What is the appropriate antibiotic regimen for a 75-year-old female with sepsis due to a skin infection?

From the Guidelines

For a 75-year-old female with sepsis due to a skin infection, I recommend empiric treatment with vancomycin 15-20 mg/kg IV every 12 hours plus piperacillin-tazobactam 3.375 g IV every 6 hours (with dose adjustment for renal function). This combination provides coverage against methicillin-resistant Staphylococcus aureus (MRSA) and gram-negative organisms including Pseudomonas, as suggested by the Surviving Sepsis Campaign guidelines 1.

Key Considerations

• Blood cultures should be obtained before starting antibiotics, and the regimen should be adjusted based on culture results and clinical response.
• For patients with beta-lactam allergies, alternatives include vancomycin plus either aztreonam 2 g IV every 8 hours or a fluoroquinolone such as levofloxacin 750 mg IV daily.
• Treatment duration typically ranges from 7-14 days depending on clinical response, with transition to oral antibiotics when the patient shows improvement (afebrile for 24-48 hours with normalized vital signs).
• In elderly patients, close monitoring of renal function is essential as they are more susceptible to nephrotoxicity from vancomycin, as noted in guidelines for the management of skin and soft tissue infections 1.
• Additionally, supportive care with IV fluids, vasopressors if needed, and source control (such as drainage of any abscess) are critical components of management for sepsis alongside antibiotic therapy, emphasizing the importance of a comprehensive approach to sepsis management 1.

Antibiotic Selection

The selection of vancomycin and piperacillin-tazobactam is based on their broad-spectrum activity and the potential for MRSA and gram-negative organisms to be involved in skin infections leading to sepsis, as discussed in guidelines for the treatment of MRSA infections 1. The dosing and potential need for adjustment are critical for optimizing outcomes and minimizing toxicity, particularly in elderly patients with potential renal impairment.

Clinical Response and Adjustment

Monitoring the patient's clinical response and adjusting the antibiotic regimen accordingly is crucial. This includes reassessing the need for broad-spectrum coverage and considering de-escalation of therapy based on culture results and clinical improvement, as recommended by guidelines for the management of sepsis and septic shock 1.

From the FDA Drug Label

The study evaluated meropenem at doses of 500 mg administered intravenously every 8 hours and imipenem-cilastatin at doses of 500 mg administered intravenously every 8 hours. The success rates in the clinically evaluable patients at the follow-up visit were 86% (225/261) in the meropenem arm and 83% (238/287) in imipenem-cilastatin arm. The clinical efficacy rates by pathogen are provided in Table 8 Patients may have more than one pretreatment pathogen.

For a 75-year-old female with sepsis due to a skin infection, meropenem is a suitable broad-spectrum antibiotic option.

• The dosage is 500 mg administered intravenously every 8 hours.
• The success rate for meropenem in treating complicated skin and skin structure infections is 86%.
• Meropenem has been shown to be effective against a variety of pathogens, including Gram-positive and Gram-negative aerobes, as well as anaerobes 2.

From the Research

Antibiotic Regimens for Sepsis due to Skin Infection

• For a 75-year-old female with sepsis due to a skin infection, the appropriate antibiotic regimen is crucial for effective treatment.
• According to the study 3, imipenem-cilastatin, meropenem, and piperacillin-tazobactam 3.375 g q6h achieved greater than 90% likelihood of achieving bactericidal exposure in serum and blister fluid until the prevalence of MRSA increased beyond 10%.
• The study 4 compared meropenem and piperacillin-tazobactam in critically ill patients with sepsis and septic shock, and found that meropenem had a lower mortality rate on ventilator-free days, vasopressor-free days, and hospital-free days.
• Another study 5 demonstrated synergy between piperacillin-tazobactam and vancomycin against methicillin-resistant Staphylococcus aureus (MRSA).
• The study 6 compared ceftazidime, carbapenems, and piperacillin-tazobactam as definitive monotherapy for Pseudomonas aeruginosa bacteremia, and found no significant difference in mortality, clinical, and microbiological outcomes or adverse events between the three antibiotics.
• A case study 7 highlighted the importance of early empiric antibiotics management in a 75-year-old female with septic shock due to Clostridium perfringens, where piperacillin-tazobactam and clindamycin were used as antibiotics.

Broad Spectrum Antibiotic Options

• Meropenem 4, 3 and piperacillin-tazobactam 5, 3, 6, 7 are broad-spectrum antibiotic options that can be considered for the treatment of sepsis due to skin infection.
• The choice of antibiotic should be based on the suspected or confirmed pathogen, as well as the patient's clinical condition and other factors such as renal function and allergy history.
• It is essential to note that the use of broad-spectrum antibiotics should be guided by antimicrobial stewardship principles to minimize the risk of antibiotic resistance and other adverse effects.