1952379

12657

Objectives: We investigated the effect of low-intensity pulsed sound waves delivered by the Exogen device, which is recommended for the treatment of delayed union and nonunion in orthopedic surgery, on the colony number, antimicrobial susceptibility, bacterial morphology, and genetics of Staphylococcus aureus, which is a frequent pathogen in orthopedic infections. Methods: Thirty tubes containing 0.5 McFarland suspen¬sions of S. aureus (ATCC 25923) were used. Fifteen tubes forming the test group were subjected to low-intensity sound waves by the Exogen device for 20 minutes. The remaining 15 tubes were untreated as controls. The two groups were then compared with respect to colony num¬ber, antibiotic susceptibility, and genotypic properties. The tubes were examined histologically by electron mi¬croscopy. Results: The test tubes treated with sound waves showed a significantly lower number of bacteria colonies compared to the control tubes (p<0.001). The two groups were simi¬lar with respect to antibiotic susceptibility and genotyp- ic properties. Bacterial cell wall structure in the control group was of normal appearance, whereas partial destruc¬tion and break-up were observed in test samples. Bacte¬rial cell wall thickness was significantly higher in the test group compared to the control group (41.54 nm and 24.27 nm, respectively; p<0.001). Conclusion: Low-intensity sound waves may be beneficial as a prophylactic measure to prevent infections in primary orthopedic operations and as an adjuvant therapy for in¬fected nonunions.

272

colony count , Microbial , genetics , Staphylococcus aureus , ultrasonic therapy , analysis , Bacteria

Studia Iranica

277

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