Effect of ultrasonic microbubbles combined with gentamicin in the treatment of diabetic foot ulcer under low-frequency ultrasound / 中华超声影像学杂志

ABSTRACT

Objective:To investigate the effect of microbubbles combined with gentamicin on the clearance of bacterial biofilms and the healing of diabetic foot ulcers under low-frequency ultrasound.Methods:From July 2021 to June 2022, 27 patients with chronic diabetic foot ulcers complicated with infection were prospectively selected from the Trauma Center of the Second Affiliated Hospital of Chongqing Medical University. The patients were divided into low-frequency ultrasound + microbubbles + gentamicin ointment group, low-frequency ultrasound + microbubbles group, and gentamicin ointment group by using a random number table, with 9 patients in each group. The three groups were all treated with simple debridement by the same surgeon.Afterward, in the low-frequency ultrasound+ microbubbles+ gentamicin ointment group, the wounds covered by 4% microbubble suspension were firstly irradiated with low-intensity focused ultrasound for 5 min, and then evenly applied with gentamicin ointment. In the low-frequency ultrasound + microbubbles group, the wounds covered by 4% microbubble suspension were irradiated with low-intensity focused ultrasound for 5 min. The gentamicin ointment group was treated with gentamicin ointment evenly. The treatment lasted for 2 weeks, and secretions and tissue specimens were collected during and 2 weeks after the treatment, respectively. The general indexes of wound surface (including ulcer depth score, secretion exudation score, fresh granulation tissue growth score, and total index score), ulcer area, ulcer healing rate, as well as negative rate of secretion culture were compared among the three groups after treatment. Additionally, the structural changes in bacterial biofilms under a scanning electron microscope and colony count under a laser confocal scanning microscope were compared among the three groups after treatment.Results:No significant differences were found in the general datas among the three groups (all P>0.05). After treatment for 2 weeks, the overall general indexes showed statistically and significant differences among the three groups (all P<0.05). Each index score in the low-frequency ultrasound + microbubbles + gentamicin ointment group was lower than that in the low-frequency ultrasound + microbubbles group and the gentamicin ointment group (all P<0.05). There were no significant differences in overall ulcer area among the three groups ( P>0.05). The overall ulcer healing rate presented significant differences among the three groups ( P<0.05). The healing rate in the low-frequency ultrasound + microbubbles + gentamicin ointment group was higher than that in the low-frequency ultrasound + microbubbles group and the gentamicin ointment group (all P<0.05). The overall negative rates of secretion culture among the three groups were significantly different ( P<0.05), the negative rate in the low-frequency ultrasound + microbubbles + gentamicin ointment group was higher than that in the low-frequency ultrasound + microbubbles group and the gentamicin ointment group (all P<0.05). Scanning electron microscopy confirmed bacterial biofilm infection in the three groups before treatment. After treatment for 2 weeks, the biofilm formation in the low-frequency ultrasound + microbubbles + gentamicin ointment group reduced significantly, while the low-frequency ultrasound + microbubbles group and the gentamicin ointment group had little change compared with that before treatment. Significant differences were detected in total colony count among the three groups under the confocal microscope ( P<0.05). The colony count in the low-frequency ultrasound + microbubbles + gentamicin ointment group was lower than that in the low-frequency ultrasound + microbubbles group and the gentamicin ointment group (both P<0.05). Conclusions:Ultrasound microbubbles combined with gentamicin can clear bacterial biofilms and promote the healing of diabetic foot ulcers.