multivariable analysis, patients who were diabetic (adjusted OR, 2.86; 95% CI, 1.22-6.70), female (OR, 2.70; 95% CI, 1.25-5.88), and >70 years old (OR, 3.43; 95% CI, 1.53-7.71) were more likely to develop POM due to MRSA. In contrast, the only independent risk factor associated with POM due to MSSA was obesity (OR, 2.49; 95% CI, 1.25-4.96). Antimicrobial prophylaxis consisted primarily of cephalosporin antibiotics (administered to 97% of the patients). Changes in perioperative antimicrobial prophylaxis, in addition to other interventions, should be considered for prevention of POM due to MRSA in targeted, high-risk populations.

Age Factors↗
PubMed2004

Prognostic factors in 61 cases of Staphylococcus aureus prosthetic valve infective endocarditis from the International Collaboration on Endocarditis merged database.

Staphylococcus aureus prosthetic valve infective endocarditis (SA-PVIE) is associated with a high mortality rate, but prognostic factors have not been clearly elucidated. The International Collaboration on Endocarditis merged database (ICE-MD) contained 2212 cases of definite infective endocarditis (as defined using the Duke criteria), 61 of which were SA-PVIE. Overall mortality rate was 47.5%, stroke was associated with an increased risk of death, and early valve replacement was not associated with a significant survival benefit in the whole population; however, patients who developed cardiac complications and underwent early valve replacement had the lowest mortality rate (28.6%).

Adult↗
PubMed2001

Staphylococcus aureus bacteremia in patients with permanent pacemakers or implantable cardioverter-defibrillators.

BACKGROUND: Although cardiac device infections (CDIs) are a devastating complication of permanent pacemakers or implantable cardioverter-defibrillators, the incidence of CDI in patients with bacteremia is not well defined. The objective of this study was to determine the incidence of CDI among patients with permanent pacemakers or implantable cardioverter-defibrillators who develop Staphylococcus aureus bacteremia (SAB). METHODS AND RESULTS: A cohort of all adult patients with SAB and permanent pacemakers or implantable cardioverter-defibrillators over a 6-year period was evaluated prospectively. The overall incidence of confirmed CDI was 15 of 33 (45.4%). Confirmed CDI occurred in 9 of the 12 patients (75%) with early SAB (<1 year after device placement). Fifteen of 21 patients (71.5%) with late SAB (>/=1 year after device placement) had either confirmed (6 of 21, 28.5%) or possible (9 of 21, 43%) CDI. In 60% of the patients (9 of 15) with confirmed CDI, no local signs or symptoms suggesting generator pocket infection were noted. CONCLUSIONS: The incidence of CDI among patients with SAB and cardiac devices is high. Neither physical examination nor echocardiography can exclude the possibility of CDI. In patients with early SAB, the device is usually involved, and approximately 40% of these patients have obvious clinical signs of cardiac device involvement. Conversely, in patients with late SAB, the cardiac device is rarely the initial source of bacteremia, and there is a paucity of local signs of device involvement. The cardiac device is involved, however, in >/=28% of these patients.

Aged↗
PubMed2001

Infection of orthopedic prostheses after Staphylococcus aureus bacteremia.

We prospectively evaluated 53 patients with prosthetic joints and 27 patients with other orthopedic prosthetic devices who developed Staphylococcus aureus bacteremia (SAB). After exclusion of patients with primary postoperative infections, the risk of a prosthesis becoming infected by means of hematogenous seeding after SAB was 34% (15 of 44 patients) for prosthetic joints and 7% (1 of 15 patients) for other orthopedic prostheses.

Adult↗
PubMed2001

The intercellular adhesin locus ica is present in clinical isolates of Staphylococcus aureus from bacteremic patients with infected and uninfected prosthetic joints.

