Polymerase chain reaction-ELISA to detect Bacillus anthracis from soil samples-limitations of present published primers.

A polymerase chain reaction (PCR)-ELISA technique to detect Bacillus anthracis from soil samples has been developed. The application of streptavidine-coated microtitre plates as well as plates covered with covalently linked oligonucleotides as catching probes led to a test sensitivity of about 100 fg pure genomic DNA or of less than 10 spores seeded into 100 g soil material. Some non-suspicious soil samples collected from different locations yielded positive results with presently published primers or probes targeting the B or C gene of pX02 and with primers targeting the chromosomal sequence B813. The former PCR products were sequenced. The number and mode of base exchanges led to the assumption that there will exist at least one unknown soil organism with high similarity within highly conserved capsule-encoding genes.