Light Modulates Important Pathogenic Determinants and Virulence in Acinetobacter baumannii , Pseudomonas aeruginosa and Staphylococcus aureus ESKAPE Pathogens

TUTTOBENE, M. R.; PÉREZ, J. F.; PAVESI, E.; PEREZ MORA, B.; BIANCOTTI, D.; CRIBB, P.; ALTILIO, M.; MÜLLER, G.; GRAMAJO, H.; TAMAGNO, G.; RAMÍREZ, M. S.; DIACOVICH, L.; MUSSI, M. A.

JOURNAL OF BACTERIOLOGY

AMER SOC MICROBIOLOGY

Lugar: Washington; Año: 2021

0021-9193

Light sensing has been extensively characterized in the human pathogenAcinetobacter baumannii at environmental temperatures. However, the influenceof light on the physiology and pathogenicity of human bacterial pathogens at temperaturesfound in warm-blooded hosts is still poorly understand. In this work,we show that Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa(ESKAPE) priority pathogens, which have been recognized by the WHO andthe CDC as critical, can also sense and respond to light at temperatures found inhuman hosts. Most interestingly, in these pathogens, light modulates importantpathogenicity determinants as well as virulence in an epithelial infection model,which could have implications in human infections. In fact, we found that alphatoxin-dependent hemolysis, motility, and growth under iron-deprived conditions aremodulated by light in S. aureus. Light also regulates persistence, metabolism, andthe ability to kill competitors in some of these microorganisms. Finally, light exerts aprofound effect on the virulence of these pathogens in an epithelial infection model,although the response is not the same in the different species; virulence was enhancedby light in A. baumannii and S. aureus, while in A. nosocomialis and P. aeruginosa it wasreduced. Neither the BlsA photoreceptor nor the type VI secretion system (T6SS) isinvolved in virulence modulation by light in A. baumannii. Overall, this fundamentalknowledge highlights the potential use of light to control pathogen virulence, eitherdirectly or by manipulating the light regulatory switch toward the lowest virulence/persistenceconfiguration.