Although polysaccharide intercellular adhesin (PIA) is thought to be crucial in the pathogenesis of prosthetic device infections caused by Staphylococcus epidermidis, its role in prosthetic device infections caused by Staphylococcus aureus is unknown. To assess the clinical impact of PIA production, isolates from 15 prospectively identified cases of S. aureus bacteremia in patients with prosthetic joints (8 infected, 7 uninfected) were characterized for biofilm production, hemagglutination, and the presence of a 419-bp amplification product within icaA. Although icaA was present in all 15 isolates, none of the isolates produced hemagglutination and only one isolate (from a patient with an uninfected prosthetic device) weakly produced biofilm in vitro. These results support the observation that the ica locus is conserved between S. epidermidis and S. aureus and that PIA may be expressed only under in vivo conditions. Future investigations should include animal models to approximate the complex milieu surrounding implanted prosthetic medical devices.

Adhesins, Bacterial↗
PubMed2000

In vitro resistance to thrombin-induced platelet microbicidal protein in isolates of Staphylococcus aureus from endocarditis patients correlates with an intravascular device source.

Platelet microbicidal proteins (PMPs) are small antimicrobial peptides secreted by mammalian platelets. In vitro resistance of Staphylococcus aureus strains to PMPs correlates with more extensive disease in experimental infective endocarditis (IE). To determine whether this same relationship exists in human S. aureus IE, we evaluated the in vitro PMP susceptibility phenotype of isolates from 58 prospectively-identified patients with definite S. aureus IE. On multivariate analyses, patients with S. aureus IE complicating an infected intravascular device were significantly more likely to have IE caused by a PMP-resistant strain (P=.0193). No correlations were detected between in vitro PMP resistance among S. aureus strains and the severity of human IE. This work supports the concept that in vitro PMP resistance in clinical S. aureus strains is associated with important clinical characteristics of S. aureus endovascular infections in vivo.

Analysis of Variance↗
PubMed2000

Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis.

Although the sensitivity and specificity of the Duke criteria for the diagnosis of infective endocarditis (IE) have been validated by investigators from Europe and the United States, several shortcomings of this schema remain. The Duke IE database contains records collected prospectively on >800 cases of definite and possible IE since 1984. Databases on echocardiograms and on patients with Staphylococcus aureus bacteremia at Duke University Medical Center are also maintained. Analyses of these databases, our experience with the Duke criteria in clinical practice, and analysis of the work of others have led us to propose the following modifications of the Duke schema. The category "possible IE" should be defined as having at least 1 major criterion and 1 minor criterion or 3 minor criteria. The minor criterion "echocardiogram consistent with IE but not meeting major criterion" should be eliminated, given the widespread use of transesophageal echocardiography (TEE). Bacteremia due to S. aureus should be considered a major criterion, regardless of whether the infection is nosocomially acquired or whether a removable source of infection is present. Positive Q-fever serology should be changed to a major criterion.

Databases, Factual↗
PubMed2000

Staphylococcus aureus bacteremia in the surgical patient: a prospective analysis of 73 postoperative patients who developed Staphylococcus aureus bacteremia at a tertiary care facility.

BACKGROUND: Staphylococcus aureus is a frequent cause of infection and bacteremia in the postoperative patient. Unfortunately, there have been no prospective studies evaluating these patients, so the incidence of complications, subsequent treatment algorithms, and prognosis remain undefined. The objectives of this prospective study of postoperative Staphylococcus aureus bacteremia (SAB) were to define the primary sources of bacteremia and to identify the common complications of SAB in the postoperative setting. METHODS: A registry was developed into which 309 consecutive adult patients with SAB were prospectively enrolled between September 1994 and December 1996. Seventy-three of these patients (23.6%) developed SAB in the postoperative setting. RESULTS: Analysis of the clinical features of these 73 postoperative patients revealed three important results. First, infective endocarditis is surprisingly common in postoperative patients with SAB and the classical stigmata of endocarditis are often absent. Transesophageal echocardiography was performed in 31 of 73 patients; 10 of these patients (32.3%) met Duke Criteria for definite endocarditis, but only 3 of these patients had vegetations detected by transthoracic echocardiography, and only 2 patients had peripheral stigmata of infective endocarditis. Second, the development of SAB after cardiothoracic surgery was strongly associated with underlying S. aureus mediastinitis. Twenty-one of the 23 patients who developed SAB after median sternotomy had mediastinitis (positive predictive value 91.3%). In many cases, the diagnosis of mediastinitis was not apparent when SAB was detected. Third, complications, relapses, and mortality were high in postoperative patients with SAB. Fourteen of 73 patients (19.2%) developed multiple noncardiac metastatic complications, including metastatic abscesses (5), septic emboli (3), pneumonia or empyema (2), septic arthritis (1), epidural abscess (1), and other metastatic foci (7). Twelve of 73 patients (16.4%) had recurrent staphylococcal infection after treatment of their first episode of SAB, including 8 patients (11.0%) with recurrent bacteremia. Of patients who survived, those with recurrent staphylococcal infection were more likely to have an infected surgical wound than were patients who were cured of infection (p = 0.05). Finally, mortality attributable to SAB (11.0%), and all-cause mortality (21.9%), was high. CONCLUSIONS: SAB in the postoperative setting is often a severe disease with high morbidity and mortality. A thorough diagnostic evaluation is indicated in surgical patients with S. aureus bacteremia to ensure the early detection of metastatic infections such as infective endocarditis and to define foci such as mediastinitis re quiring surgical intervention.

