Effect of physiological age and state on survival of desiccated Pseudomonas aeruginosa.

Cells of Pseudomonas aeruginosa harvested after 6 hr, 24 hr, 7 days, 33 days, and 120 days of incubation at 36 C varied in their resistance to the deleterious effects of desiccation. The longest survival period observed was for cells from cultures incubated for 7 days. Cells of the exponential growth phase were the most susceptible. The addition of extracellular slime from 7-day cultures to suspending medium did not increase survival of cells from the exponential growth phase. No marked differences in survival time were observed for cells of similar physiological age from cultures incubated at 20, 36, and 42 C. In comparison with the laboratory strain, P. aeruginosa OSU 64, used in this study, strains isolated from natural habitats and subjected to a minimum of manipulation in the laboratory were not better adapted to withstand the stress of desiccation.