The effects of magnesium, calcium and EDTA on slime production byStaphylococcus epidermidis strains

Abstract

Effect of magnesium, calcium and EDTA on slime production by 15 slime-positive and 13 slime-negative Staphylococcus epidermidis strains isolated from various clinical specimens was determined. The slime production on tryptic soy broth was significantly enhanced after addition of 128 mumol/L Mg2+. Similarly, the addition of Ca2+ caused a significant increase in slime production of all tested strains when concentration of Ca2+ exceeded 64 mumol/L. In contrast, in the presence of EDTA the slime production by all strains was significantly reduced. Hence Ca2+ and Mg2+ increase slime production of S. epidermidis. This finding is important in the context of the pathogenesis of biomedical implant infections caused by S. epidermidis.

Role of ethylene diamine tetra-acetic acid (EDTA) in catheter lock solutions: EDTA enhances the antifungal activity of amphotericin B lipid complex against Candida embedded in biofilm

“…Also, EDTA in combination with an antibiotic has been shown to have antifungal activity against Candida in its free-floating planktonic or biofilm state after a dwell time of 24 h [12]. Furthermore, whilst heparin has been shown to enhance biofilm formation, EDTA disrupts microbial biofilm through its chelation of calcium, magnesium and iron, which are essential components of the biofilm matrix [11,13,[33][34][35][36]. Hence, EDTA is a more appropriate anticoagulant and antimicrobial catheter lock than heparin [11].…”

Guidelines for the Prevention of Intravascular Catheter–Related Infections

“…Furthermore, adherence is enhanced through the production by microbial organisms, such as coagulase negative staphylococci [227,228], S. aureus [229], Pseudomonas aeruginosa [230], and Candida species [231] of an extracellular polymeric substance (EPS) consisting mostly of an exopolysaccharide that forms a microbial biofilm layer [218,232]. This biofilm matrix is enriched by divalent metallic cations, such as calcium, magnesium and iron, which make it a solid enclave in which microbial organisms can embed themselves [233][234][235]. Such a biofilm potentiates the pathogenicity of various microbes by allowing them to withstand host defense mechanisms (e.g., acting as a barrier to engulfment and killing by polymorphonuclear leukocytes) or by making them less susceptible to antimicrobial agents (e.g., forming a matrix that binds antimicrobials before their contact with the organism cell wall or providing for a population of metabolically quiescent, antimicrobial tolerant ''persister'' cells) [228,236,237].…”

Evaluation of Yeast Isolates as Indicators for Measurement of Bioavailable Cadmium

“…K9 and K11 showed colony colors ranging from red to dark red, indicating that they were the non-biofilm producers [9]. The cations can promote the biofilm formation by facilitating exopolysaccharide polymerization in Staphylococcus epidermidis [10]. The colony color modification of yeast was observed on Congo red when added with Cd suggests that at higher concentration, Cd may have the effects on growth and induction of biofilm formation.…”