Bacterial skin contamination before and after surgical preparation of the foot, ankle, and lower leg in patients with diabetes and intact skin versus patients with diabetes and ulceration: a prospective controlled therapeutic study

Abstract

Eradication of bacterial flora from the foot, especially the nailfolds and toe webspaces, through surgical preparation remains a challenge. All previous studies have involved healthy patients undergoing elective foot and ankle surgery or healthy volunteers. However, the patient with diabetes is considered an immunocompromised host with decreased ability to combat invasive bacterial infections. The use of an efficacious surgical preparation is therefore of paramount importance. The author conducted a prospective study involving patients with diabetes with and without ulceration who underwent the current "best evidence available" surgical preparation (i.e., chlorhexidine gluconate [4%] scrub followed by alcohol impregnated with iodine [1%] solution). Qualitative aerobic cultures before and after completion of this surgical preparation technique were obtained from the hallux nailfold; second, third, and fourth toe webspaces (as one culture); and distal anterior tibia. A total of 120 organisms were cultured before surgical preparation with 64 in the elective group and 56 in the ulcerated group. The most commonly isolated organism was methicillin-resistant Staphylococcus epidermidis, which was identified in 46 pre-preparation cultures (38.3%). This was followed by methicillin-sensitive S. epidermidis (16.7%) and "other" organisms (10.0%). There was a significant reduction for both numbers of organisms identified and positive cultures for the 3 most commonly isolated organisms after surgical preparation. Based on the results of this study, the surgical preparation used here appears to be an efficacious surgical preparation technique for eradicating aerobic bacterial pathogens from the foot in patients with diabetes both with and without ulceration. The high incidence of methicillin-sensitive and methicillin-resistant S. epidermidis found in this patient population is a cause for concern, especially when metallic fixation is intended to be implanted.