Comparison of strategies to reduce meticillin-resistant Staphylococcus aureus rates in surgical patients: a controlled multicentre intervention trial.

Objective: To compare the effect of two strategies (enhanced hand hygiene vs meticillin-resistant Staphylococcus aureus (MRSA) screening and decolonisation) alone and in combination on MRSA rates in surgical wards. Design: Prospective, controlled, interventional cohort study, with 6-month baseline, 12-month intervention and 6-month washout phases. Setting: 33 surgical wards of 10 hospitals in nine countries in Europe and Israel. Participants: All patients admitted to the enrolled wards for more than 24 h. Interventions: The two strategies compared were (1) enhanced hand hygiene promotion and (2) universal MRSA screening with contact precautions and decolonisation (intranasal mupirocin and chlorhexidine bathing) of MRSA carriers. Four hospitals were assigned to each intervention and two hospitals combined both strategies, using targeted MRSA screening. Outcome measures: Monthly rates of MRSA clinical cultures per 100 susceptible patients (primary outcome) and MRSA infections per 100 admissions (secondary outcome). Planned subgroup analysis for clean surgery wards was performed. Results: After adjusting for clustering and potential confounders, neither strategy when used alone was associated with significant changes in MRSA rates. Combining both strategies was associated with a reduction in the rate of MRSA clinical cultures of 12% per month (adjusted incidence rate ratios (aIRR) 0.88, 95% CI 0.79 to 0.98). In clean surgery wards, strategy 2 (MRSA screening, contact precautions and decolonisation) was associated with decreasing rates of MRSA clinical cultures (15% monthly decrease, aIRR 0.85, 95% CI 0.74 to 0.97) and MRSA infections (17% monthly decrease, aIRR 0.83, 95% CI 0.69 to 0.99). Conclusions: In surgical wards with relatively low MRSA prevalence, a combination of enhanced standard and MRSA-specific infection control approaches was required to reduce MRSA rates. Implementation of single interventions was not effective, except in clean surgery wards where MRSA screening coupled with contact precautions and decolonisation was associated with significant reductions in MRSA clinical culture and infection rates. Trial registration clinicaltrials.gov identifier: NCT0068586

Variable performance of models for predicting methicillin-resistant Staphylococcus aureus carriage in European surgical wards

BACKGROUND: Predictive models to identify unknown methicillin-resistant Staphylococcus aureus (MRSA) carriage on admission may optimise targeted MRSA screening and efficient use of resources. However, common approaches to model selection can result in overconfident estimates and poor predictive performance. We aimed to compare the performance of various models to predict previously unknown MRSA carriage on admission to surgical wards. METHODS: The study analysed data collected during a prospective cohort study which enrolled consecutive adult patients admitted to 13 surgical wards in 4 European hospitals. The participating hospitals were located in Athens (Greece), Barcelona (Spain), Cremona (Italy) and Paris (France). Universal admission MRSA screening was performed in the surgical wards. Data regarding demographic characteristics and potential risk factors for MRSA carriage were prospectively collected during the study period. Four logistic regression models were used to predict probabilities of unknown MRSA carriage using risk factor data: 'Stepwise' (variables selected by backward elimination); 'Best BMA' (model with highest posterior probability using Bayesian model averaging which accounts for uncertainty in model choice); 'BMA' (average of all models selected with BMA); and 'Simple' (model including variables selected >50% of the time by both Stepwise and BMA approaches applied to repeated random sub-samples of 50% of the data). To assess model performance, cross-validation against data not used for model fitting was conducted and net reclassification improvement (NRI) was calculated. RESULTS: Of 2,901 patients enrolled, 111 (3.8%) were newly identified MRSA carriers. Recent hospitalisation and presence of a wound/ulcer were significantly associated with MRSA carriage in all models. While all models demonstrated limited predictive ability (mean c-statistics <0.7) the Simple model consistently detected more MRSA-positive individuals despite screening fewer patients than the Stepwise model. Moreover, the Simple model improved reclassification of patients into appropriate risk strata compared with the Stepwise model (NRI 6.6%, P = .07). CONCLUSIONS: Though commonly used, models developed using stepwise variable selection can have relatively poor predictive value. When developing MRSA risk indices, simpler models, which account for uncertainty in model selection, may better stratify patients' risk of unknown MRSA carriage

Agreement among Health Care Professionals in Diagnosing Case Vignette-Based Surgical Site Infections

OBJECTIVE: To assess agreement in diagnosing surgical site infection (SSI) among healthcare professionals involved in SSI surveillance. METHODS: Case-vignette study done in 2009 in 140 healthcare professionals from seven specialties (20 in each specialty, Anesthesiologists, Surgeons, Public health specialists, Infection control physicians, Infection control nurses, Infectious diseases specialists, Microbiologists) in 29 University and 36 non-University hospitals in France. We developed 40 case-vignettes based on cardiac and gastrointestinal surgery patients with suspected SSI. Each participant scored six randomly assigned case-vignettes before and after reading the SSI definition on an online secure relational database. The intraclass correlation coefficient (ICC) was used to assess agreement regarding SSI diagnosis on a seven-point Likert scale and the kappa coefficient to assess agreement for superficial or deep SSI on a three-point scale. RESULTS: Based on a consensus, SSI was present in 21 of 40 vignettes (52.5%). Intraspecialty agreement for SSI diagnosis ranged across specialties from 0.15 (95% confidence interval, 0.00-0.59) (anesthesiologists and infection control nurses) to 0.73 (0.32-0.90) (infectious diseases specialists). Reading the SSI definition improved agreement in the specialties with poor initial agreement. Intraspecialty agreement for superficial or deep SSI ranged from 0.10 (-0.19-0.38) to 0.54 (0.25-0.83) (surgeons) and increased after reading the SSI definition only among the infection control nurses from 0.10 (-0.19-0.38) to 0.41 (-0.09-0.72). Interspecialty agreement for SSI diagnosis was 0.36 (0.22-0.54) and increased to 0.47 (0.31-0.64) after reading the SSI definition. CONCLUSION: Among healthcare professionals evaluating case-vignettes for possible surgical site infection, there was large disagreement in diagnosis that varied both between and within specialties

