Table 1.
Comparison of data1 of different methods for assaying B. burgdorferi viability.
Figure 1.
Representative images of B. burgdorferi culture (7 day old), observed with fluorescence microscopy equipped with Spot slider color camera using LIVE/DEAD BacLight stain (A), SYBR Green I/PI stain (B), and FDA stain (C).
Antibiotic-treated B. burgdorferi biofilm (9 day old) was stained by SYBR Green I/PI (D). Sytox Green/Hoechst 33342 stained B. burgdorferi images were recorded by the ORCA-R2 high resolution camera (E, merged from images visualized by DAPI, FITC and TRITC filters) and by Spot slider color camera with triple filter (F).
Table 2.
Comparison of performance of different methods for assaying B. burgdorferi viability.
Figure 2.
Linear relationship between the B. burgdorferi viability and Green/Red fluorescence ratio of the SYBR Green I/PI assay.
(A) The linear relationship between the number of spirochetes and Green/Red fluorescence ratio. (B) Emission spectra of suspensions of various proportions of live and isopropyl alcohol-killed B. burgdorferi were obtained, and the Green/Red fluorescence ratios were calculated for each proportion of live/dead cells. The line is a least-square fit of the relationship between percentage of live bacteria and Green/Red fluorescence ratio.
Figure 3.
The Green/Red fluorescence ratios of B. burgdorferi biofilm measured by the SYBR Green I/PI assay at different culture times.
The top panel shows the increase in Green/Red fluorescence ratios for biofilm growth over time, whereas the lower panel shows the corresponding microscopic images at different time points. All assays were run in triplicate.
Table 3.
SYBR Green I/PI assay applied to MIC test on Borrelia burgdorferia.
Table 4.
Validation of SYBR Green I/PI assay in comparison to microscopic counting for determining antibiotic susceptibility of B. burgdorferi.1.