Adult↗
PubMed2000

Prospective analysis of Staphylococcus aureus bacteremia in nonneutropenic adults with malignancy.

PURPOSE: To determine the primary sources and secondary complications of Staphylococcus aureus bacteremia (SAB) in cancer patients, as well as predictors of outcome in cancer patients with SAB. PATIENTS AND METHODS: Fifty-two patients at Duke University Medical Center met entry criteria between September 1994 and December 1996 for this prospective cohort study involving hospitalized nonneutropenic adult cancer patients with SAB. All subjects were observed throughout initial hospitalization and were evaluated again at 6 and 12 weeks or until death. RESULTS: SAB was intravascular device-related in 42%, tissue infection-related (TIR) in 44%, and unidentifiable focus-related (UFR) in 13%. Seventeen patients (33%) were found to have metastatic infections or conditions, with eight (15%) developing infectious endocarditis (IE). Patients with TIR bacteremia were less likely than other patients to develop IE (4% v 24%, P =.06). The overall mortality rate was 38%, the SAB-related mortality rate was 15%, and the rate of SAB relapse was 12%. Methicillin resistance was not associated with adverse outcome. Inability to identify a point of entry (UFR bacteremia), however, was associated with a higher overall mortality rate (100% v 24%, P =.0006). Furthermore, a 72-hour surveillance blood culture positive for organisms was associated with an increased incidence of IE (P =.0006), metastatic infections or conditions (P =.0002), SAB relapse (P =.038), and SAB-related death (P =.038). CONCLUSION: SAB in cancer patients is associated with significant morbidity from frequent metastatic infections or conditions including IE, as well as considerable mortality. Unknown initial infection site and 72-hour surveillance cultures positive for organisms were predictive of a complicated course and poor final outcome.

Adolescent↗
PubMed1999

Staphylococcus aureus bacteremia among elderly vs younger adult patients: comparison of clinical features and mortality.

BACKGROUND: Previous studies give conflicting results regarding the effect of age on outcomes in Staphylococcus aureus bacteremia (SAB). These studies have been limited by retrospective design or small sample size. METHODS: We conducted a prospective cohort study of 385 patients with SAB aged 18 to 90 years. The setting was a large academic medical center. We observed patients from diagnosis of SAB to discharge or death. Discharged patients were contacted 12 weeks after their first positive culture findings. Data were collected on demographics, comorbid conditions, focus of infection, length of stay, and outcome. Primary outcomes were total mortality and death due to SAB. RESULTS: Comparisons were made between 145 patients, aged 66 to 90 years, and 240 patients, aged 18 to 60 years. Forty-three (29.7%) of the elderly patients and 36 (15%) of the younger patients died. Death directly attributable to SAB occurred in 21 (14.5%) older and 15 (6.3%) younger patients. After adjusting for confounding variables, older patients continued to have higher total mortality (odds ratio, 2.21; 95% confidence interval, 1.32-3.70), and higher mortality from SAB (odds ratio, 2.30; 95% confidence interval, 1.13-4.69). Infection with methicillin-resistant S aureus was associated with higher total mortality in the elderly (odds ratio, 2.59; 95% confidence interval, 1.23-5.43). CONCLUSIONS: Staphylococcus aureus bacteremia among the elderly is associated with high mortality. Both total mortality and mortality directly attributable to SAB are more than twice as likely in older patients. Infection with methicillin-resistant S aureus carries a worse prognosis than infection with methicillin-sensitive S aureus in the elderly.

