Increased Mortality with Accessory Gene Regulator (agr)-Dysfunction in Staphylococcus aureus among Bacteremic Patients -- Schweizer et al., 10.1128/AAC.00918-10 -- Antimicrobial Agents and Chemotherapy.
Among 814 patient-admissions complicated by S. aureus bacteremia, 181 (22%) were infected with S. aureus isolates with agr-dysfunction. Overall, 18% of patients with agr-dysfunction in S. aureus died compared to 12% with functional agr (p=0.03). There was a trend toward higher mortality among patients with agr-dysfunctional S. aureus (adjusted hazard ratio (HR): 1.34; 95% confidence interval (CI): 0.87, 2.06). Among patients with the highest APS (score>28), agr-dysfunction in S. aureus was significantly associated with mortality (adjusted HR=1.82; 95% CI: 1.03, 3.21). This is the first study to demonstrate an independent association between agr-dysfunction and mortality among severely ill patients. The delta-hemolysin assay examining agr function may be a simple and inexpensive approach to predicting patient outcomes and potentially to optimize antibiotic therapy.
