Involvement of Small Colony Variant-Related Heme Biosynthesis Genes in Staphylococcus aureus Persister Formation in vitro

Abstract

Background: Persisters are important reasons for persistent infections, and they can lead to antibiotic treatment failure in patients and consequently chronic infection. Staphylococcus aureus small colony variants (SCVs) have been shown to be related to persistent infection. Mutations in the genes of the heme biosynthesis pathway lead to the formation of SCVs. However, the relationship between heme production genes and persister has not been tested.Methods:HemA and hemB were knocked out by allelic replacement from S. aureus strain USA500 separately, and then, the heme deficiency was complemented by overexpression of related genes and the addition of hemin. The stress-related persister assay was conducted. RNA-sequencing was performed to find genes and pathways involved in heme-related persister formation, and relative genes and operons were further knocked out and overexpressed to confirm their role in each process.Results: We found that heme biosynthesis deficiency can lead to decreased persister. After complementing the corresponding genes or hemin, the persister levels could be restored. RNA-seq on knockout strains showed that various metabolic pathways were influenced, such as energy metabolism, amino acid metabolism, carbohydrate metabolism, and membrane transport. Overexpression of epiF and operon asp23 could restore USA500∆hemA persister formation under acid stress. Knocking out operon arc in USA500∆hemA could further reduce USA500∆hemA persister formation under acid and oxidative stress.Conclusion: Heme synthesis has a role in S. aureus persister formation.

Feasibility of Using Bacteriophage Therapy to Reduce Morbidity and Mortality Associated with Spinal Epidural Abscesses

“…In SEA, the high mortality, need for repeat debridement and long term sequalae, are consequences of S. aureus virulence and the inability of conventional antibiotics to quickly reduce bacterial concentrations in the epidural space. Furthermore, recurrence of SEA can occur even after prolonged antibiotic courses given the propensity of S. aureus to reside in metabolically reduced phenotypes that antibiotics have limited ability to eradicate [ 11 ]. Bacteriophages possess innate abilities to lyse planktonic S. aureus , self-replicate on their bacterial hosts and to infect metabolically reduced phenotypes.…”

Bacterial single-cell RNA sequencing captures biofilm transcriptional heterogeneity and differential responses to immune pressure

“…75 Upregulation of genes for arginine and lysine biosynthesis (argH and dapA), cysteine transport (tcyP), histidine metabolism (hutI), oligopeptide transport (opp-4D), and glutamate regulation (gltC) suggest reliance on amino acids for a range of cellular processes within biofilm since these genes are linked to nutrition, signaling, and virulence. [81][82][83][84][85][86][87] Further, nutrient limitation and stress were evident in biofilm by increased expression of genes for biotin synthesis (bioF), copper transport (copA), and urease (ureA) that is important for pH regulation within biofilm. 59,88,89 Increased RNase Y (rny/cvfA) levels were also seen in biofilm, which has been shown to tightly control mRNA expression for coordinated virulence gene activation.…”