Blue light directly modulates the quorum network in the human pathogen Acinetobacter baumannii

TUTTOBENE, MARISEL ROMINA; MÜLLER, GABRIELA LETICIA; BLASCO, LUCÍA; ARANA, NATALIA; HOURCADE, MÓNICA; DIACOVICH, LAUTARO; CRIBB, PAMELA; TOMÁS, MARÍA; NIETO-PEÑALVER, CARLOS GABRIEL; MUSSI, MARÍA ALEJANDRA

Scientific Reports

NATURE

Año: 2021 vol. 11

Quorum sensing modulates bacterial collective behaviors including bioflm formation, motility andvirulence in the important human pathogen Acinetobacter baumannii. Disruption of quorum sensinghas emerged as a promising strategy with important therapeutic potential. In this work, we show thatlight modulates the production of acyl-homoserine lactones (AHLs), which were produced in higherlevels in the dark than under blue light at environmental temperatures, a response that dependson the AHL synthase, AbaI, and on the photoreceptor BlsA. BlsA interacts with the transcriptionalregulator AbaR in the dark at environmental temperatures, inducing abaI expression. Under bluelight, BlsA does not interact with AbaR, but induces expression of the lactonase aidA and quorumquenching, consistently with lack of motility at this condition. At temperatures found in warmblooded hosts, the production of AHLs, quorum quenching as well as abaI and aidA expression werealso modulated by light, though in this case higher levels of AHLs were detected under blue lightthan in the dark, in a BlsA-independent manner. Finally, AbaI reduces A. baumannii?s ability to kill C.albicans only in the dark both at environmental as well as at temperatures found in warm-bloodedhosts. The overall data indicate that light directly modulates quorum network in A. baumannii.