Sara E. Cosgrove

Clinical Practice Guidelines by the Infectious Diseases Society of America for the Treatment of Methicillin-Resistant Staphylococcus aureus Infections in Adults and Children

Evidence-based guidelines for the management of patients with methicillin-resistant Staphylococcus aureus (MRSA) infections were prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). The guidelines are intended for use by health care providers who care for adult and pediatric patients with MRSA infections. The guidelines discuss the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections (SSTI), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system (CNS) infections. Recommendations are provided regarding vancomycin dosing and monitoring, management of infections due to MRSA strains with reduced susceptibility to vancomycin, and vancomycin treatment failures.

Comparison of Mortality Associated with Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Bacteremia: A Meta-analysis

A meta-analysis was performed to summarize the impact of methicillin-resistance on mortality in Staphylococcus aureus bacteremia. A search of the MEDLINE database for studies published during the period of 1 January 1980 through 31 December 2000 and a bibliographic review identified English-language studies of S. aureus bacteremia. Studies were included if they contained the numbers of and mortality rates for patients with methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) bacteremia. Data were extracted on demographic characteristics of the patients, adjustment for severity and comorbid illness, source of bacteremia, and crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for in-hospital mortality. When the results were pooled with a random-effects model, a significant increase in mortality associated with MRSA bacteremia was evident (OR, 1.93; 95% CI, 1.54-2.42; P<.001); significant heterogeneity was present. We explored the reasons for heterogeneity by means of subgroup analyses. MRSA bacteremia is associated with significantly higher mortality rate than is MSSA bacteremia.

Adverse Clinical and Economic Outcomes Attributable to Methicillin Resistance among Patients with Staphylococcus aureus Surgical Site Infection

Data for 479 patients were analyzed to assess the impact of methicillin resistance on the outcomes of patients with Staphylococcus aureus surgical site infections (SSIs). Patients infected with methicillin-resistant S. aureus (MRSA) had a greater 90-day mortality rate than did patients infected with methicillin-susceptible S. aureus (MSSA; adjusted odds ratio, 3.4; 95% confidence interval, 1.5-7.2). Patients infected with MRSA had a greater duration of hospitalization after infection (median additional days, 5; P<.001), although this was not significant on multivariate analysis (P=.11). Median hospital charges were 29,455 dollars for control subjects, 52,791 dollars for patients with MSSA SSI, and 92,363 dollars for patients with MRSA SSI (P<.001 for all group comparisons). Patients with MRSA SSI had a 1.19-fold increase in hospital charges (P=.03) and had mean attributable excess charges of 13,901 dollars per SSI compared with patients who had MSSA SSIs. Methicillin resistance is independently associated with increased mortality and hospital charges among patients with S. aureus SSI.

The impact of methicillin resistance in Staphylococcus aureus bacteremia on patient outcomes: Mortality, length of stay, and hospital charges

OBJECTIVE To evaluate the impact of methicillin resistance in Staphylococcus aureus on mortality, length of hospitalization, and hospital charges. DESIGN A cohort study of patients admitted to the hospital between July 1, 1997, and June 1, 2000, who had clinically significant S. aureus bloodstream infections. SETTING A 630-bed, urban, tertiary-care teaching hospital in Boston, Massachusetts. PATIENTS Three hundred forty-eight patients with S. aureus bacteremia were studied; 96 patients had methicillin-resistant S. aureus (MRSA). Patients with methicillin-susceptible S. aureus (MSSA) and MRSA were similar regarding gender, percentage of nosocomial acquisition, length of hospitalization, ICU admission, and surgery before S. aureus bacteremia. They differed regarding age, comorbidities, and illness severity score. RESULTS Similar numbers of MRSA and MSSA patients died (22.9% vs 19.8%; P = .53). Both the median length of hospitalization after S. aureus bacteremia for patients who survived and the median hospital charges after S. aureus bacteremia were significantly increased in MRSA patients (7 vs 9 days, P = .045; 19,212 dollars vs 26,424 dollars, P = .008). After multivariable analysis, compared with MSSA bacteremia, MRSA bacteremia remained associated with increased length of hospitalization (1.29 fold; P = .016) and hospital charges (1.36 fold; P = .017). MRSA bacteremia had a median attributable length of stay of 2 days and a median attributable hospital charge of 6916 dollars. CONCLUSION Methicillin resistance in S. aureus bacteremia is associated with significant increases in length of hospitalization and hospital charges.

