Age modifies the risk of atrial fibrillation among athletes: A systematic literature review and meta-analysis

Background

The relationship between competitive sports and atrial fibrillation (AF) is controversial. We aimed to systematically evaluate and summarize all published observational data on the association between competitive sports and AF.

Methods and results

We searched PubMed, EMBASE, Scopus and SportDiskus for all observational studies that assessed the risk of AF among athletes involved in competitive sports. Data were extracted and pooled odds ratios (OR) were calculated using random effects models. Six cohort studies and 2 case-control studies with a total of 9113 subjects were included in our meta-analysis. Pooled analyses showed an increased risk of incident and prevalent AF among athletes compared to the general population (OR = 1.64 [95% confidence interval (CI): 1.10–2.43]). Age-stratified analysis revealed an effect modification with age. Studies enrolling younger adults (<54 years) had an increased risk of AF among athletes compared to controls (OR = 1.96 [95% CI: 1.06–3.65]), but this association was not seen among older adults ≥54 years (OR = 1.41 [95% CI: 0.81–2.44], p = 0.23).

Conclusion

Athletes have an increased risk of AF compared to the general population. Age appears to modify the risk of AF in athletes.

Chart validation of inpatient ICD-9-CM administrative diagnosis codes for acute myocardial infarction (AMI) among intravenous immune globulin (IGIV) users in the Sentinel Distributed Database

BACKGROUND

The Sentinel Distributed Database (SDD) is a large database of patient-level administrative health care records, primarily derived from insurance claims and electronic health records, and is sponsored by the US Food and Drug Administration for medical product safety evaluations. Acute myocardial infarction (AMI) is a common study endpoint for drug safety studies that rely on health records from the SDD and other administrative databases.

PURPOSE

In this chart validation study, we report on the positive predictive value (PPV) of inpatient International Classification of Diseases, Ninth Revision, Clinical Modification AMI administrative diagnosis codes (410.x1 and 410.x0) in the SDD.

METHODS

As part of an assessment of thromboembolic adverse event risk following treatment with intravenous immune globulin, charts were obtained for 103 potential post-intravenous immune globulin AMI cases. Charts were abstracted by trained nurses and physician-adjudicated based on prespecified diagnostic criteria.

RESULTS

Acute myocardial infarction status could be determined for 89 potential cases. The PPVs for the inpatient AMI diagnoses recorded in the SDD were 75% overall (95% CI, 65-84%), 93% (95% CI, 78-99%) for principal-position diagnoses, 88% (95% CI, 72-97%) for secondary diagnoses, and 38% (95% CI, 20-59%) for position-unspecified diagnoses (eg, diagnoses originating from separate physician claims associated with an inpatient stay). Of the confirmed AMI cases, demand ischemia was the suspected etiology more often for those coded in secondary or unspecified positions (72% and 40%, respectively) than for principal-position AMI diagnoses (21%).

CONCLUSIONS

The PPVs for principal and secondary AMI diagnoses were high and similar to estimates from prior chart validation studies. Position-unspecified diagnosis codes were less likely to represent true AMI cases.

Chart validation of inpatient International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) administrative diagnosis codes for venous thromboembolism (VTE) among intravenous immune globulin (IGIV) users in the Sentinel Distributed Database

The Sentinel Distributed Database (SDD) is a database of patient administrative healthcare records, derived from insurance claims and electronic health records, sponsored by the US Food and Drug Administration for evaluation of medical product outcomes. There is limited information on the validity of diagnosis codes for acute venous thromboembolism (VTE) in the SDD and administrative healthcare data more generally.In this chart validation study, we report on the positive predictive value (PPV) of inpatient administrative diagnosis codes for acute VTE-pulmonary embolism (PE) or lower-extremity or site-unspecified deep vein thrombosis (DVT)-within the SDD. As part of an assessment of thromboembolic adverse event risk following treatment with intravenous immune globulin (IGIV), charts were obtained for 75 potential VTE cases, abstracted, and physician-adjudicated.VTE status was determined for 62 potential cases. PPVs for lower-extremity DVT and/or PE were 90% (95% CI: 73-98%) for principal-position diagnoses, 80% (95% CI: 28-99%) for secondary diagnoses, and 26% (95% CI: 11-46%) for position-unspecified diagnoses (originating from physician claims associated with an inpatient stay). Average symptom onset was 1.5 days prior to hospital admission (range: 19 days prior to 4 days after admission).PPVs for principal and secondary VTE discharge diagnoses were similar to prior study estimates. Position-unspecified diagnoses were less likely to represent true acute VTE cases.

Increased Mortality Rates Associated with Staphylococcus aureus and Influenza Co-infection, Maryland and Iowa, USA(1)

We retrospectively analyzed data for 195 respiratory infection patients who had positive Staphyloccocus aureus cultures and who were hospitalized in 2 hospitals in Iowa and Maryland, USA, during 2003-2009. Odds for death for patients who also had influenza-positive test results were >4 times higher than for those who had negative influenza test results.

Chart validation of inpatient ICD-9-CM administrative diagnosis codes for ischemic stroke among IGIV users in the Sentinel Distributed Database

The Sentinel Distributed Database (SDD) is a large database of patient-level medical and prescription records, primarily derived from insurance claims and electronic health records, and is sponsored by the U.S. Food and Drug Administration for drug safety assessments. In this chart validation study, we report on the positive predictive value (PPV) of inpatient ICD-9-CM acute ischemic stroke (AIS) administrative diagnosis codes (433.x1, 434.xx, and 436) in the SDD.As part of an assessment of the risk of thromboembolic adverse events following treatment with intravenous immune globulin (IGIV), charts were obtained for 131 potential post-IGIV AIS cases. Charts were abstracted by trained nurses and then adjudicated by stroke experts using pre-specified diagnostic criteria.Case status could be determined for 128 potential AIS cases, of which 34 were confirmed. The PPVs for the inpatient AIS diagnoses recorded in the SDD were 27% overall [95% confidence interval (95% CI): 19-35], 60% (95% CI: 32-84) for principal-position diagnoses, 42% (95% CI: 28-57) for secondary diagnoses, and 6% (95% CI: 2-15) for position-unspecified diagnoses (which in the SDD generally originate from separate physician claims associated with an inpatient stay).Position-unspecified diagnoses were unlikely to represent true AIS cases. PPVs for principal and secondary inpatient diagnosis codes were higher, but still meaningfully lower than estimates from prior chart validation studies. The low PPVs may be specific to the IGIV user study population. Additional research is needed to assess the validity of AIS administrative diagnosis codes in other study populations within the SDD.

Dynamic transmission models for economic analysis applied to health care-associated infections: A review of the literature

BACKGROUND

Cost-effectiveness analyses are an important methodology in assessing whether a health care technology is suitable for widespread adoption. Common models used by economists, such as decision trees and Markov models, are appropriate for noninfectious diseases where treatment and exposure are independent. Diseases whose treatment and exposure are dependent require dynamic models to incorporate the nonlinear transmission effect. Two different types of models are often used for dynamic cost-effectiveness analyses: compartmental models and individual models. In this methodology-focused literature review, we describe each model type and summarize the literature associated with each using the example of health care-associated infections (HAIs).

METHODS

We conducted a review of the literature to identify dynamic cost-effectiveness analyses that examined interventions to prevent or treat HAIs. To be included in the review, studies needed to have each of 3 necessary components: involve economics, such as cost-effectiveness analysis and evidence of economic theory, use a dynamic transmission model, and examine HAIs.

RESULTS

Of the 9 articles published between 2005 and 2016 that met criteria to be included in our study, 3 used compartmental models and 6 used individual models.

CONCLUSIONS

Very few published studies exist that use dynamic transmission models to conduct economic analyses related to HAIs and even fewer studies have used these models to perform cost-effectiveness analyses.

