Pharmacist-Led Empiric Piperacillin-Tazobactam De-escalation Among Patients With Community-Acquired Intra-abdominal Infections

<b>Background:</b> Piperacillin-Tazobactam (PTZ) is often used to treat community-acquired intra-abdominal infections (CA-IAIs) despite common causative pathogens being susceptible to more narrow-spectrum agents. However, susceptibility to PTZ among these predominant pathogens has been declining. Antibiotic de-escalation to non-antipseudomonal beta-lactams whenever possible is an important strategy to prevent the development of resistance to PTZ. <b>Objective:</b> The purpose of this study is to assess PTZ length of therapy in patients with CA-IAI, by comparing patients who received a pharmacist-led intervention involving the de-escalation of PTZ to narrow-spectrum regimens with those who did not receive the intervention. <b>Methods:</b> A retrospective analysis was conducted among patients >18 years old and admitted with CA-IAI empirically placed on PTZ between January 1, 2022, through June 30, 2022 (pre-intervention group), and January 1, 2024, through June 30, 2024 (post-intervention group). A total of 246 patients were included in the pre-intervention group and 129 patients in the post-intervention group. The utilization of PTZ, hospital length of stay (LOS), and treatment-associated complications were assessed using linear and logistic regression model, respectively. <b>Results:</b> Compared with patients in the pre-intervention group, those in the post-intervention group had a mean 1.2-day reduction in PTZ length of therapy (2.3 vs 1.2 days, <i>P</i> < 0.001). There was no difference in LOS, (β = 0.001, 98% confidence interval [CI] -1.29 to 1.29; <i>P</i> = 0.477), hospital readmission within 30 days due to IAI (odds ratio [OR] = 0.85, 98% CI = 0.51 to 1.44; <i>P</i> = 0.56), treatment-associated complications during current hospitalization (OR = 0.77, 98% CI = 0.45 to 1.32; <i>P</i> = 0.35), development of <i>Clostridium difficile</i>-associated diarrhea (OR = 3.29, 98% CI = 0.77 to 22.4; <i>P</i> = 0.14), or medication toxicity (OR = 2.07, 98% CI = 0.79 to 6.08; <i>P</i> = 0.15). <b>Conclusion and relevance:</b> The use of narrow-spectrum antibiotics for the empiric treatment of CA-IAI-reduced PTZ length of therapy and did not result in adverse clinical outcomes.