Comparison of five commercially available lateral flow assays for the rapid detection of B. anthracis in environmental samples

AIMS: Anthrax is a globally occurring zoonotic disease caused by the Gram-positive, spore-forming bacterium Bacillus anthracis. Due to the long-term environmental persistence of its spores and the potential use of the pathogen in bioterrorism, rapid and reliable detection is essential for environmental surveillance and outbreak response. This study aimed to evaluate the diagnostic performance of commercially available lateral flow assays (LFAs) for environmental detection of B. anthracis. METHODS AND RESULTS: Five commercially available LFAs were assessed regarding biosafety aspects, analytical sensitivity, specificity, and applicability in complex soil matrices. Limits of detection ranged from 10⁶-10⁹ spores, indicating low analytical sensitivity. Frequent cross-reactivity with closely related Bacillus species was observed, although specificity differed considerably between assays. Soil composition significantly influenced test performance. Organic- and calcium-rich soils as well as metal-contaminated loamy soils frequently produced false-positive results, whereas sandy soil caused less interference. Most assays detected both spores and vegetative cells, broadening their potential application to different sample types. However, none of the evaluated assays met the criteria required for reliable stand-alone field diagnostics. CONCLUSIONS: Current LFAs for environmental detection of B. anthracis show limitations regarding sensitivity, specificity, and robustness in complex environmental matrices. While LFAs may serve as preliminary screening tools, confirmatory laboratory diagnostics remain essential. These findings highlight the urgent need for improved point-of-care tests with enhanced sensitivity and specificity for reliable anthrax detection in environmental samples.