Table 4. Validation of SYBR Green I/PI assay in comparison to microscopic counting for determining antibiotic susceptibility of B. burgdorferi.1.
| Antibiotics | LIVE/DEAD (Ratio Green/Red) | SYBR Green I/PI (Ratio Green/Red) | Microscope counting (live %)2 |
| Doxycycline | 9.83 | 4.35 | 35% |
| Amoxicillin | 10.18 | 5.76 | 66% |
| Metronidazole | 10.34 | 7.12 | 81% |
| Drug-free control | 10.32 | 8.85 | 95% |
1
A 5-day B. burgdorferi culture was treated with 1 mM each of doxycycline, amoxicillin or metronidazole for 5 days, followed by staining with LIVE/DEAD assay and SYBR Green I/PI assay, or microscope counting (as a gold standard) to assess their capability for antibiotic susceptibility testing. The green/red ratios were obtained for LIVE/DEAD and SYBR Green/PI assays respectively in fluorescence measurement (see Methods). Each value is the mean of three replicates.
2
The percentage of live (green) spirochetes.