Table 3. Mtb within hypoxic lipid-loaded macrophages develops phenotypic tolerance to antibiotics.

THPM or human PBMC-derived macophages infected with Mtb at an MOI of 0.1 were incubated in 1 % O₂, 5 % CO₂ or 21 % O₂, 5 % CO₂. At 0, 3 and 5 days after infection, the infected host cells were treated with antibiotics at the indicated concentrations for 2 more days under the same conditions prior to lysis of the host cells. Mtb recovered from antibiotic-treated macrophages were analyzed for antibiotic resistance and compared to Mtb recovered from macrophages unexposed to antibiotics, by CFU plating.