Journal Club

Clopidogrel Therapy in Patients With Staphylococcus aureus Bacteremia

By Zeina A. Kanafani, MS, FIDSA

New strategies for the treatment of Staphylococcus aureus bacteremia (SAB) have become a growing area of research. In a recent study in Antimicrobial Agents and Chemotherapy, the effect of clopidogrel use on the outcome of patients with SAB was evaluated. SAB is characterized by rapid clearance of platelets that have antimicrobial activity against S. aureus. Clopidogrel acts by blocking the P2Y12 receptor on the surface of platelets and protects platelets from accelerated clearance; hence, the interest in the value of clopidogrel as an adjunctive therapy in patients with SAB.

This was a retrospective cohort study in patients with SAB admitted to VA hospitals between 2010 and 2018. The cohort included 355 patients with SAB who were receiving clopidogrel and 11,144 who were not. Baseline platelet counts in both groups were similar (206,000/µL; interquartile range [IQR], 149,000-283,000 in clopidogrel users and 212,000/µL; IQR, 146,000-296,000 in nonusers; P = .42). In the propensity-matched cohort, inpatient mortality was 2.7% in clopidogrel users and 10.9% in nonusers (hazard ratio [HR], 0.11; 95% confidence interval [CI], 0.01-0.86). Thirty-day mortality also favored clopidogrel use (HR, 0.43; 95% CI, 0.19-0.98). The other clinical outcomes that were studied were not statistically different between the two study groups, including 30-day readmission, 30-day S. aureus reinfection, and microbiological clearance. In addition, the proportions of patients who developed thrombocytopenia were similar (32.6% vs. 38.1%; HR, 0.90; 95% CI, 0.57-1.40). Upon stratifying by baseline platelet count, the survival advantage of clopidogrel use was lost in the group with baseline platelet counts of ≥ 100,000/µL (HR, 0.56; 95% CI, 0.25-1.27).

The results from this study suggest that clopidogrel might be a useful adjunctive therapy in patients with SAB. Randomized controlled trials are needed to corroborate these findings.

(Caffrey et al. Antimicrob Agents Chemother. 2022;66(6): e0211721.)