[Antibiotic prophylaxis in open fractures].

The administration of antibiotics is now generally accepted as a prophylactic treatment of infection in compound fractures. Nevertheless the question is not completely resolved and many problems are still to be discussed.The efficacy of antibiotherapy in this field has just been recently demonstrated ; with the animals by Worlock et al. (1988) using an experimental rabbit model, and clinically by Braul et al. (1987) which randomized 87 patients with open fractures to receive either cloxacillin or placebo. The rate of infection was significantly lower in the antibiotic group.No reports comparing various antimicrobial drugs draw effective conclusions regarding the choice of antibiotics. In the same way it seems that the time of interval from injury to antibiotic administration was not associated with a significantly different incidence of infection.The study of duration of the treatment was perfectly conducted by Dellinger. In his prospective trial 248 patients received different doses of the same antibiotic, from a single dose to four doses daily during 5 days. In conclusion he found no relation between the duration of the treatment and the risk of infection.A semantic but very important question concerns the reality of a preventive action of antibiotics against infection in open fractures. In order to answer, it is necessary to assess the incidence of contamination, its nature and its density.According to papers reporting the results of early cultures of the fracture wound, bacterial contamination was present in 30-70% of the cases. But the bacteria most commonly isolated were members of the normal skin flora (Staphylococcus epidermidis, Propionibacterium acnes, Corynebacterium sp. Micrococcus) or environmental contaminants which infrequently were the cause of infection.The specimens taken from patients who have an infection show mostly hospitalacquired bacteria as Staphylococcus aureus or Pseudomonas aeruginosa. These findings emphasize the risk of colonization of the wound by nosocomial bacteria.In addition, it seems that the density of contamination may also be a determinant of subsequent clinical infection. Quantitative bacterial counts suggest a greater risk of infection when microorganisms were present in high number more than 105 colony forming unit per g. of tissue.In conclusion, the prophylactic action of antibiotics against infection in open fractures is well established, but many points are still subject to discussion and need further study. Furthermore antibioprophylaxis is only a complement to surgical treatment, debridement and immobilization, which remains of paramount importance.