Comparative antibacterial study between bioactive glasses and vancomycin hydrochloride against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa

Abstract

Background This work targets the comparison of the antibacterial activity of different bioactive glasses as particles and those coating the surface of 316 l stainless steel sheet, with that of vancomycin hydrochloride antibiotic, to determine the best efficiency of the aforementioned materials for medical and surgical purposes. Materials and methods Different bioactive glass composites (borate, B, S, and B5), composed of different ratios of oxides, such as SiO2, Na2O, CaO, B2O3, P2O5, and MgO, were prepared. The antimicrobial activity of different synthesized glasses as well as vancomycin hydrochloride antibiotic was carried out against various Gram-negative and Gram-positive pathogens. The different bioactive glasses (0.05 g) were placed each in wells (1 cm in diameter) of pathogen-seeded nutrient agar, as particles or coated on 316 l stainless steel 1.0×1.5 cm sheets for agar diffusion method. The antibacterial test of vancomycin hydrochloride in different concentrations (25, 50, 75, and 100 mg/ml in distilled H2O) was carried out. The pathogen cell viability in presence and absence of glass composite was investigated using electron microscopy and cell count method. Nutrient broth (50 ml) was inoculated with Staphylococcus aureus along with 0.05 g of borate particles, incubated at 37°C and 150 rpm for 6 h. Then, the samples were examined under electron microscope, and the final pH was measured. A volume of 0.1 ml of each sample was further inoculated on solid nutrient agar, incubated at 37°C for 24 h, and then colony count was carried out. Results and discussion The borate bioactive glass was effective either as particles or coated on 316 l stainless steel. The other types of bioactive glasses coating the stainless steel produced a better antibacterial activity than the particles. The transmission electron microscope, showed the damaged bacterial cells of S. aureus after incubation with borate bioactive glass. The colony count of S. aureus after bioglass treatment was 18×102, whereas in the control sample was 25×106; the final pH was 10.4.