Early detection of bacillus anthracis from saliva in anticipation of a bioterrorism attack

Objective: To assess potential for early detection of oral infection by B. anthracis spores for preparedness of a bioterrorism attack. Material and Methods: The laboratory study used saliva with a range of initial anthrax concentrations, to compare detection by direct observation from conventional blood agar culture and by anthrax-specific PCR after a shorter culture in BHI broth. Three types of saliva were collected: stimulated saliva, unstimulated/whole saliva, and unstimulated/whole saliva with antibiotic treatment (for negative control). Using bivariate Kruskal-Wallis and Mann-Whitney tests for statistical analysis for factors that could affecting anthrax detection, significant differences between the test groups was assumed at p<0.05. Results: From unstimulated whole saliva heat shock treated at 62.5⁰C, B. anthracis growth was detected with both methods. PCR detection from a BHI broth culture could shorten the time to diagnosis in comparison to conventional culture in blood agar. Conclusion: Saliva can provide useful samples for diagnosis of oropharyngeal anthrax. In comparison to conventional culture on blood agar, shorter-term culture in BHI broth provides potential for earlier detection and diagnosis.