Implementation of a Rapid Phenotypic Susceptibility Platform for Gram-Negative Bloodstream Infections With Paired Antimicrobial Stewardship Intervention: Is the Juice Worth the Squeeze?

Abstract

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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“…Robinson and colleagues conducted a single-center, pre-/postintervention study of 514 unique adult patients with GN BSIs [ 41 ]. The primary outcome of time to institutional-preferred antimicrobial therapy (IPT) was shorter in the postintervention group.…”

Susceptibility Testing by Volatile Organic Compound Detection Direct from Positive Blood Cultures: A Proof-of-Principle Laboratory Study

“…Second, direct positive blood culture testing provides a combined resistance phenotype of all bacteria present in polymicrobial specimens, which might not be clinically relevant. AST results in polymicrobial specimens varied when using another rapid system that enables AST without prior subcultures, the Accelerate Pheno™ system (Accelerate Diagnostics, Tucson, AZ) [ 37 ], based on fluorescence in-situ hybridization [ 38 , 39 ]. Follow-up studies should assess whether AST results are reliable in various polymicrobial specimens.…”

Empirical antibiotic therapy for difficult-to-treat Gram-negative infections: when, how, and how long?

“…Mortality was not different between preimplementation and postimplementation periods, whereas the median length of hospital stay in patients with GNB bloodstream infection was shorter after implementation of the Accelerate Pheno system (6.4 days and 5.4 days in the preimplementation and postimplementation periods, respectively, P ¼ 0.03) [15]. In another quasi-experimental study conducted among 514 patients with GNB bloodstream infection, the median time to AST decreased after implementation of the Accelerate Pheno system, but no differences in clinical outcomes were observed between the preimplementation and the postimplementation periods [23]. Finally, the prognostic impact of the Accelerate Pheno system was evaluated in a randomized controlled trial, in which patients with positive blood culture and gram stain showing GNB were randomized to conventional identification/AST and Accelerate Pheno system arms.…”