695. Antipseudomonal Versus Narrow-spectrum Agents for the Treatment of Community-onset Intra-abdominal Infections

Abstract Background Antipseudomonal antibiotic regiments are often used to treat community-acquired intra-abdominal infections (CA-IAI) despite common causative pathogens being susceptible to more narrow-spectrum agents. The purpose of this study was to compare post-infection complications in adult patients treated for CA-IAI with antipseudomonal or narrow-spectrum regimens Methods This retrospective cohort study included patients ≥18 years admitted for CA-IAI treated with antibiotics between January 1, 2013, and December 31, 2019. Patients who had bacteremia or peritonitis were excluded. The primary objective of this study was to compare post-infection complications within 90 days between patients treated empirically with antipseudomonal versus narrow-spectrum regimens. Post-infection complication was defined as post-operative infection, recurrence of diverticulitis, or mortality. Secondary objectives were to compare infection and treatment characteristics along with patient outcomes. Sub-group analyses were planned to compare outcomes of patients with low-risk and high-risk CA-IAI and patients who required surgical intervention versus who were medically managed Results A total of 350 patients were included: Antipseudomonal, n=204; Narrow-spectrum, n=146. There were no differences in 90-day post-infection complications between groups (Antipseudomonal 15.1% vs Narrow-spectrum 11.3%, p=0.296). Additionally, no differences were observed in hospital LOS, 90-day readmission, C. difficile, or mortality. Patients treated with Antipseudomonal regimens received longer durations of therapy (median 11 days [IQR 8-14] vs 9 days [IQR 5-12], p< 0.001). No differences were observed in 90-day post-infection complications for patient with low-risk (Antipseudomonal 15% vs Narrow-spectrum 9.6%, p=0.154) or high-risk CA-IAI (Antipseudomonal 15.8% vs Narrow-spectrum 22.2%, p=0.588), or those who were surgically (Antipseudomonal 8.5% vs Narrow-spectrum 9.2%, p=0.877) or medically managed (Antipseudomonal 17.5% vs Narrow-spectrum 13.1%, p=0.463). Conclusion Post-infection complication rates were similar among patients treated with antipseudomonal and narrow-spectrum antibiotics. Antipseudomonal therapy is likely unnecessary for most patients with CA-IAI Disclosures Lisa E. Dumkow, PharmD, BCIDP, Nothing to disclose


Optimal Duration of Prophylactic Antibiotics in Patients with Cirrhosis and Upper Gastrointestinal Bleeding
Kristin C. Davis, PharmD, MBA 1 ; Lindsay Reulbach, PharmD, BCPS 1 ; John Schrank, MD 1 ; Alex Ewing, PhD 1 ; Emily Johnson, PharmD, BCPS 1 ; 1 Prisma Health-Upstate, Greenville, South Carolina Session: P-33. Enteric Infection Background. Spontaneous bacterial peritonitis (SBP) is a serious complication of variceal hemorrhage. Guidelines recommend a maximum of seven days of antibiotics after variceal hemorrhage to prevent SBP and reduce rates of rebleeding and mortality. However, studies supporting these guidelines used varied durations of therapy including those with less than seven days. The objective of this study was to determine if less than seven days of antibiotic prophylaxis was noninferior to seven or more days in patients with cirrhosis and variceal hemorrhage.
Methods. This was a single-center, retrospective cohort conducted from August 2019 to August 2020 including adult patients who received treatment for variceal hemorrhage and antibiotics for prevention of SBP during hospitalization. Patients were excluded if they were diagnosed with non-variceal hemorrhage, received treatment with antibiotics within 72 hours prior to the variceal hemorrhage, or expired or transitioned to end of life care within 48 hours of hospital admission. The primary outcome was in-hospital mortality. Secondary outcomes included SBP within the first 30 days after variceal hemorrhage, 30-day mortality, 30-day readmission rate, incidence of rebleeding at seven and 30 days, incidence of Clostridioides difficile infection, and intensive care unit and hospital length of stay.
Results. 64 patients were included with 45 patients in the less than seven days group and 19 patients in the seven or more days of antibiotic prophylaxis group. In each group, patients were primarily male with a median age of approximately 60 years. There was no difference in the primary outcome of in-hospital mortality between the less than seven days group as compared to the seven or more days group (22.2% vs 0%, p=1). No difference was identified between the less than seven days group as compared to the seven or more days group for any of the secondary outcomes.
Conclusion. This study identified no difference in patient-centered outcomes when comparing less than seven days of prophylactic antibiotics to seven or more days in patients with variceal hemorrhage. Less than seven days of prophylactic antibiotics may be a reasonable duration for prevention of SBP.
Disclosures. Background. Clostridioides difficile infection remains a highly morbid or lethal condition in an unacceptably large proportion of patients. To date, there are limited and conflicting data to support the use of tigecycline for C. difficile infection and the optimal stratification approach, timing (i.e., initial vs. salvage therapy), and duration are unclear.
Methods. We describe in detail a retrospective cohort of 28 C. difficile inpatients treated with tigecycline at UVA Medical Center. We stratify each patient by the Infectious Diseases Society of America's guidelines on severity of infection and detail the timing and duration of tigecycline therapy in each case. We further characterize the effect of tigecycline on 90-day mortality and recurrence.
Results. 9/28 (32.1%) patients were treated with tigecycline for fulminant (presence of hypotension, shock, ileus, or megacolon), and 12/28 (42.9%) for severe (white blood cell count over 15x10 9 /L or creatinine over 1.5mg/dL) C. difficile infection. Tigecycline was used in all cases in combination with oral vancomycin +/-metronidazole. The average duration of therapy was 7.6 days, with tigecycline as initial therapy (use within the first 72 hours of the start of directed antimicrobial therapy) in 7/28 (25%) cases. 90-day mortality occurred in 10/26 (35.7%) patients (two did not reach 90-day follow-up), all 10 of which were in-hospital mortalities and 5/10 (50%) occurred in patients with fulminant infection. 7 of the 16 (43.8%) surviving patients that reached 90-day follow-up had recurrent C. difficile infection.
Conclusion. Patients selected for treatment with tigecycline for C. difficile infection suffered a high rate of in-hospital mortality, especially among the significant proportion with fulminant disease. The rate of recurrent infection was substantial, contrary to some reports of reduced recurrence with tigecycline from the literature. The outcomes of tigecycline (as adjunct or monotherapy) for treatment of severe/fulminant and refractory infection versus standard treatments warrant further retrospective analysis and the benefit of tigecycline in these settings remains to be proven in well-controlled clinical trials.
Disclosures. All Authors: No reported disclosures