Infection remains as one of the major complications associated with utilizing biomaterials. Surgical site infections account for approximately 14-16% of the 2.4-million nosocomial infections in the United States, with these infections resulting in increased patient morbidity and mortality. The inherent bulk properties of various biomaterials, including those that comprise sutures, provide a milieu for initial bacterial adhesion with subsequent biofilm production and growth. Once the pathogen(s) adheres to the biomaterial surface, treatment with antimicrobial agents is ineffective due to limited penetration of the agent through the bacterial biofilm. Thus, development of a novel infection-resistant suture would provide a localized bacteriocidal environment. In Phase I, Ciprofloxacin (Cipro), Linezolid and Doxycycline were successfully incorporated into nylon, silk and polyester (Dacron) suture materials using textile-dyeing techniques, resulting in infection- resistant suture materials with optimum antimicrobial properties while maintaining the physical properties of the materials. The goal of this Phase II is to evaluate these novel infection-resistant sutures in vivo using a wound infection model. Our hypothesis is that antibiotic-dyed sutures will release antibiotic in a slow, sustained fashion over a period of time as demonstrated in our Phase I in vitro studies, preventing bacterial infection at the suture surface as well as in the surrounding tissue. Current non-degradable suture materials do not possess these characteristics.
The specific aims of this study are to: 1) apply antibiotics to nylon, silk and Dacron sutures using dyeing parameters established in Phase I, 2) characterize the physical properties of antibiotic-dyed sutures, 3) determine antibiotic release and antimicrobial activity of antibiotic-dyed sutures using spectrophotometric and in vitro microbiological assays, 4) assess infection-resistance of antibiotic- dyed sutures using a wound infection model and 5) evaluate explanted sutures for localized healing as well as strength using histological and physical testing techniques, respectively. Based on the current infection rates in conjunction with the costs to treat these patients (an average $2,300/episode), surgical wound infection results in an annual cost to the healthcare system of greater than $5 billion. Thus, a significant market exists for application of our technology in order to prevent wound infection. ? ? ?
