Negative Pressure Wound Therapy Reduced The Infection Of Pseudomonas Aeruginosa In Burn Wound

BackgroundBurn wound infection has been reported to be the main reason of thewound sepsis which is the major cause of death in the late severe burnedpatients. Pseudomonas aeruginosa (PA) is one of the most common burn woundinfection bacterial. PA colonizes and proliferates within burn wound，and thislocalized proliferation may lead to the sepsis which has greatly increasedmortality. In recent years, the detection rate of PA and it’s multidrug-resistantrate in the burn ICU increased year by year, so that brought a great challenge toantibiotic therapy. Therefore, anti-infected dressings or vacuum-assisted closuretherapy were used to treat infected wound. A wide variety of anti-infectivedressings have their advantages and disadvantages, and themselves indications.Many datas show NPWT can reduce the local tissue edema, and increaserecord weeks blood flow, and remove wound bacteria and promote formation ofgranulation tissue and accelerate wound healing. NPWT were used in a varietyof complex wound management, but it has not yet to be studied that NPWT mayexist biological effects for treatment in infected burn wound. To this end, we verified the NPWT scavenging effects on wound bacteria in full thickness skininfected defect wound at first, and observed the infiltration of inflammatorycells around the wound edge, and tested the PA-Lux which was marked bybacterial luciferase stability of fluorescence expression. On this basis, weestablished a Pseudomonas aeruginosa infected burn-wounds mouse model, andobserved the bacterial diffusion, and the mice mortality, the levels of seruminflammatory factors, and major organ damage, studied the clinical significanceand associated biological of NPWT was used in early stage of infected burnwoundMethods1. Forty male C57mice were randomly divided into treatment and controlgroups. Full-thickness skin defects infected model was established. NPWTtreatment was used in treatment group, and the conventional vaseline gauzedressing was used in control group24hours after infection. The fluorescenceexpression level of the marked bacteria was observed on the wound. Thewound bacterial culture and counting were done. The inflammatory cellswere observed in the edge of skin tissue by HE staining at24hours aftertreatment.2. Fifty male C57mice were randomly divided into burn infection group andthe sham burn infection group. The burn infection group was caused theanimal back third degree burns, after that a certain concentration of PAbacteria was injected under burn eschar and caused a burn wound infectionmodel. The back of sham burn infection group was contacted in water vaporat room temperature atomization, and a certain concentration of PA bacteria was injected under the burn subcutaneous. Seventh day of the experimentwas determined the end of the experiment time. The labeled bacteriaproliferation and dispersion were real-time dynamic observed on the woundby IVIS and7days of mortality was recorded and, the positive rate of PA inthe spleen was detected at24hours after the modeling.3. Ninety male C57mice were randomly divided into treatment and controlgroups, the beginning of the experiment to establish the model of burnwound infection24hours before the day of the experimental removal ofburn eschar, the treatment group underwent NPWT treatment control group,conventional vaseline gauze change drugs. Seven days of the experiment forthe end of the experiment time. Observed during the wound labeled bacteriareproduce and spread, mortality at7days, the level of inflammatory factors,HE staining to observe the damage of major organs.Results1. An infected wound early use of NPWT can significantly reduce the bacteriacontent of wound marker (P <0.01), a margin of tissue infiltration ofinflammatory factors treatment group was significantly less than the controlgroup (P <0.05).2. burn group labeled bacteria fluorescence was significantly higher than thatof the sham burn group (P <0.01), fluorescence expression range comparedwith the sham burn group;7days cumulative mortality in burns weresignificantly higher than that of the sham burn group (P <0.01,83.3%vs8.3%);24hours after injury, spleen bacterial cultures of burn group was100%, the detected bacteria are PA. 3. Experiment on the third day, compared with the control group, NPWT canbe significantly reduced labeled bacteria in the wound tissue content (P<0.01), reduce the level of serum pro-inflammatory factors (P <0.01).7daysanimals of the untreated group, NPWT group compared to the modelingcumulative mortality was significantly reduced (P <0.01), but the mortalityrate compared with the control group no significant differences. The mainorgan histological observation NPWT group less organ damage.Conclusions1. The experiments showed that infected wounds using NPWT, an early stagecan effectively reduce the wound bacterial content, and reduce theinfiltration of inflammatory cells Chong tissues, thereby reducing theinflammatory response of the wound edge.2. Experiments using fluorescently labeled PA to establish a mouse woundsepsis model, easy to experimental observation and repeatability. The modelcan also be used in the experiment as a model of other related topics.3. This study shows that NPWT for Pseudomonas aeruginosa infection of burnwounds can quickly reduce the wound bacterial content, reducing the levelof systemic inflammatory response, reduce organ damage and reduce theincidence of wound sepsis and mortality.