Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Aug 23;7(9):ofaa371.
doi: 10.1093/ofid/ofaa371. eCollection 2020 Sep.

Real-world Time to Positivity of 2 Widely Used Commercial Blood Culture Systems in Patients With Severe Manifestations of Sepsis: An Analysis of the FABLED Study

Guillaume Butler-Laporte  1 , Cedric P Yansouni  1   2 , Katryn Paquette  3 , Alexander Lawandi  1 , Sarah N Stabler  4 , Murtaza Akhter  5 , Adam C Davidson  6 , Marko Gavric  7 , Rehman Jinah  7 , Zahid Saeed  8 , Koray Demir  9 , Sassan Sangsari  10 , Kelly Huang  10 , Amirali Mahpour  11 , Chris Shamatutu  7 , Chelsea Caya  12 , Jean-Marc Troquet  13 , Greg Clark  13 , Titus Wong  14 , Todd C Lee  1   2   9 , Robert Stenstrom  10 , David Sweet  10 , Matthew P Cheng  15
Affiliations

Real-world Time to Positivity of 2 Widely Used Commercial Blood Culture Systems in Patients With Severe Manifestations of Sepsis: An Analysis of the FABLED Study

Guillaume Butler-Laporte et al. Open Forum Infect Dis. .

Abstract

Background: Of all microbiological tests performed, blood cultures have the most impact on patient care. Timely results are essential, especially in the management of sepsis. While there are multiple available blood culture systems on the market, they have never been compared in a prospective study in a critically ill population.

Methods: We performed an analysis of the FABLED study cohort to compare culture results and time to positivity (TTP) of 2 widely used blood culture systems: BacT/Alert and BACTEC. In this multisite prospective study, patients with severe manifestations of sepsis had cultures drawn before antibiotics using systematic enrollment criteria and blood drawing methodology allowing for minimization of pre-analytical biases.

Results: We enrolled 315 patients; 144 had blood cultures (47 positive) with BacT/Alert and 171 with BACTEC (53 positive). Patients whose blood cultures were processed using the BacT/Alert system were younger (median, 64 vs 70 years; P = .003), had a higher proportion of HIV (9.03% vs 1.75%; P = .008) and a lower qSOFA (P = .003). There were no statistically significant differences in the most commonly identified bacterial species. TTP was shorter for BACTEC (median [interquartile range {IQR}], 12.5 [10-14] hours) compared with BacT/Alert (median [IQR], 17 [14-21] hours; P < .0001).

Conclusions: In this large prospective multi-centre study comparing the two blood culture systems among patients with severe manifestations of sepsis, and using a rigorous pre-analytical methodology, the BACTEC system yielded positive culture results 4.5 hours earlier than BacT/Alert. These results apply to commonly isolated bacteria. However, our study design did not allow direct comparison of TTP for unusual pathogens nor of clinical sensitivity between systems. More research is needed to determine the clinical implications of this finding.

Keywords: bloodstream infection; microbiology; sepsis; time to positivity.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Pre-antibiotic cumulative event time to positivity curve, with 95% confidence intervals. Blue: BACTEC. Orange: BacT/Alert.
See this image and copyright information in PMC

References

    1. Nielsen SL. The incidence and prognosis of patients with bacteremia. Dan Med J 2015; 62:B5128. - PubMed
    1. Zabbe JB, Zanardo L, Mégraud F, Bessède E. MALDI-TOF mass spectrometry for early identification of bacteria grown in blood culture bottles. J Microbiol Methods 2015; 115:45–6. - PubMed
    1. The European Committee on Antimicrobial Susceptibility Testing. Methodology - EUCAST rapid antimicrobial susceptibility testing (RAST) directly from positive blood culture bottles, version 1.1 2019. Available at: http://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/RAST/EUCAST_.... Accessed 16 March 2020.
    1. Food and Drug Administration. Review criteria for assessment of in vitro blood culturing system diagnostic devices. Silver Spring, MD: Food and Drug Administration; 1991.
    1. Flayhart D, Borek AP, Wakefield T, et al. . Comparison of BACTEC PLUS blood culture media to BacT/Alert FA blood culture media for detection of bacterial pathogens in samples containing therapeutic levels of antibiotics. J Clin Microbiol 2007; 45:816–21. - PMC - PubMed