Molecular Characterization of Clinical Rel Mutations and Consequences for Resistance Expression and Fitness in Staphylococcus aureus.

The stringent response (SR) is a universal stress response that acts as a global regulator of bacterial physiology and virulence, and is a contributor to antibiotic tolerance and resistance. In most bacteria, the SR is controlled by a bifunctional enzyme, Rel, which both synthesizes and hydrolyzes the alarmone (p)ppGpp via two distinct catalytic domains. The balance between these antagonistic activities is fine-tuned to the needs of the cell and, in a "relaxed" state, the hydrolase activity of Rel dominates.

A Novel Lipid-Based MALDI-TOF Assay for the Rapid Detection of Colistin-Resistant Species.

species are classified as high-priority pathogens due to high prevalence of multidrug resistance from persistent antibiotic use. For infections caused by multidrug-resistant isolates, colistin (polymyxin E), a last-resort antibiotic, is a potential treatment option. Treatment with colistin has been shown to lead to emergence of polymyxin resistance.

Small Intestinal Levels of the Branched Short-Chain Fatty Acid Isovalerate Are Elevated during Infection with Heligmosomoides polygyrus and Can Promote Helminth Fecundity.

Heligmosomoides polygyrus is a helminth which naturally infects mice and is widely used as a laboratory model of chronic small intestinal helminth infection. While it is known that infection with alters the composition of the host's bacterial microbiota, the functional implications of this alteration are unclear. We investigated the impact of infection on short-chain fatty acid (SCFA) levels in the mouse intestine and sera.