[Detection of toxin-producing pathogenic bacterial strains by polymerase chain reaction]

Polymerase chain reaction (PCR) was used for detection of pathogenic Clostridium botulinum, Clostridium perfringens, Clostridium difficile, and Escherichia coli. With this aim in view, primers to botulinic toxins types A, B, C1, D, E, F, and G, perfringens enterotoxin, difficile toxin, and types 1 and 2 Shigella-like toxins were chosen and synthesized. Optimal amplification conditions were selected for each pair of primers, with DNA and the respective agent as the reaction mixture matrices. PCR was highly specific and sensitive in all cases. Its sensitivity was 10-100 cells/sample. Among the tested C. botulinum, C. perfringens, C. difficile, and E. coli strains, specific amplification products of expected size were observed only in the strains containing the respective toxin genes. These findings recommend the use of these methods in clinical microbiology. Strains containing type 2 Shigella-like toxin gene were detected among E. coli strains isolated from patients with the hemolytic uremic syndrome, which for the first time indicates that the problem with E. coli epidemic strain O157 is valid for Russia. As a result of our studies, test systems for detection of types A, B, C, D, E, F, and G C. botulinum strains, C. perfringens and C. difficile, and E. coli O157 strains are now available.