Oral antibiotics in skin and soft tissue infections: An algorithm-based prospective multicentre pilot trial
Skin and soft tissue infections (SSTIs) are among the most common outpatient-acquired bacterial infections. In hospitalized patients, these infections are typically treated with intravenous antibiotics, which are switched to oral formulations during the course of treatment. The optimal time point for switching from intravenous to oral treatment is unknown and depends on numerous factors. In this study, we investigated an algorithm-based switch from intravenous to oral antibiotics within 48 hours after treatment initiation.
Hospitalized patients with uncomplicated SSTIs were screened for eligibility at 3 study sites (Langnau, Burgdorf, Biel/Bienne) from July 2019 to September 2020. Eligible participants with SSTIs were older than 18 years, required hospitalization because of the severity of the disease, were able to understand the study information and provided written informed consent. Exclusion criteria included antibiotic treatment 14 days or less before study inclusion, surgical site infections, impetigo without erysipelas/cellulitis, mastitis, nonbacterial infection or sterile skin inflammation (e.g., sweet syndrome, hypersensitivity reaction) and criteria consistent with â€ścomplicatedâ€ť SSTIs (i.e., bacteraemia with Staphylococcus aureus or Pseudomonas aeruginosa, necrotizing fasciitis, skin abscess, septic shock or infection requiring intensive medical care, septic arthritis, osteomyelitis, tenosynovitis, bursitis, foreign body infection). Patients with a diabetic foot infection, classed on perfusion, extent, depth, infection and sensation (PEDIS) classification 3, were excluded. Other exclusion criteria included gram-negative bacteria as the causative organism for the SSTI or an ecthyma gangrenosum.
After 48 hours of intravenous antibiotics, patients were assigned to either the intervention group or the non-intervention group. In the intervention group, intravenous antibiotics were switched to oral formulations. The switch was performed after 1 or more of the following predefined criteria were fulfilled: decreased pain, normalization of PEDIS grade 4 criteria, decreased or steady inflammation parameters, decreased localization and a temperature of â‰¤37.8Â°C for at least 24 hours. Patients in the non-intervention group were treated according the decision of the responsible physician. A total treatment duration of 5 to 10 days at the discretion of the treating physician was recommended. Follow-up phone calls were median conducted on day 39.
Of 128 screened patients, 90 were included (73 in the intervention group and 17 in the non-intervention group). Patients had a median age of 63 years, 64% were male, the majority had at least 1 comorbidity and the most affected site was the lower extremity (76.67%). In 7.8% of patients (7 cases) a microorganism was identified in blood cultures or swabs from skin blisters (5 in the intervention group and 2 in the non-intervention group). The most common isolated microorganism was group C or group G Streptococcus.
The median antibiotic treatment duration was 11 days in the intervention group and 15 days in the non-intervention group; the median intravenous treatment duration was 2 days in the intervention group and 4 days in the non-intervention group; and the median duration of hospitalization was 5 days in the intervention group and 7 days in the non-intervention group. Treatment failures were noted in 3 (4%) cases in the intervention group and in 1 case (6%) in the non-intervention group.
In this prospective pilot trial on uncomplicated SSTIs in hospitalized patients, an algorithm-based switch from intravenous to oral antibiotic treatment after a maximum of 48 hours was successful in 96% of cases. A prospective non-inferiority multicentre trial is required to confirm these results on level 1 evidence.