Effect Of Low Frequency Ultrasound Plus Fluorescent Composite Carrier In The Diagnosis And Treatment Of Methicillin-resistant Staphylococcus Aureus Biofilm Infection Of Bone Joint Implant

Objective: To study the effect of low frequency ultrasound targeted microbubble destruction(UTMD)on human beta-defensins-3(HBD-3)for two staphylococcus biofilm infection of implant from an animal experiment based on the primary mechanism.Methods: Biofilm-infected mouse model were used for this cohort research to study the treat effect of UTMD on HBD-3 for two staphylococcus biofilm infection.Ti sheet and staphylococcus were co-cultivated for 24 hours.After the formation of biofilm,they were placed on both sides of dorsal spine of mice subcutaneously.These mice were divided into 6 groups(8 mice for each group)according to the form of carrier,which were control group(Group A),ultrasound group(Group B),ultrasound targeted microbubble destruction group(Group C),HBD-3 group(Group D),ultrasound + HBD-3 group(Group E)and low frequency ultrasound targeted microbubble destruction + HBD-3 group(Group F).The remaining viable bacteria quantities in biofilm under different experimental treatment conditions were observed through confocal laser scanning microscopy and scanning electron microscopy.The relevant film-forming genes and drug resistant genes were analyzed quantitatively and statistically by real-time polymerase chain reaction.Results: Compared with other groups,the remaining viable bacteria percentage of Group F was significantly dropped,and the differences had statistical significance(P<0.05).The gene expression of Group F was higher than other groups,showing sta tistically significant differences(P<0.05).Conclusion: Low frequency ultrasound microbubble + HBD-3 can play a significant role on the elimination of staphylococcus in biofilm in vivo,and inhibit the further maturity of bio-film.Objective: To study the curative effect of low frequency ultrasound targeted radiation plus self-prepared human beta-defensins-3(HBD-3)lipidosome microbubble fluorescent composite carrier for methicillin-resistant Staphylococcus aureus(MRSA)biofilm infection of intra-articular implant from an animal experiment based on the primary mechanism of the long-lasting recurrence of intra-articular implant infection(bacterial biofilm and bacterial internalization).Methods: Ti sheet and MRSA were co-cultivated for 24 hours.After the formation of biofilm,they were placed on both sides of dorsal spine of mice subcutaneously.T hese mice were divided into 6 groups(6 mice for each group)according to the form of carrier,which were HBD-3 group(Group A),HBD-3 fluorescent liposome group(Group B),HBD-3 lipidosome-microbubble fluorescent composite carrier group(Group C),low frequency ultrasound + HBD-3 group(Group D),low frequency ultrasound + HBD-3 fluorescent liposome group(Group E)and low frequency ultrasound + HBD-3 lipidosome-microbubble fluorescent composite carrier group(Group F).The remaining viable bacteria quantities in biofilm under different experimental treatment conditions were observed through coated sheet count,laser scanning confocal microscope and electron microscope.The relevant film-forming genes and drug resistant genes were analyzed quantitatively and statistically by real-time PCR.Results: Compared with other groups,the remaining viable bacteria percentage of Group F was significantly dropped,and the differences had statistical significance(P<0.05).The gene expression of Group F was higher tha n other groups,showing statistically significant differences(P<0.05).Conclusion: Low frequency ultrasound + HBD-3 lipidosome microbubble fluorescent composite carrier can greatly enhance the killing effect of HBD-3 to drug resistant staphylococcus in biofilm and inhibit the further maturity of bio-film.It also can help to treat MRSA biofilm infection in femoral implant of rats,thus providing a new thought for the current antibiotic treatment of bone and joint infection,and increasing the diagnosis rate and cure rate of implant infection at early stage in bone joint.