Figure 4
Bacterial yield in DCTB assays using CF from Msm strains expressing Mtb Rpfs in various combinations. (A) Assessment of DCTB recovery from sputum cultures using CF supplementation. DCTB were detected using the MPN limiting dilution assay. For comparison, CF containing and deficient in Mtb and Msm Rpf was used to assess the role of Rpfs in growth stimulation. To control for the effect of CF in growth stimulation, fresh Middlebrook media was used. CF from various recombinant Msm strains was used to assess if expression of Mtb Rpfs in Msm yields CF that can be used to stimulate DCTB in sputum specimens in a manner that is comparable to Mtb CF. To obtain the DCTB count, MPN values (with or without CF) were divided by CFU counts, which depict conventionally culturable bacteria. (B) Histogram depicting mean DCTB counts from assays using CF from Mtb and Msm. The mean DCTB counts were compared to that obtained from no CF assays using a Wilcoxon test to determine the growth stimulatory effect of the various CFs. Error bars depict the standard error of the mean. P-values depict the comparison of any given CF to the no CF or empty vector control. Graph was generated using Graphpad Prism software, Version 6.
