2040. Cefoxitin (CFX) vs. Piperacillin-Tazobactam (PTZ) for the Treatment of Mild-to-Moderate Complicated Intra-Abdominal Infections (cIAI) in an Era of Increased Anaerobic Resistance
Session: Poster Abstract Session: Antimicrobial Resistant Infections: Treatment
Saturday, October 29, 2016
Room: Poster Hall
Background: Cefoxitin (CFX) is recommended by IDSA as empiric treatment for mild-to-moderate cIAI, which are commonly caused by Escherichia coli and Bacteroides fragilis. Increasing B. fragilisresistance towards CFX is concerning but it is unclear if this has lead to increased treatment failures.

Methods: All adult patients who were admitted between 1/2013-9/2015 to the surgical service with mild-to-moderate cIAI and received ≥ 48 hours of CFX or PTZ were evaluated retrospectively. Clinical failure defined as persistent clinical symptoms, escalation of therapy, continued microbial growth, and/or surgical intervention with ≥ 48 hours of empiric antibiotics was evaluated. Inappropriate empiric therapy based on cultures and susceptibilities, length of stay (LOS), recurrent infection, and 30 day mortality were also evaluated.

Results: One-hundred and sixty (160) patients were included with a median age of 42 years. Eighty (80) patients received CFX and 80 received PTZ with similar comorbidities. Appendicitis (49% vs. 31%, p=0.02) and cholecystitis (24% vs. 9%, p=0.01) occurred more in CFX group, while diverticulitis (14% vs. 29%, p=0.02) and intra-abdominal abscess (5% vs. 18%, p=0.02) occurred more in PTZ group. Clinical failure was 51% in CFX group and 36% in PTZ group, p=0.06. More patients in CFX group had persistent clinical symptoms (21% vs. 9%, p=0.03) or required escalation of therapy (19% vs 5%, p=0.01). Most common organism isolated was E. coli (n = 35), with only a few B. fragilis (n = 7). Only 1 B. fragilisisolate was resistant to CFX but CFX had higher rates of inappropriate empiric therapy (40% vs. 14%, p=0.06). LOS (3.8 days vs. 4.1 days, p=0.04), recurrent infection (16% vs. 8%, p=0.087) and 30 day mortality (0% vs 0%) were similar between both groups. Multivariate analysis showed cholecystitis as the only independent predictor of clinical failure (OR 4.4, 95% CI 1.7-11.2, p=0.002). The use of CFX or PTZ was not an independent predictor of clinical failure.

Conclusion: Clinical failure occurred more frequently with CFX vs. PTZ for treatment of mild-to-moderate cIAI, although more patients who received CFX had cholecysistitis, which was identified as an independent predictor of clinical failure.

Nadine Musallam, Pharm.D., Caitlin Aberle, Pharm.D., Marco R. Scipione, PharmD, Yanina Dubrovskaya, PharmD and John Papadopoulos, PharmD, Department of Pharmacy, NYU Langone Medical Center, New York, NY

Disclosures:

N. Musallam, None

C. Aberle, None

M. R. Scipione, None

Y. Dubrovskaya, None

J. Papadopoulos, None

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