Resistance to Infection of Five Different Materials in a Rat Body Wall Model

Background. Infection occurs after approximately 1% of hernia repair procedures. The resistance to infection of the repair materials is therefore an important consideration. We evaluated the infection resistance of five different materials in a rat model of body wall repair, two of which, urinary bladder matrix (UBM-ECM) and Revive, were not previously evaluated in a controlled model of infection. Materials and Methods. An inoculum of 1 3 10 8 colony forming units of Staphylococcus aureus was delivered to the wound site following implantation of an autograft, UBM-ECM, Proceed, Prolene, or Revive. Infection was monitored by white blood cell counts, body temperature, bacterial culture, and histomorphologic analysis of the implant site. Results. Infection was shown in all groups through increased white blood cell count and body temperature. Animals with UBM-ECM returned to presurgery body temperature before all other groups. Substantial bacterial clearance was found in the autograft, UBM-ECM, and Prolene. Histomorphologic analysis showed evidence for persistent bacterial infection in Prolene, Proceed, and Revive 28 d after implantation, whereas the autograft and UBM-ECM appeared free of infection. The autograft showed a pyogranulomatous inflammatory reaction at 28 d while UBM-ECM was similar to uninfected controls. Conclusions. Superior infection resistance was shown by UBM-ECM compared with the other materials, which were substantially equivalent. Histomorphologic analysis clearly showed an increased ability to resist persistent bacterial infection for UBM-ECM. Ourresults suggest UBM-ECM may be useful as a repair material in areas of high risk for infection. (C) 2012 Elsevier Inc. All rights reserved.