Effects of Aflibercept for Neovascular Age-Related Macular Degeneration: A Systematic Review and Meta-Analysis of Observational Comparative Studies

Purposes

To compare the effects of aflibercept and other anti-vascular endothelial growth factor (anti-VEGF) medications on both functional and anatomical outcomes for treatment-naïve neovascular age-related macular degeneration (nAMD) in the real world.

Methods

A systematic review and meta-analysis of observational comparative studies.

Results

A total of 18 studies remained after literature selection and quality assessment of 1697 studies. The most common aflibercept treatment regimen was three monthly injections followed by pro re nata (PRN). Aflibercept and ranibizumab had similar effects in 2-year treatment. At 3, 6, 12, and 24 months, the differences in the logarithm of minimum angle of resolution (logMAR) decrease in aflibercept and ranibizumab groups were 0.00 (95% confidence interval [CI]: −0.03 to 0.02); 0.01 (95% CI: −0.02 to 0.05); −0.03 (95% CI: −0.07 to 0.01); and –0.06 (95% CI: −0.30 to 0.17), respectively; the differences in decrease of central retinal thickness (CRT) were 3.25 μm (95% CI: −15.03 to 21.53); 7.89 μm (95% CI: −31.91 to 47.69); 2.89 μm (95% CI: −18.33 to 24.11); and −2.42 μm (95% CI: −77.87 to 73.03), respectively. However, aflibercept was significantly more effective in patients with initial reduced visual acuity (logMAR >0.6 or <55 letters; P = 0.001). In the first year, treatment frequency was not significantly different for aflibercept and ranibizumab, but aflibercept required fewer injections than ranibizumab with PRN regimen (mean −0.90; 95% CI: −1.80 to 0.00).

Conclusions

Aflibercept has comparable effects with ranibizumab for treatment-naïve nAMD in the real world, and may be more effective for patients with initial lower visual acuity.

A practical guide to systematic literature reviews and meta-analyses in infection prevention: Planning, challenges, and execution

Systematic literature reviews and meta-analyses are important research designs used to summarize and derive conclusions about the collective evidence on a focused research question in a structured, reproducible manner. The goal of this Methodology Minute is to describe how to conduct a systematic literature review and meta-analysis using a step-by-step approach to help infection preventionists (IPs) and others in the field perform their own systematic literature review and meta-analysis, and to critically evaluate published systematic literature reviews and meta-analyses.

Association of Evidence-Based Care Processes With Mortality in Staphylococcus aureus Bacteremia at Veterans Health Administration Hospitals, 2003-2014

IMPORTANCE

Staphylococcus aureus bacteremia is common and frequently associated with poor outcomes. Evidence indicates that specific care processes are associated with improved outcomes for patients with S aureus bacteremia, including appropriate antibiotic prescribing, use of echocardiography to identify endocarditis, and consultation with infectious diseases (ID) specialists. Whether use of these care processes has increased in routine care for S aureus bacteremia or whether use of these processes has led to large-scale improvements in survival is unknown.

OBJECTIVE

To examine the association of evidence-based care processes in routine care for S aureus bacteremia with mortality.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective observational cohort study examined all patients admitted to Veterans Health Administration (VHA) acute care hospitals who had a first episode of S aureus bacteremia from January 1, 2003, through December 31, 2014.

EXPOSURES

Use of appropriate antibiotic therapy, echocardiography, and ID consultation.

MAIN OUTCOMES AND MEASURES

Thirty-day all-cause mortality.

RESULTS

Analyses included 36 868 patients in 124 hospitals (mean [SD] age, 66.4 [12.5] years; 36 036 [97.7%] male), including 19 325 (52.4%) with infection due to methicillin-resistant S aureus and 17 543 (47.6%) with infection due to methicillin-susceptible S aureus. Risk-adjusted mortality decreased from 23.5% (95% CI, 23.3%-23.8%) in 2003 to 18.2% (95% CI, 17.9%-18.5%) in 2014. Rates of appropriate antibiotic prescribing increased from 2467 (66.4%) to 1991 (78.9%), echocardiography from 1256 (33.8%) to 1837 (72.8%), and ID consultation from 1390 (37.4%) to 1717 (68.0%). After adjustment for patient characteristics, cohort year, and other care processes, receipt of care processes was associated with lower mortality, with adjusted odds ratios of 0.74 (95% CI, 0.68-0.79) for appropriate antibiotics, 0.73 (95% CI, 0.68-0.78) for echocardiography, and 0.61 (95% CI, 0.56-0.65) for ID consultation. Mortality decreased progressively as the number of care processes that a patient received increased (adjusted odds ratio for all 3 processes compared with none, 0.33; 95% CI, 0.30-0.36). An estimated 57.3% (95% CI, 48.4%-69.9%) of the decrease in mortality between 2003 and 2014 could be attributed to increased use of these evidence-based care processes.

CONCLUSIONS AND RELEVANCE

Mortality associated with S aureus bacteremia decreased significantly in VHA hospitals, and a substantial portion of the decreasing mortality may have been attributable to increased use of evidence-based care processes. The experience in VHA hospitals demonstrates that increasing application of these care processes may improve survival among patients with S aureus bacteremia in routine health care settings.

Risk of surgical site infection, acute kidney injury, and Clostridium difficile infection following antibiotic prophylaxis with vancomycin plus a beta-lactam versus either drug alone: A national propensity-score-adjusted retrospective cohort study

BACKGROUND

The optimal regimen for perioperative antimicrobial prophylaxis is controversial. Use of combination prophylaxis with a beta-lactam plus vancomycin is increasing; however, the relative risks and benefits associated with this strategy are unknown. Thus, we sought to compare postoperative outcomes following administration of 2 antimicrobials versus a single agent for the prevention of surgical site infections (SSIs). Potential harms associated with combination regimens, including acute kidney injury (AKI) and Clostridium difficile infection (CDI), were also considered.

METHODS AND FINDINGS

Using a multicenter, national Veterans Affairs (VA) cohort, all patients who underwent cardiac, orthopedic joint replacement, vascular, colorectal, and hysterectomy procedures during the period from 1 October 2008 to 30 September 2013 and who received planned manual review of perioperative antimicrobial prophylaxis regimen and manual review for the 30-day incidence of SSI were included. Using a propensity-adjusted log-binomial regression model stratified by type of surgical procedure, the association between receipt of 2 antimicrobials (vancomycin plus a beta-lactam) versus either single agent alone (vancomycin or a beta-lactam) and SSI was evaluated. Measures of association were adjusted for age, diabetes, smoking, American Society of Anesthesiologists score, preoperative methicillin-resistant Staphylococcus aureus (MRSA) status, and receipt of mupirocin. The 7-day incidence of postoperative AKI and 90-day incidence of CDI were also measured. In all, 70,101 procedures (52,504 beta-lactam only, 5,089 vancomycin only, and 12,508 combination) with 2,466 (3.5%) SSIs from 109 medical centers were included. Among cardiac surgery patients, combination prophylaxis was associated with a lower incidence of SSI (66/6,953, 0.95%) than single-agent prophylaxis (190/12,834, 1.48%; crude risk ratio [RR] 0.64, 95% CI 0.49, 0.85; adjusted RR 0.61, 95% CI 0.46, 0.83). After adjusting for SSI risk, no association between receipt of combination prophylaxis and SSI was found for the other types of surgeries evaluated, including orthopedic joint replacement procedures. In MRSA-colonized patients undergoing cardiac surgery, SSI occurred in 8/346 (2.3%) patients who received combination prophylaxis versus 4/100 (4.0%) patients who received vancomycin alone (crude RR 0.58, 95% CI 0.18, 1.88). Among MRSA-negative and -unknown cardiac surgery patients, SSIs occurred in 58/6,607 (0.9%) patients receiving combination prophylaxis versus 146/10,215 (1.4%) patients who received a beta-lactam alone (crude RR 0.61, 95% CI 0.45, 0.83). Based on these associations, the number needed to treat to prevent 1 SSI in MRSA-colonized patients is estimated to be 53, compared to 176 in non-MRSA patients. CDI incidence was similar in both exposure groups. Across all types of surgical procedures, risk of AKI was increased in the combination antimicrobial prophylaxis group (2,971/12,508 [23.8%] receiving combination versus 1,058/5,089 [20.8%] receiving vancomycin alone versus 7,314/52,504 [13.9%] receiving beta-lactam alone). We found a significant association between absolute risk of AKI and receipt of combination regimens across all types of procedures. If the observed association is causal, the number needed to harm for severe AKI following cardiac surgery would be 167. The major limitation of our investigation is that it is an observational study in a predominantly male population, which may limit generalizability and lead to unmeasured confounding.

