SLR - November 2009 - Catherine Hudson
Reference:
Galkowska, H., Podbielska, A., Olszewski, W.L., Stelmach, E., Luczak, M., Rosinski, G., Karnafel, W. (2009). Epidemiology and prevalence of methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis in patients with diabetic foot ulcers: Focus on the differences between species isolated from individuals with ischemic vs. neuropathic foot ulcers. Diabetes Research and Clinical Practice, 84(2), 187-193.
Scientific Literature Reviews
Reviewed by: Catherine Hudson, DPM
Residency Program: Central Alabama Veterans Health Care System
Podiatric Relevance:
This study analyzes the differences in the microbiological profile between a neuropathic diabetic foot ulcer vs. an ischemic diabetic foot ulcer. It also supports evidence for S. epidermidis to be recognized for its potential to become a nosocomial pathogen.
Methods:
Prospective study from June 2006-December 2007. 50 patients with Grade 3 ulceration based on Wagner classification were divided into 2 groups: Neuropathic foot ulcer, insensate to 10g Semmes-Weinstein monofilament and vibratory sensation with 128 Hz tuning fork, or Ischemic foot ulcer, ABI<0.9 and confirmed with arterial color doppler. There were no statistical significant differences between the two groups except ABI. Cultures were taken of the patient's toe web space, ulcer base and ulcer edge. Frequency of MRSA and MRSE strains from wounds were then compared to a control group of 20 healthy volunteers without diabetes.
Results:
S. epidermidis isolates from the toe web and ulcer base were increased in ischemic foot ulcers compared to neuropathic foot ulcers (P<0.05). MRSE strains were prevalent from cultures of the ulcer base, skin biopsy and toe web (80%, 100%, 91%, respectively). Differences between groups and analysis of proportions were confirmed with Student's t-test, chi-square test and Fisher's exact test.
Conclusions:
This study highlights S. epidermidis as a nosocomial pathogen in diabetic foot ulcers, particularly to ischemic tissues. Drug susceptibility of pathogens is essential in determining appropriate pharmacological therapy for treatment of diabetic foot ulcers. Further studies need to be conducted to distinguish the pathogenicity and virulence differences between S. aureus and S. epidermidis to conclude separate classifications are necessary.