Diabetes-Related Foot Infections: Diagnosis and Treatment


Am Fam Physician. 2021 Oct ;104(4):386-394.

  Patient information: See related handout on preventing diabetic foot infections.

Author disclosure: No relevant financial affiliations.

Diabetes-related foot infections occur in approximately 40% of diabetes-related foot ulcers and cause significant morbidity. Clinicians should consider patient risk factors (e.g., presence of foot ulcers greater than 2 cm, uncontrolled diabetes mellitus, poor vascular perfusion, comorbid illness) when evaluating for a foot infection or osteomyelitis. Indicators of infection include erythema, induration, tenderness, warmth, and drainage. Superficial wound cultures should be avoided because of the high rate of contaminants. Deep cultures obtained through aseptic procedures (e.g., incision and drainage, debridement, bone culture) help guide treatment. Plain radiography is used for initial imaging if osteomyelitis is suspected; however, magnetic resonance imaging or computed tomography may help if radiography is inconclusive, the extent of infection is unknown, or if the infection orientation needs to be determined to help in surgical planning. Staphylococcus aureus and Streptococcus agalactiae are the most commonly isolated pathogens, although polymicrobial infections are common. Antibiotic therapy should cover commonly isolated organisms and reflect local resistance patterns, patient preference, and the severity of the foot infection. Mild and some moderate infections may be treated with oral antibiotics. Severe infections require intravenous antibiotics. Treatment duration is typically one to two weeks and is longer for slowly resolving infections or osteomyelitis. Severe or persistent infections may require surgery and specialized team-based wound care. Although widely recommended, there is little evidence on the effectiveness of primary prevention strategies. Systematic assessment, counseling, and comorbidity management are hallmarks of effective secondary prevention for diabetes-related foot infections.

Diabetes-related foot infections form in approximately 40% of foot ulcers in patients with diabetes mellitus.1 Infections can rapidly progress to cellulitis, abscess formation, osteomyelitis, and necrotizing fasciitis. In 2016, diabetes-related foot infections contributed to more than 130,000 lower-extremity amputations in the United States.2 The five-year mortality rate following amputation is approximately 50%, exceeding the mortality rate of many cancers.3

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Clinical recommendationEvidence ratingComments

Routine superficial wound cultures should not be performed because the results have poor sensitivity and specificity for identifying a pathogenic organism compared with deep tissue cultures.6,12


Systematic review and meta-analysis of lower quality diagnostic cohort studies

Initial testing in patients with diabetes mellitus and suspected osteomyelitis should include plain radiography, a C-reactive protein test, and probe-to-bone testing.6,11,15


Lower quality diagnostic cohort studies

Empiric antibiotic therapy should target Streptococcus agalactiae and Staphylococcus aureus; however, additional coverage should be considered based on local antimicrobial sensitivities, the severity of infection, and patient factors.69


Consensus guidelines and inconsistent diagnostic cohort studies

Antibiotic coverage for methicillin-resistant S. aureus may be discontinued in a patient with a diabetes-related foot infection and a negative methicillin-resistant S. aureus nares culture considering the high negative predictive value of this test.13,14


Lower quality diagnostic cohort studies

Secondary prevention of a foot infection in a patient with diabetes should include systematic foot assessment, foot care counseling, use of appropriate footwear, and comorbidity management.4244


Systematic review of lower quality clinical trials and studies with inconsistent findings

A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, go to https://www.aafp.org/afpsort.

The Authors

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ERIC M. MATHESON, MD, MS, is the transitional year residency director and associate professor in the Department of Family Medicine at the Medical University of South Carolina, Charleston....

SCOTT W. BRAGG, PharmD, BCPS, is an associate professor in the Department of Family Medicine and the Department of Clinical Pharmacy and Outcomes Sciences at the Medical University of South Carolina.

RUSSELL S. BLACKWELDER, MD, MDiv, CMD, is the director of Geriatric Education and assistant professor in the Department of Family Medicine at the Medical University of South Carolina.

Address correspondence to Eric M. Matheson, MD, MS, 9228 Medical Plaza Dr., Charleston, SC 29406 (email: matheson@musc.edu). Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.

Data Sources: A PubMed search was completed in Clinical Queries using the key terms diabetic foot ulcers, infections, antibiotics, statistics, pharmacological, and prevention. The search included meta-analyses, randomized controlled trials, clinical trials, and reviews. Also searched were Access Medicine, the Cochrane Library, Lexicomp, the National Guideline Clearing-house database, and UpToDate. Search dates: October 27, 2020 to November 4, 2020, and April 26, 2021.

Figure 1 and Figure 2 provided courtesy of Joshua Visserman, MD.


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1. Jia L, Parker CN, Parker TJ, et al.; Diabetic Foot Working Group, Queensland Statewide Diabetes Clinical Network (Australia). Incidence and risk factors for developing infection in patients presenting with uninfected diabetic foot ulcers. PLoS One. 2017;12(5):e0177916....