CONCLUSIONS

There are benefits but also unintended consequences of antimicrobial and infection prevention strategies aimed at "getting to zero" healthcare-associated infections. In our study, combination prophylaxis was associated with both benefits (reduction in SSIs following cardiac surgical procedures) and harms (increase in postoperative AKI). In cardiac surgery patients, the difference in risk-benefit profile by MRSA status suggests that MRSA-screening-directed prophylaxis may optimize benefits while minimizing harms in this selected population. More information about long-term outcomes and patient and societal preferences regarding risk of SSI versus risk of AKI is needed to improve clinical decision-making.

Diffusion of clindamycin-resistant and erythromycin-resistant methicillin-susceptible Staphylococcus aureus (MSSA), potential ST398, in United States Veterans Health Administration Hospitals, 2003-2014

Background

Changing phenotypic profiles of methicillin-susceptible Staphylococcus aureus (MSSA) isolates can indicate the emergence of novel sequence types (ST). The diffusion of MSSA ST can be tracked by combining established genotypic profiles with phenotypic surveillance data. ST398 emerged in New York City (NYC) and exhibits resistance to clindamycin and erythromycin but tetracycline susceptibility (“potential ST398”). Trends of potential ST398 were examined in a national cohort of all Veterans Health Administration patients with MSSA invasive infections during 2003–2014.

Methods

A retrospective cohort of all patients with MSSA invasive infections, defined as a positive clinical culture from a sterile site, during 2003–2014 was created. Only isolates tested against clindamycin, erythromycin and tetracycline were included. Annual hospital-level proportions of potential ST398 were compared according to facility distance from NYC and region.

Results

A total of 34,025 patient isolates from 136 VA medical centers met the inclusion criteria. Of those, 4582 (13.5%) met the definition of potential ST398. Potential ST398 increased over the 12-year cohort and diffused outwards from NYC. Incidence Rate Ratios of >1.0 (p < 0.01) reflect increases in potential ST398 over time in hospitals nearer to NYC.

Conclusions

We observe an increase in the phenotypic profile of potential ST398 MSSA isolates in invasive infections in a national cohort of patients in the US. The increase is not evenly distributed across the US but appears to diffuse outwards from NYC. Novel MSSA strain emergence may have important clinical implications, particularly for the use of clindamycin for suspected S. aureus infections.

Domperidone and Risk of Ventricular Arrhythmia and Cardiac Death: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Domperidone is a drug used globally for relieving nausea and vomiting and stimulating breast milk production. Several case reports and studies linked domperidone usage with major cardiovascular adverse events (cardiac arrhythmia and sudden cardiac death). However, multiple randomized controlled efficacy studies failed to detect such adverse events. Our objectives were to systematically review and meta-analyze the association between current domperidone exposure and cardiovascular adverse events.

METHODS

The first author performed EMBASE, PubMed and Scopus searches to identify human studies assessing the association between current domperidone exposure and cardiac arrhythmia or sudden death. Thirteen related articles were identified and the first and second authors independently reviewed the articles. Six studies were included in the final analysis. Meta-analysis was performed with a random effect model using the inverse variance approach. Heterogeneity was evaluated using the Q statistic and I(2) test.

RESULTS

Five case-control studies and one case-crossover study were included in this meta-analysis. Pooled risk estimates demonstrated that the current use of domperidone increased the risk of ventricular arrhythmia and sudden cardiac death (pooled adjusted odds ratio = 1.70; 95% confidence interval 1.47-1.97; I(2) = 0%). The I(2) test showed that the underlying population was homogeneous.

CONCLUSIONS

Evidence from this meta-analysis suggests that current domperidone use increases the risk of cardiac arrhythmia and sudden cardiac death by 70%. Domperidone usage in older populations should be discouraged. Larger observational studies or randomized controlled trials are needed to confirm the findings of this analysis.

Feasibility of monitoring compliance to the My 5 Moments and Entry/Exit hand hygiene methods in US hospitals

We compared the ability to observe hand hygiene opportunities using the World Health Organization My 5 Moments method to the Entry/Exit method. Under covert direct observation, Entry/Exit method opportunities were observed at all times. My 5 Moments were observable in 32.3% of episodes, with a lower rate in wards versus intensive care units (28.0% vs 39.4%; P < .01). In US hospitals, the Entry/Exit method appears to be more feasible for directly observed hand hygiene compliance monitoring due to line-of-sight issues and other barriers.

Establishing Evidence-Based Criteria for Directly Observed Hand Hygiene Compliance Monitoring Programs: A Prospective, Multicenter Cohort Study

Objective

Hand hygiene surveillance programs that rely on direct observations of healthcare worker activity may be limited by the Hawthorne effect. In addition, comparing compliance rates from period to period requires adequately sized samples of observations. We aimed to statistically determine whether the Hawthorne effect is stable over an observation period and statistically derive sample sizes of observations necessary to compare compliance rates.

Design

Prospective multicenter cohort study.

Setting

Five intensive care units and 6 medical/surgical wards in 3 geographically distinct acute care hospitals.

Methods

Trained observers monitored hand hygiene compliance during routine care in fixed 1-hour periods, using a standardized collection tool. We estimated the impact of the Hawthorne effect using empirical fluctuation processes and F tests for structural change. Standard sample-size calculation methods were used to estimate how many hand hygiene opportunities are required to accurately measure hand hygiene across various levels of baseline and target compliance.

Results

Exit hand hygiene compliance increased after 14 minutes of observation (from 56.2% to 60.5%; P < .001) and increased further after 50 minutes (from 60.5% to 66.0%; P < .001). Entry compliance increased after 38 minutes (from 40.4% to 43.4%; P = .005). Between 79 and 723 opportunities are required during each period, depending on baseline compliance rates (range, 35%–90%) and targeted improvement (5% or 10%).

Conclusions

Limiting direct observation periods to approximately 15 minutes to minimize the Hawthorne effect and determining required number of hand hygiene opportunities observed per period on the basis of statistical power calculations would be expected to improve the validity of hand hygiene surveillance programs.

Infect Control Hosp Epidemiol 2014;35(9):1163-1168

Economic Analysis of Veterans Affairs Initiative to Prevent Methicillin-Resistant Staphylococcus aureus Infections

INTRODUCTION

In an effort to reduce methicillin-resistant Staphylococcus aureus (MRSA) transmission through universal screening and isolation, the Department of Veterans Affairs (VA) launched the National MRSA Prevention Initiative in October 2007. The objective of this analysis was to quantify the budget impact and cost effectiveness of this initiative.

METHODS

An economic model was developed using published data on MRSA hospital-acquired infection (HAI) rates in the VA from October 2007 to September 2010; estimates of the costs of MRSA HAIs in the VA; and estimates of the intervention costs, including salaries of staff members hired to support the initiative at each VA facility. To estimate the rate of MRSA HAIs that would have occurred if the initiative had not been implemented, two different assumptions were made: no change and a downward temporal trend. Effectiveness was measured in life-years gained.

RESULTS

The initiative resulted in an estimated 1,466-2,176 fewer MRSA HAIs. The initiative itself was estimated to cost $207 million during this 3-year period, while the cost savings from prevented MRSA HAIs ranged from $27 million to $75 million. The incremental cost-effectiveness ratios ranged from $28,048 to $56,944/life-years. The overall impact on the VA's budget was $131-$179 million.

