title: Combination of therapeutic ultrasound with antibiotics interfere with the growth of bacterial culture that colonizes skin ulcers: An in-vitro study.
abstract: Staphylococcus aureus and Escherichia coli are among the major bacterial species that colonize skin ulcers. Therapeutic ultrasound (TUS) produces biophysical effects that are relevant to wound healing; however, its application over a contaminated injury is not evidence-based. The objective of this research was to analyze the effect of TUS on in vitro-isolated S. aureus and E. coli, including the combination of ultrasound and antibiotics, in order to assess their antibiotic action on bacterial susceptibility. For the experiments, the bacterial strains were suspended in saline, then diluted (10(4)CFU/mL) for irradiation (at 1 and 3MHz, 0.5 and 0.8W/cm(2) for 0 and 15min) and the combination treatment of ultrasonication and antibiotics was administered by adding nalidixic acid (S. aureus) and tetracycline (E. coli) at concentrations equivalent to 50% of the minimum inhibitory concentration (MIC). The experiments were carried out in duplicate with six repetitions. The suspensions were inoculated on to Petri plates and incubated at 37°C and the colony forming units (CFUs) were counted after 24h. The results were subjected to the Shapiro-Wilk normality test, followed by parametric ANOVA and Tukey's post hoc test at a significance level of 1%. The results demonstrated that the action of TUS at 1MHz inhibited bacterial growth while at 3MHz, bacterial growth was observed in both species. However, the synergistic combination of ultrasound and antibiotics was able to inhibit the growth of both bacteria completely after 15min of ultrasonication. The results suggest that the action of ultrasound on S. aureus and E. coli are dependent on the oscillation frequency as well as the intensity and time of application. The combination of ultrasound with antibiotics was able to inhibit bacterial growth fully at all frequencies and doses in both species.
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Laboratory of Physiotherapeutic Resources, Ribeirão Preto Medical School of University of São Paulo, Ribeirão Preto, SP, Brazil. Electronic address: ecguirro@fmrp.usp.br.
authors.forename: Elaine Caldeira de Oliveira
authors.initials: ECO
authors.lastname: Guirro
authors.affiliation: Department of Biochemistry and Microbiology, Institute of Biosciences of Rio Claro of Paulista State University, Rio Claro, SP, Brazil.
authors.forename: Dejanira de Franceschi de
authors.initials: DF
authors.lastname: Angelis
authors.affiliation: Post-Graduation Program in Rehabilitation and Performance Functional, Ribeirão Preto Medical School of University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Natanael Teixeira Alves de
authors.initials: NTA
authors.lastname: Sousa
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Laboratory of Physiotherapeutic Resources, Ribeirão Preto Medical School of University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Rinaldo Roberto de Jesus
authors.initials: RRJ
authors.lastname: Guirro
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D004926:Escherichia coli; D008826:Microbial Sensitivity Tests; D012883:Skin Ulcer / Q000401:mortality / Q000628:therapy*; D013211:Staphylococcus aureus; D014464:Ultrasonic Therapy
chemical_list: D000900:Anti-Bacterial Agents
keywords: Bacteria; Escherichia coli; Physical therapy; Staphylococcus aureus; Ultrasonic therapy