Acinetobacter baumannii utilizes a novel protective factor to combat desiccation-induced oxidative stress

by John M. Farrow III, Greg Wells, Everett C.

Pesci One of the factors that facilitates the nosocomial spread of the frequently multidrug-resistant pathogen Acinetobacter baumannii is its ability to persist on dry surfaces for weeks. These bacteria do not form spores, but instead rely on a group of protective factors to survive desiccation.

We investigated a protective factor of unknown function, referred to here as desiccation tolerance protein C (DtpC), which we found to be co-transcribed with another protective factor, the KatE catalase. A Δ dtpC Δ katE mutant strain had a greatly decreased ability to survive desiccation, but complementation with either dtpC or katE individually could restore survival to the wild-type level, showing that DtpC and KatE are each sufficient for desiccation tolerance.

Since KatE also protects cells from oxidative stress, we examined whether oxygen had an effect on desiccation survival, and analyzed the formation of reactive oxygen species in dried cells.