FIG. 8.
Impact of number of cells lysed during the processing of BAL specimens on the measurement of ELF concentrations of pyrazinamide, ethionamide, and linezolid. AUCelf/(AUCfs·K) (or Celf/[Cfs·K]) ratios are plotted against the volume percentage of lysed cells in ELF. Constant K reflects the capacity of antibiotics for penetration through alveolar epithelial cells (see text). Multiple lines of the same antibiotic are drawn based on different data sets. AUCelf/(AUCfs·K) (or Celf/]Cfs·K]) ratios for these antibiotics above 1 increase with increasing extent of cell lysis in ELF because intracellular concentrations are lower than free serum levels. The high ELF concentrations of these antibiotics cannot be explained by the contamination of lysed cells. The possibility of technical errors needs to be excluded.