2. Centers for Disease Control and Prevention. National diabetes statistics report, 2020. Accessed October 20, 2020. https://www.cdc.gov/diabetes/pdfs/data/statistics/national-diabetes-statistics-report.pdf

3. Armstrong DG, Swerdlow MA, Armstrong AA, et al. Five year mortality and direct costs of care for people with diabetic foot complications are comparable to cancer. J Foot Ankle Res. 2020;13(1):16.

4. Lipsky BA, Berendt AR, Cornia PB, et al.; Infectious Diseases Society of America. 2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections. Clin Infect Dis. 2012;54(12):e132–e173.

5. Miller JD, Carter E, Shih J, et al. How to do a 3-minute diabetic foot exam [published correction appears in J Fam Pract. 2015;64(8):452]. J Fam Pract. 2014;63(11):646–656.

6. Lipsky BA, Senneville É, Abbas ZG, et al.; International Working Group on the Diabetic Foot (IWGDF). Guidelines on the diagnosis and treatment of foot infection in persons with diabetes (IWGDF 2019 update). Diabetes Metab Res Rev. 2020;36(suppl 1):e3280.

7. Reveles KR, Duhon BM, Moore RJ, et al. Epidemiology of methicillin-resistant Staphylococcus aureus diabetic foot infections in a large academic hospital: implications for antimicrobial stewardship. PLoS One. 2016;11(8):e0161658.

8. Henig O, Pogue JM, Cha R, et al. Epidemiology of diabetic foot infection in the metro-Detroit area with a focus on independent predictors for pathogens resistant to recommended empiric antimicrobial therapy. Open Forum Infect Dis. 2018;5(11):ofy245.

9. Citron DM, Goldstein EJ, Merriam CV, et al. Bacteriology of moderate-to-severe diabetic foot infections and in vitro activity of antimicrobial agents. J Clin Microbiol. 2007;45(9):2819–2828.

10. Sadeghpour Heravi F, Zakrzewski M, Vickery K, et al. Bacterial diversity of diabetic foot ulcers: current status and future prospectives. J Clin Med. 2019;8(11):1935.

11. Lam K, van Asten SAV, Nguyen T, et al. Diagnostic accuracy of probe to bone to detect osteomyelitis in the diabetic foot: a systematic review. Clin Infect Dis. 2016;63(7):944–948.

12. Chakraborti C, Le C, Yanofsky A. Sensitivity of superficial cultures in lower extremity wounds. J Hosp Med. 2010;5(7):415–420.

13. Acquisto NM, Bodkin RP, Brown JE, et al. MRSA nares swab is a more accurate predictor of MRSA wound infection compared with clinical risk factors in emergency department patients with skin and soft tissue infections. Emerg Med J. 2018;35(6):357–360.

14. Mergenhagen KA, Croix M, Starr KE, et al. Utility of methicillin-resistant Staphylococcus aureus nares screening for patients with a diabetic foot infection. Antimicrob Agents Chemother. 2020;64(4):e02213–e02219.

15. Walker EA, Beaman FD, Wessell DE, et al.; Expert Panel on Musculoskeletal Imaging. ACR appropriateness criteria. Suspected osteomyelitis of the foot in patients with diabetes mellitus. J Am Coll Radiol. 2019;16(11S):S440–S450.

16. Bandyk DF. The diabetic foot: pathophysiology, evaluation, and treatment. Semin Vasc Surg. 2018;31(2–4):43–48.

17. Hart T, Milner R, Cifu A. Management of the diabetic foot. JAMA. 2017;318(14):1387–1388.

18. Mills JL Sr, Conte MS, Armstrong DG, et al.; Society for Vascular Surgery Lower Extremity Guidelines Committee. The Society for Vascular Surgery Lower Extremity threatened limb classification system: risk stratification based on wound, ischemia, and foot infection (WIfI). J Vasc Surg. 2014;59(1):220–234.e1–2.

19. Fagher K, Katzman P, Löndahl M. Transcutaneous oxygen pressure as a predictor for short-term survival in patients with type 2 diabetes and foot ulcers: a comparison with ankle-brachial index and toe blood pressure. Acta Diabetol. 2018;55(8):781–788.

20. Ahmed O, Hanley M, Bennett SJ, et al.; Expert Panel on Vascular Imaging. ACR appropriateness criteria. Vascular claudication-assessment for revascularization. J Am Coll Radiol. 2017;14(5S):S372–S379.

21. Sen P, Demirdal T, Emir B. Meta-analysis of risk factors for amputation in diabetic foot infections. Diabetes Metab Res Rev. 2019;35(7):e3165.

22. Ince P, Abbas ZG, Lutale JK, et al. Use of the SINBAD classification system and score in comparing outcome of foot ulcer management on three continents. Diabetes Care. 2008;31(5):964–967.