CONCLUSIONS

Wide-scale implementation of a national MRSA surveillance and prevention strategy in VA inpatient settings may have prevented a substantial number of MRSA HAIs. Although the savings associated with prevented infections helped offset some but not all of the cost of the initiative, this model indicated that the initiative would be considered cost effective.

Association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia: a retrospective cohort study

Background

Methicillin-resistant S. aureus (MRSA) pneumonia is associated with poor clinical outcomes. This study examined the association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia.

Findings

This retrospective cohort study included 75 patients with MRSA pneumonia who were admitted to two large tertiary care medical centers during 2003–2010. Multivariable models were created using Cox proportional hazards regression and ordinal logistic regression to identify predictors of mortality or increased length of stay (LOS). None of the microbial characteristics (PFGE type, agr dysfunction, SCCmec type, and detection of PVL, ACME, and TSST-1) were significantly associated with 30-day mortality or post-infection hospital length of stay, after adjusting for gender, age, previous hospital admission within 12 months, previous MRSA infection or colonization, positive influenza test, Charlson Comorbidity Index score, and treatment (linezolid or vancomycin).

Conclusion

Large prospective studies are needed to examine the impact of microbial characteristics on the risk of death and other adverse outcomes among patients with MRSA pneumonia.

Electronic supplementary material

The online version of this article (doi:10.1186/s13756-015-0092-1) contains supplementary material, which is available to authorized users.

Costs Associated With Surgical Site Infections in Veterans Affairs Hospitals

IMPORTANCE

Surgical site infections (SSIs) are potentially preventable complications that are associated with excess morbidity and mortality.

OBJECTIVE

To determine the excess costs associated with total, deep, and superficial SSIs among all operations and for high-volume surgical specialties.

DESIGN, SETTING, AND PARTICIPANTS

Surgical patients from 129 Veterans Affairs (VA) hospitals were included. The Veterans Health Administration Decision Support System and VA Surgical Quality Improvement Program databases were used to assess costs associated with SSIs among VA patients who underwent surgery in fiscal year 2010.

MAIN OUTCOMES AND MEASURES

Linear mixed-effects models were used to evaluate incremental costs associated with SSIs, controlling for patient risk factors, surgical risk factors, and hospital-level variation in costs. Costs of the index hospitalization and subsequent 30-day readmissions were included. Additional analysis determined potential cost savings of quality improvement programs to reduce SSI rates at hospitals with the highest risk-adjusted SSI rates.

RESULTS

Among 54,233 VA patients who underwent surgery, 1756 (3.2%) experienced an SSI. Overall, 0.8% of the cohort had a deep SSI, and 2.4% had a superficial SSI. The mean unadjusted costs were $31,580 and $52,620 for patients without and with an SSI, respectively. In the risk-adjusted analyses, the relative costs were 1.43 times greater for patients with an SSI than for patients without an SSI (95% CI, 1.34-1.52; difference, $11,876). Deep SSIs were associated with 1.93 times greater costs (95% CI, 1.71-2.18; difference, $25,721), and superficial SSIs were associated with 1.25 times greater costs (95% CI, 1.17-1.35; difference, $7003). Among the highest-volume specialties, the greatest mean cost attributable to SSIs was $23,755 among patients undergoing neurosurgery, followed by patients undergoing orthopedic surgery, general surgery, peripheral vascular surgery, and urologic surgery. If hospitals in the highest 10th percentile (ie, the worst hospitals) reduced their SSI rates to the rates of the hospitals in the 50th percentile, the Veterans Health Administration would save approximately $6.7 million per year.

CONCLUSIONS AND RELEVANCE

Surgical site infections are associated with significant excess costs. Among analyzed surgery types, deep SSIs and SSIs among neurosurgery patients are associated with the highest risk-adjusted costs. Large potential savings per year may be achieved by decreasing SSI rates.

Clinical Effectiveness of Mupirocin for Preventing Staphylococcus aureus Infections in Nonsurgical Settings: A Meta-analysis

A systematic literature review and meta-analysis was performed to identify effectiveness of mupirocin decolonization in prevention of Staphylococcus aureus infections, among nonsurgical settings. Of the 15 662 unique studies identified up to August 2015, 13 randomized controlled trials, 22 quasi-experimental studies, and 1 retrospective cohort study met the inclusion criteria. Studies were excluded if mupirocin was not used for decolonization, there was no control group, or the study was conducted in an outbreak setting. The crude risk ratios were pooled (cpRR) using a random-effects model. We observed substantial heterogeneity among included studies (I(2) = 80%). Mupirocin was observed to reduce the risk for S. aureus infections by 59% (cpRR, 0.41; 95% confidence interval [CI], .36-.48) and 40% (cpRR, 0.60; 95% CI, .46-.79) in both dialysis and nondialysis settings, respectively. Mupirocin decolonization was protective against S. aureus infections among both dialysis and adult intensive care patients. Future studies are needed in other settings such as long-term care and pediatrics.

Association of a bundled intervention with surgical site infections among patients undergoing cardiac, hip, or knee surgery

IMPORTANCE

Previous studies suggested that a bundled intervention was associated with lower rates of Staphylococcus aureus surgical site infections (SSIs) among patients having cardiac or orthopedic operations.

OBJECTIVE

To evaluate whether the implementation of an evidence-based bundle is associated with a lower risk of S. aureus SSIs in patients undergoing cardiac operations or hip or knee arthroplasties.

DESIGN, SETTING, AND PARTICIPANTS

Twenty hospitals in 9 US states participated in this pragmatic study; rates of SSIs were collected for a median of 39 months (range, 39-43) during the preintervention period (March 1, 2009, to intervention) and a median of 21 months (range, 14-22) during the intervention period (from intervention start through March 31, 2014).

INTERVENTIONS

Patients whose preoperative nares screens were positive for methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA) were asked to apply mupirocin intranasally twice daily for up to 5 days and to bathe daily with chlorhexidine-gluconate (CHG) for up to 5 days before their operations. MRSA carriers received vancomycin and cefazolin or cefuroxime for perioperative prophylaxis; all others received cefazolin or cefuroxime. Patients who were MRSA-negative and MSSA-negative bathed with CHG the night before and morning of their operations. Patients were treated as MRSA-positive if screening results were unknown.

MAIN OUTCOMES AND MEASURES

The primary outcome was complex (deep incisional or organ space) S. aureus SSIs. Monthly SSI counts were analyzed using Poisson regression analysis.

RESULTS

After a 3-month phase-in period, bundle adherence was 83% (39% full adherence; 44% partial adherence). Overall, 101 complex S. aureus SSIs occurred after 28,218 operations during the preintervention period and 29 occurred after 14,316 operations during the intervention period (mean rate per 10,000 operations, 36 for preintervention period vs 21 for intervention period, difference, -15 [95% CI, -35 to -2]; rate ratio [RR], 0.58 [95% CI, 0.37 to 0.92]). The rates of complex S. aureus SSIs decreased for hip or knee arthroplasties (difference per 10,000 operations, -17 [95% CI, -39 to 0]; RR, 0.48 [95% CI, 0.29 to 0.80]) and for cardiac operations (difference per 10,000 operations, -6 [95% CI, -48 to 8]; RR, 0.86 [95% CI, 0.47 to 1.57]).

CONCLUSIONS AND RELEVANCE

In this multicenter study, a bundle comprising S. aureus screening, decolonization, and targeted prophylaxis was associated with a modest, statistically significant decrease in complex S. aureus SSIs.

