Authors: Holtom PD, Shinar Z, McPherson EJ, Patzakis MJ;
Title: The Antibiotic Properties of Porcine Small Intestine Submucosa
Address: LAC+USC Medical Center, 1200 N. State St., Room 3900, Los Angeles, CA 90033
Purpose: Porcine small intestine submucosa has been used for numerous applications ranging from bladder reconstruction to capsular knee replacements. Animal studies have suggested infection resistance in porcine SIS treated soft tissue repair when compared to non-resorbable extracellular matrices. These studies, along with a study suggested bactericidal activity when porcine SIS is digested with acetic acid, have lead to the hypothesis that there are inherent antibiotic properties in the porcine SIS.
Methods: Six porcine SIS patches and six gortex patches (controls) were prepared to 17/64-inch diameter discs. On each of 18 agar plates 3 antibiotic impregnated discs, one porcine SIS disc and one gortex disc were placed. Six organisms were then grown on 3 agar plates each. Zones of inhibition were measured after 24 hours of incubation. Minimum bacterial concentrations were determined by serial dilutions of a solution of 0.85% saline, in which 1cm2 discs of gortex and pig SIS were allowed to elute for 24 hours.
Results: No organism showed inhibition of growth by the porcine SIS or gortex discs. The porcine SIS discs showed bacterial growth on top of the discs, whereas the gortex did not show growth over their respective discs. Additionally, neither the dilutional concentrations of the porcine SIS eluent nor the gortex eluent inhibited the growth of any organism.
Discussion: The lack of a zone of inhibition suggests that the porcine SIS does not intrinsically have antimicrobial properties. The growth of bacteria on top of the SIS suggests that the SIS itself may provide a favorable environment for the growth of bacteria. More research is necessary to decide what role porcine SIS plays in post surgical infection rates.
Significance: Non-dissolved porcine SIS is not bactericidal or growth inhibiting in in-vitro grown Gram positive and Gram negative cultures.