Adaptation of Pseudomonas aeruginosa to a pulsed light-induced stress


Sylvie Chevalier, Laboratoire de Microbiologie du Froid, Signaux et MicroEnvironnement, Université de Rouen, EA4312, 55 rue Saint Germain, 27000 Evreux, France. E-mail:


Aims:  Pulsed light (PL) technology is an efficient surface decontamination process. Used in low transmitted energy conditions, PL induces a stress that can be perceived by bacteria. The effect of such a PL stress was investigated on the highly environmental adaptable germ Pseudomonas aeruginosa PAO1.

Methods and Results:  Pulses of transmitted energy (fluence) reaching 1·8 J cm−2 can kill 109 bacteria. Application of a lower sublethal PL dose allowed the bacteria to resist and survive more efficiently to a subsequent dose of PL. This sublethal dose was not increasing the mutation frequency of Ps. aeruginosa, but altered the abundance of 15 proteins as revealed by a global proteome analysis, including stress-induced proteins, phage-related proteins, energy and carbon metabolisms, cell motility, and transcription and translation regulators.

Conclusions:  A response to a low-energy PL dose takes place in Ps. aeruginosa, reducing the energy conversion systems, while increasing transcription and translation processes to produce proteins involved in chaperone mechanisms and phage-related proteins, probably to protect the bacterium against a new PL-induced stress.

Significance and Impact of the Study:  Taken together, these results suggest that a low-energy PL dose is sufficient to provoke adaptation of Ps. aeruginosa, leading to enhancing its resistance to a subsequent lethal treatment.