Diabetic foot infection
From IDWiki
Background
Microbiology
- Typically polymicrobial, including:
- Staphylococcus aureus, which is by far the most common cause of monomicrobial infections
- Coagulase-negative staphylococci
- Streptococcus
- Enterococcus
- Enterobacteriaceae
- Pseudomonas aeruginosa
- Anaerobes, including Bacteroides fragilis
- Anaerobes are more likely to be involved in deeper, more chronic ulcers
Diagnosis
- Osteomyelitis should be considered in all cases of diabetic foot infection
- Probe-to-bone test should be done routinely
- Plain film X-ray can be helpful, though not sensitive
- MRI is the preferred diagnostic test, followed by bone and white cell scan
- The gold standard is still bone biopsy for histopathology and culture
Management
| Severity | Common Pathogens | Antibiotics | Notes |
|---|---|---|---|
| Mild | methicillin-susceptible Staphylococcus aureus, Streptococcus | dicloxacillin | qid dosing and very narrow-spectrum |
| clindamycin | active against MRSA but higher risk of CDAD | ||
| cephalexin | qid dosing | ||
| levofloxacin | not as effective against Staphylococcus aureus | ||
| amoxicillin-clavulanic acid | broad-spectrum, includes anaerobic coverage | ||
| methicillin-resistant Staphylococcus aureus | doxycycline | uncertain activity against streptococci | |
| TMP-SMX | uncertain activity against streptococci | ||
| moderate or severe | MSSA, Streptococcus, Enterobacteriaceae, anaerobes | levofloxacin | suboptimal against MSSA |
| cefoxitin | |||
| ceftriaxone | |||
| ampicillin-sulbactam | |||
| moxifloxacin | |||
| ertapenem | |||
| tigecycline | |||
| fluoroquinolone with clindamycin | |||
| imipenem-cilastatin | |||
| MRSA | linezolid | ||
| daptomycin | |||
| vancomycin | |||
| Pseudomonas aeruginosa | piperacillin-tazobactam |
Duration
| Site of Infection | Severity | Duration |
|---|---|---|
| soft tissue only | mild | 1 to 2 weeks; up to 4 weeks if slow-to-resolve |
| moderate | 1 to 3 weeks | |
| severe | 2 to 4 weeks | |
| bone and joint infection | postamputation, with no residual infection | 2 to 5 days |
| postamputation, with residual soft tissue infection | 1 to 3 weeks | |
| postamputation, with residual bone infection | 4 to 6 weeks | |
| no surgery | ≥3 months |
- Osteomyelitis
- Traditionally, 6 weeks of parenteral therapy
- May be able to shorten to 3 weeks if adequately debrided, based on more recent evidence1
Further Reading
- The Neuropathic Diabetic Foot Ulcer Microbiome IsAssociated With Clinical Factors. Diabetes. 2013;62:923-930.
References
- ^ Karim Gariani, Truong-Thanh Pham, Benjamin Kressmann, François R Jornayvaz, Giacomo Gastaldi, Dimitrios Stafylakis, Jacques Philippe, Benjamin A Lipsky, İlker Uçkay. Three versus six weeks of antibiotic therapy for diabetic foot osteomyelitis: A prospective, randomized, non-inferiority pilot trial. Clinical Infectious Diseases. 2020. doi:10.1093/cid/ciaa1758.
