FIG 2.

Persister levels and dynamics in Burkholderiales. (A) Survivor frequencies with various bacterial isolates. Aliquots of bacterial cultures were incubated in the presence of 100× the MIC of ceftazidime, and the surviving proportion was enumerated after 24 h incubation with antibiotics. Bth, B. thailandensis; Bps, B. pseudomallei; Eco, E. coli. The MIC of ceftazidime under atmospheric oxygen levels against each isolate is given in brackets after the strain designation. (B) Relationship between killing efficiencies of different antibiotics and oxygen levels. Aliquots of B. thailandensis strain E264 exposed to 100× the MIC of ceftazidime or 10× the MIC of ciprofloxacin were incubated in 24-well plates in different incubators: aerobic (atmospheric levels of oxygen), microaerophilic (5% O₂), and anaerobic (no oxygen). The survival frequencies were assessed after 24 h incubation and are defined as the number of cells that survived the antibiotic treatment (T₂₄) divided by the input CFU (T₀). (C) Time-kill curves with two different antibiotics. Aliquots of bacterial cultures of B. thailandensis strain E264 were incubated in the presence of 100× the MIC of ceftazidime or 10× the MIC of ciprofloxacin under aerobic conditions. The surviving proportion was enumerated at the indicated time points and is plotted on a logarithmic scale over time. The error bars represent the standard deviation (SD) over the mean from at least three independent experiments.