Effects of sub-lethal concentrations of mupirocin on global transcription in Staphylococcus aureus 8325-4 and a model for escape from inhibition.

Effects of sub-lethal concentrations of mupirocin on global transcription in Staphylococcus aureus 8325-4 and a model for escape from inhibition. J Med Microbiol. 2016 May 16; Authors: AlHoufie ST, Foster HA Abstract Staphylococcus aureus is a major pathogen in both hospital and community settings causing infections ranging from mild skin and wound infections to life-threatening systemic illness. Gene expression changes due to the stringent response have been studied in Staphylococcus aureus using lethal concentrations of mupirocin but no studies have investigated the effects of sub-lethal concentrations. S. aureus 8325-4 was exposed to sub-inhibitory concentrations of mupirocin. The production of ppGpp was determined via HPLC and the effects on global transcription were studied by RNAseq analysis. Growth inhibition had occurred after 1 h of treatment and metabolic analysis revealed that the stringent response alarmone ppGpp was detected and GTP concentrations decreased. Transcriptome profiles showed that global transcriptional alterations were similar to those for S. aureus after treatment with lethal concentrations of mupirocin including the repression of genes involved in transcription, translation and replication machineries. Furthermore, up-regulation for genes involved in stress responses, amino acid biosynthesis and transport as well as for some virulence factor genes was observed. However, ppGpp was not detectable after 12 or...
Source: Journal of Medical Microbiology - Category: Microbiology Authors: Tags: J Med Microbiol Source Type: research