Anaerobic Conditions Induce Expression of Polysaccharide Intercellular Adhesin in Staphylococcus aureus and Staphylococcus epidermidis

Abstract

Products of the intercellular adhesion (ica) operon in Staphylococcus aureusand Staphylococcus epidermidis synthesize a linear ␤-1,6-linked glucosaminylglycan. This extracellular polysaccharide mediates bacterial cell-cell adhesion and is required for biofilm formation, which is thought to increase the virulence of both pathogens in association with prosthetic biomedical implants. The environmental signal(s) that triggers ica gene product and polysaccharide expression is unknown. Here we demonstrate that anaerobic in vitro growth conditions lead to increased polysaccharide expression in both S. aureus and S. epidermidis, although the regulation is less stringent in S. epidermidis. Anaerobiosis also dramatically stimulates ica-specific mRNA expression in ica-and polysaccharide-positive strains of both S. aureus and S. epidermidis. These data suggest a mechanism whereby ica gene expression and polysaccharide production may act as a virulence factor in an anaerobic environment in vivo.

Phosphorylation controls the functioning ofStaphylococcus aureusisocitrate dehydrogenase – favours biofilm formation

“…The results of the current study also explain unambiguously how IDH become completely inactive on phosphorylation with PknB and are restored upon dephosphorylation with alp III (Table 4). This shift in phosphorylation and dephosphorylation plays vital role in maintaining the redox status in S. aureus, which in turn has profound effect in the formation of biofilms 11,[15][16][17]35,36,38,39 ( Figure 3). …”

Staphylococcus aureus Biofilm Metabolism and the Influence of Arginine on Polysaccharide Intercellular Adhesin Synthesis, Biofilm Formation, and Pathogenesis

“…This is exemplified by increased expression of genes of the arginine deiminase and mixed acid fermentation pathways and pyruvate formate lyase. Support for the idea that staphylococci growing in a biofilm are growing microaerobically can be found in the observations that anaerobiosis increases biofilm formation and polysaccharide intercellular adhesin (PIA) synthesis (11,53).…”

“…As examples, S. aureus regulates the formation of biofilms in response to nutrient availability, oxygen tension, and a variety of stresses (11,21,25,33,43). Importantly, these observations highlight a recurrent regulatory theme in pathogenesis: environmental factors alter the metabolic status of the bacteria, resulting in an alteration of virulence (38) or, in this case, biofilm-forming capacity (6).…”

Characterization of inosine monophosphate dehydrogenase from Staphylococcus aureus ATCC12600 and its involvement in biofilm formation

“…Studies of Staphylococcus species, which normally inhabit the human oral cavity, suggest that the key purine metabolic gene, purL in the purine metabolic pathway plays an important role in the oral biofilm formation known as dental plaque. [35][36][37][38][39][40][41][42] Further evidence is also available suggesting that purine is usually combined with sugars to participate in the synthesis of the polysaccharide components of cell walls and capsules causing biofilm formation. 39 Therefore, it is reasonable to predict that biofilm formation is highly influenced by purine metabolism.…”