Impact of microbiology cascade reporting on antibiotic de-escalation in cefazolin-susceptible Gram-negative bacteremia

Abstract

Cascade reporting (CR) involves reporting the susceptibilities of broad-spectrum agents only when the organism is resistant to more narrow-spectrum agents. The purpose of this study is to evaluate the impact of CR on antibiotic de-escalation practices and to characterize the impact of CR on clinical outcomes. CR rules were implemented in the microbiology laboratory at Atlantic Health System (AHS) in June 2013. A retrospective chart review was conducted at two community teaching hospitals in adult patients who had a blood culture positive for a Gram-negative organism susceptible to cefazolin and who were empirically treated with broad-spectrum beta-lactam (BSBL) antibiotics. De-escalation practices were compared in the pre-CR (July 2012–December 2012) and post-CR (July 2013–December 2013) periods. The primary endpoint was the percentage of patients whose BSBL agent was de-escalated to agents listed on the post-CR antibiotic susceptibility report within 48 h of the final report. Secondary endpoints include the difference in pre-CR and post-CR periods in terms of hospital length of stay, in-hospital mortality, 30-day readmission, Clostridium difficile infections, and re-initiation of a BSBL agent within 7 days. A total of 73 patients were included; 31 in the pre-CR and 42 in the post-CR period. Patients had similar baseline characteristics. Therapy was de-escalated in 48 % of pre-CR vs 71 % of post-CR patients (p = 0.043). No significant differences were observed in secondary endpoints between patients in the pre-CR and post-CR periods. CR resulted in significant improvements in de-escalation practices without affecting safety outcomes.