Supplemental treatment of air in airborne infection isolation rooms using high-throughput in-room air decontamination units.

BACKGROUND: Evidence has recently emerged indicating that in addition to large airborne droplets, fine aerosol particles can be an important mode of influenza transmission that may have been hitherto underestimated. Furthermore, recent performance studies evaluating airborne infection isolation (AII) rooms designed to house infectious patients have revealed major discrepancies between what is prescribed and what is actually measured. METHODS: We conducted an experimental study to investigate the use of high-throughput in-room air decontamination units for supplemental protection against airborne contamination in areas that host infectious patients. The study included both intrinsic performance tests of the air-decontamination unit against biological aerosols of particular epidemiologic interest and field tests in a hospital AII room under different ventilation scenarios. RESULTS: The unit tested efficiently eradicated airborne H5N2 influenza and Mycobacterium bovis (a 4- to 5-log single-pass reduction) and, when implemented with a room extractor, reduced the peak contamination levels by a factor of 5, with decontamination rates at least 33% faster than those achieved with the extractor alone. CONCLUSION: High-throughput in-room air treatment units can provide supplemental control of airborne pathogen levels in patient isolation rooms

A continuous quality-improvement program reduces nosocomial infection rates in the ICU.

OBJECTIVE: To assess the impact of a continuous quality-improvement program on nosocomial infection rates. DESIGN AND SETTING: Prospective single-center study in the medical-surgical ICU of a tertiary care center. PATIENTS. We admitted 1764 patients during the 5-year study period (1995-2000); 55% were mechanically ventilated and 21% died. Mean SAPS II was 37+/-21 points and mean length of ICU stay was 9.7+/-16.1 days. INTERVENTIONS: Implementation of an infection control program based on international recommendations. The program was updated regularly according to infection and colonization rates and reports in the literature. MEASUREMENTS AND RESULTS: Prospective surveillance showed the following rates per 1000 procedure days: ventilator-associated pneumonia (VAP) 8.7, urinary tract infection (UTI) 17.2, central venous catheter (CVC) colonization 6.1, and CVC-related bacteremia and 2.0; arterial catheter colonization did not occur. In the 5 years following implementation of the infection control program there was a significant decline in the rate per patient days of UTI, CVC colonization, and CVC-related bacteremia but not VAP. Between the first and second 2.5-year periods the time to infection increased significantly for UTI and CVC-related colonization. CONCLUSIONS: A continuous quality-improvement program based on surveillance of nosocomial infections in a nonselected medical-surgical ICU population was associated with sustained decreases in UTI and CVC-related infections

Risk factors for previously unknown meticillin-resistant Staphylococcus aureus carriage on admission to 13 surgical wards in Europe.

BACKGROUND: Early identification of meticillin-resistant Staphylococcus aureus (MRSA) carriers may be helpful for clinical and epidemiological reasons. AIM: To identify and compare risk factors of previously unknown MRSA carriage on admission to 13 surgical wards in France, Greece, Italy, and Spain. METHODS: The study was a prospective observational cohort study which enrolled consecutive patients screened for MRSA on admission to surgical wards. Sociodemographic data, comorbidities and possible risk factors for MRSA were recorded. A multivariate logistic regression model was used to predict probabilities of previously unknown MRSA colonization on admission based on patient characteristics. Prediction rules for MRSA carriage were developed and evaluated using the c-statistic. FINDINGS: Of 2901 patients enrolled, admission screening identified 111 (3.8%) new MRSA carriers. Independent risk factors for MRSA carriage were urinary catheterization (odds ratio: 4.4; 95% confidence interval: 2.0-9.9), nursing home residency (3.8; 1.9-7.7), chronic skin disease (2.9; 1.5-5.8), wounds/ulcers (2.4; 1.5-4.0), recent hospitalization (2.2; 1.5-3.3), diabetes (1.6, 1.02-2.5), and age &gt;70 years (1.5; 1.03-2.3). However, risk factors varied between centres. The c-statistic for the common prediction rule for all centres was 0.64, indicating limited predictive power. CONCLUSIONS: Risk profiles for MRSA carriers vary between surgical wards in European countries. Identifying local risk factors is important, as a common European prediction rule was found to be of limited clinical value

Risk factors for previously unknown meticillin-resistant Staphylococcus aureus carriage on admission to 13 surgical wards in Europe

Early identification of meticillin-resistant Staphylococcus aureus (MRSA) carriers may be helpful for clinical and epidemiological reasons