Effects of ultrasonic specific energy on time-dependent inactivation rate of proteus mirabilis and streptococcus sanguinis

Abstract

Ultrasound has been used as an alternative and enhancer approach for the inhibition of microorganisms in recent years. The purpose of the current study was to determine the inactivation of Streptococcus sanguinis and Proteus mirabilis bacteria species via ultrasound. For this purpose, bacterial suspensions with 5x103, 1.5x104, and 3x104 colony forming unit (cfu/ml) concentrations were ultra-sonicated with 30 kHz frequency and 100 W power ultrasound for various sonication time periods. As a result, time-dependent inhibition rates were observed with bacteria concentration differences. The specific energy (γ) of different concentrations of S. sanguinis and P. mirabilis was also calculated. The rate constant of ultrasonic inhibition was evaluated in the linear region against sonication time. Then, the t-test was applied to all of the data. The results of 5x103, 1.5x104, and 3x104 cfu/ml for S. sanguinis and P. mirabilis were statistically significant at <p= 0.02, 0.02, 0.006 for S. sanguinis, and at <p=0.003, 0.004, 0.003 for P. mirabilis, respectively.