The PCR conditions used in this study were not rigorously optimized for either specificity or low-input target. In general, these conditions seem to give a dependable yield of full-sized product. Additional products of varying intensities were produced from some of the DNAs. As shown in Fig. 2, the smaller-sized band produced from Bacteroides fragilis DNA, derived from both culture and lyophilized ampoule, is the most abundant spurious band within the bacterial strains examined.