Figure_3.tif (232.33 kB)

Growth of strains H37Ra and HR1 in the presence of RIF.

figure

posted on 2013-02-21, 01:05 authored by Alice L. den Hertog, Dennis W. Visser, Colin J. Ingham, Frank H. A. G. Fey, Paul R. Klatser, Richard M. Anthony

Microcolonies of RIF susceptible strain H37Ra and resistant strain HR1 were grown without RIF for 7 days, then moved to fresh agar with or without RIF from day 7 onwards. A, C: Averaged sizes of H37Ra (A) and HR1 (C) colonies incubated with (open symbols) and without RIF (closed symbols). Average colony size is plotted; bars indicate ±1 standard deviation of measured colony sizes. A statistically significant difference (indicated by an asterisk (*), p<0.001) between the groups at day 7 and 8 (unpaired T-test) was found between H37Ra with and without RIF at day 8. B: Growth rate of individual H37Ra (B) and HR1 (D) colonies incubated with (white bars) and without (black bars) RIF. Statistical analysis was performed using a paired T-test on colony growth between day 6 and day 7, and day 6 and day 8. Statistical significance is indicated by an asterisk (*; p<0.001). Although there is a statistically significant difference between the growth rate of HR1 at day 6 and 7 in the presence of RIF, the change in growth rate is so small compared to the sensitive strain that we consider this effect irrelevant.