Ann Lab Med.  2019 May;39(3):278-283. 10.3343/alm.2019.39.3.278.

Comparison of Clinical Performance Between BacT/Alert Virtuo and BacT/Alert 3D Blood Culture Systems

• Kim SC
• Lee S
• Kim S
• Cho OH
• Park H
• Yu SM

• KMID: 2431605
• DOI: http://doi.org/10.3343/alm.2019.39.3.278

Abstract

BACKGROUND
BacT/Alert Virtuo (BioMérieux, Durham, NC, USA) is a recently developed blood culture system that includes functions of automatic registration, loading, and unloading of the blood culture bottles, as well as measurement of blood volume. We compared the performances between the BacT/Alert Virtuo and 3D (BioMérieux) blood culture systems.
METHODS
A total of 952 patients (1,904 sets) visiting an university-affiliated hospital in Korea for blood cultures were enrolled. Five milliliters of blood was added into each of the two aerobic (FA Plus) and two anaerobic (FN Plus) bottles of the Virtuo and 3D systems for a single set. Positive rate and time to detection (TTD) were compared between the two systems.
RESULTS
The positive rates were 8.3% and 8.4% in FA Plus bottles and 7.8% and 8.3% in FN Plus bottles, in the Virtuo and 3D systems, respectively (P>0.05). Median TTDs were shorter in the Virtuo than in the 3D system for all isolates (11.5 hours [N=305] vs 11.8 hours [N=318], P < 0.001), Staphylococcus aureus (N=38; 14.3 hours vs 16.0 hours, P=0.021), and Escherichia coli (N=117; 10.4 hours vs 11.0 hours, P < 0.001).
CONCLUSIONS
The Virtuo has the potential to detect pathogens early in all bottle types. This might improve the prognosis of sepsis by allowing for implementation of expeditious management.

Keyword

BacT/Alert Virtuo; Blood cultures; Performance; Detection; Positive rate; Time to detection

MeSH Terms

Blood Volume
Escherichia coli
Humans
Korea
Prognosis
Sepsis
Staphylococcus aureus

Figure

• 

  Fig. 1 Correlation of time to detection (TTD) between the Virtuo and 3D systems in (A) FA Plus bottles, (B) FN Plus bottles, and (C) total bottles. Total isolates (gram-negative, gram-positive, and yeast) concurrently growing in the Virtuo and 3D systems were compared for TTD. The shaded area indicates the 95% confidence interval of the linear regression line. There were two outlier isolates for which the difference in TTD was more than 20 hours: Klebsiella pneumoniae (detected earlier in the 3D system) and Streptococcus species (detected earlier in the Virtuo system).

• 

  Fig. 2 Cumulative proportions for positives according to time to detection (TTD), showing close similarity between the Virtuo and 3D systems (274 isolates). Approximately 50% of the samples were positive by 12 hours, 80% by 16 hours, and 90% by 24 hours.

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