What is the recommended IV antibiotic for a 69-year-old diabetic patient with right foot cellulitis?

From the Guidelines

For a 69-year-old diabetic patient with right foot cellulitis, the recommended IV antibiotic is ertapenem 1 gram every 24 hours, as it provides broad-spectrum coverage against the most common causative organisms in diabetic foot infections, including Streptococcus species, Staphylococcus aureus, and Enterobacteriaceae 1. This recommendation is based on the most recent guidelines from the International Working Group on the Diabetic Foot (IWGDF) and the Infectious Diseases Society of America (IDSA), which suggest using systemic antibiotic regimens that have been shown to be effective in published randomized controlled trials at standard dosing 1.

Some key points to consider when treating diabetic foot infections include:

• Selecting antibiotic agents based on the likely or proven causative pathogens, their antibiotic susceptibilities, the clinical severity of the infection, evidence of efficacy for DFI, and costs 1
• Administering antibiotic therapy for a duration of 1–2 weeks, with the possibility of extending treatment up to 3–4 weeks if the infection is improving but is extensive and is resolving slower than expected or if the patient has severe peripheral arterial disease (PAD) 1
• Monitoring the patient's response to treatment and reassessing within 48-72 hours to evaluate treatment response and potentially transition to oral antibiotics once clinical improvement is observed
• Considering the patient's diabetic status and carefully monitoring blood glucose levels during antibiotic therapy, as infections and certain antibiotics can affect glycemic control

It's also important to note that the patient should elevate the affected foot, apply warm compresses, and receive appropriate wound care if any breaks in the skin are present. If MRSA is suspected based on risk factors or local prevalence, vancomycin, daptomycin, or linezolid may be more appropriate first-line choices.

The choice of ertapenem is supported by studies that have shown its efficacy in treating diabetic foot infections, including a randomized controlled trial that compared ertapenem to piperacillin/tazobactam 1. However, it's essential to follow the most recent guidelines and consider the specific circumstances of each patient when selecting an antibiotic regimen.

From the FDA Drug Label

1.3 Skin and Skin Structure Infections Piperacillin and Tazobactam for Injection is indicated in adults for the treatment of uncomplicated and complicated skin and skin structure infections, including cellulitis, cutaneous abscesses and ischemic/diabetic foot infections caused by beta-lactamase producing isolates of Staphylococcus aureus.

The recommended IV antibiotic for a 69-year-old diabetic patient with right foot cellulitis is Piperacillin-Tazobactam (IV), as it is indicated for the treatment of complicated skin and skin structure infections, including diabetic foot infections 2.

• The usual total daily dosage of piperacillin and tazobactam for injection for adult patients with indications other than nosocomial pneumonia is 3.375 grams every six hours [totaling 13.5 grams (12.0 grams piperacillin and 1.5 grams tazobactam)], to be administered by intravenous infusion over 30 minutes 2.
• The usual duration of piperacillin and tazobactam for injection treatment is from 7 to 10 days 2.

From the Research

Recommended IV Antibiotics for Diabetic Foot Cellulitis

The following IV antibiotics have been studied for the treatment of diabetic foot infections:

• Piperacillin/tazobactam: This antibiotic has been shown to be effective in treating diabetic foot infections, with clinical cure rates ranging from 76% to 93% 3, 4, 5.
• Ampicillin/sulbactam: This antibiotic has also been shown to be effective, with clinical cure rates of 83.1% 4.
• Moxifloxacin: This antibiotic has been compared to piperacillin-tazobactam/amoxicillin-clavulanate and shown to have similar clinical cure rates (68% vs 61%) 6.
• Sulbactam-ampicillin: This antibiotic has been shown to be effective in treating diabetic foot infections, with clinical cure rates of 86% to 100% 7.

Considerations for Antibiotic Choice

When choosing an antibiotic for a patient with diabetic foot cellulitis, consider the following:

• The severity of the infection: More severe infections may require broader-spectrum antibiotics such as piperacillin/tazobactam or sulbactam-ampicillin.
• The presence of methicillin-resistant Staphylococcus aureus (MRSA): Vancomycin may be added to the treatment regimen in cases where MRSA is suspected or confirmed 4.
• The patient's renal function: Dose adjustments may be necessary for patients with impaired renal function.
• The potential for adverse events: All antibiotics have the potential for adverse events, and the choice of antibiotic should take into account the patient's medical history and current medications.