1995 William J. Stickel Bronze Award. Prevalence of mixed infections in the diabetic pedal wound. A retrospective review of 112 infections

Abstract

This retrospective study reviewed the culture results of 112 admissions to a multidisciplinary diabetic foot care team with a primary diagnosis of infected diabetic pedal ulceration. An average of 1.5 +/- 0.9 species per patient (P < 0.0001) were isolated. Eighty-nine percent of wounds cultured grew two or fewer organisms. Anaerobic species were isolated in only 5% of all cultures. Of these isolates, the distinction between anaerobic colonization and true anaerobic infection is made. Results suggest that aggressive early hospitalization, coupled with aggressive intraoperative debridement, may yield less microbiologically complex infections that may be controlled with less expensive narrow spectrum antibiotic therapy. Diagnosis of the infected pedal ulceration of a patient with diabetes is a clinical one. If this diagnosis is combined with appropriate surgical intervention, microbiologic correlation, and antimicrobial therapy, the result may be a less complex hospital course and improved outcome.

Bacteriology of Moderate-to-Severe Diabetic Foot Infections and In Vitro Activity of Antimicrobial Agents

“…Some have found that tissue specimens are more sensitive and specific, containing fewer apparent contaminants and more pathogens than swab cultures (2,7,14,18,34,36,46). Others have reported that with adequate preliminary debridement, the use of a wound swab is as reliable as the use of a tissue specimen, at least for initial monitoring (5,41,45,48).…”

“…The role of anaerobes is particularly unclear, because in many studies specimens were not collected or cultured properly to recover these organisms. Among those that did use appropriate methods, some report that anaerobes play a minimal role (2,7,15,21,46), while others suggest that Bacteroides fragilis is the predominant anaerobe isolated (1,3,17,57).…”

“…The role of anaerobes is particularly unclear, because in many studies specimens were not collected or cultured properly to recover these organisms. Among those that did use appropriate methods, some report that anaerobes play a minimal role (2,7,15,21,46), while others suggest that Bacteroides fragilis is the predominant anaerobe isolated (1,3,17,57).These discrepancies could be partly due to differences in the causative organisms occurring over time, geographical variations, or the types and severity of infection included in the studies (1,20,47,51). In addition, some studies used a relatively small number of specimens, failed to report recent or concomitant antibiotic therapy, did not ensure that the specimen collection techniques would exclude superficial or colonizing organisms, or even make clear whether or not the wound was clinically infected.…”

Wound Microbiology and Associated Approaches to Wound Management

“…Plantar ulcers associated with diabetes mellitus are susceptible to infection due to the high incidence of mixed wound microflora (62) and the inability of the PMNs to deal with invading microorganisms effectively (8). However, with optimal treatment involving debridement of devitalized tissue, the use of appropriate dressings, and pressure relief, wound infection can be minimized.…”

“…As in most wound types, S. aureus is a prevalent isolate in diabetic foot ulcers, together with other aerobes including S. epidermidis, Streptococcus spp., P. aeruginosa, Enterococcus spp., and coliform bacteria (8,121,185). With good microbiological techniques, anaerobes have been isolated from up to 95% of diabetic wounds (78), the predominant isolates being Peptostreptococcus, Bacteroides, and Prevotella spp.…”