Epidemiology of bacterial infection during management of open leg fractures

In a randomised double-blind trial conducted between 1990 and 1994, 616 pat ients from 43 centres, pefloxacin (group P, 316 patients) and a cefazolin-o xacillin combination (group C, 300 patients) were compared in the prophylax is of bone infection after grade 1 and 2 open leg fractures. Samples were o btained at emergency, before and during surgery, and from drain aspirates. Antimicrobial susceptibility, slime production and adherence properties of the bacteria were tested. Cultures at emergency and before surgery showed s imilar distributions of gram-positive and gram-negative bacteria in both gr oups, while wound closure and infecting isolates showed prevailing gram-pos itive bacteria in group P and gram-negative bacteria in group C. Positive c ultures at each stage were correlated with the occurrence of infection but were not predictive of the infecting species, which were nosocomial bacteri a in most cases. Positive cultures at wound closure warn of a higher infect ion risk. Twenty-one of 316 (6.6%) patients in group P and 24 of 300 (8%) i n group C were considered infected within 3 months. The difference is not s ignificant (chi-square test = 0.42; P=0.51). Infecting strains were isolate d from 38 patients (group P, 18; group C, 20). Infecting species,although n ot predictable, appear to be those escaping the spectrum of the prescribed antimicrobial prophylaxis.