Accelerate Pheno Blood Culture Detection System Found to Shorten Blood Analysis Time

Updated 10/24/2018 at 4:40 PM EST

Use of the US Food and Drug Administration—cleared Accelerate Pheno blood culture detection system (Accelerate Diagnostics) can shorten the time required to analyze patients’ blood samples leading to improved clinical outcomes, according to the results of a recent study.

“Our preliminary work has shown that following implementation of this system in our clinical microbiology laboratory, both laboratory turnaround time and clinical outcomes were improved,” commented Ryan Dare, MD, MS, Infectious Diseases Division at the University of Arkansas for Medical Sciences, in Little Rock, in an interview with Contagion^®. “By providing identification and susceptibility results approximately 40 hours sooner than standard of care, [the system led to] a 3-day decrease in [patients’] length of stay, a 36-hour decreased time to what we felt was the most optimal therapy, and a significant decrease in in-hospital antimicrobial administration, with a 40% decrease in broad gram-negative antibiotic usage.”

The results of a single-center retrospective chart review were presented by Dr. Dare in an oral abstract session at the 2018 Annual IDWeek Conference held in San Francisco, California, from October 3 to 7, 2018.

“This technology allows for more rapid turnaround times of positive blood cultures in the microbiology lab. Our goal was to see [whether] this improved turnaround time translate[d] to improved clinical outcomes for patients in our hospital,” explained Dr. Dare.

The Pheno system was superior in a battery of clinical outcomes compared with the current standard of care (SOC) involving the Vitek MS matrix-assisted laser desorption/ionization—time of flight mass spectrometry system and the Vitek 2 automated bacterial identification and antibiotic susceptibility test system. These included (all mean ± SD) the primary outcome of hospital length of stay (9.1 ± 7.6 days for the Pheno system and 12.1 ± 11.9 days for SOC; P = .03) and the secondary outcomes of time to optimal treatment (37.5 ± 32.7 and 73.5 ± 50.2 hours, respectively; P <.001), total duration of antibiotic treatment (7.0 ± 4.6 and 9.0 ± 7.5 days, respectively; P = .05), and length of treatment with meropenem (3.7 ± 2.1 and 6.6 ± 3.7 days, respectively; P = .03).

For the study, investigators examined medical records of laboratory and clinical data of adult inpatients with bacteremia before (January to April 2017) and after (February and March 2018) the implementation of the Pheno system. The hospital had an active antimicrobial stewardship program operating during both time periods. Polymicrobial cultures, off-panel isolates, previous positive culture, and patients discharged prior to the final information concerning antibiotic susceptibility were excluded from the analyses.

The record review identified 143 positive cultures following the implementation of the Pheno system. Of the 118 (83%) identified following implementation of the Pheno system, 75 (64%) met inclusion criteria. Of the 113 SOC cultures identified, 79 (70%) met inclusion criteria. The patients in both time periods were comparable for comorbidities (P = not significant), Modified Early Warning Severity score (P = .10), source of bacteremia (P = not significant), and pathogen detected (P = .30).

The time from the collection of the sample to bacterial identification was significantly shorter following implementation of the Pheno system compared with the time before implementation (28.2 ± 12.7 vs 53.8 ± 20.9 hours; P <.001). The time from sample collection to the determination of antibiotic susceptibility was also significantly shorter when the Pheno system was in place (31.9 ± 11.0 vs 71.8 ± 20.0 hours; P <.001).

“Delayed or inactive empiric antimicrobial selection in some patients is associated with increased lengths of stay, increased costs of care, and poor outcomes,” said Dr. Dare. “By decreasing the time to final identification and susceptibility results of certain bacteria growing in blood cultures, this technology may lead to improvements in these areas. In addition, faster susceptibility results will allow providers to choose final antibiotics with the most narrow and appropriate spectrum of activity, possibly helping to prevent future problems with antimicrobial resistance.”

The findings are immediately applicable. “These data were collected on real hospitalized bacteremic patients reflecting a direct impact on patient care. We are continuing the study with additional cases to verify these outcomes,” commented Dr. Dare.

This was an unfunded, investigator-initiated study.

[Editor's note: An earlier version of this article misquoted Dr. Dare and stated, "[the system led to] a 2-day decrease in [patients’] length of stay." The correct time decrease is 3 days. The article has since been updated to reflect the correct length of time.]

DISCLOSURES

Ryan Dare, MD, MS: None

PRESENTATIONS

Poster Session: Oral Abstract Session: Diagnostics Making a Difference

Ryan Dare, MD

University of Arkansas for Medical Sciences

Oral Presentation 1758. Impact of Accelerate Pheno Rapid Blood Culture Detection System on Laboratory and Clinical Outcomes in Bacteremic Patients

Brian Hoyle, PhD, is a medical and science writer and editor from Halifax, Nova Scotia, Canada. He has been a full-time freelance writer/editor for over 15 years. Prior to that, he was a research microbiologist and a lab manager of a provincial government water-testing lab. He can be reached at hoyle@square-rainbow.com.