Objective: To study the efficacy of two different lasers in vitro, in disrupting biofilm and killing planktonic pathogenic bacteria.
Materials and Methods:
Biofilms of S. aureus Xen 31, a stable bioluminescent clinical MRSA construct, were grown in a 96 well microtiter plate for three days. The study included seven arms; a) control, b) ciprofloxacin (0.3 mg/L,) alone, c) SW laser alone, d) NIR laser alone e) SW laser and ciprofloxacin, f) SW and NIR lasers, g) SW, NIR lasers and ciprofloxacin. The results were evaluated with an IVIS biophotonic system (for live bacteria) and optical density (for total bacteria).
Results: With no antibiotics there was a 43% reduction in OD (P<0.05) caused by the combination of SW and NIR suggesting that biofilm had been disrupted. There was an 88% reduction (P<0.05) in live biofilm. Ciprofloxacin alone resulted in a decrease of 28% of total live cells (biofilm remaining attached and disrupted planktonic cells) and 58% of biofilm cells (both P>0.05). Ciprofloxacin in combination with SW and SW + NIR lasers caused a decrease of over 60% in total live biomass and over 80% of biofilm cells, which was significantly greater than ciprofloxacin alone (P<0.05).
Conclusions: SW and NIR
Laser combination is a powerful alternative for control or eradication of MRSA biofilms.