ABSTRACT
BACKGROUND. Silk and cotton sutures are the most commonly used materials for skin closure, the choice being largely based on tradition. We undertook this study to compare the bacterial adherence in vitro to these two materials because it is well known that the physicochemical characteristics of a suture material influence its ability to attract bacteria and consequently promote wound infection. METHODS. We determined the bacterial adherence in vitro to cotton and silk for Staphylococcus aureus and Escherichia coli, common organisms found in postoperative infection at our institute, using three inoculum strengths. The sutures were incubated with the organisms and bacterial counts per suture material calculated after 20, 60, 120 and 180 hours of incubation. The bacterial counts for the sutures were then compared at these intervals. RESULTS. The bacterial adherence for both organisms at all time intervals was significantly greater to silk than to cotton, except at 60 hours for Staphylococcus aureus. The bacterial count for each suture material appeared to be an intrinsic property of the suture and did not vary with the concentration of the bacteria in the initial inoculum. The cost of an equivalent thickness of silk is 50 times that of cotton. CONCLUSION. We suggest that cotton should be the preferred suture for skin closure because bacterial adherence to it is lower and it is much cheaper than silk.