Adult↗
PubMed1999

Cost-effectiveness of transesophageal echocardiography to determine the duration of therapy for intravascular catheter-associated Staphylococcus aureus bacteremia.

BACKGROUND: The appropriate duration of therapy for catheter-associated Staphylococcus aureus bacteremia is controversial. Conventional practice dictates that all patients receive prolonged courses of intravenous antibiotics. Some clinicians recommend abbreviated therapeutic courses, but an alternate approach involves prospectively identifying patients for whom abbreviated therapy is appropriate. OBJECTIVE: To determine the cost-effectiveness of transesophageal echocardiography (TEE) in establishing duration of therapy for catheter-associated S. aureus bacteremia. DESIGN: Cost-effectiveness analysis. DATA SOURCES: MEDLINE search of literature; clinical data from patients with S. aureus bacteremia (n = 196) and patients with endocarditis (n = 60); and costs obtained from the study institution, regional home health agency, and national estimates of professional and technical fees. TARGET POPULATION: Patients with catheter-associated S. aureus bacteremia on native heart valves without intravenous drug use or clinically apparent metastatic infection, immunosuppression, or indwelling prosthetic devices. TIME HORIZON: Patient lifetime. PERSPECTIVE: Societal. INTERVENTIONS: Antibiotic treatment based on TEE results compared with 2- or 4-week empirical therapy. OUTCOME MEASURES: Quality-adjusted life expectancy, costs, and incremental cost-effectiveness ratios. RESULTS OF BASE-CASE ANALYSIS: Compared with empirical short-course therapy, the TEE strategy cost $4938 per quality-adjusted life-year (QALY) gained. The effectiveness of the TEE strategy and the effectiveness of the long-course strategy were sufficiently similar that the additional cost of empirical long-course therapy ($1,667,971 per QALY) was higher than that which society usually considers cost-effective. RESULTS OF SENSITIVITY ANALYSES: In a four-way sensitivity analysis (endocarditis prevalence, TEE cost, short-course relapse rate, and TEE specificity), compared with empirical short-course therapy, the TEE strategy results ranged from cost savings to $155,624 per QALY. CONCLUSION: Within the limitations of existing empirical data, this study suggests that for patients with clinically uncomplicated catheter-associated S. aureus bacteremia, the use of TEE to determine therapy duration is a cost-effective alternative to 2- or 4-week empirical therapy.

Anti-Bacterial Agents↗
PubMed1999

Recurrent Staphylococcus aureus bacteremia: pulsed-field gel electrophoresis findings in 29 patients.

To identify risk factors for relapse among 309 prospectively identified cases of Staphylococcus aureus bacteremia, patients with recurrent S. aureus bacteremia were identified, and pulsed-field gel electrophoresis (PFGE) was performed on isolates from both episodes. PFGE banding patterns from both isolates were identical in 23 patients, consistent with relapsed infection. Patients with PFGE-confirmed relapse were more likely by both univariate and multivariate analyses to have an indwelling foreign body (odds ratio [OR]=18.2, 95% confidence interval [CI]=7. 6-43.6; P<.001), to have received vancomycin therapy (OR=4.1, 95% CI=1.5-11.6; P=.008), or be hemodialysis-dependent (OR=4.1, 95% CI=1. 8-9.3; P=.002) than patients who did not develop recurrent bacteremia. These results suggest that recurrent episodes of S. aureus bacteremia are primarily relapses and are associated with an indwelling foreign body, receiving vancomycin therapy, and hemodialysis dependence.

Adult↗