Multicenter Clinical Evaluation of BacT/Alert Virtuo Blood Culture System

Abstract

BacT/Alert Virtuo is an advanced, automated blood culture system incorporating improved automation and an enhanced detection algorithm to shorten time to detection. A multicenter study of the investigational Virtuo system (bioMérieux, Inc., Durham, NC) compared to BacT/Alert 3D (BTA3D) for detection of bacteremia/fungemia in four bottle types, SA and FA Plus (aerobic) and SN and FN Plus (anaerobic), was performed in a clinical setting with patient samples in a matched system design clinical trial. Blood was added to paired aerobic or anaerobic bottles, with the volume in each bottle in each pair required to be ≤10 ml and with the volumes required to be within 30% of each other. Of 5,709 bottle sets (52.5% aerobic pairs and 47.5% anaerobic pairs), 430 (7.5%) were positive for bacterial or fungal growth, with 342 (6.0%) clinically significant and 83 (1.5%) contaminated. A total of 3,539 sets (62.0%) were volume compliant, with 203 sets (5.7%) clinically significant. The positivity rates for volume-compliant bottle pairs determined by the two systems were comparable, with 68.7% of clinically significant isolates detected by both instruments, 15.7% by Virtuo only, and 15.7% by BTA3D only. Virtuo detected microbial growth nearly 2 h sooner overall than BTA3D (mean, 15.9 h versus 17.7 h). Shorter time to detection by Virtuo was related to organism group, with the time to detection being significantly shorter for enteric Gram-negative bacilli and enterococci (means, 3.6 h and 2.3 h shorter, respectively). This large clinical study demonstrated that the Virtuo blood culture system produced results comparable to those seen with the long-established BTA3D system, with significantly shorter time to detection.

Blood culture time-to-positivity: making use of the hidden information

“…In this issue, Puerta-Alcade et al advocate, based on a retrospective study, early deescalation at 24 h [2] instead of 48e96 h as commonly advised because (i) the great majority of episodes with positive blood culture are positive within the first 24 h, (ii) positive episodes with TTP 24 h are commonly optimally treated infections, catheter-related infections, or infections caused by slowly growing microorganisms such as Candida or anaerobic Gram-negative bacteria, and (iii) growth of multidrug-resistant Gram-negative bacilli is exceptional beyond 24 h. With similar logistics, other studies show short TTP in agreement with Puerta-Alcade et al's results: median TTP, although it varied between bacterial groups, was 24 h except for yeasts (see ref. [4]); most TTPs in other patient populations were 24 h (see ref. [5]).…”

Reconfigurable measuring system for the automatic detection of bacterial growth in a specimen processing platform

“…The combination of such techniques with automation has resulted in the appearance on the market of systems aiming to meet the abovementioned goals. For instance, both the BACTEC™ (Becton, Dickinson, and Company) [11]- [12] and the BacT/ALERT (bioMérieux SA) [12]- [14], in their different versions, monitor the change in fluorescence caused by ABSTRACT The detection of bacterial infections in biological samples represents a fundamental task in human health preservation. This paper describes a measuring system that aims to detect bacterial growth in Petri dishes while they are inside the incubator of the WASPLab® specimen processing platform (COPAN Italia S.p.A.).…”

Método fenotípico automatizado versus método manual na identificação de micro-organismos isolados de hemoculturas: desfechos clínicos e microbiológicos

“…Microbiological automation minimizes errors 1 improves quality of microbiological examination 2 reduces incubation time 3,4 and decreases hospital costs 5 . There are also studies demonstrating the advantages in cost-effectiveness of automated methods based on molecular analysis opposite to the conventional method 6 .…”