We studied 119 bacterial strains isolated from postoperative infected wounds. All these strains were considered to be strains that derived from the same number of nosocomial infections, all the postoperative infections of the wounds being nosocomial infections. Regarding their frequency, we isolated the following strains: E. coli--68 strains (57%), S. aureus--37 strains (31%), Pseudomonas spp.--9 strains (8%) and Proteus spp.--5 strains (4%). We performed the bacteriological study of these strains and some correlations between them and the surgical diagnosis. In order to help the surgical therapy of the overinfected wounds, we tested the drug sensitivity of all these strains. The results regarding the drug sensitivity show that these strains have different types of resistance to antibiotics, the Pseudomonas strains being the most resistant. We noticed a continuous decrease of the sensitivity of the isolated strains to certain antimicrobial drugs, and this focuses the attention on the necessity of monitoring the antibiotic prescriptions in hospitals. Taking into account the results obtained after this study, we should reconsider the concept of nosocomial infections control through prevention activities, in order to reduce the incidence and to identify the potential causes that can lead to nosocomial infections.