[Detection of Brucella with an automatic hemoculture system: Bact/Alert]

Area of Science:

• Microbiology
• Clinical Diagnostics
• Infectious Diseases

Background:

• Brucellosis diagnosis relies on timely detection of Brucella spp.
• The Bact/Alert system is a common method for blood culture analysis.
• Evaluating new diagnostic systems is crucial for improving patient outcomes.

Purpose of the Study:

• To assess the efficacy of the Bact/Alert system for detecting Brucella species (spp.) in vitro and in vivo.
• To compare the detection times of the Bact/Alert system with biphasic Hemóline bottles.
• To determine if blind passes are necessary for accurate Brucella detection using the Bact/Alert system.

Main Methods:

• Inoculation of various Brucella strains (B. melitensis, B. abortus) at different concentrations into Bact/Alert and Hemóline bottles.
• Processing of 8,216 clinical blood culture bottles using the Bact/Alert system over nine months.
• Analysis of detection times and comparison between automated and conventional methods.

Main Results:

• The Bact/Alert system detected Brucella growth in 2–3 days, compared to 14 days for biphasic bottles.
• Of 8,216 processed bottles, 11 positive for Brucella were from 5 patients with confirmed brucellosis.
• Bact/Alert detected B. melitensis in one bottle at 2.9 days, and in seven additional bottles after blind passes (10–20 days).

Conclusions:

• The Bact/Alert system alone is insufficient for the complete diagnosis of brucellosis.
• Blind subculturing (passes) of blood cultures is essential for maximizing Brucella detection rates.
• Further refinement of automated blood culture systems may be needed for improved sensitivity in diagnosing Brucella infections.