A Comparison of Six Ultrasound Stimulation Types on Pseudomonas Aeruginosa Growth in Vitro

BACKGROUND: This work evaluated the efficiency of common ultrasound stimulation (U.S.S) types on bacterial growth in vitro using clinically relevant conditions. OBJECTIVE: To estimate different frequencies ultrasound bactericidal ability on bacteria in bacteria of Pseudomonas Aeruginosa. MATERIAL AND METHODS: Six types of U.S.S (continuous wave, 7w/cm(2), 20 KHz; continuous wave, 35w/0.8L, 40 KHz; continuous wave, 5w/cm(2), 1.1 MHz; pulsed wave, 5w/cm(2), 3.3 MHz; continuous wave, 5w/cm(2), 3.3 MHz and continuous wave, 0.5w/cm(2), 3.5 MHz) were applied to a separate set of culture plates containing Pseudomonas aeruginosa for 10 minutes at room temperature on four sample sets to inhibit bacterial growth. After US.S treatment, the zone of inhibition at the US probe location was measured. RESULTS: Zone of inhibition measurements demonstrated a significant inhibitory effect for continuous wave US.S of 5w/cm(2), 1.1 MHz; pulsed wave US.S of 5w/cm(2), 3.3 MHz; and continuous wave US.S of 5w/cm(2), 3.3 MHz (p < 0.05), but not for continuous wave US.S of 7w/cm(2), 20 KHz; continuous wave US.S of 35w/0.8L, 40 KHz; and continuous wave US.S of 0.5w/cm(2), 3.5 MHz. CONCLUSION: The data suggest that for infected wounds, continuous wave US.S of 5w/cm(2) and 1.1 MHz; pulsed wave US.S of 5w/cm(2) and 3.3 MHz; and continuous wave US.S of 5w/cm(2) and 3.3 MHz ultrasound treatments may have an initial bacterial inhibitory effect, which does not significantly change with subsequent treatments.