Investigating the antimicrobial potential of medically important glycosaminoglycans against Staphylococcus aureus

Abstract

Staphylococcus aureus is gram-positive cocci bacteria found in humans. It is the main cause of bacteriaemia leading to sepsis and also causes other infections in the skin and cardio and respiratory systems. S. aureus is responsible for the development of resistance to multiple classes of antibiotics, and some strains became resistant to alternative antibiotic treatments. Recently, researchers have paid more attention to the class of glycosaminoglycans (GAGs), such as heparin, since they have been successfully used as anticoagulants. GAGs have been shown to treat many diseases involved in tumours, Alzheimer’s disease and many infectious diseases. Here, three kind of polysaccharides were modified by sulphation as GAG analogues and heparin as neutrally sulphated GAGs, and the antimicrobial effect of these GAGs and heparin were investigated against S. aureus using the broth microdilution method to determinate any inhibition to the growth survival at 620 nm. The data were analysed using the independent samples t-test, assuming the equality of variance to measure the significance differences between the means of 100 percent survival and of each percentage of survival of each concentration in the total of four GAGs. Significance was taken at p≤0.05. Heparin provided the largest set of significance differences at the concentrations 1000, 3.9, 1.95, 0.5, 0.125, 0.0625, 0.0312, 0.0156, 0.0078, 0.0039, 0.0019 and 0.00097 µgml; second was sulphated Locust bean gum at concentrations 65.25, 28.125, 14.0625, 7.0312, 1.758 and 0.879 µgml; with sulphated carrageenan, inhibition was detected at the concentrations 137.5, 68.75, 34.375, 17.1875, 8.59 and 4.3 (µgml); sulphated ethyl cellulose showed the least significance differences in four concentrations, with inhibitions at 90, 45, 22.5 and 11.25 µgml.