Chronic wounds are defined as "hard-to-heal" wounds that are caused by disordered mechanisms of wound healing. Chronic wounds have a high risk of infection and can form biofilms, leading to the release of planktonic bacteria, which causes persistent infections locally or remotely. Therefore, infection control and removal of the biofilm in chronic wounds are essential. Recently, ultrasonic debridement was introduced as a new method to reduce infection and promote the healing of chronic wounds. This scoping review aimed to evaluate the effectiveness of ultrasonic debridement on the changes in bacteria and biofilms, and consequently the wound healing rate of chronic wounds. A total of 1021 articles were identified through the database search, and nine papers were eligible for inclusion. Findings suggest that non-contact devices are useful for wound healing as they reduce the inflammatory response, although the bacterial load is not significantly changed. Ultrasonic debridement devices that require direct contact with the wound promote wound healing through reduction of biofilm or bacterial load. The optimum settings for ultrasonic debridement using a non-contact device are relatively consistent, but the settings for devices that require direct contact are diverse. Further studies on ultrasonic debridement in chronic wounds are required. K E Y W O R D S foot ulcer, leg ulcer, pressure ulcer, ultrasound, wound healing 1 | INTRODUCTION Chronic wounds occur as a result of disordered mechanisms of wound healing, 1,2 and include pressure ulcers, diabetic foot ulcers (DFUs), venous leg ulcers (VLUs), and arterial ulcers. Chronic wounds are experienced by 1% to 2% of the population in developed countries, and as many as 4.5 million people are estimated to suffer from chronic wounds in the US. 3,4 Recently, a meta-analysis showed a pooled prevalence of 2.21 per 1000 individuals for chronic wounds of mixed etiologies and an estimated prevalence of 1.51 per 1000 individuals for chronic leg ulcers. 5 As chronic wounds are a high-risk factor for infections, 6 which increases the probability of limb

All open wounds are often colonized by commensal microbes as a loss of skin can provide a ready portal of entry for microorganisms. Although the wound microbiota is known to be associated with wound infection and with delayed healing, the factors related to the formations of wound microbiota contributing to such poor clinical outcomes are not clear and have not led to effective infection prevention interventions. This review aimed to scope the factors related to the composition and diversity of wound microbiota that have been investigated using culture-independent molecular methods. Original articles on wound microbiota published from January 1986 to February 2020 were included in this review. Thirty-one articles met the inclusion criteria and were grouped according to wound types: chronic, acute, and animal model wounds. The factors identified were categorized according to patient characteristics, wound characteristics, treatment, and sampling. Although some studies reported the effect size of the factors, the values were small. No studies elucidated the mechanism of wound microbiota formation. The results of this scoping review highlight that the factors associated with the diversity of wound microbiota are poorly understood and that further studies are needed.

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