RESUMO
AIM: Combination of immunomagnetic separation (IMS) and lateral flow device (LFD) assays for the development of a sensitive, rapid, on-site methodology that enables concentration and detection of Bacillus anthracis spores in complex samples. METHODS AND RESULTS: The data presents the development of an optimized, 30 min, IMS assay, with about 95% capture of B. anthracis spores from different dairy products (n = 38). No cross reactivity was detected with typical milk flora and some closely related Bacilli. To enable direct application of the IMS captured spores on the LFD, spores were eluted from the bead-spore complex utilizing 95% (v/v) formamide-10 mmol l(-1) EDTA for 30 s in a microwave oven. Detached spores were analysed on LFD enabling detection within 10 min. The combined IMS-LFD methodology (40 min) demonstrates a 60-fold improvement in sensitivity, relative to samples that were applied directly on the LFD without the IMS concentrating step. CONCLUSIONS: The IMS-LFD method is a powerful platform, combining rapidity, specificity and efficiency for concentrating and detecting B. anthracis from water and milk contaminated samples. SIGNIFICANT AND IMPACT OF THE STUDY: The combination of IMS and LFD enhances the sensitivity and flexibility of B. anthracis spore detection from complex samples. This method can potentially be extended to other toxins and micro-organisms in a variety of matrices.
