Background Implementation of the Accelerate Pheno TM Gram-negative platform (RDT) paired with antimicrobial stewardship program (ASP) intervention projects to improve time to institutional-preferred antimicrobial therapy (IPT) for Gram-negative bacilli (GNB) bloodstream infections (BSI). However, few data describe the impact of discrepant RDT results from standard of care (SOC) methods on antimicrobial prescribing. Methods A single-center, pre-/post-intervention study of consecutive, non-duplicate blood cultures for adult inpatients with GNB BSI following combined RDT + ASP intervention was performed. The primary outcome was time to IPT. An a priori definition of IPT was utilized to limit bias and allow for an assessment of the impact of discrepant RDT results with the SOC reference standard. Results Five hundred fourteen patients (PRE 264; POST 250) were included. Median time to antimicrobial susceptibility testing (AST) results decreased 29.4 hours (p < 0.001) post-intervention, and median time to IPT was reduced by 21.2 hours (p <0.001). Utilization (days of therapy [DOTs]/1000 days present) of broad-spectrum agents decreased (PRE 655.2 vs. POST 585.8; p = 0.043) and narrow-spectrum beta-lactams increased (69.1 vs 141.7; p <0.001). Discrepant results occurred in 69/250 (28%) post-intervention episodes, resulting in incorrect ASP recommendations in 10/69 (14%). No differences in clinical outcomes were observed. Conclusions While implementation of a phenotypic RDT + ASP can improve time to IPT, close coordination with Clinical Microbiology and continued ASP follow up are needed to optimize therapy. Although uncommon, the potential for erroneous ASP recommendations to de-escalate to inactive therapy following RDT results warrants further investigation.

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OBJECTIVE Postprocedural infection is a consequential complication of neurosurgical intervention. Periprocedural antimicrobial prophylaxis is routinely administered to prevent infection, and in some cases, continued for extended periods while surgical drains remain in place. However, there is little evidence that extended antimicrobial administration is necessary to reduce postprocedural infection, and extended antimicrobials can be associated with harm, such as Clostridioides difficile infection. The authors sought to evaluate whether shortening the duration of postprocedural antimicrobial prophylaxis would decrease the incidence of C. difficile infection without increasing the incidence of postprocedural infection. METHODS In this retrospective study, two general neurosurgical cohorts were examined. In one cohort, postoperative antimicrobial prophylaxis was limited to 24 hours; in the other, some patients received extended postoperative antimicrobial prophylaxis while surgical drains or external ventricular drains (EVDs) remained in place. Rates of infection with C. difficile as well as postprocedural infection after surgery and EVD placement were compared. RESULTS Seven thousand two hundred four patients undergoing 8586 surgical procedures and 413 EVD placements were reviewed. The incidence of C. difficile infection decreased significantly from 0.5% per procedural encounter to 0.07% with the discontinuation of extended postprocedural antibiotics within 90 days of a procedure. Rates of postprocedural infection and EVD infection did not significantly change. Results were similar in subgroups of patients with closed suction drains as well as cranial and spine subgroups. CONCLUSIONS Discontinuation of extended antimicrobial prophylaxis was associated with a significant decrease in the incidence of C. difficile infection without a concomitant change in postprocedural infections or EVD-associated infection. This study provides evidence in support of specialtfy-wide discontinuation of extended postoperative antimicrobial prophylaxis, even in the presence of closed suction drains.

Background While GNB BSIs remain a major cause of morbidity and mortality, no clear guidelines exist on the utilization of FUBCs to guide management. Despite the recognition of persistent bacteremia as a risk factor for increased mortality, early studies suggested FUBCs were low yield in this setting, and thus had low utility. More recently, some controversy has arisen with multivariate analyses suggesting FUBC acquisition may be associated with lower mortality. We sought to characterize the utilization and yield of FUBCs for GNB BSIs at our institution. Methods We performed a retrospective review of 514 episodes of consecutive blood cultures from unique adult inpatients with GNB BSI between July 2017-July 2019. Exclusion criteria included prior positive culture, polymicrobial Gram stain, or discharge, death, or comfort measures only within 24 hours of Gram stain. FUBCs were defined as blood cultures collected between 24 hours to 7 days after the index blood culture. Baseline clinical and microbiologic characteristics were compared between groups, as well as clinical outcomes. Results Of 514 episodes, 338 (66%) had FUBCs performed, with a median of 2 FUBCs/episode. The majority of FUBCs (322/338; 95%) were negative, with 9 (3%) yielding the same organism and 9 (3%) yielding a different organism. Most initial FUBCs were obtained prior to index antimicrobial susceptibility results (227/338; 67%). Patients with FUBCs performed had a higher median Pitt bacteremia score (2 vs 1; p = 0.015) and were more likely to have hospital onset (36% vs 22%; p = 0.002), severe neutropenia (16% vs 4%; p < 0.001) and a catheter-associated source (13% vs 4%; p = 0.001). 30-day mortality did not differ between patients with or without FUBCs (10% vs 11%; p = 0.84). Conclusion FUBCs were frequently obtained, but were of low yield even in comparison to recent similar studies. Though FUBCs were performed in more severe cases, a difference in mortality was not observed. Delaying the decision of whether to obtain FUBCs until after index antimicrobial susceptibility results are available would reduce unnecessary testing in most cases. Further study could better define where FUBCs after antimicrobial susceptibility testing would be most helpful. Disclosures All Authors: No reported disclosures

Background Limited data exist to guide blood culture ordering in persistent febrile neutropenia, resulting in substantial variation in practice. Unnecessary repeat blood cultures have been associated with patient harm including increased antimicrobial exposure, hospital length of stay, catheter removal and overall cost. Methods We conducted a single-center study of adult hematology-oncology patients with ≥3 days of febrile neutropenia (FN). The yield of blood cultures was first evaluated in a two-year historical cohort. Additionally, a pilot PRE/POST-intervention study was performed in non-stem cell transplant (SCT) patients following a change in our population clinical practice guideline from a recommendation of daily blood cultures to a clinically-guided approach. The primary outcome was cultures collected per days of FN after day 3 of persistent FN. Results One-hundred forty-six episodes of ≥3 days of FN in 108 patients were identified during the historical period. Day 1 blood cultures were positive in 23/146 (16%) episodes. Blood cultures were drawn on 374/513 (73%) subsequent episode days (day 2-12) and were negative in 366/374 (98%). After the intervention, a 53% decrease was observed in the rate of total blood cultures collected (PRE 1.4 vs POST 0.7; p = 0.03). Blood cultures obtained after 48 hours rarely yielded clinically significant organisms. Conclusions Repeat blood cultures are low-yield in persistent FN without new clinical change. A pilot intervention in non-SCT patients successfully reduced the frequency of blood culture collection.