Shorter durations of systemic antibiotic therapy did not increase the risk for clinical or microbiologic failure among patients with diabetic foot infection (DFI), according to results of a study published in the International Journal of Infectious Diseases.

This study was a retrospective review of patient records collected between 2000 and 2020 at the Balgrist University Hospital in Switzerland. Patients (N=331) with DFI who received surgical and antibiotic combinatorial therapy were evaluated for outcomes at 1 year on the basis of systemic antibiotic therapy duration. Clinical failure was defined as any event requiring surgical revision, and microbiologic failure was defined as a true microbiologic recurrence with at least 50% of causative pathogens identical to the index infection.

Among patients included in the analysis, the mean age was 66.0 years, 79.8% were men, the mean BMI was 30.0 kg/m2, 73% had peripheral artery disease, and 84.7% had type 2 diabetes.


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Among all DFI events, 25.9% were associated with coagulase-negative staphylococci, 21.7% with Staphylococcus aureus, 9.8% with enterococci, 6.0% with streptococci, and 5.1% with Pseudomonas aeruginosa, among others.

Patients with osteomyelitis (n=537) had increased rates of coagulase-negative staphylococci (28.1% vs 15.2%; P =.000) and S aureus (22.9% vs 16.1%; P =.028) compared with patients with gangrene (n=102). After stratification by new and revision DFI episodes, new episodes of DFI were more likely to be caused by S aureus (22.3% vs 19.2%; P =.045) and streptococci (6.8% vs 2.6%; P =.017) pathogens vs revision episodes.

The average duration of intravenous (IV) antibiotic therapy was 13 (SD, 17) days. New DFI episodes were associated with shorter IV treatment duration (mean, 12 vs 16 days; P =.021). The overall mean duration of postoperative antibiotic therapy was 36 days, and new DFI episodes were associated with a shorter overall mean duration of postoperative antibiotic therapy vs revision episodes (34 vs 43 days; P =.010).

The researchers found that more patients with gangrene received no IV antibiotic therapy (33.3% vs 23.3%; P =.031) and fewer than 7 days of postoperative antibiotic therapy (13.7% vs 7.1%; P =.024) vs those with osteomyelitis.

Further analysis showed that the risk for diabetic foot osteomyelitis was increased among patients who previously underwent contralateral major (hazard ratio [HR], 3.1) and minor amputations (hazard ratio [HR], 1.8). However, a decreased risk was observed among women (HR, 0.4) and those who received between 8 and 21 days of postoperative antibiotic therapy (HR, 0.3).

This study was limited by its retrospective design and heterogeneous study population.

These data indicated that “…relatively short postoperative regimens of total [antibiotic therapy] do not yield an [increased] risk [for] clinical or microbiologic failures [among patients with DFI],” the researched concluded.

Reference

Haug F, Waibel FWA, Lisy M, Winkler E, Uçkay I, Schöni M. The impact of the length of total and intravenous systemic antibiotic therapy for the remission of diabetic foot infections. Int J Infect Dis. 2022;S1201-9712(22)00187-4. doi:10.1016/j.ijid.2022.03.049