Increased Age-Dependent Risk of Death Associated With -Positive Bacteremia.

Background: Panton-Valentine leucocidin is a virulence factor encoded by and that is infrequent in bacteremia (SAB), and, therefore, little is known about risk factors and outcome of /-positive SAB.

Methods: This report is a register-based nationwide observational cohort study. was detected by polymerase chain reaction. Factors associated with the presence of were assessed by logistic regression analysis. Adjusted 30-day hazard ratios of mortality associated with status were computed by Cox proportional hazards regression analysis.

Results: Of 9490 SAB cases, 129 were -positive (1.4%), representing 14 different clonal complexes. was associated with younger age, absence of comorbidity, and methicillin-resistant . In unadjusted analysis, mortality associated with -positive SAB was comparable to SAB. However, -positive SAB nonsurvivors were significantly older and had more comorbidity. Consequently, by adjusted analysis, the risk of 30-day mortality was increased by 70% for -positive SAB compared with SAB (hazard ratio, 1.70; 95% confidence interval, 1.20-2.42; = .003).

Conclusions: -positive SAB is rare in Denmark but associated with a significantly increased risk of mortality. Although the risk of -positive SAB was highest in the younger age groups, >80% of deaths associated with -positive SAB occurred in individuals older than 55 years.