Unexpected relations of historical anthrax strain

In 1998, it was claimed that an 80-year-old glass tube intentionally filled with Bacillus anthracis and embedded in a sugar lump as a WWI biological weapon still contained viable spores. Today, genome sequencing of three colonies isolated in 1998 and subjected to phylogenetic analysis surprisingly identified a well-known B. anthracis reference strain isolated in the United States in 1981, pointing to accidental laboratory contamination. IMPORTANCE Next-generation sequencing and subsequent phylogenetic analyses are useful and reliable tools for the classification of recent and historical samples. The reliability of sequences obtained and bioinformatic algorithms has increased in recent years, and research has uncovered the identity of a presumed bioweapon agent as a contaminant.