Detection of 16S rRNA and toxin genes of C. perfringens by PCR. (A) Sensitivity of the PCR assay for the detection of 16S rRNA and toxin genes (cpa, cpb, and etx) of C. perfringens. Genomic DNA was serially diluted 10-fold from 5 × 105 to 5 copies. The results showed that the sensitivity of detecting each gene was between 50 and 500 copies. (B) Specific amplification of the 16S rRNA gene of C. perfringens (279 bp) by PCR. Lane 1, C. perfringens type B (5 × 105 copies); lane 2, C. perfringens type B (5 × 102 copies); lane 3, blank (no target); lane 4, C. difficile; lane 5, C. sordelli; lane 6, P. aeruginosa; lane 7, E. coli; lane 8, S. enterica serovar Typhimurium; lane 9, P. vulgaris. Lanes M in panels A and B contain DNA size markers (pBR322 DNA MspI digest). Genomic DNA (5 × 105 copies) was tested for bacteria other than C. perfringens.