Comparative transcriptional analysis of Staphylococcus epidermidis biofilm matrix variants in human platelet concentrates

This study is focused on understanding the molecular basis of protein- and polysaccharide intercellular adhesin (PIA)- mediated biofilm formation by S. epidermidis in PCs. Comparative transcriptomic analysis of S. epidermidis PIA- biofilm positive (AZ22, AZ39) and PIA+ biofilm positive (ST02) strains was performed using a RNAseq approach. Pathway enrichment analysis revealed cellular component GO term (AZ22), two KEGG pathways (AZ39), and two molecular function GO term and 8 KEGG pathways (ST02) were enriched. Remarkably, glutamate biosynthesis and tricarboxylic acid cycle (TCA) genes were upregulated in AZ22 and AZ39, respectively whereas arginine deiminase (ADI) pathway genes were downregulated in ST02. Moreover, genes conferring resistance against antimicrobial peptides (AMPs) and antibiotics such as lysostaphin, fusidic acid and tetracycline were upregulated, thus implying their increased resistance in S. epidermidis grown in PCs. Notably, expression of genes conferring resistance against aminoglycoside (in AZ22) and methicillin (in AZ39 and ST02) were downregulated. This study provided an overview, how biofilm-mediated virulence, antibiotic resistance and metabolic pathways are interlinked and reprogrammed during biofilm maturation in PCs which will be intriguing in development of novel preventive strategies against S. epidermidis transfusion-transmitted infections. Comparative transcriptomic analysis of S. epidermidis PIA- biofilm positive (AZ22, AZ39) and PIA+ biofilm positive (ST02) strain's mature biofilm formed in tryptic soya broth supplemented with 0.5% glucose (TSBg) and human platelet concentrates