Adaptation of Pseudomonas aeruginosa to a pulsed light-induced stress

Abstract

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 1AE8 J cm )2 can kill 10 9 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.

Recent findings in pulsed light disinfection

“…Farrell et al (2011) found PL-induced cytosolic localization of ROS with concomitant lipid hydroperoxidation in C. albicans while Kramer et al (2015a) detected intracellular ROS and lipid peroxidation in E. coli at high treatment intensities. Massier et al (2012Massier et al ( , 2013 on the other hand did not find a PL-induced oxidative stress defence mechanism in Ent. faecalis or Ps.…”

“…Massier et al . (, ) on the other hand did not find a PL‐induced oxidative stress defence mechanism in Ent. faecalis or Ps.…”

“…Based on a proteomic approach, Massier et al . (, ) found an active stress response of Ent. faecalis and P. aeruginosa after applying energy doses, which led to count reductions by 2·2 and 0·5 log respectively.…”

“…Massier et al . () found that P. aeruginosa may adapt to PL stress caused by low energy doses, leading to a higher resistance. The same was also found for Enterococcus faecalis (Massier et al .…”

“…Different results have been obtained concerning a potential resistance development among bacteria so far. Massier et al (2012) found that P. aeruginosa may adapt to PL stress caused by low energy doses, leading to a higher resistance. The same was also found for Enterococcus faecalis (Massier et al 2013).…”