Sharon B. Wright

Glycopeptides Are No More Effective than β-Lactam Agents for Prevention of Surgical Site Infection after Cardiac Surgery: A Meta-analysis

A meta-analysis was performed to investigate whether a switch from beta-lactams to glycopeptides for cardiac surgery prophylaxis should be advised. Results of 7 randomized trials (5761 procedures) that compared surgical site infections (SSIs) in subjects receiving glycopeptide prophylaxis with SSIs in those who received beta -lactam prophylaxis were pooled. Neither agent proved to be superior for prevention of the primary outcome, occurrence of SSI at 30 days (risk ratio [RR], 1.14; 95% confidence interval [CI], 0.91-1.42). In subanalyses, beta-lactams were superior to glycopeptides for prevention of chest SSIs (RR, 1.47; 95% CI, 1.11-1.95) and approached superiority for prevention of deep-chest SSIs (RR, 1.33; 95% CI, 0.91-1.94) and SSIs caused by gram-positive bacteria (RR, 1.36; 95% CI, 0.98-1.91). Glycopeptides approached superiority to beta-lactams for prevention of leg SSIs (RR, 0.77; 95% CI, 0.58-1.01) and were superior for prevention of SSIs caused by methicillin-resistant gram-positive bacteria (RR, 0.54; 95% CI, 0.33-0.90). Standard prophylaxis for cardiac surgery should continue to be beta-lactams in most circumstances.

Raising Standards While Watching the Bottom Line: Making a Business Case for Infection Control

While society would benefit from a reduced incidence of nosocomial infections, there is currently no direct reimbursement to hospitals for the purpose of infection control, which forces healthcare institutions to make economic decisions about funding infection control activities. Demonstrating value to administrators is an increasingly important function of the hospital epidemiologist because healthcare executives are faced with many demands and shrinking budgets. Aware of the difficulties that face local infection control programs, the Society for Healthcare Epidemiology of America (SHEA) Board of Directors appointed a task force to draft this evidence-based guideline to assist hospital epidemiologists in justifying and expanding their programs. In Part 1, we describe the basic steps needed to complete a business-case analysis for an individual institution. A case study based on a representative infection control intervention is provided. In Part 2, we review important basic economic concepts and describe approaches that can be used to assess the financial impact of infection prevention, surveillance, and control interventions, as well as the attributable costs of specific healthcare-associated infections. Both parts of the guideline aim to provide the hospital epidemiologist, infection control professional, administrator, and researcher with the tools necessary to complete a thorough business-case analysis and to undertake an outcome study of a nosocomial infection or an infection control intervention.

Administrative Databases Provide Inaccurate Data for Surveillance of Long-Term Central Venous Catheter-Associated Infections

BACKGROUND Efficient methods are needed to monitor infections associated with long-term central venous catheters (CVCs) in both inpatient and outpatient settings. Automated medical records and claims data have been used for surveillance of these infections without evaluation of their accuracy or validity. OBJECTIVE To determine the feasibility of using electronic records to identify CVC placement and design a system for identifying CVC-associated infections. DESIGN AND SETTING Retrospective cohort study at an HMO and two teaching hospitals in Boston, one adult (hospital A) and one pediatric (hospital B), between January 1991 and December 1997. Tunneled catheters, totally implanted catheters, and hemodialysis catheters were examined. Claims databases of both the HMO and the hospitals were searched for 10 CPT codes, 2 ICD-9 codes, and internal charge codes indicating CVC insertion. Lists were compared with each other and with medical records for correlation and accuracy. PATIENTS All members of the HMO who had a CVC inserted at one of the two hospitals during the study period. RESULTS There was wide variation in the CVC insertions identified in each database. Although ICD-9 codes at each hospital and CPT/ICD-9 combinations at the HMO found similar total numbers of CVCs, there was little overlap between the individuals identified (62% for hospital A with HMO and 4% for hospital B). CONCLUSION Claims data from different sources do not identify the same CVC insertion procedures. Current administrative databases are not ready to be used for electronic surveillance of CVC-associated complications without extensive modification and validation.

Methicillin-Resistant Staphylococcus aureus Colonization, Behavioral Risk Factors, and Skin and Soft-Tissue Infection at an Ambulatory Clinic Serving a Large Population of HIV-Infected Men Who Have Sex with Men

We conducted a prospective cohort study of 795 outpatients, many of whom were human immunodeficiency virus-infected men who have sex with men, to characterize risk of skin and soft-tissue infection (SSTI) associated with methicillin-resistant Staphylococcus aureus (MRSA) nares and perianal colonization. Multivariate analysis revealed that perianal colonization, drug use, and prior SSTIs were strongly associated with development of an SSTI. Of the patients who were colonized with MRSA at study entry, 36.7% developed an SSTI during the ensuing 12 months, compared with 8.1% of persons who were not colonized with MRSA.