Strategies to prevent healthcare-associated infections through hand hygiene

Previously published guidelines provide comprehensive recommendations for hand hygiene in healthcare facilities. The intent of this document is to highlight practical recommendations in a concise format, update recommendations with the most current scientific evidence, and elucidate topics that warrant clarification or more robust research. Additionally, this document is designed to assist healthcare facilities in implementing hand hygiene adherence improvement programs, including efforts to optimize hand hygiene product use, monitor and report back hand hygiene adherence data, and promote behavior change. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

Comparative effectiveness of beta-lactams versus vancomycin for treatment of methicillin-susceptible Staphylococcus aureus bloodstream infections among 122 hospitals

BACKGROUND

Previous studies indicate that vancomycin is inferior to beta-lactams for treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections. However, it is unclear if this association is true for empiric and definitive therapy. Here, we compared beta-lactams with vancomycin for empiric and definitive therapy of MSSA bloodstream infections among patients admitted to 122 hospitals.

METHODS

This retrospective cohort study included all patients admitted to Veterans Affairs hospitals from 2003 to 2010 who had positive blood cultures for MSSA. Hazard ratios (HR) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression. Empiric therapy was defined as starting treatment 2 days before and up to 4 days after the first MSSA blood culture was collected. Definitive therapy was defined as starting treatment between 4 and 14 days after the first positive blood culture was collected.

RESULTS

Patients who received empiric therapy with a beta-lactam had similar mortality compared with those who received vancomycin (HR, 1.03; 95% CI, .89-1.20) after adjusting for other factors. However, patients who received definitive therapy with a beta-lactam had 35% lower mortality compared with patients who received vancomycin (HR, 0.65; 95% CI, .52-.80) after controlling for other factors. The hazard of mortality decreased further for patients who received cefazolin or antistaphylococcal penicillins compared with vancomycin (HR, 0.57; 95% CI, .46-.71).

CONCLUSIONS

For patients with MSSA bloodstream infections, beta-lactams are superior to vancomycin for definitive therapy but not for empiric treatment. Patients should receive beta-lactams for definitive therapy, specifically antistaphylococcal penicillins or cefazolin.

Molecular characterization of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization and infection isolates in a Veterans Affairs hospital

Background

Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is associated with increased infection risk, yet colonization and infection isolates are rarely compared within the same study. The objectives of this study were to compare colonization and infection isolates from a Veterans Administration hospital in Iowa, and to determine the prevalence of livestock-associated MRSA (LA-MRSA) colonization and infection in a state with high livestock density.

Methods

All patients with available MRSA isolates collected through routine nasal screening (73%; n = 397) and from infections (27%; n = 148) between December 2010 and August 2012 were included and tested for spa type and presence of PVL and mecA genes. Clinical isolates were tested for antibiotic resistance patterns. Paired colonization and infection isolates were compared for genetic and phenotypic congruity.

Results

The most common spa types were t002 (and other CC5-associated strains; 65%) and t008 (and other CC8-associated strains; 20%). No classic LA-MRSA spa types were identified. CC5-associated strains were less likely to be associated with infections (22%; 77/353) compared with CC8-associated strains (49%; 53/109). MRSA colonization was more common among patients with infections (71%) compared with the general screening population (7%). In most cases (82%; 28/34), paired colonization and infection isolates were genetically and phenotypically indistinguishable.

Conclusions

Our data demonstrate a direct link between antecedent nasal colonization and subsequent MRSA infection. Further, our data indicate variability in colonization and infection efficiency among MRSA genotypes, which points to the need to define the molecular determinants underlying emergence of S. aureus strains in the community and nosocomial setting.

Strategies to Prevent Healthcare-Associated Infections through Hand Hygiene

Previously published guidelines provide comprehensive recommendations for hand hygiene in healthcare facilities. The intent of this document is to highlight practical recommendations in a concise format, update recommendations with the most current scientific evidence, and elucidate topics that warrant clarification or more robust research. Additionally, this document is designed to assist healthcare facilities in implementing hand hygiene adherence improvement programs, including efforts to optimize hand hygiene product use, monitor and report back hand hygiene adherence data, and promote behavior change. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

Assessment of empirical antibiotic therapy optimisation in six hospitals: an observational cohort study

BACKGROUND

Modification of empirical antimicrobials when warranted by culture results or clinical signs is recommended to control antimicrobial overuse and resistance. We aimed to assess the frequency with which patients were started on empirical antimicrobials, characteristics of the empirical regimen and the clinical characteristics of patients at the time of starting antimicrobials, patterns of changes to empirical therapy at different timepoints, and modifiable factors associated with changes to the initial empirical regimen in the first 5 days of therapy.

METHODS

We did a chart review of adult inpatients receiving one or more antimicrobials in six US hospitals on 4 days during 2009 and 2010. Our primary outcome was the modification of antimicrobial regimen on or before the 5th day of empirical therapy, analysed as a three-category variable. Bivariate analyses were used to establish demographic and clinical variables associated with the outcome. Variables with p values below 0·1 were included in a multivariable generalised linear latent and mixed model with multinomial logit link to adjust for clustering within hospitals and accommodate a non-binary outcome variable.

FINDINGS

Across the six study sites, 4119 (60%) of 6812 inpatients received antimicrobials. Of 1200 randomly selected patients with active antimicrobials, 730 (61%) met inclusion criteria. At the start of therapy, 220 (30%) patients were afebrile and had normal white blood cell counts. Appropriate cultures were collected from 432 (59%) patients, and 250 (58%) were negative. By the 5th day of therapy, 12·5% of empirical antimicrobials were escalated, 21·5% were narrowed or discontinued, and 66·4% were unchanged. Narrowing or discontinuation was more likely when cultures were collected at the start of therapy (adjusted OR 1·68, 95% CI 1·05-2·70) and no infection was noted on an initial radiological study (1·76, 1·11-2·79). Escalation was associated with multiple infection sites (2·54, 1·34-4·83) and a positive culture (1·99, 1·20-3·29).

INTERPRETATION

Broad-spectrum empirical therapy is common, even when clinical signs of infection are absent. Fewer than one in three inpatients have their regimens narrowed within 5 days of starting empirical antimicrobials. Improved diagnostic methods and continued education are needed to guide discontinuation of antimicrobials.

FUNDING

US Centers for Disease Control and Prevention, Division of Healthcare Quality Promotion; Robert Wood Johnson Foundation; US Department of Veterans Administration; US Department of Homeland Security.

Methicillin-resistant Staphylococcus aureus prevention practices in hospitals throughout a rural state

BACKGROUND

The Institute for Healthcare Improvement (IHI) created an evidence-based bundle to help reduce methicillin-resistant Staphylococcus aureus (MRSA) health care-associated infections. The study aim was to identify which components of the IHI's MRSA bundle that rural hospitals have implemented and to identify barriers that hindered implementation of bundle components.

METHODS

Four surveys about the IHI's MRSA bundle were administered at the Iowa Statewide Infection Prevention Seminar between 2007 and 2011. Surveys were mailed to infection preventionists (IPs) who did not attend the meetings.

RESULTS

The percentage of IPs reporting that their hospital implemented a hand hygiene program (range by year, 87%-94%) and used contact precautions for patients infected (range by year, 97%-100%) or colonized (range by year, 77%-92%) with MRSA did not change significantly. The number of hospitals that monitored the effectiveness of environmental cleaning significantly increased from 23%-71% (P < .01). Few hospitals assessed daily if central lines were necessary (range by year, 22%-26%). IPs perceived lack of support to be a major barrier to implementing bundle components.

CONCLUSION

Most IPs reported that their hospitals had implemented most components of the MRSA bundle. Support within the health care system is essential for implementing each component of an evidence-based bundle.

HIV quality report cards: impact of case-mix adjustment and statistical methods

BACKGROUND

There will be increasing pressure to publicly report and rank the performance of healthcare systems on human immunodeficiency virus (HIV) quality measures. To inform discussion of public reporting, we evaluated the influence of case-mix adjustment when ranking individual care systems on the viral control quality measure.

METHODS

We used data from the Veterans Health Administration (VHA) HIV Clinical Case Registry and administrative databases to estimate case-mix adjusted viral control for 91 local systems caring for 12 368 patients. We compared results using 2 adjustment methods, the observed-to-expected estimator and the risk-standardized ratio.

