Antipseudomonal Versus Narrow-Spectrum Agents for the Treatment of Community-Onset Intra-abdominal Infections.

Background: Antipseudomonal antibiotics are often used to treat community-acquired intra-abdominal infections (CA-IAIs) despite common causative pathogens being susceptible to more narrow-spectrum agents. The purpose of this study was to compare treatment-associated complications in adult patients treated for CA-IAI with antipseudomonal versus narrow-spectrum regimens.

Methods: This retrospective cohort study included patients 18 years admitted for CA-IAI treated with antibiotics. The primary objective of this study was to compare 90-day treatment-associated complications between patients treated empirically with antipseudomonal versus narrow-spectrum regimens. Secondary objectives were to compare infection and treatment characteristics along with patient outcomes. Subgroup analyses were planned to compare outcomes of patients with low-risk and high-risk CA-IAIs and patients requiring surgical intervention versus medically managed.

Results: A total of 350 patients were included: antipseudomonal, n=204; narrow spectrum, n=146. There were no differences in 90-day treatment-associated complications between groups (antipseudomonal 15.1% vs narrow spectrum 11.3%, =.296). In addition, no differences were observed in hospital length of stay, 90-day readmission, , or mortality. In multivariate logistic regression, treatment with a narrow-spectrum regimen (odds ratio [OR], 0.75; 95% confidence interval, 0.39-1.45) was not independently associated with the primary outcome. No differences were observed in 90-day treatment-associated complications for (1) patients with low-risk (antipseudomonal 15% vs narrow spectrum 9.6%, =.154) or high-risk CA-IAI (antipseudomonal 15.8% vs narrow spectrum 22.2%, =.588) or (2) those who were surgically (antipseudomonal 8.5% vs narrow spectrum 9.2%, =.877) or medically managed (antipseudomonal 23.1 vs narrow spectrum 14.5, =.178).

Conclusions: Treatment-associated complications were similar among patients treated with antipseudomonal and narrow-spectrum antibiotics. Antipseudomonal therapy is likely unnecessary for most patients with CA-IAI.