A Comparative Study Of Bacteriology In The Infected Wounds Of Open Fractures Between The Management Of Vacuum Sealing Drainage And Traditional Dressing Change

Objective：With the quickened pace of social economy, the open fracturescaused by high-energy is becoming more and more common. The serioussoft tissue defect of open fractures brings great challenge to orthopedistsbesides debridement and fixation. The traditional method is dressing change.Grafts or flaps can be placed when the wound’s granulation tissue is out of theacute inflammatory phase. However, the dressing treatment should bechanged frequently because of the dressings are easy to be saturated and inwhich process the wound is exposed to the outside environment. It usuallyleads to nosocomial infection especially multi-resistant bacteria infectionwhich increases the difficulty of treatment and the period of healing,sometimes even results in serious complications with a permanent loss of limbfunction. Recently the introduction of VSD (vacuum sealing drainage)technology has greatly improved the treatment of open fractures with skin andsoft tissue defect. According to the reports in the literature, the VSDtechnology can reduce the incidence of wound infection, promote woundhealing, but does not prevent infection. As compared with conventionaldressing change, what will be the difference of the bacteriology in the infectedwounds? For this reason, we made a comparative study of bacteriology in theinfected wounds of121open fractures with the management of vacuumsealing drainage and traditional dressing change.Methods:1Case collection We collected121patients who had wound infection afteremergency surgery for open fractures from October2010to July2013.Theywere88males and33females. The range of age was4to75years old(averaging39.9years old). Causes: traffic accident78cases, be injured by a crashing object23cases, sharp instrument injury/cutting12cases, the other8cases. The interval from injury to admission ranged from1to16hours(averaging6hours).All patients were divided into2groups according to the methods ofwounds management following emergency surgery. VSD was used in group Aof60patients, while traditional dressing change in group B of61patients.According to the Gustilo Classification: Group A, typeⅢA,27cases（45.0%）;type ⅢB,21cases（35.0%）;typeⅢC,12cases（20.0%）.Group B,typeⅡ,8cases（13.1%）; typeⅢA,16cases（26.2%）;type ⅢB,24cases（39.3%）;typeⅢC,13cases（21.3%）.2Specimen collection The cephalosporin antibiotics of the first generationwas applied to all patients admitted to hospital before and after emergencydebridement surgery to prevent infection. Specimens were obtained when theVSD device was removed for5to7days in group A and when the wound wasinfected in group B. The bacterial culture and drug sensitive test resultssampled from the infected wound were compared between the two groups. Allthe patients’ wounds were placed with grafts or flaps be when the wound’sgranulation tissue was out of the inflammatory phase.3Bacterial culture and drug sensitive test All samples were sent to thehospital bacterial culture laboratory immediately. The drug sensitive tests wereanalyzed with the disc diffusion method (K-B method). The bacterial culturewas carried out in strict accordance with principles of the “National ClinicalLaboratory Procedures”. The laboratory environment quality was controlledby the standard strains of Staphylococcus aureus ATCC25923, Escherichiacoli ATCC25922, Pseudomonas aeruginosa ATCC27853.4Statistical analysis To sum up the bacterial species, calculate themulti-resistant bacterial infection rate and the main pathogenic bacterial’s drugresistant rate to commonly used antibiotics of the two groups. Have a chisquare test of the above information with the application of SPSS17.0statistical software. If P<0.05, the difference is statistically significant.Results: There are60strains,8kinds of pathogenic bacterial in group A and69strains,11kinds of bacterial in group B. The majority of pathogenicbacteria of the two groups were gram-negative bacteria (group A83.3%, groupB91.3%). Acinetobacter baumannii was the main pathogenic bacteria (groupA36.7%, group B9.34%). followed by pseudomonas aeruginosa (group A21.7%, group B21.7%). Gram-positive bacteria were relatively less (group A16.7%, group B8.7%). Group A has12multi-resistant bacteria strainsincluding10strains of acinetobacter baumannii (83.3%,10/12),1strain ofpseudomonas aeruginosa and1strain sewer enterobacter (8.3%,1/12). GroupB has42multi-resistant bacteria strains including34strains of acinetobacterbaumannii (80.92%,34/42),4strains of staphylococcus aureus (9.6%,4/42),2strains of E. coli (4.7%,2/42),1strain of pseudomonas aeruginosa and1strainof proteus ordinary (2.4%,1/42). The infection rate of multi-drug resistantbacteria (MDR) was20%in group A and60.8%in group B, respectively.There was significant statistical difference between the two groups (P<0.001).Acinetobacter baumannii accounted for a main proportion of multi-drugresistant bacteria (group A83.3%, group B80.9%). The drug resistance ofacinetobacter baumannii to cefoperazone sulbactam was relatively low (groupA9.1%, group B44.1%). There was significant statistical difference betweenthe two groups (P=0.005). The main pathogenic bacteria of the two groupswas drug resistant to commonly used antibiotics such aspenicillin,cephalosporins, quinolone and aminoglycoside.Conclusions: The majority of pathogenic bacteria of open fracturesare gram-negative bacteria. The main pathogenic bacteria were acinetobacterbaumannii.VSD technique can reduce the infection rate of multi-drugresistant bacteria of open fractures significantly. It is helpful to control thenosocomial infection and reduce the main pathogenic bacteria’s drugresistance to some antibiotics.