23. Chuan F, Tang K, Jiang P, et al. Reliability and validity of the perfusion, extent, depth, infection and sensation (PEDIS) classification system and score in patients with diabetic foot ulcer. PLoS One. 2015;10(4):e0124739.

24. Chuan F. PEDIS score for diabetic foot ulcers. MDCalc. Accessed December 30, 2020. https://www.mdcalc.com/pedis-score-diabetic-foot-ulcers

25. Selva Olid A, Solà I, Barajas-Nava LA, et al. Systemic antibiotics for treating diabetic foot infections. Cochrane Database Syst Rev. 2015;(9):CD009061.

26. Bader MS. Diabetic foot infection. Am Fam Physician. 2008;78(1):71–79. Accessed April 6, 2021. https://www.aafp.org/afp/2008/0701/p71.html

27. Gemechu FW, Seemant F, Curley CA. Diabetic foot infections. Am Fam Physician. 2013;88(3):177–184. Accessed April 6, 2021. https://www.aafp.org/afp/2013/0801/p177.html

28. Lexicomp. Accessed October 27, 2020. https://online.lexi.com/lco/action/login

29. Dudareva M, Kümin M, Vach W, et al. Short or long antibiotic regimes in orthopaedics (SOLARIO): a randomised controlled open-label non-inferiority trial of duration of systemic antibiotics in adults with orthopaedic infection treated operatively with local antibiotic therapy. Trials. 2019;20(1):693.

30. Gariani K, Pham TT, Kressmann B, et al. Three versus six weeks of antibiotic therapy for diabetic foot osteomyelitis: a prospective, randomized, non-inferiority pilot trial. Clin Infect Dis. 2020;ciaa1758.

31. Dumville JC, Lipsky BA, Hoey C, et al. Topical antimicrobial agents for treating foot ulcers in people with diabetes. Cochrane Database Syst Rev. 2017;(6):CD011038.

32. Wukich DK, Raspovic KM, Suder NC. Patients with diabetic foot disease fear major lower-extremity amputation more than death. Foot Ankle Spec. 2018;11(1):17–21.

33. Zhan LX, Branco BC, Armstrong DG, et al. The Society for Vascular Surgery lower extremity threatened limb classification system based on wound, ischemia, and foot infection (WIfI) correlates with risk of major amputation and time to wound healing. J Vasc Surg. 2015;61(4):939–944.

34. Peripheral Vascular Diagnosis Made Intelligent. WIfI classification system. Accessed December 30, 2020. https://www.perimed-instruments.com/content/wifi-classification-system/

35. Vas P, Rayman G, Dhatariya K, et al. Effectiveness of interventions to enhance healing of chronic foot ulcers in diabetes: a systematic review. Diabetes Metab Res Rev. 2020;36(suppl 1):e3284.

36. Everett E, Mathioudakis N. Update on management of diabetic foot ulcers. Ann N Y Acad Sci. 2018;1411(1):153–165.

37. Sharma R, Sharma SK, Mudgal SK, et al. Efficacy of hyperbaric oxygen therapy for diabetic foot ulcer, a systematic review and meta-analysis of controlled clinical trials. Sci Rep. 2021;11(1):2189.

38. Sun X, Jiang K, Chen J, et al. A systematic review of maggot debridement therapy for chronically infected wounds and ulcers. Int J Infect Dis. 2014;25:32–37.

39. Cruciani M, Lipsky BA, Mengoli C, et al. Granulocyte-colony stimulating factors as adjunctive therapy for diabetic foot infections. Cochrane Database Syst Rev. 2013;(8):CD006810.

40. Thanigaimani S, Singh T, Golledge J. Topical oxygen therapy for diabetes-related foot ulcers: a systematic review and meta-analysis. Diabet Med. 2021;e14585.

41. Huang J, Chen J, Xiong S, et al. The effect of low-level laser therapy on diabetic foot ulcers: a meta-analysis of randomised controlled trials. Int Wound J. March 9, 2021. Accessed April 25, 2021. https://onlinelibrary.wiley.com/doi/epdf/10.1111/iwj.13577

42. van Netten JJ, Price PE, Lavery LA, et al.; International Working Group on the Diabetic Foot. Prevention of foot ulcers in the at-risk patient with diabetes: a systematic review. Diabetes Metab Res Rev. 2016;32(suppl 1):84–98.

43. American Diabetes Association. Microvascular complications and foot care: standards of medical care in diabetes–2020. Diabetes Care. 2020;43(suppl 1):S135–S151.

44. Xiang J, Wang S, He Y, et al. Reasonable glycemic control would help wound healing during the treatment of diabetic foot ulcers. Diabetes Ther. 2019;10(1):95–105.

45. Marn Pernat A, Peršič V, Usvyat L, et al. Implementation of routine foot check in patients with diabetes on hemodialysis: associations with outcomes. BMJ Open Diabetes Res Care. 2016;4(1):e000158.



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