The influence of pH on Staphylococcus saprophyticus iron metabolism and the production of siderophores
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2019
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Resumo
Staphylococcus saprophyticus is a gram-positive coagulase negative bacteria which shows clinical
importance due to its capability of causing urinary tract infections (UTI), as well as its ability to persist in
this environment. Little is known about how S. saprophyticus adapts to the pH shift that occurs during
infection. Thus, in this study we aim to use a proteomic approach to analyze the metabolic adaptations
which occur as a response by S. saprophyticus when exposed to acid (5.5) and alkaline (9.0) pH envi ronments. Proteins related to iron storage are overexpressed in acid pH, whilst iron acquisition proteins
are overexpressed in alkaline pH. It likely occurs because iron is soluble at acid pH and insoluble at
alkaline pH. To evaluate if S. saprophyticus synthesizes siderophores, CAS assays were performed, and the
results confirmed their production. The chemical characterization of siderophores demonstrates that
S. saprophyticus produces carboxylates derived from citrate. Of special note is the fact that citrate syn thase (CS) is down-regulated during incubation at acid pH, corroborating this result. This data was also
confirmed by enzymatic assay. Our results demonstrate that iron metabolism regulation is influenced by
different pH levels, and show, for the first time, the production of siderophores by S. saprophyticus.
Enzymatic assays suggest that citrate from the tricarboxylic acid cycle (TCA) is used as substrate for
siderophore production.
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pH, Iron metabolism, S. saprophyticus, Carboxylate siderophores, Citrate synthase
Citação
SOUZA, Bianca Silva Vieira de et al. The influence of pH on S. saprophyticus iron metabolism and the production of 2 siderophores. Microbes and Infection, Paris, v. 21, n. 10, p. 456-463, 2019. DOI: 10.1016/j.micinf.2019.04.008. Disponível em: https://www.sciencedirect.com/science/article/pii/S1286457919300565?via%3Dihub. Acesso em: 22 nov. 2024.