When policy gets it right: variability in u.s. Hospitals' diagnosis of ventilator-associated pneumonia*.

Objective:The Centers for Disease Control has recently proposed a major change in how ventilator-associated pneumonia is defined. This has profound implications for public reporting, reimbursement, and accountability measures for ICUs. We sought to provide evidence for or against this change by quantifying limitations of the national definition of ventilator-associated pneumonia that was in place until January 2013, particularly with regard to comparisons between, and ranking of, hospitals and ICUs. Design:A prospective survey of a nationally representative group of 43 hospitals, randomly selected from the American Hospital Association Guide (2009). Subjects classified six standardized vignettes of possible cases of ventilator-associated pneumonia as pneumonia or no pneumonia. Subjects:Individuals responsible for ventilator-associated pneumonia surveillance at 43 U.S. hospitals. Interventions:None. Measurements and Main Results:We measured the proportion of standardized cases classified as ventilator-associated pneumonia. Of 138 hospitals consented, 61 partially completed the survey and 43 fully completed the survey (response rate 44% and 31%, respectively). Agreement among hospitals about classification of cases as ventilator-associated pneumonia/not ventilator-associated pneumonia was nearly random (Fleiss &kgr; 0.13). Some hospitals rated 0% of cases as having pneumonia; others classified 100% as having pneumonia (median, 50%; interquartile range, 33–66%). Although region of the country did not predict case assignment, respondents who described their region as “rural” were more likely to judge a case to be pneumonia than respondents elsewhere (relative risk, 1.25, Kruskal-Wallis chi-square, p = 0.03). Conclusions:In this nationally representative study of hospitals, assignment of ventilator-associated pneumonia is extremely variable, enough to render comparisons between hospitals worthless, even when standardized cases eliminate variability in clinical data abstraction. The magnitude of this variability highlights the limitations of using poorly performing surveillance definitions as methods of hospital evaluation and comparison, and our study provides very strong support for moving to a more objective definition of ventilator-associated complications.

Treatment with Fluoroquinolones or with β-Lactam-β-Lactamase Inhibitor Combinations Is a Risk Factor for Isolation of Extended-Spectrum-β-Lactamase-Producing Klebsiella Species in Hospitalized Patients

ABSTRACT Antibiotic exposure exerts strong selective pressure and is an important modifiable risk factor for antibiotic resistance. We aimed to identify the role of various antibiotics as risk factors for the isolation of extended-spectrum-β-lactamase (ESBL)-producing Klebsiella spp. in hospitalized patients at a tertiary-care hospital. A parallel multivariable model was created to compare two groups of cases with either nosocomially acquired ESBL- or non-ESBL-producing Klebsiella spp. to a common control group of hospitalized patients (a case-case-control design). Seventy-eight ESBL cases, 358 non-ESBL cases, and 444 controls were analyzed. Significant factors associated with the isolation of Klebsiella spp. were an age of >65 years, transfer from a health care facility, an intensive care unit (ICU) stay, and the presence of a comorbid malignancy or lung, hepatic, or renal disease. A propensity score was generated from the above, and our ability to discriminate between Klebsiella cases and controls (area under the receiver-operating-characteristic [ROC] curve, 0.78) was good. The ESBL phenotype was tightly linked with fluoroquinolone resistance (95% versus 18%, P < 0.001). Factors associated with isolation of ESBL Klebsiella spp. in a multivariable analysis, adjusting for the propensity score, included exposure to β-lactam-β-lactamase inhibitor combinations (odds ratio [OR], 10.17; 95% confidence interval [CI], 1.19 to 86.92) and to fluoroquinolones (OR, 2.86; 95% CI, 1.37 to 5.97). Exposure to broad-spectrum cephalosporins was statistically associated with ESBL Klebsiella spp. only among the subgroup of patients not treated with fluoroquinolones. In our institution, where the ESBL-producing-Klebsiella phenotype is coselected with fluoroquinolone resistance, fluoroquinolone and β-lactam-β-lactamase inhibitor combinations, rather than cephalosporins, are the main risk factors for ESBL isolates. Formulary interventions to limit the spread of ESBL-producing isolates should be tailored to each setting.

Clinical Significance of Varying Degrees of Vancomycin Susceptilibity in Methicillin-Resistant Staphylococcus aureus Bacteremia

We conducted a retrospective study of the clinical aspects of bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA) with heterogeneously reduced susceptibility to vancomycin. Bloodstream MRSA isolates were screened for reduced susceptibility by using brain-heart infusion agar, including 4 mg/L vancomycin with and without 4% NaCl. Patients whose isolates exhibited growth (case-patients) were compared with those whose isolates did not (controls) for demographics, coexisting chronic conditions, hospital events, antibiotic exposures, and outcomes. Sixty-one (41%) of 149 isolates exhibited growth. Subclones from 46 (75%) of these had a higher MIC of vancomycin than did their parent isolates. No isolates met criteria for vancomycin heteroresistance. No differences in potential predictors or in outcomes were found between case-patients and controls. These data show that patients with vancomycin-susceptible MRSA bacteremia have similar baseline clinical features and outcomes whether or not their bacterial isolates exhibit growth on screening media containing vancomycin.