The Relationship between Antimicrobial Resistance and Patient Outcomes: Mortality, Length of Hospital Stay, and Health Care Costs

There is an association between the development of antimicrobial resistance in Staphylococcus aureus, enterococci, and gram-negative bacilli and increases in mortality, morbidity, length of hospitalization, and cost of health care. For many patients, inadequate or delayed therapy and severe underlying disease are primarily responsible for the adverse outcomes of infections caused by antimicrobial-resistant organisms. Patients with infections due to antimicrobial-resistant organisms have higher costs (approximately 6,000-30,000 dollars) than do patients with infections due to antimicrobial-susceptible organisms; the difference in cost is even greater when patients infected with antimicrobial-resistant organisms are compared with patients without infection. Strategies to prevent nosocomial emergence and spread of antimicrobial-resistant organisms are essential.

Implementing an Antibiotic Stewardship Program: Guidelines by the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America

Evidence-based guidelines for implementation and measurement of antibiotic stewardship interventions in inpatient populations including long-term care were prepared by a multidisciplinary expert panel of the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America. The panel included clinicians and investigators representing internal medicine, emergency medicine, microbiology, critical care, surgery, epidemiology, pharmacy, and adult and pediatric infectious diseases specialties. These recommendations address the best approaches for antibiotic stewardship programs to influence the optimal use of antibiotics.

The Impact of Antimicrobial Resistance on Health and Economic Outcomes

Despite an increasing prevalence of antimicrobial-resistant pathogens, the health and economic impact of colonization and infection with these organisms has not been fully elucidated. We explore how antimicrobial resistance can affect patient outcomes by enhancing virulence, causing a delay in the administration of appropriate therapy, and limiting available therapy. Next, we examine the different perspectives held by hospitals, third-party payers, patients, and society on the impact of resistance. Finally, we review methodological issues in designing and assessing studies that address the clinical outcomes for patients infected or colonized with resistant pathogens, including adjustment for important confounding variables, control group selection, and the quantification of economic outcomes.

Sustaining reductions in catheter related bloodstream infections in Michigan intensive care units: observational study

Objectives To evaluate the extent to which intensive care units participating in the initial Keystone ICU project sustained reductions in rates of catheter related bloodstream infections. Design Collaborative cohort study to implement and evaluate interventions to improve patients’ safety. Setting Intensive care units predominantly in Michigan, USA. Intervention Conceptual model aimed at improving clinicians’ use of five evidence based recommendations to reduce rates of catheter related bloodstream infections rates, with measurement and feedback of infection rates. During the sustainability period, intensive care unit teams were instructed to integrate this intervention into staff orientation, collect monthly data from hospital infection control staff, and report infection rates to appropriate stakeholders. Main outcome measures Quarterly rate of catheter related bloodstream infections per 1000 catheter days during the sustainability period (19-36 months after implementation of the intervention). Results Ninety (87%) of the original 103 intensive care units participated, reporting 1532 intensive care unit months of data and 300 310 catheter days during the sustainability period. The mean and median rates of catheter related bloodstream infection decreased from 7.7 and 2.7 (interquartile range 0.6-4.8) at baseline to 1.3 and 0 (0-2.4) at 16-18 months and to 1.1 and 0 (0.0-1.2) at 34-36 months post-implementation. Multilevel regression analysis showed that incidence rate ratios decreased from 0.68 (95% confidence interval 0.53 to 0.88) at 0-3 months to 0.38 (0.26 to 0.56) at 16-18 months and 0.34 (0.24-0.48) at 34-36 months post-implementation. During the sustainability period, the mean bloodstream infection rate did not significantly change from the initial 18 month post-implementation period (−1%, 95% confidence interval −9% to 7%). Conclusions The reduced rates of catheter related bloodstream infection achieved in the initial 18 month post-implementation period were sustained for an additional 18 months as participating intensive care units integrated the intervention into practice. Broad use of this intervention with achievement of similar results could substantially reduce the morbidity and costs associated with catheter related bloodstream infections.

Health and economic impact of surgical site infections diagnosed after hospital discharge.

Although surgical site infections (SSIs) are known to cause substantial illness and costs during the index hospitalization, little information exists about the impact of infections diagnosed after discharge, which constitute the majority of SSIs. In this study, using patient questionnaire and administrative databases, we assessed the clinical outcomes and resource utilization in the 8-week postoperative period associated with SSIs recognized after discharge. SSI recognized after discharge was confirmed in 89 (1.9%) of 4,571 procedures from May 1997 to October 1998. Patients with SSI, but not controls, had a significant decline in SF-12 (Medical Outcomes Study 12-Item Short-Form Health Survey) mental health component scores after surgery (p=0.004). Patients required significantly more outpatient visits, emergency room visits, radiology services, readmissions, and home health aide services than did controls. Average total costs during the 8 weeks after discharge were US

Multidrug-resistant Acinetobacter Infection Mortality Rate and Length of Hospitalization

5,155 for patients with SSI and