RESULTS

Overall, 10 913 patients (88.2%) achieved viral control (viral load ≤400 copies/mL). Prior to case-mix adjustment, system-level viral control ranged from 51% to 100%. Seventeen (19%) systems were labeled as low outliers (performance significantly below the overall mean) and 11 (12%) as high outliers. Adjustment for case mix (patient demographics, comorbidity, CD4 nadir, time on therapy, and income from VHA administrative databases) reduced the number of low outliers by approximately one-third, but results differed by method. The adjustment model had moderate discrimination (c statistic = 0.66), suggesting potential for unadjusted risk when using administrative data to measure case mix.

CONCLUSIONS

Case-mix adjustment affects rankings of care systems on the viral control quality measure. Given the sensitivity of rankings to selection of case-mix adjustment methods-and potential for unadjusted risk when using variables limited to current administrative databases-the HIV care community should explore optimal methods for case-mix adjustment before moving forward with public reporting.

Gentamicin/collagen sponge use may reduce the risk of surgical site infections for patients undergoing cardiac operations: a meta-analysis

OBJECTIVE

A meta-analysis of all published randomized controlled trials of the effectiveness of gentamicin/collagen sponges for preventing surgical site infections (SSIs).

BACKGROUND

Despite routine use of systemic prophylactic antimicrobial agents, SSIs continue to be associated with substantial morbidity. RESULTS conflict of studies of the efficacy of gentamicin/collagen sponges for preventing SSIs. However, many of these studies have assessed sponge use in only a single specific type of operation. The general effect of sponge use among different types of operations has not been previously assessed.

METHODS

The PubMed and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases were searched for articles appearing from 1990 through January 2012 that were related to gentamicin/collagen sponge use and SSIs. Summary estimates were obtained through a random effects model. After reviewing 714 article abstracts and reviewing 22 articles in detail, we pooled the odds ratios (OR) for 13 independent study populations (cardiac, n=4; colorectal, n=4; pilonidal sinus, n=2; hernia, n=2; gastrointestinal, n=1) in which the association between prophylactic use of gentamicin/collagen sponges and SSIs was assessed.

RESULTS

Pooling of the results of all studies included in the review in a random effects model showed a significant protective effect of prophylactic use of gentamicin/collagen sponges against SSI (pooled OR: 0.66; 95% confidence interval [CI]: 0.45, 0.97; n=13). However, when the data were stratified by type of operation, a significant protective effect was observed in cardiac procedures (pooled OR: 0.59; 95% CI: 0.37, 0.96; n=4) but not in colorectal procedures (pooled OR: 0.74; 95% CI: 0.29-1.92; n=4).

CONCLUSION

Use of gentamicin/collagen sponges was associated with a reduced risk of SSI following cardiac operations but not following colorectal procedures.

Automated and electronically assisted hand hygiene monitoring systems: a systematic review

BACKGROUND

Hand hygiene is one of the most effective ways to prevent transmission of health care-associated infections. Electronic systems and tools are being developed to enhance hand hygiene compliance monitoring. Our systematic review assesses the existing evidence surrounding the adoption and accuracy of automated systems or electronically enhanced direct observations and also reviews the effectiveness of such systems in health care settings.

METHODS

We systematically reviewed PubMed for articles published between January 1, 2000, and March 31, 2013, containing the terms hand AND hygiene or hand AND disinfection or handwashing. Resulting articles were reviewed to determine if an electronic system was used.

RESULTS

We identified 42 articles for inclusion. Four types of systems were identified: electronically assisted/enhanced direct observation, video-monitored direct observation systems, electronic dispenser counters, and automated hand hygiene monitoring networks. Fewer than 20% of articles identified included calculations for efficiency or accuracy.

CONCLUSIONS

Limited data are currently available to recommend adoption of specific automatic or electronically assisted hand hygiene surveillance systems. Future studies should be undertaken that assess the accuracy, effectiveness, and cost-effectiveness of such systems. Given the restricted clinical and infection prevention budgets of most facilities, cost-effectiveness analysis of specific systems will be required before these systems are widely adopted.

Effect of antibiotic stewardship programmes on Clostridium difficile incidence: a systematic review and meta-analysis

OBJECTIVES

Despite vigorous infection control measures, Clostridium difficile continues to cause significant disease burden. Antibiotic stewardship programmes (ASPs) may prevent C. difficile infections by limiting exposure to certain antibiotics. Our objective was to perform a meta-analysis of published studies to assess the effect of ASPs on the risk of C. difficile infection in hospitalized adult patients.

METHODS

Searches of PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature and two Cochrane databases were conducted to find all published studies on interventions related to antibiotic stewardship and C. difficile. Two investigators independently assessed study eligibility and extracted data. Risk of bias was assessed using the Downs and Black tool. Risk ratios were pooled using random effects models. Heterogeneity was evaluated using the I(2) statistic.

RESULTS

The final search yielded 891 articles; 78 full articles were reviewed and 16 articles were identified for inclusion. Included articles used quasi-experimental (interrupted time series or before-after) or observational (case-control) study designs. When the results of all studies were pooled in a random effects model, a significant protective effect (pooled risk ratio 0.48; 95% CI: 0.38, 0.62) was observed between ASPs and C. difficile incidence. When stratified by intervention type, a significant effect was found for restrictive ASPs (complete removal of drug or prior approval requirement). Furthermore, ASPs were particularly effective in geriatric settings.

CONCLUSIONS

Restrictive ASPs can be used to reduce the risk of C. difficile infection.

Effectiveness of local vancomycin powder to decrease surgical site infections: a meta-analysis

BACKGROUND CONTEXT

Some surgeons use systemic vancomycin to prevent surgical site infections (SSIs), but patients who do not carry methicillin-resistant Staphylococcus aureus have an increased risk of SSIs when given vancomycin alone for intravenous prophylaxis. Applying vancomycin powder to the wound before closure could increase the local tissue vancomycin level without significant systemic levels. However, the effectiveness of local vancomycin powder application for preventing SSIs has not been established.

PURPOSE

Our objective was to systematically review and evaluate studies on the effectiveness of local vancomycin powder for decreasing SSIs.

STUDY DESIGN

Meta-analysis.

SAMPLE

We included observational studies, quasi-experimental studies, and randomized controlled trials of patients undergoing surgical procedures that involved vancomycin powder application to surgical wounds, reported SSI rates, and had a comparison group that did not use local vancomycin powder.

OUTCOME MEASURES

The primary outcome was postoperative SSIs. The secondary outcomes included deep incisional SSIs and S. aureus SSIs.

METHODS

We performed systematic literature searches in PubMed, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, the Cochrane Central Register of Controlled Trials via Wiley, Scopus (including EMBASE abstracts), Web of Science, ClinicalTrials.gov, BMC Proceedings, ProQuest Dissertation, and Thesis in Health and Medicine, and conference abstracts from IDWeek, the Interscience Conference on Antimicrobial Agents and Chemotherapy, the Society for Healthcare Epidemiology of America, and the American Academy of Orthopedic Surgeons annual meetings, and also the Scoliosis Research Society Annual Meeting and Course. We ran the searches from inception on May 9, 2013 with no limits on date or language. After reviewing 373 titles or abstracts and 22 articles in detail, we included 10 independent studies and used a random-effects model when pooling risk estimates to assess the effectiveness of local vancomycin powder application for preventing SSIs, the outcome of interest. We used the I²-index, Q-statistic, and corresponding p value to assess the heterogeneity of the risk estimates, and funnel plots to assess publication bias.