Highly Active Antiretroviral Therapy and Viral Response in HIV Type 2 Infection

Human immunodeficiency virus type 2 (HIV-2), the second human retrovirus known to cause AIDS, is endemic to West Africa but is infrequently found outside this region. We present a case series of 10 HIV-2--infected individuals treated in the United States. Physicians applied the principles of highly active antiretroviral therapy (HAART), normally used in treating HIV type 1, with modifications considered appropriate for treating HIV-2. CD4+ cell count, HIV-2 virus load, and clinical status were found to correlate well, providing evidence that HIV-2 virus load is useful in managing treatment of patients with HIV-2 who are receiving therapy. However, HAART regimens with predicted efficacy for treatment of HIV type 1 infection are not as efficacious for treatment of HIV-2. Controlled clinical trials of HIV-2-infected patients receiving various HAART regimens are needed to provide therapeutic guidance to the medical community.

The Magnitude of the Association between Fluoroquinolone Use and Quinolone-Resistant Escherichia coli and Klebsiella pneumoniae May Be Lower than Previously Reported

ABSTRACT Case-control analyses of resistant versus susceptible isolates have implicated fluoroquinolone exposure as a strong risk factor for fluoroquinolone-resistant isolates of Enterobacteriaceae. We suspect that such methodology may overestimate this association. A total of 84 cases with fluoroquinolone-resistant isolates and 578 cases with fluoroquinolone-susceptible isolates of Escherichia coli or Klebsiella pneumoniae were compared with 608 hospitalized controls in parallel multivariable analyses. For comparison of previous estimates, the results of 10 published case-control studies of risk for fluoroquinolone resistance in isolates of Enterobacteriaceae were pooled by using a random-effects model. Exposure to fluoroquinolones was significantly positively associated with fluoroquinolone resistance (odds ratio [OR], 3.17) and negatively associated with fluoroquinolone susceptibility (OR, 0.18). Multivariable analyses yielded similar estimates (ORs, 2.04 and 0.10, respectively). As data on antibiotic exposure were limited to inpatient prescriptions, misclassification of fluoroquinolone exposure in persons who received fluoroquinolones as outpatients may have led to an underestimation of the true effect size. Pooling the results of previously published studies in which a direct comparison of fluoroquinolone-resistant and fluoroquinolone-susceptible cases was used resulted in a markedly higher effect estimate (OR, 18.7). Had we directly compared resistant and susceptible cases, our univariate OR for the association between fluoroquinolone use and the isolation of resistant Enterobacteriaceae would have been 19.3, and the multivariate OR would have been 16.5. Fluoroquinolone use is significantly associated with the isolation of fluoroquinolone-resistant Enterobacteriaceae; however, previous studies likely exaggerated the magnitude of this association.

Spread of Methicillin-Resistant Staphylococcus aureus in a Large Tertiary NICU: Network Analysis

OBJECTIVE: Methicillin-resistant Staphylococcus aureus (MRSA) colonization in NICUs increases the risk of nosocomial infection. Network analysis provides tools to examine the interactions among patients and staff members that put patients at risk of colonization. METHODS: Data from MRSA surveillance cultures were combined with patient room locations, nursing assignments, and sibship information to create patient- and unit-based networks. Multivariate models were constructed to quantify the risk of incident MRSA colonization as a function of exposure to MRSA-colonized infants in these networks. RESULTS: A MRSA-negative infant in the NICU simultaneously with a MRSA-positive infant had higher odds of becoming colonized when the colonized infant was a sibling, compared with an unrelated patient (odds ratio: 8.8 [95% confidence interval [CI]: 5.3–14.8]). Although knowing that a patient was MRSA-positive and was placed on contact precautions reduced the overall odds of another patient becoming colonized by 35% (95% CI: 20%–47%), having a nurse in common with that patient still increased the odds of colonization by 43% (95% CI: 14%–80%). Normalized group degree centrality, a unitwide network measure of connectedness between colonized and uncolonized patients, was a significant predictor of incident MRSA cases (odds ratio: 18.1 [95% CI: 3.6–90.0]). CONCLUSIONS: Despite current infection-control strategies, patients remain at significant risk of MRSA colonization from MRSA-positive siblings and from other patients with whom they share nursing care. Strategies that minimize the frequency of staff members caring for both colonized and uncolonized infants may be beneficial in reducing the spread of MRSA colonization.