A second RA, blinded to clinical and historical data and using the hospital’s microbiology laboratory reporting record, recorded whether or not a culture was ordered in the ED and recorded the resulting isolates’ antimicrobial susceptibilities. RAs were trained by the primary investigator (PI), who met regularly with RAs for monitoring of case selection and data management. ED visits identified by ICD-9 code that were in fact not for SSTIs (i.e. coding errors) were excluded following verification by the PI. The PI reviewed ten percent of records for data quality

and to assess interrater reliability Inhibitors,research,lifescience,medical on three key variables. The kappa statistic for performance of culture in the ED was 0.81, for performance of I&D was 0.79, and for infection type was 0.90. Outcome measures Descriptive measures included MRSA prevalence and antibiotic prescribing patterns among cultured SSTIs in the

study ED populations. Primary outcomes measured were (a) the frequency of in vitro activity of ED clinicians’ empiric antibiotic therapy against the cultured Inhibitors,research,lifescience,medical isolates among ED patients with cultured SSTIs, (b) factors associated with use of discordant antibiotic therapy or multi-drug antibiotic therapy, and (c) antibiotic resistance patterns among the most common pathogens identified. Data analysis We estimated that 25% of all SSTI patients evaluated in the ED would undergo culture and that 90% of these patients Inhibitors,research,lifescience,medical would receive antibiotics, with 50% concordance for MRSA treatment when MRSA was isolated.

Given these assumptions, between 674 and 1199 patient records Inhibitors,research,lifescience,medical would need to be abstracted to arrive at an estimate of antibiotic/culture discordance with 95% confidence intervals encompassing a range of 15 to 20 percentage points. Antibiotic usage was stratified by culture results, and age groups were compared using Pearson’s chi-square and 2-sample tests of binomial proportions. Antibiotics were categorized based Inhibitors,research,lifescience,medical on their spectrum of activity. Anti-staphylococcal antibiotics typically active against CA-MRSA include trimethoprim-sulfamethoxazole, tetracycline, doxycycline, clindamycin, rifampin, linezolid or vancomycin [1,2,13]. Antibiotics with anti-staphylococcal properties but typically ineffective against CA-MRSA were categorized as “MSSA antibiotics”: penicillins, first-generation cephalosporins, macrolides, and fluoroquinolones. “Double coverage” describes treatment with two or more antibiotics with gram-positive coverage. Three univariable logistic models MRIP were created to identify demographic or clinical variables associated with (1) in vitro coverage of any organism isolated by the empiric ED antibiotic therapy, (2) use of double antibiotic coverage, and (3) discordance between treatment and culture. In the third regression model, concordance was defined as presence of MRSA in culture when any anti-MRSA treatment was MGCD0103 price prescribed or presence of MSSA in culture when only anti-MSSA treatment was prescribed.