109. Clinical Characteristics and Outcomes of Staphylococcus aureus Bacteremia From a Biliary Source

Abstract Background Staphylococcus aureus can cause various types of infection, but involvement of biliary tract is rare. There were only few case reports and no clinical studies. We assessed the clinical characteristics and outcomes of S. aureus bacteremia from a biliary source (biliary SAB) in a large cohort of SAB patients and compared the cases with those of catheter-related SAB. Methods We performed a matched case–control study within a prospective observational cohort of patients with SAB at a 2,700-bed tertiary hospital. All adult patients with SAB were observed for 12 weeks from July 2008 to July 2018. Biliary SAB was defined as the case of S.aureus isolated from blood culture with appropriate clinical biliary infection symptoms (fever, abdominal pain, or jaundice) and signs (abdominal tenderness or liver enzyme elevation with obstructive pattern). Biliary SAB cases were matched 1:3 to control patients with catheter-related SAB based on age, gender, ward, and case year. Results A total of 1,818 patients with SAB were enrolled in the entire cohort, and 42 (2%) were biliary SAB. Among patients with biliary SAB, 32 (76%) had solid tumor involving pancreaticobiliary tract or liver, 30 (71%) had biliary drainage stent, 14 (33%) were biliary procedure-related infection, and 24 (57%) had recent broad-spectrum antibiotics exposure (Table 1). When biliary SAB patients were compared with 126 patients with catheter-related SAB, they were significantly more likely to have community-onset SAB, solid tumor, and lower APACHE II score; and less likely to have metastatic infection (P = 0.03) (Table 2). Biliary SAB, solid tumor, and a high Charlson comorbidity index were associated with 12-week mortality. In multivariate analysis, biliary SAB (aOR, 5.5; 95% CI, 2.47–12.25) and a high Charlson comorbidity index (aOR, 1.32; 95% CI, 1.12–1.54) were independent risk factors for 12-week mortality. Conclusion Biliary SAB was relatively rare and developed mainly in pancreaticobiliary cancer patients and in recent broad-spectrum antibiotic users. High mortality was probably attributable to underlying cancers. When biliary tract infection caused by S. aureus is clinically suspected, early aggressive treatment for SAB should be considered. Disclosures All authors: No reported disclosures.