Infection

Recommendations

Identify and Treat the Cause
1 Take a careful history (general history, diabetic control and complications). Level of Evidence
Not Assessed
2 Conduct a foot inspection and examine for decreased sensation. Correct (if possible) risk factors for ulcer formation/amputation:§ Vascular supply§ Infection§ Pressure (including bony deformity)Remember the mnemonic VIP Level of Evidence
Not Assessed
3 It is critical that clinicians are able to recognize the clinical signs of superficial and deep infection in diabetic foot ulcers, as culture is an unreliable indicator of infection. Level of Evidence
Not Assessed
4 Culture infected diabetic foot ulcers to determine the predominant organisms and guide selection of antibiotic therapy. Level of Evidence
Not Assessed
5 Perform blood cultures if sepsis is suspected. Level of Evidence
Not Assessed
6 Laboratory tests may be used to support clinical findings of infection. Level of Evidence
Not Assessed
7 Imaging studies may be used to detect bone involvement and to confirm the diagnosis. Level of Evidence
Not Assessed


Address patient-centered Concerns
8 Provide individualized education to enhance Glycemic control, Adherence to treatment, Plantar pressure redistribution/daily foot inspection. (GAP) Level of Evidence
Not Assessed


Provide Local Wound Care
9 Optimize wound healing environment through Debridement, Infection (bacterial burden control) and Moisture balance. (DIM) Level of Evidence
Not Assessed


Provide Organizational Support
10 Establish and empower an interprofessional team to work with Persons With Diabetes (PWD). Level of Evidence
Not Assessed


Background

Infection is frequently associated with the diabetic foot. Undetected small erosions may become infected and develop into local cellulitis or lymphadentitis. Loss of protective sensation makes a daily foot examination critical for early detection of infection. One study found a handheld infrared skin temperature monitoring device for home use to be effective in identifying early warning signs of inflammation and tissue injury. Patients not using the device had more than ten times the foot complication rate of patients using the device.

All skin ulcers are contaminated with bacteria, and more than three bacterial species are usually found in chronic wounds. As a result, swabbing and culturing an infected wound does not reliably identify causative organisms. Microbial flora in a chronic wound change predictably over time. Over the first few days, only cutaneous flora are found in the wound. From 1 to 4 weeks, these flora are accompanied by Gram-positive aerobic cocci, often beta-hemolytic Streptococci and Staphylococcus aureus. A purulent discharge may be present. After 4 weeks, cutaneous flora are accompanied by Gram-negative facultative anaerobic bacteria, especially coliforms, anaerobes and Psuedomonas. Tissue necrosis, undermining and deep tissue involvement may be seen clinically.

The signs of chronic infection differ from those associated with acute infection. Changes in odour, colour, tissue quality and exudate are seen in infected diabetic wounds. Validated signs and symptoms of chronic wound infection include the following:
· Increased pain (100% specificity)
· Wound breakdown (100% specificity)
· Foul odour (85% specificity)
· Friable granulation tissue (76% specificity).

Deep tissue infection often results in warmth and erythema extending 2 cm beyond the wound margin. It is necessary to probe undermined wounds and those with sinus tracts, as contact with bone or ligaments indicates osteomyelitis. Signs of deep or systemic infection indicate a potentially limb-threatening or life-threatening situation, which demands immediate attention.

Wound cultures, although not diagnostic for infection, can provide information about predominant flora to guide antibiotic selection for treatment of non-healing or deteriorating wounds with heavy exudate. Blood culture is appropriate if sepsis is suspected. Levels of C-reactive protein tend to increase in severe infection. A white blood cell count and erythrocyte sedimentation rate may indicate sepsis, but normal values do not rule out infection. Radiography is a useful initial investigation to detect osteomyelitis, gas, foreign bodies and bony abnormalities. Bone destruction takes 10 to 21 days to be apparent after infection. Gallium scanning, computed tomography, and magnetic resonance imaging may be ordered to detect infection not evident on plain films or to confirm the diagnosis.

