Antimicrobial activity of CO2 and Er:YAG lasers against Staphylococcus aureus and Escherichia coli

The antimicrobial effect of CO2 and Erbium-doped yttrium aluminium garnet (Er:YAG) lasers against Escherichia coli, Staphylococcus aureus and a mixed culture of both organisms was assessed. Bacterial isolates were exposed to lasers utilising a range of parameters. Both lasers demonstrated a reduction in bacterial viability with increased number of passes and increased power. Against the individual bacterial cultures, the CO2 laser demonstrated greater a reduction in bacterial numbers with higher density and pulse durations. At a lower power and pulse duration, the CO2 laser demonstrated a complete reduction against combined bacterial species with increased passes. Use of the Er:YAG laser against the individual bacterial species demonstrated that the reduction in bacterial viability was increased with an increased overlap. The Er:YAG laser was the most effective at reducing the bacterial co-cultures and was influenced by the power, overlap and number of passes. Throughout this study, S. aureus was more difficult to eradicate than E. coli. The findings from this work showed promising antimicrobial effects of both the CO2 and Er:YAG lasers and demonstrates that the use of such instruments is one potential avenue to be explored to develop effective novel therapies to reduce bacterial viability in infections.