# Comparison of the time to detection (TTD) of different blood culture systems and antibiotic adsorption capacity of different pediatric blood culture bottles of BD and bioMérieux

## TL;DR

This study compares blood culture systems for speed of detection and antibiotic adsorption in pediatric patients, showing some systems detect infections faster and better handle antibiotics.

## Contribution

The study provides a direct comparison of pediatric blood culture systems' performance in TTD and antibiotic adsorption, which are under-evaluated in this context.

## Key findings

- BacT/Alert VIRTUO with BacT/Alert-PF plus had the shortest median TTD of 11.62 hours for bacteria.
- Bactec-PF and BacT/Alert-PF plus showed significantly higher detection rates for most antibiotics compared to BacT/Alert-PF.
- Detection rates varied by antibiotic and bacterial resistance, with 100% detection for amikacin and 0% for ceftriaxone and meropenem.

## Abstract

We evaluated the time to detection (TTD) of pediatric blood culture bottles (BacT/Alert-PF, BacT/Alert-PF plus, and Bactec-PF) and instruments (BacT/Alert 3D, BacT/Alert VIRTUO, and Bactec FX) via in vitro simulations of bacterial and fungal bloodstream infections. We also assessed the antibiotic adsorption capacity of the three pediatric bottles under simulated peak antibiotic concentrations. Among all tested bacteria, the median TTDs for BacT/Alert VIRTUO with BacT/Alert-PF plus and for Bactec FX with Bactec-PF were 11.62 h and 13.48 h, respectively, both of which are shorter than those of BacT/Alert 3D with BacT/Alert-PF (17.25 h). Within the BacT/Alert 3D system, BacT/Alert-PF plus demonstrated a shorter median TTD than BacT/Alert-PF (13.92 h vs 17.25 h). Under identical bottle conditions (BacT/Alert-PF plus), BacT/Alert VIRTUO achieved a shorter median TTD than BacT/Alert 3D (11.62 h vs 13.92 h). In the antibiotic adsorption evaluation, Bactec-PF (51.3%) and BacT/Alert-PF plus (46.1%) achieved significantly higher detection rates than BacT/Alert-PF (13%) for ampicillin, oxacillin, ceftriaxone, ceftazidime, cefepime, cefoperazone/sulbactam, piperacillin/tazobactam, meropenem, amikacin, and vancomycin. The detection rates of Bactec-PF and BacT/Alert-PF plus varied by antibiotic–strain combination and increased with the level of bacterial resistance. All three bottles achieved 100% detection in the amikacin group, whereas the detection rates were 0% in the ceftriaxone and meropenem groups. These findings provide important guidance for selecting blood culture systems in patients who have received prior antibiotic therapy and for improving the prognosis of bloodstream infections.

Rapid reporting of positive blood cultures can directly influence physicians’ treatment decisions, thereby reducing mortality and improving patient outcomes. This study compared the time to detection (TTD) and antibiotic adsorption capacity of commonly used pediatric blood culture bottles and instruments, which are currently less evaluated. Providing optimized testing options for blood culture is essential to shorten the TTD and improve culture positivity rates in patients who have already received antibiotics.