Rapid detection of Bacillus anthracis by γ phage amplification and lateral flow immunochromatography

• We exploited phage amplification for rapid point-of-need B. anthracis detection.
• Species-specific amplification was combined with LFI for simple, accurate detection.
• Detection was achieved in two hours with a sensitivity of ~ 2.5 × 104 cfu/mL.
• Results were achieved in a fraction of the time required by conventional assays.

New, rapid point-of-need diagnostic methods for Bacillus anthracis detection can enhance civil and military responses to accidental or deliberate dispersal of anthrax as a biological weapon. Current laboratory-based methods for clinical identification of B. anthracis require 12 to 120 h, and are confirmed by plaque assay using the well-characterized γ typing phage, which requires an additional minimum of 24 h for bacterial culture. To reduce testing time, the natural specificity of γ phage amplification was investigated in combination with lateral flow immunochromatography (LFI) for rapid, point-of-need B. anthracis detection. Phage-based LFI detection of B. anthracis Sterne was validated over a range of bacterial and phage concentrations with optimal detection achieved in as little as 2 h from the onset of amplification with a threshold sensitivity of 2.5 × 104 cfu/mL. The novel use of γ phage amplification detected with a simple, inexpensive LFI assay provides a rapid, sensitive, highly accurate, and field-deployable method for diagnostic ID of B. anthracis in a fraction of the time required by conventional techniques, and without the need for extensive laboratory culture.