Open AccessComplex Responses to Hydrogen Peroxide and Hypochlorous Acid by the Probiotic Bacterium Lactobacillus reuteri
Author(s) -
Poulami Basu Thakur,
Abagail R. Long,
Benjamin Nelson,
Ranjit Kumar,
Alexander F. Rosenberg,
Michael J. Gray
Publication year - 2019
Publication title -
msystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.931
H-Index - 39
ISSN - 2379-5077
DOI - 10.1128/msystems.00453-19
Subject(s) - lactobacillus reuteri , hypochlorous acid , hydrogen peroxide , bacteria , microbiology and biotechnology , lactic acid , probiotic , lactobacillus , chemistry , antimicrobial , microbiome , immune system , biology , biochemistry , immunology , bioinformatics , genetics
Inflammatory diseases of the gut are associated with increased intestinal oxygen concentrations and high levels of inflammatory oxidants, including hydrogen peroxide (H 2 O 2 ) and hypochlorous acid (HOCl), which are antimicrobial compounds produced by the innate immune system. This contributes to dysbiotic changes in the gut microbiome, including increased populations of proinflammatory enterobacteria ( Escherichia coli and related species) and decreased levels of health-associated anaerobic Firmicutes and Bacteroidetes The pathways for H 2 O 2 and HOCl resistance in E. coli have been well studied, but little is known about how commensal and probiotic bacteria respond to inflammatory oxidants. In this work, we have characterized the transcriptomic response of the anti-inflammatory, gut-colonizing Gram-positive probiotic Lactobacillus reuteri to both H 2 O 2 and HOCl. L. reuteri mounts distinct but overlapping responses to each of these stressors, and both gene expression and survival were strongly affected by the presence or absence of oxygen. Oxidative stress response in L. reuteri required several factors not found in enterobacteria, including the small heat shock protein Lo18, polyphosphate kinase 2, and RsiR, an L. reuteri -specific regulator of anti-inflammatory mechanisms. IMPORTANCE Reactive oxidants, including hydrogen peroxide and hypochlorous acid, are antimicrobial compounds produced by the immune system during inflammation. Little is known, however, about how many important types of bacteria present in the human microbiome respond to these oxidants, especially commensal and other health-associated species. We have now mapped the stress response to both H 2 O 2 and HOCl in the intestinal lactic acid bacterium Lactobacillus reuteri .