Open AccessOxidative stress response plays a role in antibiotic tolerance of Streptococcus mutans biofilms
Author(s) -
Marie Nilsson,
Tim Holm Jakobsen,
Michael Givskov,
Svante Twetman,
Tim TolkerNielsen
Publication year - 2019
Publication title -
microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.352
H-Index - 35
eISSN - 1465-2080
pISSN - 1350-0872
DOI - 10.1099/mic.0.000773
Subject(s) - biofilm , multidrug tolerance , microbiology and biotechnology , streptococcus mutans , mutant , oxidative stress , antibiotics , biology , reactive oxygen species , bacteria , gene , biochemistry , genetics
Knowledge about biofilm-associated antibiotic tolerance mechanisms is warranted in order to develop effective treatments against biofilm infections. We performed a screen of a Streptococcus mutans transposon mutant library for mutants with reduced biofilm-associated antimicrobial tolerance, and found that the spxA1 gene plays a role in tolerance towards gentamicin and other antibiotics such as vancomycin and linezolid. SpxA1 is a regulator of genes involved in the oxidative stress response in S. mutans. The oxidative stress response genes gor and ahpC were found to be up-regulated upon antibiotic treatment of S. mutans wild-type biofilms, but not spxA1 mutant biofilms. The gor gene product catalyses the formation of glutathione which functions as an important antioxidant during oxidative stress, and accordingly biofilm-associated antibiotic tolerance of the spxA1 mutant could be restored by exogenous addition of glutathione. Our results indicate that the oxidative stress response plays a role in biofilm-associated antibiotic tolerance of S. mutans, and add to the on-going debate on the role of reactive oxygen species in antibiotic mediated killing of bacteria.