Antibacterial Efficacy Testing of Composite Materials

In a hospital environment when materials are used, they attract bacteria, which cause medical device associated infections. Therefore, it would be useful to prepare materials that will have antimicrobial properties. Two antimicrobial agents, one synthetic; Triclosan and one natural; Manuka oil were used in this study. The aim of this project was to compare the synthetic antimicrobial to the natural one and identify which one was more active against Gram-positive and Gram-negative bacteria; Staphylococcus (S.) aureus and Escherichia (E.) coli respectively. Zones of inhibition, minimum inhibitory and minimum bactericidal concentration (MIC) and (MBC) assays were used. Afterwards, the antimicrobials were formulated to biodegradable polymers, using Polycaprolactone (PCL). These polymers were tested against the same bacteria using the zone of inhibition testing together with the absorbance studies as well as Scanning Electron Microscopy (SEM). According to the findings, Triclosan was the most effective against S. aureus and E. coli. In addition to that, the Triclosan that was formulated into the PCL was still active against both bacterial strains. This indicates that there was release of Triclosan from the PCL, that was sufficient to cause a zone of inhibition. Finally, there was a lot of more S. aureus adhering on the PCL only compared to the PCL with Triclosan, as confirmed by absorbance and SEM studies.