RESULTS

We included seven quasi-experimental studies, two cohort studies, and one randomized controlled trial, encompassing 5,888 surgical patients. The pooled effects showed that applying local vancomycin powder was significantly protective against SSIs (pooled odds ratio [pOR] 0.19; 95% confidence interval [CI] 0.09-0.38), deep incisional SSIs (pOR 0.23; 95% CI 0.09-0.57), and SSIs caused by S. aureus (pOR 0.22; 95% CI 0.08-0.58). However, significant heterogeneity was present for studies evaluating all SSIs or deep incisional SSIs. When we pooled the risk estimates from the eight studies that assessed patients undergoing spinal operations, vancomycin powder remained significantly protective against SSIs (pOR 0.16; 95% CI 0.09-0.30), deep incisional SSIs (pOR 0.18; 95% CI 0.09-0.36), and SSIs caused by S. aureus (pOR 0.11; 95% CI 0.03-0.36). The pooled ORs from studies of spinal operations were lower than those for all studies and the estimates from spinal operation studies were homogeneous. However, there was evidence of publication bias.

CONCLUSIONS

Local administration of vancomycin powder appears to protect against SSIs, deep incisional SSIs, and S. aureus SSIs after spinal operations. Large, high-quality studies should be performed to evaluate this intervention before it is used routinely.

Residential proximity to large numbers of swine in feeding operations is associated with increased risk of methicillin-resistant Staphylococcus aureus colonization at time of hospital admission in rural Iowa veterans

Among 1,036 patients, residential proximity within 1 mile of large swine facilities was associated with nearly double the risk of methicillin-resistant Staphylococcus aureus (MRSA) colonization at admission (relative risk, 1.8786 [95% confidence interval, 1.0928-3.2289]; P = .0239) and, after controlling for multiple admissions and age, was associated with nearly triple the odds of MRSA colonization (odds ratio, 2.76 [95% confidence interval, 1.2728-5.9875]; P = .0101).

Mortality among patients with methicillin-resistant Staphylococcus aureus USA300 versus non-USA300 invasive infections: a meta-analysis

BACKGROUND

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been found to be epidemiologically and microbiologically distinct from healthcare-associated MRSA. Most CA-MRSA infections are not invasive; however, fatal outcomes have been reported among healthy people with CA-MRSA invasive infections. Epidemiological studies have attributed a major burden of CA-MRSA infections in the United States to the predominant clone USA300. We investigated the association between USA300 invasive infections and mortality by conducting a systematic review and meta-analysis of studies that reported mortality rates associated with USA300 strains.

METHODS

We searched PubMed, bibliographies of other publications, and gray literature between January 2001 and December 2013. Observational studies of patients with an invasive MRSA infection were included. The exposure of interest was presence of USA300 invasive infection. Studies were included only if they provided MRSA PFGE types and if corresponding mortality data were the measured outcome. We pooled crude odds ratios (cORs) using a random-effects model. Woolf test of homogeneity and Q and I(2) statistics were assessed.

RESULTS

Of 574 articles identified by the search strategy, 8 met the inclusion criteria. Risk of mortality was significantly lower among patients with USA300 MRSA infections (pooled cOR, 0.63 [95% confidence interval (CI)], 0.49-0.81). There was a moderate degree of heterogeneity among study results (P = .29; I(2) = 18%). Results were observed to be heterogeneous due to study design, quality of studies, and definition of mortality.

CONCLUSIONS

MRSA invasive infection with USA300 does not appear to be associated with higher mortality compared with infections due to non-USA300 strains. Nevertheless, larger well-designed studies are warranted to further evaluate this association.

Optimizing antimicrobial prescribing: Are clinicians following national trends in methicillin-resistant staphylococcus aureus (MRSA) infections rather than local data when treating MRSA wound infections

Background

Clinicians often prescribe antimicrobials for outpatient wound infections before culture results are known. Local or national MRSA rates may be considered when prescribing antimicrobials. If clinicians prescribe in response to national rather than local MRSA trends, prescribing may be improved by making local data accessible. We aimed to assess the correlation between outpatient trends in antimicrobial prescribing and the prevalence of MRSA wound infections across local and national levels.

Methods

Monthly MRSA positive wound culture counts were obtained from The Surveillance Network, a database of antimicrobial susceptibilities from clinical laboratories across 278 zip codes from 1999–2007. Monthly outpatient retail sales of linezolid, clindamycin, trimethoprim-sulfamethoxazole and cephalexin from 1999–2007 were obtained from the IMS Health Xponent^TM database. Rates were created using census populations. The proportion of variance in prescribing that could be explained by MRSA rates was assessed by the coefficient of determination (R²), using population weighted linear regression.

Results

107,215 MRSA positive wound cultures and 106,641,604 antimicrobial prescriptions were assessed. The R² was low when zip code-level antimicrobial prescription rates were compared to MRSA rates at all levels. State-level prescriptions of clindamycin and linezolid were not correlated with state MRSA rates. The variance in state-level prescribing of clindamycin and linezolid was correlated with national MRSA rates (clindamycin R² = 0.17, linezolid R² = 0.22).

Conclusions

Clinicians may rely on national, not local MRSA data when prescribing clindamycin and linezolid for wound infections. Providing local resistance data to prescribing clinicians may improve antimicrobial prescribing and would be a possible target for future interventions.

Benefits of universal gloving on hospital-acquired infections in acute care pediatric units

BACKGROUND

To prevent transmission, some pediatric units require clinicians to wear gloves for all patient contacts during RSV season. We sought to assess whether a mandatory gloving policy reduced the risk of other health care-acquired infections (HAIs).

METHODS

This retrospective cohort study included all patients admitted to pediatric units of a tertiary care center between 2002 and 2010. Poisson regression models were used to measure the association between mandatory gloving and HAI incidence. Autoregressive models were used to adjust for time correlation.

RESULTS

During the study period, 686 HAIs occurred during 363 782 patient-days. The risk of any HAI was 25% lower during mandatory gloving periods compared with during nongloving periods (relative risk [RR]: 0.75; 95% confidence interval [CI]: 0.69-0.93; P = .01), after adjusting for long-term trends and seasonal effect. Mandatory gloving was associated with lower risks of bloodstream infections (RR: 0.63; 95% CI: 0.49-0.81; P < .001), central line-associated bloodstream infections (RR: 0.61; 95% CI: 0.44-0.84; P = 0.003), and hospital-acquired pneumonia (RR: 0.20; 95% CI: 0.03-1.25; P= 0.09). The reduction was significant in the PICU (RR: 0.63; 95% CI: 0.42-0.93; P = .02), the NICU (RR: 0.62; 95% CI: 0.39-0.98; P = .04), and the Pediatric Bone Marrow Transplant Unit (RR: 0.52; 95% CI: 0.29-0.91, P = .02).

CONCLUSIONS

Universal gloving during RSV season was associated with significantly lower rates of bacteremia and central line-associated bloodstream infections, particularly in the ICUs and the Pediatric Bone Marrow Transplant Unit.

The effect of contact precautions on healthcare worker activity in acute care hospitals

BACKGROUND AND OBJECTIVE

Contact precautions are a cornerstone of infection prevention but have also been associated with less healthcare worker (HCW) contact and adverse events. We studied how contact precautions modified HCW behavior in 4 acute care facilities.

DESIGN

Prospective cohort study.

PARTICIPANTS AND SETTING

Four acute care facilities in the United States performing active surveillance for methicillin-resistant Staphylococcus aureus.

METHODS

Trained observers performed "secret shopper" monitoring of HCW activities during routine care, using a standardized collection tool and fixed 1-hour observation periods.

RESULTS

A total of 7,743 HCW visits were observed over 1,989 hours. Patients on contact precautions had 36.4% fewer hourly HCW visits than patients not on contact precautions (2.78 vs 4.37 visits per hour; [Formula: see text]) as well as 17.7% less direct patient contact time with HCWs (13.98 vs 16.98 minutes per hour; [Formula: see text]). Patients on contact precautions tended to have fewer visitors (23.6% fewer; [Formula: see text]). HCWs were more likely to perform hand hygiene on exiting the room of a patient on contact precautions (63.2% vs 47.4% in rooms of patients not on contact precautions; [Formula: see text]).

CONCLUSION

Contact precautions were found to be associated with activities likely to reduce transmission of resistant pathogens, such as fewer visits and better hand hygiene at exit, while exposing patients on contact precautions to less HCW contact, less visitor contact, and potentially other unintended outcomes.

