ANTIMICROBIAL ACTIVITY OF COMMERCIAL INTEREST ALLOYS AGAINST Staphylococcus aureus

The most commonly used Ti-based alloy for production of prostheses and special medical/dental devices is Ti-4Al-4V alloy. However, recent studies have shown that these elements can be harmful when used in the long term, and the development of new materials is important. The promising alloys containing different wt% niobium (Nb), tantalum (Ta), zirconium (Zr) and molybdenum (Mo) have been investigated. All biomaterials have modulus of elasticity similar or close to bone, good mechanical strength and resistance to corrosion, but at the same time microorganisms colonize them. The main limiting factor for use biomaterials on implant are infections that don’t allow the material to remain in the body. Staphylococcus aureus is a largely disseminated pathogen in both intra- and interhospital environment and is often found colonizing healthcare professionals, hospital devices, and patients. This bacteria is commonly found in the form of biofilms, which are organized communities of a certain type of microorganism that adhere to an extracellular matrix, in order to increase its survival in the colonized place. Thus, the aim of this study was to evaluate the antimicrobial potential of new titanium alloys composed of niobium, zirconium and tantalum against Staphylococcus aureus MSSA (methicillin susceptible strains). The Staphylococcus aureus strain ATCC 25923 was tested with new Ti-based alloys: Ti-13Nb-13Zr and Ti-35Nb-7Zr-5Ta and a commercial type Ti-6Al-4V alloy. The antimicrobial activity was measured through a CFU (colony forming unit) analysis with the biofilm cultured for 24 hours in Mueller Hinton broth in 24 well plates, combined with alloys and with the control group, where there was only a bacterium and the culture medium, this test was done with different concentrations (dilutions of 105 to 108). The results varied from 25% to 84% inhibition rate, with the Ti-35Nb-7Zr-5Ta alloy having the highest inhibition rates ranging from 44% to 84%, showing to be a promising biomaterial. The Ti-13Nb-13Zr alloy had inhibition rate results ranging from 25% to 74% having a proximate result of the commercial alloy Ti-6Al-4V which obtained a result between 25% and 57%. With these results can be observed that the variation of elements associated with titanium may be a solution against microorganisms depending on the concentration and type.