References

Essential Publications
1 Infection Quality Indicator
 Type: CPG (Clinical Practice Guideline)
Lipsky BA. A report from the international consensus on diagnosing and treating the infected diabetic foot. Diabetes/Metabolism Research and Reviews 2004; 20(Suppl 1): S68-S77.
This CPG is specifically concerned with guiding the treatment of infections. There are approximately 20 recommendations, of which 4 are based on level I evidence and 6 are based on level II-III, the rest are III to IV.
2 Infection Quality Indicator
 Type: Systematic review
Nelson EA, O’Meara S, Craig D, Iglesias C, Golder S, Dalton J, et al. A series of systematic reviews to inform a decision analysis for sampling and treating infected diabetic foot ulcers. Health Technol Assess 2006;10(12).
This very well conducted systematic review that indicated that infection in DFUs cannot be reliably identified using clinical assessment and provided no strong evidence for recommending any particular antimicrobial agents for the prevention of amputation, resolution of infection or ulcer healing.
3 Diagnosis of Infection Quality Indicator
 Type: Systematic review
O’Meara S et al.. Systematic reviews of methods to diagnose infection in foot ulcers in diabetes.. Diabet. Med. 23, 341–347 (2006)
This systematic review of cross sectional studies was conducted to explore the diagnostic performance of clinical examination, sample acquisition and sample analysis in infected foot ulcers in diabetes. The study is important for demonstrating that the evidence is weak. Thus, we are encouraged to determine better methods of diagnosing infection in foot ulceration in people with diabetes.
4 Infection risk factors Quality Indicator
 Type: RCT
Lavery LA, Armstrong DG, Wunderlich RP, Mohler MJ, Wendel CS, Lipsky BA. Risk factors for foot infections in individuals with diabetes. Diabetes Care 2006;29:1288-1293.
Over a 2 year period, 1666 consecutive patients with diabetes were had a standardized general medical examination, a detailed foot exam and received education for proper foot care. The following independent variables (risk ratios) were found by multivariate analysis to be risk factors for foot infections: wound depth to bone (6.7), wound duration > 30 days (4.7), recurrent foot wound (2.4), traumatic wound etiology (2.4), and peripheral vascular disease (1.9). This paper will be useful to clinicians who need to know the characteristics of patients who are likely to develop infections.
5 Ischemia and infection in patients with diabetic foot disease Quality Indicator
 Type: Narrative Review
Prompers L, Huijberts M, Apelqvist J, Jude E, Piaggesi A, Bakker K, Edmonds M, Holstein P, Jirkovska A, Mauricio D, Ragnarson Tennvall G, Reike H, Spraul M, Uccioli L, Urbancic V, Van Acker K, van Baal J, van Merode F, Schaper N. High prevalence of ischaemia, infection and serious comorbidity in patients with diabetic foot disease in Europe. Baseline results from the Eurodiale study. Diabetologia. 2007 Jan;50(1):18-25. Epub 2006 Nov 9.
This publication demonstrates that severity of diabetic foot ulcers at presentation is greater than previously reported. It also demonstrated that serious comorbidities are associated with increasing severity of foot disease. Finally, the study underscores the need for future research to examine clinical outcomes.
6 Surgical versus antimicrobial Treatment for Osteomyelitis Quality Indicator
 Type: Narrative Review
Jeffcoate WJ, Lipsky BA. Controversies in diagnosing and managing osteomyelitis of the foot in diabetes. Clin Infect Dis. 2004 Aug 1;39 Suppl 2:S115-22.
This publication compares surgical and antimicrobial treatment strategies in the management of osteomyelitis. It presents the benefits and shortcomings of each approach, and concludes that both are viable and important treatment strategies for osteomyelitis.
7 Non-surgical osteomyelitis management Quality Indicator
 Type: Narrative Review
Game FL, Jeffcoate WJ. Primarily non-surgical management of osteomyelitis of the foot in diabetes. Diabetologia. 2008 Jun;51(6):962-7. Epub 2008 Apr 3.
The authors acknowledge that further research is necessary, but the results suggest that non-surgical management is beneficial in most cases. In cases where urgent surgery is not absolutely required, the results show optimized effects through non-surgical management.
8 Non-surgical osteomyelitis management Quality Indicator
 Type: Cohort study (2 groups)
Senneville E, Lombart A, Beltrand E, Valette M, Legout L, Cazaubiel M, Yazdanpanah Y, Fontaine P. Outcome of diabetic foot osteomyelitis treated nonsurgically: a retrospective cohort study. Diabetes Care. 2008 Apr;31(4):637-42. Epub 2008 Jan 9.
The results of this study demonstrate that bone culture based antibiotic therapy is effective in preventing remission in diabetic patients treated non-surgically for osteomyelitis.
9 Bacteriological Diagnosis of Osteomyelitis Quality Indicator
 Type: Longitudinal study (1 group)
Kessler L, Piemont Y, Ortega F, Lesens O, Boeri C, Averous C, Meyer R, Hansmann Y, Christmann D, Gaudias J, Pinget M. Comparison of microbiological results of needle puncture vs. superficial swab in infected diabetic foot ulcer with osteomyelitis. Diabet Med. 2006 Jan;23(1):99-102.
This study examines the effectiveness of needle puncture and superficial swabbing in detecting osteomyelitis in diabetic patients with foot ulcers. The results showed that needle puncture is a generally effective technique, and should be used when surgical debridement is contraindicated.
10 Tetanus Prophylaxis Quality Indicator
 Type: Narrative Review
Rogers LC, Frykberg RG. Tetanus prophylaxis for diabetic foot ulcers. Clin Podiatr Med Surg. 2006 Oct;23(4):769-75, vii-i.
This publication examines the possibility of tetanus infection in diabetic foot wounds. In order to combat this issue, the publication asserts that all patients with diabetic foot wounds should receive tetanus prophylaxis.


Enablers for practice

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