| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5144784 | Ultrasonics Sonochemistry | 2017 | 8 Pages |
•Low-intensity ultrasound increases the permeability of M. smegmatis.•Thermal effect didn’t provide the basis for bacterial deformation during sonication.•Ultrasound augments antibacterial action of levofloxacin on M. smegmatis.
Tuberculosis is an infectious disease caused by the bacterium M. tuberculosis. The aim of this study was to investigate the bactericidal effect and underlying mechanisms of low-frequency and low-intensity ultrasound combined with levofloxacin treatment against M. smegmatis (a surrogate of M. tuberculosis). As part of this study, M. smegmatis was continuously irradiated with low frequency ultrasound (42 kHz) using several different doses whereby both intensity (0.138, 0.190 and 0.329 W/cm2) and exposure time (5, 15 and 20 min) were varied. Flow cytometric analyses revealed that the permeability of M. smegmatis increased following ultrasound exposure. The survival rate, structure and morphology of bacteria in the lower-dose (ISATA = 0.138 W/cm2 for 5 min) ultrasound group displayed no significant differences upon comparison with the untreated group. However, the survival rate of bacteria was significantly reduced and the bacterial structure was damaged in the higher-dose (ISATA = 0.329 W/cm2 for 20 min) ultrasound group. Ultrasound irradiation (0.138 W/cm2) was subsequently applied to M. smegmatis in combination with levofloxacin treatment for 5 min. The results demonstrated that the bactericidal effect of ultrasonic irradiation combined with levofloxacin is higher compared to ultrasound alone or levofloxacin alone.