Association between methicillin-resistant Staphylococcus aureus colonization and infection may not differ by age group

We assessed whether age modified the association between methicillin-resistant Staphylococcus aureus (MRSA) anterior nares colonization and subsequent infection. Among 7,405 patients (9,511 admissions), MRSA colonization was significantly associated with infection (adjusted odds ratio, 13.7 [95% confidence interval, 7.3-25.7]) but did not differ significantly by age group.

Staphylococcus aureus colonization before infection is not associated with mortality among S. aureus-infected patients: a meta-analysis

BACKGROUND AND OBJECTIVE

The literature is conflicted as to whether people colonized with Staphylococcus aureus are at an increased risk of mortality. The aim of this meta-analysis was to review and analyze the current literature to determine whether prior history of S. aureus colonization is associated with mortality among S. aureus-infected patients.

METHODS

The PUBMED databases were searched with keywords related to S. aureus colonization and mortality. After reviewing 380 article abstracts and 59 articles in detail, only 7 studies had data on the association between S. aureus colonization and mortality among S. aureus-infected patients. Crude estimates of study odds ratios (ORs) were calculated on the basis of data from subset analyses. We pooled crude ORs from the 7 studies using a random-effects model. Woolf's test for heterogeneity was assessed.

RESULTS

When all studies were pooled in a random-effects model, no association between S. aureus colonization and mortality among S. aureus-infected patients was seen (pooled OR, 1.08 [95% confidence interval (CI), 0.32-3.66]; [Formula: see text]; heterogeneity [Formula: see text]). When the analyses were restricted to infection-attributable mortality, the association between colonization and mortality among S. aureus-infected patients was not statistically significant (pooled OR, 0.42 [95% CI, 0.15-1.21]; [Formula: see text]; heterogeneity [Formula: see text]).

CONCLUSIONS

S. aureus colonization was not associated with mortality among patients who developed an S. aureus infection. Interventions to decolonize S. aureus carriers may prevent S. aureus infections but may not be sufficient to prevent mortality.

National Institute of Allergy and Infectious Disease (NIAID) Funding for Studies of Hospital-Associated Bacterial Pathogens: Are Funds Proportionate to Burden of Disease?

BACKGROUND

Hospital-associated infections (HAIs) are associated with a considerable burden of disease and direct costs greater than $17 billion. The pathogens that cause the majority of serious HAIs are Enterococcus faecium, Staphylococcus aureus, Clostridium difficile, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species, referred as ESCKAPE. We aimed to determine the amount of funding the National Institute of Health (NIH) National Institute of Allergy and Infectious Diseases (NIAID) allocates to research on antimicrobial resistant pathogens, particularly ESCKAPE pathogens.

METHODS

The NIH Research Portfolio Online Reporting Tools (RePORT) database was used to identify NIAID antimicrobial resistance research grants funded in 2007-2009 using the terms "antibiotic resistance," "antimicrobial resistance," and "hospital-associated infection."

RESULTS

Funding for antimicrobial resistance grants has increased from 2007-2009. Antimicrobial resistance funding for bacterial pathogens has seen a smaller increase than non-bacterial pathogens. The total funding for all ESKCAPE pathogens was $ 22,005,943 in 2007, $ 30,810,153 in 2008 and $ 49,801,227 in 2009. S. aureus grants received $ 29,193,264 in FY2009, the highest funding amount of all the ESCKAPE pathogens. Based on 2009 funding data, approximately $1,565 of research money was spent per S. aureus related death and $750 of was spent per C. difficile related death.

CONCLUSIONS

Although the funding for ESCKAPE pathogens has increased from 2007 to 2009, funding levels for antimicrobial resistant bacteria-related grants is still lower than funding for antimicrobial resistant non-bacterial pathogens. Efforts may be needed to improve research funding for resistant-bacterial pathogens, particularly as their clinical burden increases.

Community-associated methicillin-resistant Staphylococcus aureus bacteremia and endocarditis among HIV patients: a cohort study

BACKGROUND

HIV patients are at increased risk of development of infections and infection-associated poor health outcomes. We aimed to 1) assess the prevalence of USA300 community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) among HIV-infected patients with S. aureus bloodstream infections and. 2) determine risk factors for infective endocarditis and in-hospital mortality among patients in this population.

METHODS

All adult HIV-infected patients with documented S. aureus bacteremia admitted to the University of Maryland Medical Center between January 1, 2003 and December 31, 2005 were included. CA-MRSA was defined as a USA 300 MRSA isolate with the MBQBLO spa-type motif and positive for both the arginine catabolic mobile element and Panton-Valentin Leukocidin. Risk factors for S. aureus-associated infective endocarditis and mortality were determined using logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI). Potential risk factors included demographic variables, comorbid illnesses, and intravenous drug use.

RESULTS

Among 131 episodes of S. aureus bacteremia, 85 (66%) were MRSA of which 47 (54%) were CA-MRSA. Sixty-three patients (48%) developed endocarditis and 10 patients (8%) died in the hospital on the index admission Patients with CA-MRSA were significantly more likely to develop endocarditis (OR = 2.73, 95% CI = 1.30, 5.71). No other variables including comorbid conditions, current receipt of antiretroviral therapy, pre-culture severity of illness, or CD4 count were significantly associated with endocarditis and none were associated with in-hospital mortality.

CONCLUSIONS

CA-MRSA was significantly associated with an increased incidence of endocarditis in this cohort of HIV patients with MRSA bacteremia. In populations such as these, in which the prevalence of intravenous drug use and probability of endocarditis are both high, efforts must be made for early detection, which may improve treatment outcomes.

Comparative effectiveness of nafcillin or cefazolin versus vancomycin in methicillin-susceptible Staphylococcus aureus bacteremia

Background

The high prevalence of methicillin-resistant S. aureus (MRSA) has led clinicians to select antibiotics that have coverage against MRSA, usually vancomycin, for empiric therapy for suspected staphylococcal infections. Clinicians often continue vancomycin started empirically even when methicillin-susceptible S. aureus (MSSA) strains are identified by culture. However, vancomycin has been associated with poor outcomes such as nephrotoxicity, persistent bacteremia and treatment failure. The objective of this study was to compare the effectiveness of vancomycin versus the beta-lactam antibiotics nafcillin and cefazolin among patients with MSSA bacteremia. The outcome of interest for this study was 30-day in-hospital mortality.

Methods

This retrospective cohort study included all adult in-patients admitted to a tertiary-care facility between January 1, 2003 and June 30, 2007 who had a positive blood culture for MSSA and received nafcillin, cefazolin or vancomycin. Cox proportional hazard models were used to assess independent mortality hazards comparing nafcillin or cefazolin versus vancomycin. Similar methods were used to estimate the survival benefits of switching from vancomycin to nafcillin or cefazolin versus leaving patients on vancomycin. Each model included statistical adjustment using propensity scores which contained variables associated with an increased propensity to receive vancomycin.

Results

267 patients were included; 14% (38/267) received nafcillin or cefazolin, 51% (135/267) received both vancomycin and either nafcillin or cefazolin, and 35% (94/267) received vancomycin. Thirty (11%) died within 30 days. Those receiving nafcillin or cefazolin had 79% lower mortality hazards compared with those who received vancomycin alone (adjusted hazard ratio (HR): 0.21; 95% confidence interval (CI): 0.09, 0.47). Among the 122 patients who initially received vancomycin empirically, those who were switched to nafcillin or cefazolin (66/122) had 69% lower mortality hazards (adjusted HR: 0.31; 95% CI: 0.10, 0.95) compared to those who remained on vancomycin.

Conclusions

Receipt of nafcillin or cefazolin was protective against mortality compared to vancomycin even when therapy was altered after culture results identified MSSA. Convenience of vancomycin dosing may not outweigh the potential benefits of nafcillin or cefazolin in the treatment of MSSA bacteremia.