Template DNA ratio can affect detection by genus-specific PCR-denaturing gradient gel electrophoresis of bacteria present at low abundance in mixed populations.

The detection of Helicobacter species by genus-specific polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was compared with that by species-specific PCR in murine intestinal samples. Results suggest that, in samples containing multiple Helicobacter species, genus-specific PCR-DGGE may fail to detect all Helicobacter species present and that this relates to the initial template DNA ratio.